Oily trap identification method based on reverse fault control

Abstract

The invention belongs to the technical field of oil and gas basin exploration, and particularly relates to an oily trap identification method based on reverse fault control. The method comprises the following steps: firstly, according to seismic data and drilling and logging data, determining a homosedimentary fracture plane distribution diagram in each period of a research area, establishing a stress field model in each period of the research area based on the plane distribution diagram, predicting a reverse fault development zone of the research area in combination with a salt rock development area of the research area, and preferably selecting a zone for reverse fault development of an extended basin; then, on a reverse fault development zone, comprehensive judgment is carried out on multiple aspects by comprehensively utilizing judgment elements such as earthquakes, well drilling, well logging and stratigraphic dip angles, and the determined reverse fault is finely depicted to determine the activity time and the formation mechanism of the reverse fault, so that whether the oily trap exists under the control of the reverse fault or not is accurately identified; and the accuracy of a reverse fault near-lying zone oily trap identification result is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas basin exploration, and in particular relates to a method for identifying oil-bearing traps controlled by reverse faults. Background Art

[0002] Basin evolution is often affected by the superposition of tectonic stresses of multiple periods, different directions, and different natures. Most basins have superimposed or composite characteristics of compression, tension, and strike-slip deformation. Since the Mesozoic and Cenozoic, affected by the subduction and retreat of the western Pacific tectonic plate, a series of fault basins such as the Songliao Basin, Bohai Bay Basin, and the Subei-South Yellow Sea Basin have developed in eastern China. They have been in a tectonic extension environment for a long time and it is difficult to form a compressional structural style. In recent years, reverse faults have been discovered in the Liaohe Depression, Liaodong Bay Depression, Jizhong Depression, Jiyang Depression, and Huanghua Depression in the Bohai Bay Basin; and in the Jinhu Depression and Gaoyou Depression in the Subei Basin.

[0003] The genesis mechanism of reverse faults in extensional basins can be roughly divided into four types: strike-slip induction, fluid extrusion, gravity sliding, and tectonic inversion. The strike-slip induction is a combination of faults with strike-slip properties, and the resulting structural styles are complex and diverse. The bending of the strike-slip fault in the plane will produce a compression component, forming a positive flower-shaped reverse fault in the section. The fluid extrusion is a geometric deformation feature caused by diapir structure. Diapirs are found more in depressions. Faults slip in the salt layer, resulting in the local vertical migration and aggregation of salt layers, forming an arched anticline structure, and the plastic flow of salt rock forms local compression-induced reverse faults. The gravity sliding is caused by the fact that during the basement extension and tilting movement, due to sedimentation, settlement and other reasons, the semi-consolidated stratified sediments slide along the fault as a whole under the action of gravity and thrust backward to form a structure. The tectonic inversion is caused by the deformation of folds and thrust structures after the graben and half-graben structures controlled by the normal fault system are compressed.

[0004] At present, the identification technology of oil-bearing traps controlled by reverse faults in extensional basins is mainly based on high-precision three-dimensional seismic data, and the structural interpretation method is applied under the guidance of structural theory to study the oil-bearing traps controlled by reverse faults. However, due to the relatively messy phase axis of seismic data, there are multiple solutions for the structural interpretation scheme using seismic phase axis offset, which brings a lot of uncertainty to the identification of oil-bearing traps controlled by reverse faults, resulting in the inability to accurately identify the traps. Summary of the invention

[0005] The purpose of the present invention is to provide a method for identifying oil-bearing traps controlled by reverse faults, so as to solve the problem that the existing methods for identifying oil-bearing traps controlled by reverse faults cannot accurately identify traps.

[0006] In order to solve the above technical problems, the present invention provides a method for identifying oil-bearing traps controlled by reverse faults, which method comprises the following steps:

[0007] Step 1), regional structural interpretation is performed based on the seismic profile and drilling and logging data of the study area to determine the structural profile characteristics of the study area;

[0008] Step 2), according to the structural profile characteristics of the study area, obtain the plane distribution map of syn-sedimentary faults in each period of the study area;

[0009] Step 3), determine the stress field model of each period in the study area according to the plane distribution diagram of syn-sedimentary faults in each period in the study area, and determine the zone where reverse faults are developed in the study area according to the salt rock development area in the study area;

[0010] Step 4), judging whether there is repeated formation based on the drilling data, and then combining at least one of the well logging and formation dip data to determine whether there is a reverse fault in the zone where the reverse fault is developed;

[0011] Step 5), finely characterize the reverse faults that are confirmed to exist, and determine the activity time and cause mechanism of the reverse faults;

[0012] Step 6) According to the activity time and genetic mechanism of the reverse fault and the oil and gas generation time and migration time of the oil reservoir in the reverse fault development zone, it is judged whether the conditions for becoming an oil-bearing trap are met, and whether there is an oil-bearing trap controlled by the reverse fault.

[0013] The beneficial effects of the above technical scheme are as follows: the present invention first determines the structural profile characteristics of the study area according to the seismic profile and drilling and logging data of the study area, determines the planar distribution diagram of syn-sedimentary faults in each period of the study area according to the structural profile characteristics, determines the stress field model of each period of the study area according to the planar distribution diagram of syn-sedimentary faults in each period of the study area, and predicts the zone of reverse fault development in the study area in combination with the salt rock development area of ​​the study area. Since salt rock can be used as a cap rock to seal and shield the closed space, the present invention first combines the stress field model and the salt rock development area for preliminary judgment, and optimizes the zone of reverse fault development. Then, in the zone of reverse fault development, comprehensive judgment factors such as earthquakes, drilling, logging and formation dip angle are comprehensively used to make comprehensive judgments from multiple aspects. Finally, the reverse faults that are confirmed to exist are finely characterized to determine their activity time and causal mechanism, thereby improving the accuracy of the identification results of oil-bearing traps in the near-sag zone of the reverse fault, and avoiding the problem of inaccurate identification of oil-bearing traps controlled by reverse faults due to the multi-solution and uncertainty caused by relying solely on seismic data information for structural interpretation.

[0014] Furthermore, in the step 4), after determining the existence of repeated formations based on the drilling data, it is then determined whether the logging curve characteristics between the repeated formations are similar based on the logging data, and whether the dip characteristics between the repeated formations are similar based on the formation dip data. If the logging curve characteristics and dip characteristics between the repeated formations are similar, it is determined that reverse faults exist in the zone where reverse faults are developed.

[0015] The beneficial effect of the above technical solution is that the accuracy of reverse fault identification is improved by judging whether there are repeated formations, whether the logging curve characteristics between repeated formations are similar, and whether the dip characteristics between repeated formations are similar.

[0016] Furthermore, in step 5), the reverse faults are finely characterized to obtain the planar distribution pattern of the reverse faults in each period, and the activity time and genetic mechanism of the reverse faults are determined in combination with the drilling data passing through the reverse faults.

[0017] The beneficial effect of the above technical solution is: in the area where the reverse faults are optimized, the reverse faults that are confirmed to exist are further finely characterized, and the activity time and causal mechanism of the reverse faults are jointly determined by combining the planar distribution law and the drilling data passing through the reverse faults, so as to accurately judge whether there are oil-bearing closures on the reverse faults.

[0018] Furthermore, in the step 3), based on the planar distribution diagram of syn-sedimentary faults in the study area in each period, the tectonic evolution method of superimposed basins and composite basins is used to establish the stress field model of the study area in each period.

[0019] The beneficial effects of the above technical solution are: based on the method of deducing structural superimposed basins and conforming basins at various times and locations, combined with the plane distribution diagram of syn-sedimentary faults in different periods in the study area, stress field models of different periods are established, which can clearly and unambiguously discover areas where reverse faults are developed.

[0020] Furthermore, in step 2), a fracture plane combination method is used to obtain the syn-sedimentary fracture plane distribution diagrams of the study area in different periods.

[0021] The beneficial effect of the above technical solution is: by constructing the syn-sedimentary fault plane distribution map of the study area in different periods through the method of fault plane combination, it can clearly and intuitively display the fracture conditions and dynamic evolution characteristics of faults under different stress conditions in different periods.

[0022] Furthermore, in step 1), a structural analysis method is used to interpret the regional structure based on the seismic profile and drilling and logging data of the study area to obtain a geological interpretation map of the seismic profile of the study area, and then converted into a geological profile through a velocity formula to determine the structural profile characteristics of the study area.

[0023] The beneficial effect of the above technical solution is that the geological structure profile characteristics of the study area can be accurately obtained through structural analysis and velocity formula.

[0024] Furthermore, after determining the existence of oil-bearing traps controlled by reverse faults, the oil-bearing characteristics of the traps controlled by reverse faults are obtained based on the favorable reservoir thickness in the zone where reverse faults are developed.

[0025] The beneficial effect of the above technical solution is that by studying the oil-bearing characteristics of the closure controlled by the reverse fault, it is possible to predict favorable exploration zones and targets based on the oil-bearing characteristics, point out the direction for detailed exploration near the depression, and avoid blind mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart corresponding to the reverse fault-controlled oil-bearing trap identification method of the present invention;

[0027] Figure 2 It is a geological interpretation map of the north-south large cross-section area of ​​the Dongpu Depression in an embodiment of the present invention;

[0028] Figure 3 It is a geological cross-section diagram of the north-south large cross-section area of ​​the Dongpu Depression of the present invention;

[0029] Figure 4 It is a geological interpretation map of the east-west large cross-section area of ​​the Dongpu Depression of the present invention;

[0030] Figure 5 It is a geological cross-section diagram of the east-west large cross-section area of ​​the Dongpu Depression of the present invention;

[0031] Figure 6-a It is the plane distribution diagram of the syn-sedimentary faults in the upper Sha II period of the Dongpu Depression of the present invention;

[0032] Figure 6-b It is the plane distribution diagram of the syn-sedimentary faults in the Shasanzhong 1-4 period of the Dongpu Depression of the present invention;

[0033] Figure 6-c It is the plane distribution diagram of the syn-sedimentary faults in the Lower Shah III period of the Dongpu Sag of the present invention;

[0034] Figure 6-d It is the plane distribution diagram of the syn-sedimentary faults in the Sha 4 period of the Dongpu Depression of the present invention;

[0035] Figure 7 It is the stress field model diagram of different periods of the present invention;

[0036] Figure 8 This is the structural paleogeographic map of the Upper Shashi period of the Dongpu Depression of the present invention;

[0037] Fig. 9 The present invention is a structural paleogeographic map of the Dongpu Depression during the Lower Shah III period;

[0038] Fig.10 This is the structural paleogeographic map of the Shasanzhong 1-4 period of the Dongpu Depression of the present invention;

[0039] Fig.11 It is a structural interpretation diagram of the seismic profile constructed under the normal fault scheme in the prior art;

[0040] Fig.12 It is a seismic profile structural interpretation diagram of the structure under the reverse fault scheme of the present invention;

[0041] Fig.13 It is a comparison diagram of adjacent well strata of the present invention;

[0042] Fig.14 It is the comprehensive histogram of well logging of the present invention;

[0043] Fig.15 is a formation dip diagram of the present invention;

[0044] Fig.16 is a reverse fault plane layout diagram of the present invention;

[0045] Fig.17 is a cross-sectional view of a single well reservoir through a reverse fault of the present invention;

[0046] Fig.18 It is a distribution map of favorable exploration targets of the present invention. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the present invention more clear, the specific implementation methods of the present invention are further described below in conjunction with the accompanying drawings.

[0048] The present invention first obtains the planar distribution diagram of syn-sedimentary faults in each period of the study area according to the seismic data and drilling and logging data of the study area, and then establishes the stress field model of each period of the study area, and then obtains the zone where the reverse faults are developed in the study area in combination with the salt rock development area of ​​the study area; then, the reverse faults developed in the zone are identified by comprehensively using the seismic data interpretation, drilling formation comparison, logging curve response, formation dip angle and other data, and finally, the distribution law and causal mechanism of the reverse faults are clarified through the fine characterization of the reverse faults, and then the oil-bearing closures controlled by the reverse faults are determined, thereby improving the accuracy of the identification results of the oil-bearing closures in the near-sag zone of the reverse faults, and avoiding the problem of inaccurate identification of the oil-bearing closures controlled by the reverse faults due to the multi-solution and uncertainty caused by relying solely on the seismic data information for structural interpretation.

[0049] Specifically, the flowchart corresponding to the reverse fault-controlled oil-bearing trap identification method is as follows: Figure 1 As shown, the specific implementation method of this method is described in detail below using a depression in a basin in my country as an example. It includes the following steps:

[0050] 1. Using structural analysis methods, regional structural interpretation is carried out based on seismic profiles and drilling and logging data in the study area, and a geological interpretation map of the seismic profile of the study area is obtained. The map is converted into a geological profile map through the velocity formula to determine the current structural profile characteristics of the study area, including fault positions, fault attitudes, and fault-cutting strata relationships.

[0051] Figure 2 This is a geological interpretation map of the north-south large section area of ​​the Dongpu Sag. Figure 3 This is a geological cross-section of the north-south large cross-section area of ​​the Dongpu Depression. Figure 2 and Figure 3 It can be determined that on the north-south regional connecting survey line, the northern and southern areas are large anticlines; the central area is a large syncline, with small anticlines in some parts. The compression amplitude was large at the end of the Triassic, and the north-south division was obvious.

[0052] Figure 4 This is a geological interpretation map of the east-west large section area of ​​the Dongpu Sag. Figure 5 This is a geological cross-section of the east-west large cross-section area of ​​the Dongpu Depression. Figure 4 and Figure 5 It can be determined that on the east-west main survey line, weak compression and thrust developed vertically from east to west before the Paleogene, strong tension developed during the fourth and third stages of the Shahejie Formation, and right-lateral strike-slip and weak tension developed during the second stage of the Shahejie Formation and thereafter, with obvious east-west zoning.

[0053] The Wendong Fault is gentle on the upper side and steep on the lower side, nearly vertical, pinching out upward in the Quaternary and Neogene, and pinching out downward in the Carboniferous-Permian System, with multiple reverse adjustment faults developed in the hanging wall. The Wenxi Fault pinches out upward below the Quaternary and Neogene System, and intersects with the east-dipping Shijiaji Fault downward.

[0054] 2. According to the characteristics of the structural profile of the study area, the fracture planes are combined to obtain the distribution of the syn-sedimentary fracture planes in the study area at different periods and in different stress directions.

[0055] According to the geological profile, the fracture planes are combined to obtain the syn-sedimentary fracture plane distribution diagrams of the four periods, such as Figure 6-a The planar distribution of syn-sedimentary faults in the upper Shahejie period in the Dongpu Sag is shown in the figure. Figure 6-b The plane distribution of syn-sedimentary faults during the Shasanzhong 1-4 period in the Dongpu Sag is shown in the figure. Figure 6-c The planar distribution of syn-sedimentary faults in the Lower Shahejie Period in the Dongpu Sag is shown in Figure 1. Figure 6-d The plane distribution of synsedimentary faults in the Dongpu Depression during the Sha 4 period is shown in the figure. According to the plane distribution of synsedimentary faults during these four periods, it can be concluded that under the influence of the east-west fold basement, the fault activity in the Paleogene has staged and segmented changes: the Sha 4 period is a single faulted large depression with strong tension; the lower Sha 3 period and the middle Sha 3 1-4 period are strong tension and weak strike-slip, and the faults in the middle area show lateral formations; in the upper Sha 2 and later periods, the tensile stress is weakened and the strike-slip stress is strengthened, and obvious fault feather intersections can be seen in the middle area. That is, the strike-slip stress gradually strengthened in the Paleogene, the secondary and tertiary faults continued to evolve, and the single faulted large depression changed to multiple faults, multiple convexities and multiple depressions.

[0056] 3. Using the research methods of superimposed basin and composite basin tectonic evolution, combined with the planar distribution diagrams of syn-sedimentary faults in different periods, the stress field models of the study area in different periods are established; and combined with the salt rock development area in the study area, the zones of reverse fault development in the study area are predicted.

[0057] Among them, superimposed basins are evolved according to the tectonic evolution at the same position in different periods, and complex basins are evolved according to the tectonic evolution at different positions in the same period. The present invention uses the research method of the tectonic evolution of superimposed basins and composite basins for inversion, and combines the plane distribution diagrams of syn-sedimentary faults in different periods to establish stress field models for the study area in different periods. The model can clearly show the different stresses and stratigraphic occurrences in each period, and because of the push effect of salt rock fluid, it can also serve as the dynamic background for the development of reverse faults. Since salt rock can be used as a cap rock to seal and shield the enclosed space, the present invention combines the stress field model and the salt rock development area for preliminary judgment, so as to judge whether the study area is prone to reverse fault development according to the stress field model.

[0058] like Figure 7 As shown in the figure, the Dongpu Sag was subjected to near north-south compression stress during the Indosinian period, forming a north-south tectonic pattern, and a thrust fault system with a near east-west distribution was developed; in the Yanshanian period, it was subjected to near east-west weak compression to form the prototype of the east-west zoning, and a near northeast thrust fault system was developed; during the sedimentary period of the fourth to third members of the Paleogene Shahejie Formation, under the near east-west strong tension, the structural characteristics of the east-west zoning and fault-controlled depression were formed, and a near northeast strong tension fault system was developed; from the sedimentary period of the second member of the Paleogene Shahejie Formation to the present, the tension weakened, the right-lateral strike-slip effect in the middle area strengthened, forming a complex fault block group, developing a right-lateral strike-slip-weak compression fault system, and prone to reverse faults.

[0059] Then, combined with the development area of ​​the Paleogene salt rock in the Dongpu Depression, the reverse fault development zone in the study area was predicted. Figure 8-10 From the tectonic paleogeographic maps of the Dongpu Depression in different periods, it can be seen that salt rocks are mainly developed in the middle area. Therefore, it is predicted that the central area of ​​the Dongpu Depression has the stress conditions for the development of reverse faults under the Paleogene extensional stress.

[0060] 4. Determine whether there are repeated formations based on the drilling data. If there are repeated formations, combine at least one of the logging and formation dip data to determine whether there are reverse faults in the zone where reverse faults are developed. Specifically, through single well formation division and well connection comparison, obtain the breakpoint position of the reverse fault, the repeated section caused by the reverse fault, the repeated thickness and the repeated layer position to determine whether there are formation duplications in different strata; based on the logging curve response characteristics in the logging data, determine whether the logging curve characteristics of the repeated section caused by the reverse fault are similar to those of the formation with the corresponding repeated thickness above the reverse fault breakpoint. The logging curve includes:

[0061] 1) Curves for measuring rock properties: wellbore CAL, natural gamma GR and natural potential SP;

[0062] 2) Physical property curves: density RHOB, acoustic wave time difference AC and neutron porosity NPHI;

[0063] 3) Resistance curve;

[0064] 4) Oil and gas display curves: total hydrocarbon curve and methane curve.

[0065] Based on the formation dip data, it is determined whether the dip and dip characteristics between the reverse fault repeating segment and the formation of the corresponding repeated thickness above the reverse fault breakpoint are similar. If at least one of the data judgment conditions is met, it is determined that the reverse fault exists in the zone where the reverse fault is developed.

[0066] Taking the A depression zone in the middle area of ​​Dongpu Depression as an example, Fig.11 As shown in the figure, the existing technology interprets the Paleogene faults of the Dongpu Depression as normal faults, and believes that a series of normal faults developed in the downthrown plate of the Pu 31 fault. However, the cross-axis phenomenon occurs during the interpretation process. According to the reflection characteristics of the seismic wave group, the reverse fault scheme is considered to be relatively reasonable. Therefore, the reverse faults in the A depression zone are firstly finely interpreted, and the following is obtained: Fig.12 The seismic profile structural interpretation diagram is shown. Then, combined with other data, it is determined whether there are reverse faults in the zone where reverse faults are developed: A depression zone is divided by single well stratigraphy and well comparison. There are 10 wells with stratigraphic duplication in different layers of the Paleogene; Take the comparison of Pu 138-7 and Pu 159 wells in Shasanzhong 1 as an example. Fig.13 As shown, the breakpoint of the reverse fault in Well Pu 159 is at 3682m, and the stratum thickness of Sha 3 Zhong 1 is significantly thicker than that of Sha 3 Zhong 1 in the adjacent well Pu 138-7. The repeated section caused by the reverse fault is 3682-3728m, with a repeated thickness of 46m. The repeated layers are Sha 3 Shang 10 and part of Sha 3 Zhong 1. Fig.14 From the comprehensive logging histogram of Pu 159 well shown, it can be seen that in the repeated section 3682-3728m caused by the reverse fault, the curves for measuring rock lithology (CAL, GR, SP), physical property curves (RHOB, AC, NPHI), resistivity curves, oil and gas display curves (total hydrocarbons, methane), etc. are all significantly similar to those of 3636-3682m corresponding to the reverse fault breakpoint. Fig.15 From the Pu 159 well formation dip map shown, it can be seen that the reverse fault repeating section 3682-3728m and the corresponding 3636-3682m above the reverse fault breakpoint also have obvious similarities in their dip and dip characteristics. Therefore, it is judged that a reverse fault exists there.

[0067] 5. The number, overall trend, fault distance, extension distance, profile characteristics and plane characteristics of reverse faults are carefully characterized to obtain the plane distribution diagram of reverse faults in different periods and clarify the distribution law of reverse faults.

[0068] Taking the A depression zone as an example, the reverse faults there are analyzed in detail. There are 6 reverse faults on the east wing of the depression zone, 4 reverse faults on the west wing, a total of 10 reverse faults, with an overall trend of NNE, cutting the 6th sand group in the middle of Sha 3 to the 8th sand group in the lower part of Sha 2. The main reverse fault has a fault throw of 15-170 meters and an extension distance of 1.2-5.7km. The secondary reverse fault has a fault throw of 12-60 meters and an extension distance of 0.8-1.9km. The 6 reverse faults developed on the east wing of the depression zone have an eastward inclination, a fault throw of 20-170 meters, and an extension distance of 1.2-4.3km; among them, the No. 1, 2, and 3 reverse faults are the main faults, which are parallel in profile and intertwined in plane; 5 secondary small faults are developed on the east wing, which are parallel to the main fault in both plane and profile. The four reverse faults developed on the west wing of the depression zone have a fault throw of 12 to 170 meters and an extension distance of 0.5 to 5.7 km. Among them, No. 7 and No. 9 are the main faults, with a dip to the NW and a fault throw of 15 to 170 meters. The secondary fault is the Dongqing reverse fault with a fault throw of 12 to 60 meters. The No. 7 and No. 8 reverse faults are developed in a Y-shaped profile style, and the plane is an oblique combination; the No. 9 and No. 10 reverse faults are in an antagonistic relationship, and the plane is a herringbone. Fig.16 This is the plan distribution diagram of the reverse fault.

[0069] 6. Determine the strike of the reverse fault, the position of the disconnected strata and the thickness of the two plates at the breakpoint based on the planar distribution map of the reverse fault, drilling data and seismic axis reflection characteristics. Then determine the activity time of the reverse fault based on the thickness of the two plates at the breakpoint, and determine the causal mechanism of the reverse fault based on the strike of the reverse fault and the position of the disconnected strata.

[0070] Taking the reverse fault in the A depression as an example, the reverse fault breakpoint is 3682m, and the repeated section of the 1st sand group in the middle subsection of Sha 3 is 3682-3728m, with a fault distance of 46m. Fig.17 From the single well reservoir profile of the reverse fault, it can be seen that the stratum affected by the reverse fault activity is the third section of the Shahejie Formation, which has no control over the stratum deposition of the third section of the Shahejie Formation at that time. The fault is shovel-shaped and intersects downward on the Pucheng Fault Zone. It is a secondary fault with compression and torsion properties formed by the strike-slip movement of the Pucheng Fault System in the second section of the Shahejie Formation and later periods, and is manifested as a reverse fault. At the same time, salt rock is developed in the third section of the Shahejie Formation in this depression zone, and plastic flow deformation of the salt rock will occur under the action of gravity equilibrium sedimentation. In summary, the formation of the reverse fault in the A depression zone is mainly induced by strike-slip and controlled by the local push of salt rock fluids. The formation time is the deposition period of the second section of the Shahejie Formation and later.

[0071] 7. Based on the activity time and genetic mechanism of the reverse faults and the oil and gas generation time and migration time of the oil reservoirs in the reverse fault development zone, determine whether the conditions for becoming an oil-bearing trap are met and determine whether there is an oil-bearing trap controlled by the reverse fault.

[0072] Taking the above-mentioned A depression zone as an example, the reverse fault in the A depression zone was formed during the deposition period of the second member of the Shahejie Formation and later, which matches the oil and gas accumulation period of the A depression in the Dongpu Depression (the deposition period of the second member of the Shahejie Formation, the deposition period of the Dongying Formation, the deposition period of the Guantao Formation, and the deposition period of the Minghuazhen Formation), forming a good blocking effect on the migration and accumulation of oil and gas. Therefore, the trap controlled by the reverse fault contains oil.

[0073] 8. In areas where reverse faults are developed, the oil-bearing characteristics of the traps controlled by reverse faults are clarified in combination with the favorable reservoir thickness and oil-bearing data of the target strata, and favorable exploration zones and targets are predicted.

[0074] Taking the above-mentioned A depression zone as an example, according to the drilling, logging and oil testing data in the area, the lower limit standard of the physical properties of the oil layer in the A depression zone is determined to be porosity ≥ 10%. The effective reservoir is delineated according to the porosity ≥ 10%. It is predicted that the effective reservoir thickness of the 3rd and 4th sand groups in Shasanzhong in this depression zone is 10-30m. The thick value area is mainly developed in the lake fan and beach bar phase area, and is distributed in a strip shape on both sides of the fault. The local existence of reservoir sweet spots is conducive to oil and gas enrichment. According to the oil source comparison results of Wei 42 and Wei 43 blocks in the adjacent area, it is shown that the crude oil of the 1-4 sand groups in Shasanzhong comes from the source rocks in the same layer, which is a combination of self-generation, self-storage and self-capping, forming a closed, high-pressure independent reservoir system, showing a full depression oil-bearing situation. Through the dissection of the Wei 42-43 block and the Pu 138 block oil reservoir, it is divided into two sets of oil-dry systems and one set of oil-water system. The oil-dry layers and shales in the lower part of the 3rd and 4th sand groups of Sha3 are well developed, which are favorable exploration layers for tight oil and shale oil, and have the conditions for full depression exploration. According to the thickness of the formation, sandstone and oil layer in the depression zone revealed by Pu 159 well, in the area of ​​reverse fault blocking near the depression zone, it is predicted that the lake bottom fan thickness value area with shallow burial and relatively good physical properties in the east wing of the depression zone is a favorable exploration target. Fig.18 The distribution map of favorable exploration targets.

[0075] The present invention first obtains the planar distribution diagram of syn-sedimentary faults in each period of the study area based on the seismic data and drilling and logging data of the study area, and then establishes the stress field model of each period of the study area, and selects the zone where the reverse fault is developed by analyzing the stress field background, and uses the comprehensive research of seismic data interpretation, drilling formation comparison, logging curve response, formation dip angle and other data to finely characterize and identify the reverse faults developed in the zone, clarify the distribution law and cause mechanism of the reverse fault, and improve the accuracy of the identification result of the oil-bearing closure in the near-sag zone of the reverse fault, avoiding the problem of inaccurate identification of the oil-bearing closure controlled by the reverse fault due to the multi-solution and uncertainty caused by relying solely on seismic data information for structural interpretation. And by studying the oil-bearing characteristics of the closure controlled by the reverse fault in the near-sag zone, the favorable exploration zone and target are predicted, which points out the direction for the fine exploration of the near-sag.

Claims

1. A method for identifying oil-bearing traps controlled by reverse faults, characterized in that: The method comprises the following steps: Step 1), regional structural interpretation is performed based on the seismic profile and drilling and logging data of the study area to determine the structural profile characteristics of the study area; Step 2), according to the structural profile characteristics of the study area, obtain the plane distribution map of syn-sedimentary faults in each period of the study area; Step 3), determine the stress field model of each period in the study area according to the plane distribution diagram of syn-sedimentary faults in each period in the study area, and determine the zone where reverse faults are developed in the study area according to the salt rock development area in the study area; Step 4), judging whether there is repeated formation based on the drilling data, and then combining at least one of the well logging and formation dip data to determine whether there is a reverse fault in the zone where the reverse fault is developed; Step 5), finely characterize the reverse faults that are confirmed to exist, and determine the activity time and cause mechanism of the reverse faults; Step 6) According to the activity time and genetic mechanism of the reverse fault and the oil and gas generation time and migration time of the oil reservoir in the reverse fault development zone, it is judged whether the conditions for becoming an oil-bearing trap are met, and whether there is an oil-bearing trap controlled by the reverse fault.

2. The method for identifying oil-bearing traps controlled by reverse faults according to claim 1, characterized in that: In the step 4), after determining the existence of repeated formations based on the drilling data, it is then determined whether the logging curve characteristics between the repeated formations are similar based on the logging data, and whether the dip characteristics between the repeated formations are similar based on the formation dip data. If both the logging curve characteristics and the dip characteristics between the repeated formations are similar, it is determined that reverse faults exist in the zone where reverse faults are developed.

3. The method for identifying oil-bearing traps controlled by reverse faults according to claim 1, characterized in that: In the step 5), the reverse faults are finely characterized to obtain the planar distribution pattern of the reverse faults in each period, and the activity time and genetic mechanism of the reverse faults are determined in combination with the drilling data passing through the reverse faults.

4. The method for identifying oil-bearing traps controlled by reverse faults according to claim 1, characterized in that: In the step 3), based on the planar distribution diagram of syn-sedimentary faults in the study area in each period, the stress field model of the study area in each period is established by using the superimposed basin and composite basin tectonic evolution method.

5. The method for identifying oil-bearing traps controlled by reverse faults according to claim 1, characterized in that: In the step 2), the fracture plane combination method is used to obtain the syn-sedimentary fracture plane distribution diagrams of the study area in different periods.

6. The method for identifying oil-bearing traps controlled by reverse faults according to claim 1, characterized in that: In the step 1), the regional structural interpretation is carried out using the structural analysis method according to the seismic profile and drilling and logging data of the study area to obtain the geological interpretation map of the seismic profile of the study area, and then the map is converted into a geological profile through the velocity formula to determine the structural profile characteristics of the study area.

7. The method for identifying oil-bearing traps controlled by reverse faults according to claim 1, characterized in that: After determining the existence of oil-bearing traps controlled by reverse faults, the oil-bearing characteristics of the traps controlled by reverse faults are obtained based on the favorable reservoir thickness in the zone where reverse faults are developed.

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