2D seismic exploration method Study of deep geological structure. seismic prospecting and MDS. Excitation by explosive sources

home » ecosystems 2D seismic exploration method Study of deep geological structure. seismic prospecting and MDS. Excitation by explosive sources

List of abbreviations

Introduction

1. General part

1.3 Tectonic structure

1.4 Oil and gas content

2.Special part

3.Design part

3.3 Apparatus and equipment

3.4 Methodology for processing and interpreting field data

4.Special task

4.1 AVO analysis

4.1.1 Theoretical aspects AVO analysis

4.1.2 AVO classification of gas sands

4.1.3 AVO crossplotting

4.1.4 Elastic inversion in AVO analysis

4.1.5 AVO analysis in an anisotropic environment

4.1.6 Examples practical application AVO Analysis

Conclusion

List of sources used

stratigraphic seismic field anisotropic

List of abbreviations

GIS-geophysical surveys of wells

MOB-method of the reflected wave

CDP method total point depth

Oil and gas complex

Oil and Gas Region

NGR-gas-bearing region

OG-reflecting horizon

CDP-common depth point

PV item explosion

PP-point of reception

s/n-seismic party

hydrocarbons

Introduction

This bachelor's thesis provides for the substantiation of CDP-3D seismic surveys in the Vostochno-Michayuskaya area and consideration of AVO-analysis as a special issue.

Seismic surveys and drilling data carried out in recent years have established the complex geological structure of the work area. Further systematic study of the East Michayu structure is necessary.

The work provides for the study of the area in order to clarify geological structure seismic survey CDP-3D.

Bachelor's thesis consists of four chapters, introduction, conclusion, set out on pages of text, contains 22 figures, 4 tables. The bibliographic list contains 10 titles.

1. General part

1.1 Physical and geographical outline

The Vostochno-Michayuskaya area (Figure 1.1) is administratively located in the Vuktyl region.

Figure 1.1 - Map of the area of the East Michayu area

Not far from the study area is the city of Vuktyl and the village of Dutovo. The area of work is located in the Pechora River basin. The area is a hilly, gently undulating plain, with pronounced valleys of rivers and streams. The work area is swampy. The climate of the region is sharply continental. Summers are short and cool, winters are harsh with strong winds. Snow cover is established in October and disappears at the end of May. In terms of seismic work, this area belongs to the 4th category of difficulty.

1.2 Lithological and stratigraphic characteristics

The lithological and stratigraphic characteristics of the section (Figure 1.2) of the sedimentary cover and foundation are given based on the results of drilling and seismic logging of wells 2-, 4-, 8-, 14-, 22-, 24-, 28-Michayu, 1 - S. Savinobor, 1 - Dinyu-Savinobor.

Figure 1.2 - Lithological and stratigraphic section of the Vostochno-Michayuskaya area

Paleozoic erathema - PZ

Devonian - D

Middle Devonian - D 2

Terrigenous formations of the Middle Devonian, Givetian Stage unconformably overlie the carbonate rocks of the Silurian sequence.

Deposits of the Givetian stage with a thickness of wells 1-Dinyu-Savinobor 233 m is represented by clays and sandstones in the volume of the Stary Oskol superhorizon (I - in the reservoir).

Upper Devonian - D 3

The Upper Devonian is distinguished in the volume of the Frasnian and Famennian stages. Fran is represented by three sub-tiers.

The deposits of the Lower Frasnian are formed by the Yaran, Dzhier, and Timan horizons.

Frasnian - D 3 f

Upper Franzian Substage - D 3 f 1

Yaransky horizon - D 3 jr

The section of the Yaran horizon (88 m thick in Q. 28-Mich.) is composed of sandy layers (from bottom to top) V-1, V-2, V-3 and interstratal clays. All layers are not consistent in composition, thickness and number of sand interlayers.

Jyers skyline - D 3 dzr

Clayey rocks occur at the base of the Dzhyer horizon, and sandy beds Ib and Ia are distinguished higher along the section, separated by a clay unit. The thickness of the jier varies from 15 m (KV. 60 - Yu.M.) to 31 m (KV. 28 - M.).

Timan horizon - D 3 tm

Deposits of the Timan horizon, 24 m thick, are composed of clayey-siltstone rocks.

Middle Fransian Substage - D 3 f 2

The Middle Fransian substage is represented in the volume of the Sargaev and Domanik horizons, which are composed of dense, silicified, bituminous limestones with black shale interbeds. The thickness of the sargay is 13 m (borehole 22-M) - 25 m (borehole 1-Tr.), domanik - 6 m in the well. 28-M. and 38 m in well 4-M.

Upper Frasnian - D 3 f 3

The undivided Vetlasyan and Sirachoi (23 m), Evlanovsk and Liven (30 m) deposits form the section of the Upper Frasnian substage. They are formed by brown and black limestones interbedded with shale.

Famennian - D 3 fm

The Famennian stage is represented by the Volgograd, Zadonsk, Yelets, and Ust-Pechora horizons.

Volgograd horizon - D 3 vlg

Zadonsky horizon - D 3 zd

The Volgograd and Zadonsk horizons are composed of clay-carbonate rocks 22 m thick.

Yelets horizon - D 3 el

The deposits of the Yelets horizon are formed by organogenic-detrital limestone areas, in the lower part by strongly clayey dolomites, at the base of the horizon there are marls and calcareous, dense clays. The thickness of the deposits varies from 740 m (wells 14-, 22-M) to 918 m (well 1-Tr.).

Ust-Pechora horizon - D 3 up

The Ust-Pechora horizon is represented by dense dolomites, black argillite-like clays, and limestones. Its thickness is 190m.

Carboniferous system - C

Above unconformity deposits of the Carboniferous system occur in the volume of the lower and middle sections.

Lower Carboniferous - C 1

Visean - C 1 v

Serpukhovian - C 1 s

The lower section is composed of the Visean and Serpukhovian stages, formed by limestones with clay interbeds, with a total thickness of 76 m.

Upper Carboniferous Division - C 2

Bashkirian - C 2 b

Moscow Stage - C 2 m

The Bashkirian and Moscow stages are represented by clay-carbonate rocks. The thickness of the Bashkir deposits is 8 m (borehole 22-M.) - 14 m (borehole 8-M.), and in the well. 4-, 14-M. they are missing.

The thickness of the Moscow stage varies from 24 m (borehole 1-Tr) to 82 m (borehole 14-M).

Permian system - R

Moscow deposits are unconformably overlain by Permian deposits in the volume of the lower and upper sections.

Nizhnepermsky department - R 1

The lower section is presented in full and is composed of limestones and clayey marls, and in the upper part - clays. Its thickness is 112m.

Upper Permian department - R 2

The upper section is formed by the Ufa, Kazan and Tatar stages.

Ufimian - P 2 u

The Ufim deposits with a thickness of 275 m are represented by intercalation of clays and sandstones, limestones and marls.

Kazanian - P 2 kz

The Kazanian stage is composed of dense and viscous clays and quartz sandstones; there are also rare interlayers of limestones and marls. The layer thickness is 325 m.

Tatarian - P 2 t

The Tatarian stage is formed by terrigenous rocks 40 m thick.

Mesozoic erathema - MZ

Triassic system - T

The Triassic deposits in the volume of the lower section are composed of alternating clays and sandstones with a thickness of 118 m (well 107) - 175 m (well 28-M.).

Jurassic - J

The Jurassic system is represented by terrigenous formations with a thickness of 55 m.

Cenozoic erathema - KZ

Quaternary - Q

The section is completed by loams, sandy loams and sands of Quaternary age 65 m thick in well 22-M. and 100 m in well 4-M.

1.3 Tectonic structure

In tectonic terms (Figure 1.3), the area of work is located in the central part of the Michayu-Pashninsky swell, which corresponds to the Ilych-Chiksha fault system along the foundation. The fault system is also reflected in the sedimentary cover. Tectonic disturbances in the work area are one of the main structural-forming factors.

Figure 1.3 - Copy from tectonic map Timano-Pechora province

Three zones of tectonic faults were identified on the work area: western and eastern submeridional strike, and, in the southeast, the area of northeast strike.

Tectonic disturbances observed in the west of this area can be traced along all reflecting horizons, and disturbances in the east and southeast fade, respectively, in Famennian and Frasnian times.

The tectonic faults in the western part are a graben-like trough. The sagging of horizons is most clearly seen on profiles 40990-02, 40992-02, -03, -04, -05.

The amplitude of the vertical displacement along the horizons ranges from 12 to 85 m. In plan view, the faults are oriented northwest. They stretch in the southeast direction from the reporting area, limiting the Dinya-Savinobor structure from the west.

Faults probably separate the axial part of the Michayu-Pashninskii swell from its eastern slope, which is characterized by continuous eastward subsidence of sediments.

In geophysical fields g, disturbances correspond to intense zones of gradients, the interpretation of which made it possible to single out a deep fault here, separating the Michayu-Pashninskaya zone of uplifts along the basement from the relatively lowered Lemyu step and being, probably, the main structure-forming fault (Krivtsov K.A., 1967 , Repin E.M., 1986).

The western zone of tectonic faults is complicated by northeast-trending feathering faults, due to which separate uplifted blocks are formed, as on profiles 40992-03, -10, -21.

The amplitude of the vertical displacement along the horizons of the eastern fault zone is 9-45 m (project 40990-05, station 120-130).

The southeastern fault zone is represented by a graben-like trough, the amplitude of which is 17-55 m (project 40992-12, site 50-60).

The western tectonic zone forms an elevated near-fault structural zone, consisting of several tectonically limited folds - Srednemichayuskaya, East Michayuskaya, Ivan-Shorskaya, Dinyu-Savinoborskaya structures.

The deepest horizon OG III 2-3 (D 2-3), on which structural constructions were made, is confined to the boundary between the Upper Devonian and Middle Devonian deposits.

Based on structural constructions, analysis of time sections and drilling data, the sedimentary cover has a rather complex geological structure. Against the background of the submonocline subsidence of the layers in the east direction, the East Michayu structure is distinguished. It was first identified as an open complication of the "structural nose" type with materials s\n 8213 (Shmelevskaya I.I., 1983). Based on the work of the 1989-90 season. (S\n 40990) the structure is presented as a fault fold, contoured along a sparse network of profiles.

Reporting data established the complex structure of the East Michayu structure. According to OG III 2-3, it is represented by a three-dome, linearly elongated, northwest-trending anticlinal fold, the dimensions of which are 9.75 × 1.5 km. The northern dome has an amplitude of 55 m, the central one - 95 m, the southern one - 65 m. From the west, the East Michayu structure is limited by a graben-like trough of northwest strike, from the south - by a tectonic fault, with an amplitude of 40 m. In the north, the East Michayu anticline fold is complicated by an uplifted block (project nos. 40992-03), and in the south - a subsided block (projects 40990-07, 40992-11), due to feathering disturbances of the northeast strike.

To the north of the East Michayu uplift, the Middle Michayu near-fault structure was revealed. We assume that it closes to the north of the reporting area, where earlier work was carried out with / p 40991 and structural constructions were made along reflecting horizons in Permian deposits. The Middle Michayu structure was considered within the East Michayu uplift. According to the work with \ n 40992, the presence of a deflection between the East Michayu and Srednemichayu structures on the project 40990-03, 40992-02 was revealed, which is also confirmed by the reporting works.

In the same structural zone with the uplifts discussed above, there is the Ivan-Shorskaya anticline structure, identified by works s\n 40992 (Misyukevich N.V., 1993). From the west and south it is framed by tectonic faults. The dimensions of the structure according to OG III 2-3 are 1.75×1 km.

To the west of the Srednemichayuskaya, Vostochno-Michayuskaya and Ivan-Shorskaya structures are the South-Lemyuskaya and Yuzhno-Michayuskaya structures, which are affected only by the western ends of the reported profiles.

Southeast of the South-Michayu structure, a low-amplitude East-Tripanyel structure was revealed. It is represented by an anticline fold, the dimensions of which according to OG III 2-3 are 1.5×1 km.

In the western marginal part of the submeridional-trending graben in the north of the reporting area, small near-fault structures are isolated. To the south, similar structural forms are formed due to small tectonic faults of various strikes, which complicate the graben zone. All these small structures in the blocks lowered relative to the East Michayu uplift are united by us under the general name of the Central Michayu structure and require further seismic exploration.

Reference point 6 is associated with OG IIIf 1 at the top of the Yaran horizon. Structural plan of reflecting horizon IIIf 1, inherited from OG III 2-3. The dimensions of the East Michayu near-fault structure are 9.1 × 1.2 km, in the contour of the isohypse - 2260 m, the northern and southern domes are distinguished with an amplitude of 35 and 60 m, respectively.

The dimensions of the Ivan-Shorskaya near-fault fold are 1.7 × 0.9 km.

The structural map of OG IIId reflects the behavior of the base of the Domanik horizon of the Middle Frasnian substage. In general, there is an uplift of the structural plan to the north. To the north of the reporting area, the base of the domanik was exposed by well No. 2-Sev.Michayu, 1-Sev.Michayu at absolute elevations - 2140 and - 2109 m, respectively, to the south - in the borehole. 1-Dinyu-Savinobor at the mark - 2257 m. The East Michayu and Ivan-Shor structures occupy an intermediate hypsometric position between the North-Michayu and Dinyu-Savinobor structures.

At the level of the Domanik horizon, the feathering disturbance at Project 40992-03 fades out; instead of the uplifted block, a dome has formed, covering the adjacent profiles 40990-03, -04, 40992-02. Its dimensions are 1.9 × 0.4 km, the amplitude is 15 m. To the south of the main structure, to another feathering fault on project 40992-10, a small dome closes with an isohypse of -2180 m. Its dimensions are 0.5 × 0.9, the amplitude is 35 m. The Ivan-Shor structure is located 60 m below the East Michayu structure.

The structural plan of the OG Ik confined to the top of the carbonates of the Kungurian stage differs significantly from the structural plan of the underlying horizons.

The graben-like trough of the western fault zone on the time sections has a cup-like shape; in connection with this, the structural plan of the OG Ik was restructured. The shielding tectonic faults and the arch of the East Michayu structure are shifting to the east. The size of the East Michayu structure is much smaller than in the underlying deposits.

The tectonic disturbance of the northeast strike breaks the East Michayu structure into two parts. Two domes stand out in the contour of the structure, and the amplitude of the southern one is greater than that of the northern one and is 35 m.

To the south is the Ivan-Shorsky fault uplift, which is now a structural nose, in the north of which a small dome stands out. The fault is fading, screening the Ivan-Shor anticline in the south along the lower horizons.

The eastern flank of the South Lemew structure is complicated by a slight tectonic disturbance of the submeridional strike.

Throughout the area, there are small rootless tectonic disturbances, with an amplitude of 10-15 m, which do not fit into any system.

Productive at the Severo-Savinoborsky, Dinyu-Savinoborsky, Michayusky deposits, the sandy reservoir V-3 is located below the benchmark 6, which is identified with OG IIIf1, by 18-22 m, and in the well. 4-Mich. at 30 m.

On the structural plan of the top of the V-3 formation, the highest hypsometric position is occupied by the Michayuskoye field, the northeastern part of which is confined to the South Lemyu structure. The WOC of the Michayuskoye field runs at a level of - 2160 m (Kolosov V.I., 1990). The East Michayu structure closes with an isohypse - 2280 m, an uplifted block at a level of - 2270 m, a lowered block at the southern end at a level of - 2300 m.

At the level of the Vostochno-Michayu structure, to the south there is the Severo-Savinoborskoye field with OWC at a level of - 2270 m. 1-Dinyu-Savinobor is defined at the level of - 2373 m.

Thus, the East Michayu structure, which is located in the same structural zone as the Dinya-Savinobor one, is much higher than it and may well be a good trap for hydrocarbons. The screen is a graben-shaped trough of northwestern strike of an asymmetric shape.

The western side of the graben runs along low-amplitude normal faults, except for some profiles (projects 40992-01, -05, 40990-02). Violations of the eastern side of the graben, the most subsided part of which is located at pr. 40990-02, 40992-03, are high-amplitude. According to them, the alleged permeable formations are in contact with the Sargaev or Timan formations.

To the south, the disturbance amplitude decreases and, at the level of profile 40992-08, the graben closes in the south. Thus, the southern periclinal of the Vostochno-Michayuskaya structure is in the lowered block. In this case, the V-3 formation may be in contact with the interstratal clays of the Yaran horizon.

To the south in this zone is the Ivan-Shorskaya near-fault structure, which is crossed by two meridional profiles 13291-09, 40992-21. The absence of seismic profiles across the strike of the structure does not allow us to judge the reliability of the object identified by s\n 40992.

The graben-like trough, in turn, is broken by tectonic disturbances, due to which isolated uplifted blocks are formed within it. They are named by us as the Central Michayu structure. On profiles 40992-04, -05, fragments of the East Michayu structure were reflected in the lowered block. There is a small low-amplitude structure at the intersection of profiles 40992-20 and 40992-12, which we called East Trypanyelskaya.

1.4 Oil and gas content

The area of work is located in the Izhma-Pechora oil and gas region within the Michayu-Pashninsky oil and gas region.

At the fields of the Michayu-Pashninsky region, a wide complex of terrigenous-carbonate deposits from the Middle Devonian to the Upper Permian, inclusive, is oil-bearing.

Near the area under consideration are the Michayuskoye and Yuzhno-Michayuskoye deposits.

Deep prospecting and exploratory drilling, carried out in 1961 - 1968. at the Michayuskoye field, wells No. 1-Yu. tiers. The deposit is layered, arched, partially waterfowl. The height of the deposit is about 25 m, the dimensions are 14 × 3.2 km.

At the Michayuskoye field, commercial oil-bearing capacity is associated with sandy formations at the base of the Kazanian stage. For the first time, oil from the Upper Permian deposits at this field was obtained in 1982 from well 582. The oil-bearing capacity of the R 2 -23 and R 2 -26 formations was established by testing in it. Oil deposits in the P 2 -23 formation are confined to sandstones, presumably of channel genesis, stretching in the form of several strips of submeridional strike through the entire Michayuskoye field. Oil-bearing capacity is established in the well. 582, 30, 106. Light oil, with a high content of asphaltenes and paraffin. The deposits are confined to a trap of a structural-lithological type.

Oil deposits in the layers P 2 -24, P 2 -25, P 2 -26 are confined to sandstones, presumably of channel genesis, stretching in the form of strips through the Michayuskoye field. The width of the strips varies from 200 m to 480 m, the maximum thickness of the seam is from 8 to 11 m.

Reservoir permeability is 43 mD and 58 mD, porosity is 23% and 13.8%. Starting stocks cat. A + B + C 1 (geol. / izv.) are equal to 12176/5923 thousand tons, category C 2 (geol. / izv.) 1311/244 thousand tons. Remaining reserves as of 01.01.2000 in categories А+В+С 1 are 7048/795 thousand tons, in category С 2 1311/244 thousand tons, cumulative production is 5128 thousand tons.

The Yuzhno-Michayuskoye oil field is located 68 km northwest of the city of Vuktyl, 7 km from the Michayuskoye field. It was discovered in 1997 by well 60 - Yu.M., in which an oil inflow of 5 m 3 /day was obtained from the interval 602 - 614 m according to PU.

The reservoir oil deposit, lithologically shielded, confined to the sandstones of the P 2 -23 formation of the Kazanian stage of the Upper Permian.

The depth of the formation roof in the crest is 602 m, the reservoir permeability is 25.4 mD, and the porosity is 23%. The oil density is 0.843 g/cm 3 , the viscosity in reservoir conditions is 13.9 MPa. s, the content of resins and asphaltenes 12.3%, paraffins 2.97%, sulfur 0.72%.

Initial stocks are equal to residual stocks on 01.01.2000. and amount to 1,742/112 thousand tons for categories A+B+C, and 2,254/338 thousand tons for category C.

At the Dinyu-Savinoborskoye field, an oil deposit in terrigenous deposits of the V-3 formation of the Yaran horizon of the Frasnian stage of the Upper Devonian was discovered in 2001. well 1-Dinyu-Savinobor. In the well section, 4 objects were tested (Table 1.2).

When testing the interval 2510-2529 m (formation V-3), an inflow (solution, filtrate, oil, gas) was obtained in the amount of 7.5 m 3 (of which oil - 2.5 m 3).

When testing the interval 2501-2523 m, oil was obtained with a flow rate of 36 m 3 / day through a choke with a diameter of 5 mm.

When testing the overlying reservoirs of the Yaran and Dzhier horizons (layers Ia, Ib, B-4) (test interval 2410-2490 m), no oil shows were observed. A solution was obtained in a volume of 0.1 m 3.

To determine the productivity of the V-2 formation, a test was carried out in the interval of 2522-2549.3 m. As a result, a solution, filtrate, oil, gas and formation water in the amount of 3.38 m 3 were obtained, of which 1.41 m3 were due to leaks in the tool 3, inflow from the reservoir - 1.97 m 3.

When studying the Lower Permian deposits (test interval 1050 - 1083.5 m), a solution in the volume of 0.16 m 3 was also obtained. However, in the process of drilling, according to the core data, signs of oil saturation were noted in the indicated interval. In the interval 1066.3-1073.3 sandstones are inequigranular, lenticular. Oil effusions were observed in the middle of the interval, 1.5 cm - a layer of oil-saturated sandstone. In the intervals of 1073.3-1080.3 m and 1080.3-1085 m, interlayers of sandstones with oil effusions and thin (in the interval of 1080.3-1085 m, core removal 2.7 m) interlayers of polymictic oil-saturated sandstone are also noted.

Signs of oil saturation according to the core data in the well 1-Dinyu-Savinobor were also noted in the top of the member of the Zelenetsky horizon of the Famennian stage (core sampling interval 1244.6-1253.8 m) and in layer Ib of the Dzhiersky horizon of the Frasnian stage (core sampling interval 2464.8-2470 m).

In reservoir V-2 (D3 jr) there are sandstones with hydrocarbon odor (core sampling interval 2528.7-2536 m).

Information about the results of testing and oil shows in the wells is given in tables 1.1 and 1.2.

Table 1.1 - Well testing results

			formation.	Test results.
				1 object. Mineralized water inflow Q=38 m 3 /day according to PU.
				2 object. Min. water Q \u003d 0.75 m 3 / day according to PU.
				3 object. No inflow received.
				1 object. Min. water Q \u003d 19.6 m 3 / day.
				2 object. Minor inflow min. water Q \u003d 0.5 m 3 / day.
				1 object. IP reservoir min. water with an admixture of the filtrate solution Q=296 m 3 /day.
				2 object. IP reservoir min. water with the smell of hydrogen sulfide, dark green.
				3 object. Min. water Q \u003d 21.5 m 3 / day.
				4 object. Min. water Q \u003d 13.5 m 3 / day.
				In the column, the free flow of oil is 10 m 3 /day.
				Oil Q=21 t/day at 4 mm choke.
				1 object. Industrial oil inflow Q=26 m 3 /day on a 4 mm choke.
				1 object. Oil gusher Q \u003d 36.8 m 3 / day on a 4 mm fitting.
				Oil inflow 5 m 3 /day according to PU.
				3, 4, 5 objects. Weak oil inflow Q \u003d 0.1 m 3 / day.


				IP oil 25 m 3 in 45 min.



				The initial oil flow rate is 81.5 tons/day.

				5.6 m 3 of oil in 50 minutes.
				The initial oil flow rate is 71.2 tons/day.
				Oil Q beg. =66.6 t/day.




				Oil inflow Q=6.5 m 3 /hour, P pl. =205 atm.

				The initial oil flow rate is 10.3 t/day.



				Oil Q \u003d 0.5 m 3 / hour, R pl. =160 atm.

				Mineral water with films of oil.

				Solution, filtrate, oil, gas. Inflow volume 7.5 m 3 (of which oil 2.5 m 3). R sq. =27.65 MPa.
				Solution, filtrate, oil, gas, formation water. V pr. \u003d 3.38 m 3, R pl. =27.71 MPa.
				Oil flow rate 36 m 3 /day, diam. PCS. 5 mm.
				No inflow received.

Table 1.2 - Information about oil shows

		Interval		The nature of manifestations.
				Limestones with oil smears in caverns and pores.

				Films of oil during drilling.
				According to GIS, oil-saturated sandstone.
				Limestone with suture joints filled with bituminous clay.
				Oil-saturated core.
				Alternation of oil-saturated sandstones, siltstones, thin layers of clays.
				Oil-saturated core.
				Oil-saturated polymictic sandstones.
				Water-saturated sandstones.
				Oil-saturated limestones.
				The limestone is cryptocrystalline, with rare cracks containing bituminous material.
				Argillite, limestone. Mid-interval oil effusion; 1.5 cm - layer of oil-saturated sandstone.
				The sandstone is inequigranular and fine-grained with oil exudates.
				Limestone and individual layers of oil-saturated sandstone.
				Alternation of dolomite and dolomitic limestone with oil exudates.
				Argillite with effusions and films of oil along cracks; siltstone with the smell of oil.
				Alternation of sandstones with effusions and oil stains.
				Alternation of sandstones with HC odor and mudstones with bitumen interspersed.
				Fine-grained sandstones with hydrocarbon odor, bituminous along fissures.
				Limestone with oil exudates and hydrocarbon smell; sandstone and mudstone with oil exudates.
				Dense and strong sandstone with a hydrocarbon smell.
				Alternation of quartz sandstone with hydrocarbon smell, siltstone and mudstone.
				Quartz sandstones with low hydrocarbon odor.

2. Special part

2.1 Geophysical work carried out in this area

The report was compiled based on the results of reprocessing and reinterpretation of seismic data obtained in the northern block of the Dinyu-Savinobor field in different years by seismic crews 8213 (1982), 8313 (1984), 41189 (1990), 40990 (1992), 40992 (1993) according to the agreement between Kogel LLC and Dinyu LLC. The methodology and technique of work is shown in Table 2.1.

Table 2.1 - Information about the methodology of field work


			" Progress"	"Progress - 2"	"Progress - 2"
Observation system	Central	Central naya	flank	flank	flank
Source Options
	Explosive	Explosive	non-explosive"dropping weight" - SIM	Non-explosive "drop weight" - SIM	Non-explosive "Yenisei - SAM"
Number of wells in a group
Charge amount
Distance between shots
Placement Options
multiplicity
Geophone grouping	26 joint ventures based on 78 m	26 joint ventures based on 78 m	12 joint ventures on a base of 25 m	11 joint ventures on the base of 25 m	11 joint ventures on the base of 25 m
Distance between PP
Minimum explosion-device distance
Maximum distance explosion-device

The Vostochno-Michayu tectonic-limited structure identified by the works s / p 40991 was transferred to drilling on the Lower Frasnian, Lower Famennian and Lower Permian deposits in 1993 s / p 40992. Seismic surveys were generally focused on the study of the Permian part of the section, structural constructions in the lower part of the section performed only on the reflecting horizon III f 1 .

To the west of the work area are the Michayuskoye and Yuzhno-Michayuskoye oil fields. The commercial oil and gas potential of the Michayuskoye field is associated with the Upper Permian deposits, the oil deposit is contained in the sandstones of the V-3 formation at the top of the Yaran horizon.

South-east of the Vostochno-Michayu structure in 2001, the 1-Dinyu-Savinobor well discovered an oil deposit in the Lower Frasnian deposits. The Dinyu-Savinobor and East Michayu structures are located in the same structural zone.

In connection with these circumstances, it became necessary to revise all available geological and geophysical materials.

The reprocessing of seismic data was carried out in 2001 by Tabrina V.A. in the ProMAX system, the volume of reprocessing was 415.28 km.

Pre-processing consisted of converting the data to the internal ProMAX format, assigning the geometry, and restoring the amplitudes.

Interpretation of the seismic material was carried out by the leading geophysicist I.Kh. Mingaleeva, geologist E.V. Matyusheva, category I geophysicist N.S. The interpretation was carried out in the Geoframe exploration system on the SUN 61 workstation. The interpretation included the correlation of reflective horizons, the construction of isochron, isohyps, and isopach maps. The workstation was loaded with digitized logs for wells 14-Michayu, 24-Michayu. To recalculate the logging curves to the time scale, the velocities obtained from the seismic logging of the corresponding wells were used.

The construction of isochron, isohyps, and isopach maps was carried out automatically. If necessary, they were corrected manually.

Velocity models needed to transform isochrone maps into structural ones were determined from drilling and seismic data.

The isohypse cross section was determined by the construction error. In order to preserve the features of the structural plans and for better visualization, the isohypse section was taken to be 10 m along all reflective horizons. Map scale 1:25000. Stratigraphic confinement of reflecting horizons was carried out according to seismic logging of wells 14-,24-Michayu.

6 reflecting horizons were traced on the area. Structural constructions were presented for 4 reflecting horizons.

OG Ik is confined to benchmark 1, identified by analogy with the Dinyu-Savinobor well in the upper Kungurian, 20-30 m below the Ufim deposits (Figure 2.1). The horizon is well correlated in the positive phase, the reflection intensity is low, but the dynamic features are consistent over the area. The next reflecting horizon II-III is identified with the boundary of the Carboniferous and Devonian deposits. GO is quite easily recognized on the profiles, although in places there is interference of two phases. At the eastern ends of the latitudinal profiles, an additional reflection appears above OG II-III, which wedges out to the west in the form of a plantar overlap.

OG IIIfm 1 is confined to benchmark 5, identified in the lower part of the Yeletsk Horizon of the Lower Famennian. In wells 5-M., 14-M, benchmark 5 coincides with the bottom of the Yelets horizon identified by TP NIC, in other wells (2,4,8,22,24,28-M) 3-10 m above the official breakdown of the bottom D 3 el. The reflecting horizon is a reference horizon, has pronounced dynamic features and high intensity. Structural constructions for OG IIIfm 1 are not provided by the program.

OG IIId is identified with the base of the Domanik deposits and is confidently correlated in time sections in the negative phase.

Reference point 6 at the top of the Lower Franian Yaran horizon is associated with OG IIIf 1 . Benchmark 6 stands out quite confidently in all wells 10-15m below the base of the Dzher deposits. Reflecting horizon IIIf 1 is tracked well, despite the fact that it has a low intensity.

Productive at the Michayuskoye, Dinyu-Savinoborskoye fields, the V-3 sandy reservoir is located 18-22 m below the IIIf 1 OG, only in the 4-M well. the thickness of the deposits enclosed between the OG IIIf 1 and the V-3 formation is increased to 30 m.

Figure 2.1 - Comparison of sections of wells 1-C. Michayu, 24-Michayu, 14-Michayu and snap reflective horizons

The next reflecting horizon III 2-3 is weakly expressed in the wave field, traced near the top of the Middle Devonian terrigenous deposits. OG III 2-3 is correlated in negative phase as an erosion surface. In the south-west of the reporting area, there is a decrease in the temporal thickness between OG IIIf 1 and III 2-3, which is especially clearly seen on profile 8213-02 (Figure 2.2).

Structural constructions (Figures 2.3 and 2.4) were made along reflectors Ik, IIId, IIIf 1 , III 2-3 , an isopach map was built between OG IIId and III 2-3 , a structural map is presented along the top of the B-3 sand bed, for the entire Dinho - Savinoborskoye deposit.

Figure 2.2 - Fragment of the time section along the profile 8213-02

2.2 Results of geophysical surveys

As a result of reprocessing and reinterpretation of seismic data on the northern block of the Dinyu-Savinobor field.

We studied the geological structure of the northern block of the Dinyu-Savinoborskoye field based on the Permian and Devonian deposits,

Figure 2.3 - Structural map along the reflecting horizon III2-3 (D2-3)

Figure 2.4 - Structural map along the reflecting horizon III d (D 3 dm)

- traced and linked across the area 6 reflectors: Ik, II-III, IIIfm1 , IIId, IIIf1 , III2-3 ;

Performed structural constructions on a scale of 1:25000 for 4 OG: Ik, IIId, IIIf1, III2-3;

A general structural map was built along the top of the V-3 formation for the Dinyu-Savinobor structure and the northern block of the Dinyu-Savinobor field, and an isopach map between OG IIId and III2-3;

We built deep seismic sections (horizon scales 1:12500, ver. 1:10000) and seismo-geological sections (horizon scales 1:25000, ver. 1:2000);

We built a comparison scheme for the Lower Frasnian deposits by wells in the Michayuskaya area, well No. 1-Dinyu-Savinobor and 1-Tripanyel on a scale of 1:500;

Clarified the geological structure of the East Michayu and Ivan-Shor structures;

Revealed Middle Michayu, Central Michayu, East Trypanyelskaya structures;

A NE-trending graben-like trough was traced, which is a screen for the northern block of the Dinyu-Savinobor structure.

In order to study the oil potential of the Lower Frasnian deposits within the central block of the East Michayu structure, drill an exploration well No. 3 on the profile 40992-04 pk 29.00 with a depth of 2500 m until the opening of the Middle Devonian deposits;

On the southern block - exploratory well No. 7 at the cross of profiles 40990-07 and 40992 -21 with a depth of 2550 m;

On the northern block - exploratory well No. 8 profile 40992-03 pk 28.50 with a depth of 2450 m;

Carrying out detailed seismic surveys within the Ivan-Shor structure;

To carry out reprocessing and reinterpretation of seismic surveys on the South-Michayuskaya and Srednemichayuskaya structures.

2.3 Rationale for choosing 3D seismic

The main reason that justifies the need to use a rather complex and rather expensive 3D areal seismic technology at the exploration and detailing stages is the transition in most regions to the study of structures and deposits with more and more complex reservoirs, which leads to the risk of drilling empty wells. It has been proven that with an increase in spatial resolution by more than an order of magnitude, the cost of 3D works in comparison with detailed 2D survey (~ 2 km/km 2) increases only 1.5-2 times. At the same time, the detail and total amount of 3D shooting information is higher. A practically continuous seismic field will provide:

· Higher detail description of structural surfaces and mapping accuracy compared to 2D (errors are reduced by 2-3 times and do not exceed 3-5 m);

· Unambiguity and reliability of tracing by area and volume of tectonic faults;

· Seismic facies analysis will provide identification and tracking of seismic facies in volume;

· Possibility of interpolation into the interwell space of reservoir parameters (layer thickness, porosity, boundaries of reservoir development);

· Refinement of oil and gas reserves by detailing the structural and estimated characteristics.

This indicates the possible economic and geological feasibility of using a three-dimensional survey on the East Michayu structure. When choosing economic feasibility, it must be borne in mind that the economic effect of applying 3D to the entire complex of exploration and development of deposits also takes into account:

· growth of reserves in categories C1 and C2;

· savings by reducing the number of uninformative exploration and low-rate production wells;

· optimization of the development mode by refining the reservoir model;

· growth of C3 resources due to the identification of new objects;

· cost of 3D survey, data processing and interpretation.

3. Design part

3.1 Substantiation of the work methodology CDP - 3D

The choice of an observation system is based on the following factors: tasks to be solved, features of seismogeological conditions, technical capabilities, and economic benefits. The optimal combination of these factors determines the observation system.

In the Vostochno-Michayuskaya area, CDP-3D seismic surveys will be carried out in order to study in detail the structural-tectonic and lithofacies features of the structure of the sedimentary cover in sediments from Upper Permian to Silurian; mapping of zones of development of lithofacies heterogeneities and improved reservoir properties, discontinuous tectonic disturbances; study of the geological history of development based on paleostructural analysis; identification and preparation of oil-promising objects.

To solve the tasks, taking into account the geological structure of the region, the factor of minimal impact on the natural environment and the economic factor, an orthogonal observation system is proposed with excitation points located between the reception lines (i.e., with overlapping reception lines). Explosions in wells will be used as excitation sources.

3.2 Example of calculation of a "cross" observing system

The observation system of the "cross" type is formed by successive overlapping of mutually orthogonal arrangements, sources and receivers. Let us illustrate the principle of areal system formation on the following idealized example. Let us assume that the geophones (a group of geophones) are evenly distributed along the line of observation coinciding with the X axis.

Along the axis intersecting the arrangement of seismic receivers in the center, m is placed uniformly and symmetrically at the sources. The step of the sources of do and the seismic receivers of dx is the same. The signals generated by each source are received by all geophones of the array. As a result of such testing, a field of m 2 midpoints of reflection is formed. If we sequentially shift the arrangement of seismic receivers and the line of sources orthogonal to it along the X axis by a step dx and repeat the registration, then the result will be a multiple overlap of the band, the width of which is equal to half the excitation base. Sequential displacement of the excitation and reception base along the Y-axis by a step du leads to an additional - multiple overlap, and the total overlap will be. Naturally, in practice, more technologically advanced and economically sound variants of a system with mutually orthogonal lines of sources and receivers should be used. It is also obvious that the overlap ratio must be chosen in accordance with the requirements determined by the nature of the wave field and processing algorithms. As an example, Figure 3.1 shows an eighteen-fold areal system, for the implementation of which one 192-channel seismic station is used, which sequentially receives signals from 18 excitation pickets. Consider the parameters of this system. All 192 geophones (groups of geophones) are distributed on four parallel profiles (48 on each). The step dx between the reception points is 0.05 km, the distance d between the reception lines is 0.05 km. The step of Sy sources along the Y axis is 0.05 km. A fixed distribution of sources and receivers will be called a block. After receiving vibrations from all 18 sources, the block is shifted by a step x (in this particular case equal to 0.2 km), reception from all 18 sources is repeated again, and so on. This is how a strip is worked out along the X axis from the beginning to the end of the study area. The next lane of four reception lines is placed parallel to the previous one so that the distance between adjacent (nearest) reception lines of the first and second lanes is equal to the distance between the reception lines in the block (?y = 0.2 km). In this case, the source lines of the first and second bands overlap by half the excitation base. When working out the third band, the source lines of the second and third bands overlap by half, etc. Therefore, in this version of the system, the receiving lines are not duplicated, and at each source point (excluding the extreme ones) the signals are excited twice.

Let us write down the main relations that determine the parameters of the system and its multiplicity. To do this, following Figure 8, we introduce additional notation:

W - number of receiving lines,

m x - number of receiving points on each receiving line of the given block;

m y - the number of sources on each excitation line of the given block,

P is the width of the interval in the center of the excitation line, within which the sources are not placed,

L - offset (displacement) along the X axis of the source line from the nearest reception points.

In all cases, the intervals ?x, ?y, and L are multiples of the step dx. This ensures the uniformity of the network of midpoints corresponding to each source-receiver pair, i.e. do it! requirement of the condition necessary for the formation of seismograms of common midpoints (CMP). Wherein:

Ax=Ndx N=1, 2, 3…

tSy-MdyM=1, 2, 3…

L=q qxq=1, 2, 3…

Let us explain the meaning of the parameter P. The shift between the lines of the midpoints is equal to half the step? If the sources are uniformly distributed (there is no discontinuity), then for similar systems the overlap factor along the Y axis is equal to W (the number of receiving lines). To reduce the multiplicity of overlaps along the Y axis and to reduce costs due to a smaller number of sources, a gap is made in the center of the excitation line by a value P equal to:

Where, k = 1,2,3 ...

When k=1,2, 3, respectively, the overlap ratio decreases by 1, 2, 3, i.e. becomes equal to W-K.

The general formula relating the multiplicity of overlaps n y with the parameters of the system

hence the expression for the number of sources m y on one excitation line can be written as follows:

For the observation system (Figure 3.1), the number of sources on the excitation line is 18.

Figure 3.1 - Observation system of the "cross" type

It follows from expression (3.3) that since the step of the profiles? y is always a multiple of the step of sources dy, the number of sources t y for this type of system is an even number. Distributed on a straight line parallel to the Y axis symmetrically to the reception profiles included in this block, the excitation points either coincide with the reception points, or are shifted relative to the reception points by 1/2·dy. If the overlap multiplicity n y in a given block is an odd number, the sources always do not coincide with the receiving points. If n y is an even number, two situations are possible: ?y/du is an odd number, the sources coincide with the reception points, ?y/du is an even number, the sources are shifted relative to the reception points by dy/2. This fact should be taken into account when synthesizing the system (choosing the number of reception profiles W and the step? y between them), since it depends on whether the vertical times necessary to determine the static corrections will be recorded at the reception points.

The formula that determines the multiplicity of overlaps n x along the X axis can be written similarly to formula (3.2)

thus, the total multiplicity of overlaps n xy by area is equal to the product of n x and n y

In accordance with the accepted values of m x, dx and? x, the multiplicity of overlaps n x along the X axis calculated by formula (3.4) is 6, and the total multiplicity n xy = 13 (Figure 3.2).

Figure 3.2 - Multiplicity of overlaps nx = 6

Along with the observation system, which provides for overlapping sources without overlapping reception lines, systems are used in practice in which the excitation lines do not overlap, but part of the reception lines is duplicated. Let us consider six receiving lines, on each of which seismic receivers receiving signals sequentially excited by sources are evenly distributed. When working out the second band, three reception lines are duplicated by the next block, and the source lines go as a continuation of the orthogonal profiles of the first band. Thus, the applied work technology does not provide for duplication of excitation points. With double overlapping of the reception lines, the multiplicity n y is equal to the number of overlapping reception lines. The full equivalent of a system of six profiles followed by an overlap of three receive lines is a system with overlapping sources, the number of which is doubled to achieve the same fold. Therefore, systems with overlapping sources are economically unprofitable, because. this technique requires a large amount of drilling and blasting.

Transition to 3D seismic.

The design of a 3D survey is based on the knowledge of a number of characteristics of the seismological section of the work site.

Information about the geoseismic section includes:

Multiplicity of shooting 2D

maximum depths of target geological boundaries

minimal geological boundaries

the minimum horizontal size of local geological objects

maximum frequencies of reflected waves from target horizons

· average speed in the layer lying on the target horizon

time of registration of reflections from the target horizon

the size of the study area

To register the time field in MOGT-3D, it is rational to use telemetry stations. The number of profiles is selected depending on the multiplicity n y =u.

The distance between the common midpoints on the reflective surface along the X and Y axes determines the bin size:

The maximum allowable minimum offset of the source line is selected based on the minimum depth of the reflecting boundaries:

Minimum offset.

Maximum offset.

To ensure the multiplicity n x, the distance between the excitation lines?x is determined:

For the recording unit, the distance between the receiving lines? y:

Taking into account the technology of work with double overlapping of the receiving line, the number of sources m y in one block to ensure the multiplicity n y:

Figure 3.3 - Multiplicity ny =2

Based on the results of planning a 3D survey, the following data set is obtained:

distance between channels dx

the number of active channels on one receiving line m x

total number of active channels m x u

minimum offset Lmin

bin size

total multiplicity n xy

Story

Born in the early 60s of the last century, it became the main method of seismic exploration for many decades. Rapidly developing both quantitatively and qualitatively, it has completely supplanted the simple method of reflected waves (ROW). On the one hand, this is due to the no less rapid development of computer (first analog and then digital) processing methods, and on the other hand, the possibility of increasing the productivity of field work by using large reception bases that are impossible in the SW method. Not the last role was played here by the rise in the cost of work, that is, the increase in the profitability of seismic exploration. To justify the increase in the cost of work, many books and articles were written on the perniciousness of multiple waves, which since then have become the basis for justifying the application of the common depth point method.

However, this transition from the oscilloscope MOB to the machine-based MOGT was not so cloudless. The SVM method was based on linking hodographs at mutual points. This linking reliably ensured the identification of hodographs belonging to the same reflecting boundary. The method did not require any corrections to ensure phase correlation - neither kinematic nor static (dynamic and static corrections). Changes in the shape of the correlated phase were directly related to changes in the properties of the reflecting horizon, and only with them. Neither inaccurate knowledge of the reflected wave velocities nor inaccurate static corrections affected the correlation.

Coordination at mutual points is impossible at large distances of receivers from the point of excitation, since the hodographs are intersected by trains of low-speed interference waves. Therefore, CDP processors abandoned the visual linking of mutual points, replacing them with obtaining a sufficiently stable signal shape for each result point by obtaining this shape by summing approximately homogeneous components. The exact quantitative correlation of times has been replaced by a qualitative estimate of the form of the resulting total phase.

The process of registering an explosion or any source of excitation other than a vibroseis is similar to taking a photograph. flash illuminates environment and the response of this environment is fixed. However, the response to an explosion is much more complex than a photograph. The main difference is that a photograph captures the response of a single, albeit arbitrarily complex surface, while an explosion evokes the response of multiple surfaces, one under or inside another. Moreover, each overlying surface leaves its mark on the image of the underlying ones. This effect can be seen if you look at the side of a spoon immersed in tea. It seems broken, while we firmly know that there is no break. The surfaces themselves (the boundaries of the geological section) are never flat and horizontal, which is manifested in their responses - hodographs.

Treatment

The essence of CDP data processing is that each trace of the result is obtained by summing the original channels in such a way that the sum includes signals reflected from the same point of the deep horizon. Before summing, it was necessary to introduce corrections to the recording times in order to transform the recording of each individual trace, bring it to a form similar to the trace at the shot point, i.e., convert it to the form t0. This was the original idea of the authors of the method. Of course, it is impossible to select the necessary channels for stacking without knowing the structure of the medium, and the authors set the condition for applying the method to the presence of a horizontally layered section with inclination angles not exceeding 3 degrees. In this case, the coordinate of the reflecting point is quite exactly equal to half the sum of the coordinates of the receiver and source.

However, practice has shown that if this condition is violated, nothing terrible happens, the resulting cuts have a familiar look. The fact that in this case the theoretical justification of the method is violated, that reflections from one point, but from the site, are summed up, the greater, the greater the angle of inclination of the horizon, did not bother anyone, because the assessment of the quality and reliability of the section was no longer accurate, quantitative, but approximate quality. It turns out a continuous axis of in-phase, which means that everything is in order.

Since each trace of the result is the sum of a certain set of channels, and the quality of the result is assessed by the stability of the phase shape, it is sufficient to have a stable set of the strongest components of this sum, regardless of the nature of these components. So, summing up some low-speed interference, we get a quite decent cut, approximately horizontally layered, dynamically rich. Of course, it will have nothing to do with a real geological section, but it will fully meet the requirements for the result - the stability and length of the in-phase phases. In practical work, a certain amount of such interference always enters the sum, and, as a rule, the amplitude of these interferences is much greater than the amplitude of the reflected waves.

Let's return to the analogy of seismic exploration and photography. Imagine that on a dark street we meet a man with a lantern, with which he shines into our eyes. How can we consider it? Apparently, we will try to cover our eyes with our hands, shield them from the lantern, then it becomes possible to examine a person. Thus, we divide the total lighting into components, remove the unnecessary, focus on the necessary.

When processing CDP materials, we do exactly the opposite - we summarize, combine the necessary and the unnecessary, hoping that the necessary will come forward on its own. Furthermore. From photography, we know that the smaller the image element (the graininess of the photographic material), the better, the more detailed the picture. You can often see in documentary television films, when you need to hide, distort the image, it is presented with large elements, behind which you can see some object, see its movements, but it is simply impossible to see such an object in detail. This is exactly what happens when the channels are summed during the processing of CDP materials.

In order to obtain in-phase addition of signals even with a perfectly flat and horizontal reflecting boundary, it is necessary to provide corrections that ideally compensate for the inhomogeneities of the relief and the upper part of the section. It is also ideally necessary to compensate for the curvature of the hodograph in order to move the reflection phases obtained at distances from the point of excitation by times corresponding to the time of passage of the seismic beam to the reflecting surface and back along the normal to the surface. Both are impossible without a detailed knowledge of the structure of the upper part of the section and the shape of the reflecting horizon, which is impossible to provide. Therefore, when processing, point, fragmentary information about the zone of low velocities and approximation of reflecting horizons by a horizontal plane are used. The consequences of this and methods for extracting maximum information from the richest material provided by the CDP are discussed in the description of "Dominant Processing (Baybekov's Method)".

Keywords

CDP SEISMIC / DIRECT SEARCH FOR HYDROCARBONS / INDUCED GEODYNAMIC NOISE / EXPLORATION DRILLING SUCCESS RATE/ CDPM SEISMIC / DIRECT HYDROCARBON EXPLORATION/ INDUCED GEODYNAMIC NOISE / PROSPECTING AND EXPLORATORY DRILLING SUCCESS RATIO

annotation scientific article on Earth sciences and related ecological sciences, author of scientific work - Maksimov L.A., Vedernikov G.V., Yashkov G.N.

Information is given on the technology of passive-active seismic survey using the common depth point method (CDP CPS), which solves the problem direct exploration of hydrocarbon deposits according to dynamic parameters emitted by these deposits induced geodynamic noise. It is shown that the use of this technology makes it possible to prevent the drilling of unproductive wells. Materials and Methods The proposed CDP DAS technology combines the registration and interpretation of HC radiated by deposits and waves reflected from seismic boundaries. This ensures high efficiency in studying the geometry of reflecting boundaries and recording hydrocarbons emitted by deposits. induced geodynamic noise. Results The ACS CDP technology has been tested at dozens of hydrocarbon fields in Western and Eastern Siberia and showed its effectiveness: all fields are marked by anomalies in the intensity of geodynamic noise and the absence of such anomalies outside the fields. Conclusions The above possibilities of the PAS CDP technology are very relevant at the present time, when the crisis in the economy continues to intensify. This technology will allow oilmen to drill hydrocarbon traps, rather than structures, which will increase the efficiency of geological exploration (by several times) in the search for oil and gas.

The text of the scientific work on the topic "Geodynamic noise of hydrocarbon deposits and passive-active seismic exploration of CDP"

GEOPHYSICS

Geodynamic noise of hydrocarbon deposits and passive-active seismic exploration of CDP

L.A. maxims

Candidate of G.M.S., Art. teacher1 [email protected]

G.V. Vedernikov

d.g.-m.-sci., deputy. science director2 [email protected]

G.N. Yashkov

ch. geophysicist2 [email protected]

Novosibirsk State University, Novosibirsk, Russia 2NMT-Seis LLC, Novosibirsk, Russia

Information is given on the technology of passive-active seismic survey using the common depth point method (CDP CPS), which solves the problem of direct search for hydrocarbon deposits by dynamic parameters emitted by these deposits of induced geodynamic noise. It is shown that the use of this technology makes it possible to prevent the drilling of unproductive wells.

Materials and methods

The proposed CDP DAS technology combines the registration and interpretation of induced geodynamic noise emitted by hydrocarbon deposits and waves reflected from seismic boundaries. This ensures high efficiency in studying the geometry of reflecting boundaries and recording induced geodynamic noise emitted by hydrocarbon deposits.

Keywords

CDP seismic, direct search for hydrocarbon deposits, induced geodynamic noise, exploration drilling success rate

The main task of currently used seismic methods is to study the spatial distribution of physical parameters and indicators of spontaneous seismic activity.

Seismic exploration today is the main method of preparing objects for prospecting and exploratory drilling. It reveals with a sufficient degree of certainty structures that, under certain favorable conditions, may or may not contain oil deposits. Only a well will confirm this uncertainty, but at what cost?

The success of the search for oil and gas deposits was within 10 ... 30% in the past (in the USSR and the USA), and remains within these limits today (Fig. 1). And it will hold on tomorrow and the day after tomorrow, and until the oilmen turn from looking for structures to looking for oil-containing traps. The meaning of increasing the efficiency of prospecting and exploration works comes down to an obvious task - to separating the structures identified by seismic exploration into productive and unproductive oil and gas traps. If this problem is solved, then huge amounts of money are saved, which are spent on prospecting and exploratory drilling in obviously unproductive structures.

It is known that oil and gas deposits, being unstable thermodynamic systems, emit an increased level of spontaneous and induced geodynamic noise. To analyze such noise for the purpose of direct search for hydrocarbon (HC) deposits, an innovative technology of passive-active seismic survey using the common depth point method (PAS CDP) developed at NMT-Seis LLC (an analogue of the active version of the ANCHAR technology) can be used.

Modern standard CDP seismic is inherently passive-active. Indeed, microseisms and geodynamic noises are recorded on the seismic trace in the area before the first arrivals of regular waves - the passive component of the record. In the rest of the record, together with microseisms and geodynamic noise, oscillations of regular waves are recorded - the active component of the record, which contains information about the geometry of seismic boundaries in the earth's thickness. The passive component contains information about the presence (absence) of hydrocarbon deposits emitting geodynamic noise.

The proposed PAS CDP technology combines registration and

Rice. 1 - Dynamics of changes in the success rate (in%) when drilling prospecting and exploration wells in the USA

Rice. 2 - Time seismic section (A), amplitude-frequency spectrum of microseisms (B) and spectrum intensity plots in frequency bands (C)

interpretation of artificially induced geodynamic noise emitted by hydrocarbon deposits and waves reflected from seismic boundaries. This ensures both high efficiency in studying the geometry of reflecting boundaries and velocities between them due to repeated tracking of waves reflected from these boundaries, and high efficiency in searching for hydrocarbon deposits due to repeated exposure to seismic waves and registration of induced geodynamic noise emitted by them. An important advantage of the method lies in the possibility of independent parallel extraction of information from wave fields that have a fundamentally different nature and are recorded almost simultaneously in one place. In principle, the CDP DAS technology is one of the modifications of multiwave seismic, in the broader sense of the term "multiwave seismic" - that is, not only waves of different polarizations. Thus, having carried out a joint interpretation of the reflected waves and noise, we will have information about the geometry of the boundaries in the medium and the presence of SWs in the medium, i.e., we will be able to solve the problem of direct searches for SW traps, and not structures, as is done today. And this moment is very fundamental, since it becomes possible to solve the main problem in prospecting and exploratory drilling. At the same time, the success of drilling increases sharply (many times).

The PAS CDP technology has been tested on dozens of hydrocarbon fields in Western and Eastern Siberia and has shown its effectiveness: all fields are marked with anomalies

the intensity of geodynamic noise (Fig. 2) and the absence of such anomalies outside the fields (Fig. 3).

Over the past 7 years, under State contracts, together with the Federal State Unitary Enterprise SNIIGGiMS, work was carried out on the forecast of oil and gas accumulation zones in Western and Eastern Siberia in the amount of more than 13 thousand linear meters. km of profiles and shows the efficiency of using the CDP DAS technology at all stages of geological exploration:

In regional work - identifying promising areas for prospecting and exploration;

At the pre-exploration stage - preparation of information packages for licensing subsoil plots;

During exploration work

Identification and ranking of promising objects, especially non-anticlinal type;

When planning drilling operations

The principal feature of CDP DAS technologies is the excitation of oscillations and the registration of microseisms and regular waves using the multiple overlap technique. This results in the following unique advantages of these technologies in comparison with the ANCHAR technology:

impact on hydrocarbon deposits by waves generated by a man-made source. The multiplicity of such impact is equal to the multiplicity of the CDP observation system. The duration of exposure with an average time interval of excitation of oscillations from PV to PV, equal to 2-3 minutes, is 60-180 minutes (1-3 hours). As a result, hydrocarbon deposits are affected by a continuous train of seismic waves for 1-3 hours with an increase in their intensity periodically repeating every 2-3 minutes. This provides a higher, in the frequency band up to 40 Hz, the intensity of induced geodynamic noise from hydrocarbon deposits, the registration of which is possible with standard seismic equipment.

2. Registration of microseisms is carried out by a multi-channel CDP observation system, which ensures a high density of SPs on the profile with a duration of registration of microseisms at each SP of about 2-6 hours. it

by an order of magnitude or more increases the amount of information obtained about geodynamic noise and improves the reliability and accuracy of their selection without additional costs for such work.

3. This technology can also be implemented based on the results of previous CDP work using stock materials. This allowed from 2006 to 2014. to process CDP data in the amount of about 13,000 linear meters using this technology without the cost of special field work. km obtained in many areas

Rice. 3 - Time seismic section (A) and characteristics of microseisms (B, C) in the area of non-productive wells

Rice. 5 - Location of zones 1-5 of geodynamic noise and the structural plan of the B10 formation at the Alenka license area

Rice. 4 - A typical example of the location of a hydrocarbon deposit on the wings of a fold. South of the West Siberian Lowland

Rice. 6 - Time section (A) and noise spectrum (B) in the zone of transition from oil to gas deposits

Western and Eastern Siberia, including the areas of more than 30 known fields with more than 200 productive and "empty" wells. It was found that the location of areas (on the profile) and zones (on the area) of geodynamic noise can determine the contours of hydrocarbon deposits (Fig. 2) and the type of traps (anticlinal, non-anticlinal) (Fig. 4, 5). Based on such features of the noise spectrum as their general intensity, prevailing frequency and modality, one can predict the relative volume of hydrocarbon reserves in the object and predict the presence of the type of fluids (oil, gas, condensate) in the object (Fig. 6).

The possibilities of the PAS CDP technology mentioned above are very relevant at the present time, when the crisis in the economy continues to intensify. The use of this technology will allow oilmen to drill hydrocarbon traps, rather than structures, which will increase the efficiency of geological exploration (many times) in the search for oil and gas.

In Russia, 6,500 exploration wells were drilled in 2013, and 5,850 wells in 2014. The cost of drilling one prospecting and exploratory well in the Russian Federation ranges from

100 to 500 million rubles depending on the geographical location wells, structures, existing infrastructure, etc.; the average cost is about 300 million rubles. With a drilling success of 10..30% in 2013, out of 6,500 wells drilled, 3,900 wells turned out to be unproductive, about 1.2 trillion rubles were spent on their drilling.

The PAS CDP technology has been tested on dozens of hydrocarbon fields in Western and Eastern Siberia and has shown its effectiveness: all fields are marked by anomalies in the intensity of geodynamic noise and the absence of such anomalies outside the fields.

The possibilities of the PAS CDP technology mentioned above are very relevant at the present time, when the crisis in the economy continues to intensify. This technology will allow oilmen to drill hydrocarbon traps, rather than structures, which will increase the efficiency of geological exploration (by several times) in the search for oil and gas.

Bibliography

1. Puzyrev N.N. Methods and Objects

seismic research. Introduction to General Seismology. Novosibirsk: SO

RAS; NITs OIGGM, 1997. 301 p.

2. Timurziev A.I. Current state practices and methodology of oil prospecting - from delusions of stagnation to a new outlook of progress // Geology, geophysics and development of oil and gas fields. 2010. No. 11.

3. Grafov B.M., Arutyunov S.A., Kazarinov

B.E., Kuznetsov O.L., Sirotinsky Yu.V., Suntsov A.E. Analysis of geoacoustic radiation of an oil and gas deposit using the ANCHAR technology // Geophysics. 1998. No. 5. pp. 24-28.

4. Patent No. 2 263 932 C1 in 01 U/00 Russian Federation. seismic exploration method. Appl. 07/30/2004.

5. Vedernikov G.V. Methods of passive seismic exploration // Instruments and systems of exploration geophysics. 2013. No. 2.

6. Vedernikov G.V., Maksimov L.A., Chernyshova T.I., Chusov M.V. Innovative technologies. What does the experience of seismic exploration work on the Shushukskaya area say about // Geology and mineral resources of Siberia. 2015. No. 2 (22). pp. 48-56.

Geodynamical noise of hydrocarbon pools and passive and active seismic CDPM

Leonid A. Maksimov - Ph. D., lecturer1; [email protected] Gennadiy V. Vedernikov - Sc. D., deputy of science work2; [email protected] Georgiy N. Yashkov - chief geoscientist2; [email protected]

Novosibirsk State University, Novosibirsk, Russian Federation 2"NMT-Seis" LLC, Novosibirsk, Russian Federation

The information on the technology of passive and active seismic using the common-depth-point method (hereinafter "the PAS CDPM"), solving the problem of direct exploration of hydrocarbon accumulations using the amplitude information of induced geodynamic noise emitted by these accumulations is containing .

It is shown that the use of this technology can prevent drilling of nonproductive wells.

materials and methods

The proposed PAS CDPM technology complexes registration and interpretation of induced

geodynamic noises emitted by hydrocarbon accumulations, and waves reflected from the seismic horizons. This provides high efficiency of studying of reflectors geometry and registration of induced geodynamic noises emitted by hydrocarbon accumulations.

The PAS CDPM technology tested in dozens of hydrocarbon accumulations of Western and Eastern Siberia has proven its efficiency, namely all accumulations have displayed intensity anomalies of geodynamic noises, and no such anomalies have been observed outside accumulations.

The above mentioned PAS CDPM technology capability is relevant nowadays, when the economic crisis is gathering pace. The defined technology will make it possible for petroleum experts to drill traps instead of drilling structures that will increase severalfold efficiency of oil and gas geological exploration.

CDPM seismic, direct hydrocarbon exploration, induced geodynamic noise, prospecting and exploratory drilling success ratio

1. Puzyrev N.N. Metody i ob "ekty seysmicheskikh issledovaniy. Vvedenie v obshchuyu seysmologiyu. Novosibirsk: SO RAN; NITs OIGGM, 1997, 301 p.

2. Timurziev A.I. Sovremennoe sostoyanie praktiki i metodologii poiskov nefti

Otzabluzhdeniyzastoya k novomu mirovozzreniyu progressa. Geology,

geofizika i razrabotka neftyanykh i gazovykh mestorozhdeniy, 2010, issue 11, pp. 20-31.

3. Grafov B.M., Arutyunov S.A., Kazarinov V.E., Kuznetsov O.L., Sirotinskiy Yu.V., Suntsov A.E. Analiz geoakusticheskogo izlucheniya neftegazovoyzalezhi pri ispol "zovanii tekhnologiiANChAR. Geofizika, 1998, issue 5, pp. 24-28.

4. Patent Russian Federation No. 2 263 932 CI G 01 V/00 Sposob seysmicheskoy razvedki. Declared 07/30/2004.

5. Vedernikov G.V. Methody passivnoy ceysmorazvedki. Pribory i sistemy razvedochnoygeofiziki, 2013, issue 2, pp. 30-36.

6. Vedernikov G.V., Maksimov L.A., Chernyshova T.I., Chusov M.V. Innovation technologies. O chem govorit opytseysmorazvedochnykh work na Shushukskoy ploshchadi. Geologiya i mineral "no-syr" evye resursy Sibiri, 2015, issue 2 (22), pp. 48-56.

The experience of conducting field seismic surveys using the classical method and the high-performance Slip-Sweep method by the forces of Samaraneftegeofizika is considered.

The experience of conducting field seismic surveys using the classical method and the high-performance Slip-Sweep method by Samaraneftegeofizika is considered.

The advantages and disadvantages of the new technique are revealed. The economic indicators of each of the methods are calculated.

At present, the productivity of field seismic surveys depends on many factors:

Land use intensity;

Movement of cars and rail Vehicle, through the area under study;

Activity on the territory of settlements located on the study area; influence of meteorological factors;

Rough terrain (ravines, forests, rivers).

All of the above factors significantly reduce the speed of seismic surveys.

In fact, during the day there are 5-6 hours of night time for seismic observations. This is critical and insufficient to fulfill the volumes within the stipulated time, and also significantly increase the cost of work.

The time of work, in the 1st stage, depends on the following stages:

Topogeodetic preparation of the observation system - installation of pickets of profiles on the ground;

Installation, adjustment of seismic equipment;

Excitation of elastic vibrations, registration of seismic data.

One way to reduce the time spent is to use the Slip-Sweep technique.

This technique allows to significantly speed up the production of the excitation stage - registration of seismic data.

Slip-sweep is a high-performance seismic system based on the overlapping sweep method, in which the vibrators work simultaneously.

In addition to increasing the speed of field work, this technique allows you to compact the points of the explosion, thus increasing the density of observations.

This improves the quality of work and increases productivity.

The Slip-Sweep technique is relatively new.

The first experience of CDP-3D seismic exploration using the Slip-Sweep method was obtained in the amount of only 40 km 2 in Oman (1996).

As you can see, the Slip-Sweep technique was used mainly in the desert area, with the exception of work in Alaska.

In Russia, in experimental mode (16 km2), the Slip-Sweep technology was tested in 2010 by Bashneftegeofizika.

The article presents the experience of conducting field work using the Slip-Sweep method and comparing the indicators with the standard method.

The physical foundations of the method and the possibility of compacting the observation system simultaneously with the use of the Slip-Sweep technology are shown.

The primary results of the work are given, the shortcomings of the method are indicated.

In 2012, using the Slip-Sweep method, Samaraneftegeofizika performed 3D work at the Zimarny and Mozharovsky license blocks of Samaraneftegaz in the amount of 455 km2.

The increase in productivity due to the Slip-Sweep technique at the stage of excitation-registration in the conditions of the Samara region occurs due to the use of short-term periods of time allotted for the registration of seismic data during the daily work cycle.

That is, the task of performing the largest number of physical observations in a short time is performed by the Slip-Sweep technique most efficiently by increasing the performance of recording physical observations by 3-4 times.

The Slip-Sweep technique is a high-performance seismic survey system based on the method of overlapping vibratory sweep signals, in which vibrators at different SP operate simultaneously, recording is continuous. ranges (Fig. 1).

The emitted sweep signal is one of the operators of the cross-correlation function in the process of obtaining a corelogram from a vibrogram.

At the same time, in the process of correlation, it is also a filter operator that suppresses the influence of frequencies other than the frequency emitted at a given time, which can be applied to suppress radiation from simultaneously operating vibrators.

With sufficient response time of vibration units, their emitted frequencies will be different, thus it is possible to completely eliminate the influence of neighboring vibration radiation (Fig. 2).

Therefore, with a correctly selected slip-time, the influence of simultaneously operating vibration units is eliminated in the process of converting the vibrogram into a corelogram.

Rice. 1. Slip-time delay. Simultaneous emission of different frequencies.

Rice. 2. Evaluation of the use of an additional filter for the influence of neighboring vibrations: A) correlogram without filtering; B) corelogram with filtering by vibrogram; C) frequency-amplitude spectrum of filtered (green light) and unfiltered (red) corelograms.

The use of one vibrator instead of a group of 4 vibrators is based on the sufficiency of the vibroradiation energy of one vibrator for the formation of reflected waves from the target horizons (Fig. 3).

Rice. 3. Sufficiency of vibration energy of one vibration unit. A) 1 vibration unit; B) 4 vibration units.

The Slip-Sweep technique is more efficient when applying surveillance system compaction.

For the conditions of the Samara region, a 4-fold compaction of the observation system was applied. 4-fold division of one physical observation (f.n.) into 4 separate f.n. is based on the equality of the distance between the vibrator plates (12.5 m) with a group of 4 vibrators, a 50 m PV step and the use of one vibrator with a 12.5 m PV step (Fig. 4).

Rice. 4. Sealing the surveillance system with 4-fold separation of physicalobservations.

In order to combine the results of observation by the standard method and the sleep-sweep method with 4-fold compaction, the principle of parity of the total vibro-radiation energies is considered.

The parity of the energy of vibration action can be estimated by the total time of vibration action.

Total vibration exposure time:

St = Nv *Nn * Tsw * dSP,

where Nv is the number of vibration units in the group, Nn is the number of accumulations, Tsw is the duration of the sweep signal, dSP is the number of f.n. within the basic step PV=50m.

For the traditional technique (ST step = 50m, a group of 4 sources):

St = 4 * 4 * 10 * 1 = 160 sec.

For the slip-sweep method:

St = 1 * 1 * 40 * 4 = 160 sec.

The result of the parity of energies by the equality of the total time shows the same result in the total Bin 12.5m x 25m.

To compare the methods, Samara geophysicists received two sets of seismograms: 1st set - 4 seismograms processed by one vibrator (Slip-Sweep method), 2nd set - 1 seismogram processed by 4 vibrators (standard method). Each of the 4 seismograms of the first set is about 2-3 times weaker than the seismogram of the second set (Fig. 3). Accordingly, the signal-to-microseism ratio is 2-3 times lower. However, a more qualitative result is the use of compacted 4 relatively weak in energy individual seismograms (Fig. 5).

In the case of junction of areas worked out by different methods, the application of processing procedures oriented to the wave field of the standard method, the result turned out to be practically equivalent (Fig. 6, Fig. 7). However, if you apply processing parameters adapted to the Slip-Sweep technique, the result will be time sections with increased time resolution.

Rice. Fig. 5. A fragment of the primary total time section by INLINE (without filtering procedures) at the junction of two areas worked out using the slip-sweep method (left) and standard technique (right).

Comparison of time sections and spectral characteristics of the standard method and the Slip-Sweep method shows a high comparability of the resulting data (Fig. 8). The difference lies in the presence of higher energies of the high-frequency component of the Slip-Sweep seismic data signal (Fig. 7).

This difference is explained by the high noise immunity of the compacted observation system, the high multiplicity of seismic data (Fig. 6).

Also an important point is the point impact of one vibrator instead of a group of vibrators and its single impact instead of the sum of vibration impacts (accumulations).

The use of a point source of excitation of elastic vibrations instead of a group of sources expands the spectrum of recorded signals in the high-frequency region, reduces the energy of near-surface interference waves, which affects the increase in the quality of the recorded data, the reliability of geological constructions.

Rice. Fig. 6. Amplitude-frequency spectra from seismograms processed according to differentmethods (according to the results of processing): A) Slip-sweep technique; B) Standard method.

Rice. 7. Comparison of time sections worked out by different methods(according to the results of processing): A) Slip-sweep technique; B) Standard method.

Benefits of the Slip-Sweep technique:

1. High productivity of work, expressed in an increase in the productivity of registration of f.n. 3-4 times, an increase in overall productivity by 60%.

2. Improved quality of field seismic data due to the compression of shots:

High noise immunity of the surveillance system;

High frequency of observations;

Possibility of increasing the space;

Increase in the share of the high-frequency component of the seismic signal by 30% due to point excitation (vibration impact).

Disadvantages of using the technique.

Operation in the Slip-Sweep technique mode is operation in a "conveyor" mode in a streaming information environment with non-stop registration of seismic data. With non-stop recording, the visual control of the seismic complex operator over the quality of seismic data is significantly limited. Any failure can lead to a mass marriage or stop work. Also, at the stage of subsequent control of seismic data at the field computer center, the use of more powerful computer systems for field support of data preparation and preliminary field processing is required. However, the costs of acquiring computer equipment, as well as equipment for retrofitting the recording complex, are paid off within the framework of the profit of the work contractor by reducing the time for their implementation. Among other things, more efficient logistical procedures are required for preparing profiles for the development of physical observations.

During the work of Samaraneftegeofizika using the Slip-Sweep method in 2012, the following economic indicators were obtained (table 1).

Table 1.

Economic indicators of comparison of methods of work.

These data allow us to draw the following conclusions:

1. With the same amount of work, the overall productivity of Slip-Sweep is 63.6% higher than when conducting work with the "standard" method.

2. Growth in productivity directly affects the duration of work (decrease by 38.9%).

3. When using the Slip-Sweep technique, the cost of field seismic surveys is 4.5% lower.

Literature

1. Patsev V.P., 2012. Report on the performance of work on the object of field seismic surveys MOGT-3D within the Zimarny licensed area of JSC Samaraneftegaz. 102 p.

2. Patsev V.P., Shkokov O.E., 2012. Report on the performance of work on the object of field seismic surveys MOGT-3D within the Mozharovsky licensed area of JSC Samaraneftegaz. 112 p.

3. Gilaev G.G., Manasyan A.E., Ismagilov A.F., Khamitov I.G., Zhuzhel V.S., Kozhin V.N., Efimov V.I., 2013. Experience in conducting seismic surveys MOGT-3D according to the Slip-Sweep method. 15 s.

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