A method for predicting target buried-hill reservoir formation based on transport system evaluation

Abstract

The present invention relates to the technical field of oil and gas exploration, and relates to a method for predicting the accumulation of target buried hills based on the evaluation of a conduction system, comprising the following steps: S1 characterizes the distribution of structural features of the target buried hill and identifies the type of conduction system; S2 establishes a conduction system evaluation parameter system according to the distribution of structural features of the target buried hill and the type of conduction system; S3 determines the weight of each evaluation parameter of the conduction system evaluation parameter system; S4 establishes a quantitative evaluation standard for the conduction system of the target buried hill, and obtains an evaluation conclusion of the corresponding target buried hill; S5 presets the corresponding relationship between the evaluation conclusion and the accumulation situation, and judges the accumulation situation of the target buried hill according to the evaluation conclusion of the target buried hill. The present invention can meet the quantitative evaluation of the conduction system of buried hill gas reservoirs, especially in the field of high temperature and high pressure, has a good application effect, can predict the accumulation situation of buried hill gas reservoirs, and provide a basis for exploration direction and zone prediction.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploration, and more specifically, to a method for predicting target buried hill reservoir formation conditions based on conduction system evaluation. Background Art

[0002] The transport system refers to the network of all pathways and related surrounding rocks that oil and gas go through during the migration from source rocks to traps, including connected sand bodies, faults, unconformities and their combinations. As a "bridge" between source rocks and oil and gas reservoirs, the transport system is a key controlling factor in the accumulation of oil and gas. Due to the complexity of factors affecting the transport system, the research level of the transport system is far lower than that of source rock conditions, traps and preservation conditions, and it has always been a weak link in the field of oil and gas research.

[0003] There are many research methods for the transport system of sandstone reservoirs, tight sandstone reservoirs and carbonate reservoirs in major onshore oil and gas fields at home and abroad. The transport system is analyzed from the perspective of the oil and gas migration process from the aspects of the combination relationship of transport elements, the classification of transport systems of oil and gas transport mechanisms, transport theoretical models and geochemical characteristics: the combination of transport elements and the establishment of theoretical models belong to semi-quantitative research, which mainly observes the morphology of seismic profiles, classifies the transport elements according to the combination style, and compares and analyzes the favorable transport system style; the geochemical characteristic method belongs to quantitative research, but since the acquisition of geochemical parameters on the oil and gas migration path requires a large amount of analytical test data, its research accuracy is difficult to guarantee when there are few sample test points, thus affecting the reliability of oil and gas resource evaluation and prediction of favorable exploration zones; the seismic attribute characterization method has a good quantitative evaluation effect, but it has high requirements on the resolution of the seismic data body and is highly dependent on the well calibration of adjacent wells. It is only applicable to research areas with a high degree of exploration. Therefore, the existing technology fails to directly study its combination type, spatiotemporal configuration and transport capacity from the perspective of source rock charging power and the transport system itself. At the same time, current research mainly focuses on the research and evaluation of tight sandstone gas reservoirs and a small amount of carbonate oil and gas reservoirs in onshore oil and gas fields. There is little research on judging the accumulation situation of buried hill gas reservoirs under the background of deep water, high temperature and high pressure based on the evaluation of the transport system. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiency that there is little research on the formation of buried-hill gas reservoirs under the background of deep water, high temperature and high pressure based on the evaluation of the transport system, and to provide a method for predicting the formation of target buried-hill gas reservoirs based on the evaluation of the transport system. The present invention can meet the quantitative evaluation of the transport system of buried-hill gas reservoirs in the field of high temperature and high pressure, especially, and has a good application effect. It can predict the formation of buried-hill gas reservoirs and provide a basis for exploration direction and zone prediction.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A method for predicting target buried-hill reservoir formation based on transport system evaluation specifically comprises the following steps:

[0007] S1: Describe the distribution of structural characteristics of the target buried hill and identify the type of transport system;

[0008] S2: Establish a transport system evaluation parameter system based on the distribution of target buried-hill structural characteristics and the type of transport system;

[0009] S3: Determine the weight of each evaluation parameter of the transport system evaluation parameter system;

[0010] S4: Establish quantitative evaluation criteria for the target buried-hill transport system and obtain the evaluation conclusion of the corresponding target buried-hill;

[0011] S5: The corresponding relationship between the preset evaluation conclusion and the reservoir formation situation is determined, and the reservoir formation situation of the target buried hill is determined according to the evaluation conclusion of the target buried hill.

[0012] The method of the present invention can be applied to target buried hills with relatively recent formation time, fast sedimentation rate, and generally developed high temperature and high pressure characteristics. The source rocks of these buried hills have the characteristics of high maturity, high pressure coefficient, and sufficient charging power, so they contribute greatly to the comprehensive performance of the transport system. The present invention is based on the distribution of the structural characteristics of the target buried hill and the type of the transport system, and integrates various transport system influencing factors, divides the transport system elements, establishes a transport system evaluation parameter system, clarifies and quantifies the transport system quantitative evaluation standard, so as to achieve the comprehensive evaluation of various transport system elements to predict the distribution law of the target buried hill oil and gas reservoir. The method of the present invention can meet the quantitative evaluation of the transport system of the buried hill gas reservoir in the field of high temperature and high pressure, especially with good application effect and easy operation. It can be promoted and applied to other buried hill natural gas exploration areas, especially for the prediction of the reservoir formation of the buried hill gas reservoir, and can provide a basis for the exploration direction and zone prediction.

[0013] Furthermore, the structural features in step S1 include one or more combinations of gully-source faults, sand bodies, structural ridges, unconformities, buried-hill fractures and step faults.

[0014] Furthermore, the distribution characterization method of the structural features in step S1 is specifically as follows: based on the three-dimensional seismic data body of the target buried-hill gas reservoir, the top interface seismic strata and fault system of the target buried-hill are interpreted and tracked, the top interface strata and fault interpretation data of the target buried-hill are obtained, and the structural feature distribution of the top interface of the target buried-hill is formed according to the top interface strata and fault interpretation data.

[0015] Furthermore, the method for identifying the type of the conduction system in step S1 is specifically as follows: based on the distribution of structural characteristics of the top interface of the target buried hill, the conduction system type of the target buried hill is identified according to the main conduction system types in petroleum geology, and then according to the spatial combination relationship of different conduction system types and their relationship with source rocks, the combination pattern of the conduction system type of the target buried hill is determined.

[0016] It should be noted that based on the three-dimensional seismic data body, the three-dimensional seismic data body work area of ​​the target buried hill can be established through seismic processing software (such as DSG, Petrel, etc.), and the two-dimensional profile interception function of the software can be used to intercept representative seismic profile reflection maps of the target buried hill and the surrounding source area in the seismic work area. Through the seismic profile reflection map of the target buried hill in the study area, the distribution of gully source faults, sand bodies and unconformity surfaces can be identified; based on the three-dimensional seismic data body, the seismic horizons and fault systems of the buried hill top interface are interpreted and tracked, and the horizons and faults of the buried hill top interface are obtained. According to the top interface horizon and fault interpretation data, the structural contour map of the buried hill top interface (i.e., the depth structural map without faults and the depth structural map with faults) is drawn. Based on the structural contour map of the buried hill top interface, the structural characteristics and structural ridges of the buried hill can be further identified. According to the main types of transport systems in petroleum geology (such as faults, unconformities, sand bodies, structural ridges, fractures, etc.), the target buried-hill transport system is identified, and then the combination style of the buried-hill transport system types is determined according to the spatial combination relationship of each transport system type and its relationship with the source rock, such as: the combination type of high-pressure injection of source rocks and long-distance composite transport of faults-sand bodies-unconformities-structural ridges, and the transport type dominated by high-pressure injection of source rocks and source-reservoir contact transport.

[0017] Furthermore, the evaluation parameters of the transport system in step S2 include hydrocarbon supply power parameters and transport performance parameters of the transport system itself;

[0018] The hydrocarbon supply dynamic parameters include source rock maturity and pressure coefficient;

[0019] The transport performance parameters of the transport system itself include transport efficiency parameters and hydrocarbon supply efficiency parameters; the transport efficiency parameters include the area of ​​the unconformity surface, the fault throw and dip angle of the channel source fault, and the area and thickness of the sand body; the hydrocarbon supply efficiency includes the length of the structural ridge and the distance of natural gas migration.

[0020] The present invention comprehensively considers two aspects: the hydrocarbon source rock hydrocarbon supply dynamic parameters and the conduction performance parameters of the conduction system itself: the source rock will show the characteristics of hydrocarbon generation and pressure increase during the hydrocarbon generation process, and this characteristic has reached a general consensus in the petroleum geology community. Therefore, for hydrocarbon generation depressions, after entering the hydrocarbon generation window, the maturity of the source rock and the pressure coefficient in the depression have a positive correlation, and it is generally believed that the residual pressure of the source rock in the depression can be used as the original power for oil and gas injection. Therefore, the present invention believes that the maturity of the source rock and the pressure coefficient are used to reflect the hydrocarbon supply dynamic parameters; for the conduction system transport performance parameters, the maturity of the source rock and the pressure coefficient are used to reflect the hydrocarbon supply dynamic parameters. In terms of conductivity, faults are the main channels for vertical migration of oil and gas, and unconformities and sand bodies are the main channels for lateral migration of oil and gas. These understandings have reached a consensus in the industry. Therefore, the present invention measures the vertical migration capacity of oil and gas by the fault distance and dip angle of the source fault, and measures the lateral migration capacity of oil and gas by the unconformity surface. At present, most studies have mentioned that structural ridges are the dominant path for long-distance migration of oil and gas, and believe that the closer to the hydrocarbon-generating depression, the higher the conductivity of the structural ridge. Therefore, the present invention measures the hydrocarbon supply efficiency of oil and gas transportation by the length of the structural ridge and the distance of natural gas migration.

[0021] Therefore, the characteristic parameters of the transportation system evaluation parameters are determined based on the hydrocarbon supply dynamics (i.e., maturity of source rocks and pressure coefficient), transportation efficiency of the transportation system (i.e., fault throw and dip of the channel source fault, sand body area and thickness, unconformity surface area) and hydrocarbon supply efficiency (i.e., length of structural ridge and natural gas migration distance).

[0022] The specific method for determining each parameter is as follows:

[0023] (1) Maturity and pressure coefficient of source rocks: When drilling data is available, the maturity and pressure coefficient of source rocks can be directly obtained through the vitrinite reflectance of source rocks and the formation pressure measurement data of drilling cables. When there is no drilling data in hydrocarbon-generating depressions, the maturity Ro and pore fluid pressure Pf of different types of source rocks (such as type III organic matter, or type III + part of type II) can be obtained through basin simulation to establish virtual wells, and then the formation pressure coefficient C can be calculated.

[0024] The formation pressure coefficient is calculated as shown in Formula 1:

[0025] C=Pf / ρgh (Formula 1)

[0026] Where: ρ is the density of water, kg / m 3 ; g is the acceleration due to gravity, m / s 2 ; h is the burial depth, m; Pf is the pore fluid pressure, MPa.

[0027] (2) Distance and dip of the gully source fault: Based on the three-dimensional seismic data volume in the work area, a seismic section perpendicular to the fault strike direction is intercepted in the seismic volume by intercepting the two-dimensional seismic section, and the two-way reflection time xline and inline values ​​in the software are read to calculate the distance L (Formula 2) and dip α (Expression 3) of each part of the section.

[0028] L = f(t 上 )-f(t 下 ) (Formula 2)

[0029] Where: L is the fault throw, m; f(t) is the time-depth conversion function of the study area, obtained based on the seismic velocity body or the wellbore seismic velocity body; t 上 is the round trip time of the upper plate breakpoint, ms; t 下 is the round trip time of the lower plate breakpoint, ms.

[0030] α=arctan (Δy / Δx) (Formula 3)

[0031] Among them, α represents the fault dip, Δy is the vertical distance between two points on the cross section (m), and Δx is the lateral distance between two points on the cross section (m).

[0032] (3) Area and thickness of sand bodies: Based on the three-dimensional seismic data in the work area, the distribution range and thickness of the sand bodies are determined through seismic sand body tracking.

[0033] Through the top and bottom envelope of the sand body, the corresponding sand body area is delineated, and the sand body thickness H 砂 Depth H through the top of the envelope 砂包络顶 and the depth H of the bottom of the envelope 砂包络底 , predicted or actual drilling sand content and other parameters are calculated as follows:

[0034] H 砂 =(H 砂包络底 -H 砂包络顶 )*Sand content (Formula 4)

[0035] (4) Unconformity surface area: The distribution range of unconformity surface can be determined by tracking the unconformity surface in the 3D seismic volume.

[0036] (5) Length of structural ridge: It is determined by measuring the structural contour map of the buried hill top.

[0037] (6) Distance of natural gas migration: refers to the horizontal distance from the gas generation center to the target trap in the buried hill. It can be calculated based on the hydrocarbon generation intensity results map of the main source rock (generally based on a relative scale gas generation intensity of 2 billion cubic meters / km2). 2 The boundary is determined) and the relationship between the buried hill target area is obtained together.

[0038] Furthermore, the method for determining the weight of each evaluation parameter of the transport system evaluation parameter system in step S3 is specifically: determining the contribution weight of each evaluation parameter of the transport system evaluation parameter system of the target buried hill to the migration and charging of natural gas according to the geological characteristics of the target buried hill.

[0039] Based on the reservoir formation of the drilled wells and the corresponding natural gas transportation conditions, the influence of each transportation system evaluation parameter is determined; based on the evaluation parameters of each transportation system and combined with the geological characteristics of the known buried-hill gas reservoirs, the weight of each transportation system evaluation parameter is determined.

[0040] Furthermore, the pressure intensity of each source rock is divided according to the pressure measurement data of the wells drilled in the area where the target buried hill is located or the pressure coefficient is calculated by basin simulation, and the weights corresponding to the hydrocarbon dynamic parameters are determined by the pressure intensity zoning; there is large-scale abnormally high pressure in the deep hydrocarbon-generating depressions of the target buried hill, which is caused by undercompaction and hydrocarbon generation pressurization and is the main power source for natural gas migration. Therefore, the pressure measurement data of the wells drilled in the area where the target buried hill is located can be integrated or the pressure coefficient is calculated by basin simulation, and the pressure intensity of each source rock can be divided, and the weights corresponding to the hydrocarbon dynamic parameters can be determined by the pressure intensity zoning.

[0041] The weights corresponding to the fault throw and dip of the gully source fault are determined by the zoning, staging and corresponding characteristics of the target buried hill. If there are many faults, small fault throw, unclear cross-section ridge, large dip and weak activity, the fault transport capacity is weak, and the amount of oil and gas migrating to the target buried hill is small. If there are few faults, large fault throw, developed cross-section ridge, small dip and strong activity, the fault transport capacity is strong, and the amount of oil and gas migrating to the target buried hill is large.

[0042] The weights corresponding to the area and thickness of the sand body are comprehensively determined by the scale and physical properties of the sand body. The sand body related to the migration of buried hill natural gas is obviously affected by the paleogeographic pattern of the sedimentary period. If the paleo-geomorphology is high, the burial time is early, and the material source is rich, it is easy to form a large number of sand body deposits with large areas. Therefore, the weights corresponding to the area and thickness of the sand body can be comprehensively determined by the scale and physical properties of the sand body.

[0043] The weight corresponding to the area of ​​the unconformity surface is comprehensively determined according to the scale and number of the unconformity surface;

[0044] The weight corresponding to the hydrocarbon supply efficiency is determined by the distance from the hydrocarbon generation center to the target buried hill.

[0045] Furthermore, the method for establishing the quantitative evaluation standard of the target buried hill conduction system in step S4 is:

[0046] S41: according to the effectiveness of each evaluation parameter of the transport system evaluation parameter system on the target buried hill reservoir formation, the evaluation parameters are divided into different zones and quantitatively weighted;

[0047] S42: determining actual values ​​of the evaluation parameters according to the actual values ​​of the evaluation parameters of the target buried hill;

[0048] S43: Calculating the weights of the evaluation parameters of the target buried hill and the actual values ​​of the parameters to obtain the score values ​​of the evaluation parameters of the target buried hill;

[0049] S44: Add the score values ​​of each evaluation parameter of the target buried hill to obtain an evaluation conclusion.

[0050] Furthermore, the partition quantitative weighting method in step S41 is:

[0051] Assign a score of 0-10 to each evaluation parameter of each target buried hill, and divide the score of 0-10 into 5 equal assignment intervals;

[0052] According to the effectiveness of the known actual statistical values ​​of each evaluation parameter on the target buried-hill reservoir formation, the actual statistical values ​​of each evaluation parameter are divided into corresponding assignment intervals.

[0053] It should be noted that the actual statistical values ​​of each evaluation parameter reflect the effectiveness of the target buried-hill reservoir, which is derived from the industry evaluation standards of the corresponding evaluation parameters. For example, the maturity of source rocks is determined by the boundaries of immature, mature, high maturity, and overmature, and different maturity levels have corresponding numerical critical points in the industry. Therefore, the division of each assignment interval can refer to the industry evaluation standards; such as the pressure coefficient is determined by the boundaries of no pressure, normal pressure, low-amplitude overpressure, overpressure, and strong overpressure; in addition, the relationship between the corresponding parameters and their conductivity can be determined. For example, by analyzing the relationship between parameters such as fault dip, sand body area, thickness, hydrocarbon supply distance and oil and gas conductivity, it is comprehensively determined to determine which assignment interval the actual statistical values ​​of each evaluation parameter should be divided into.

[0054] Furthermore, the correspondence between the preset evaluation conclusion and the reservoir formation situation in step S5 is: when the evaluation conclusion is greater than 6, the target buried hill has formed reservoirs; when the evaluation conclusion is between 5 and 6, the target buried hill has a certain migration; when the evaluation conclusion is less than 5, the target buried hill has not formed reservoirs.

[0055] It should be noted that certain migration means that the target buried hill has a certain oil and gas response, but it does not reach the scale of reservoir formation. The well logging interpretation is that the target buried hill has a gas-water layer or a gas-water layer.

[0056] The comprehensive evaluation conclusion of the present invention is displayed in the form of the numerical value of the scores of each evaluation parameter of the target buried hill. The comprehensive score value is in the range of 0 to 10 points. The higher the comprehensive score, the more conducive it is to oil and gas transportation and accumulation.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] (1) The method of the present invention can be applied to target buried hills with relatively recent formation time, fast sedimentation rate, and generally developed high temperature and high pressure characteristics. The source rocks of these buried hills have the characteristics of high maturity, high pressure coefficient, and sufficient charging power, and therefore contribute greatly to the comprehensive performance of the transport system. The present invention divides the elements of the transport system according to the distribution of the structural characteristics of the target buried hill and the type of the transport system, comprehensively considers the influencing factors of various transport systems, establishes a transport system evaluation parameter system, clarifies and quantifies the quantitative evaluation standards of the transport system, so as to achieve the prediction of the distribution law of the target buried hill oil and gas reservoir by comprehensively considering the elements of various transport systems.

[0059] (2) The method of the present invention can meet the requirements of quantitative evaluation of the transportation system of buried-hill gas reservoirs, especially in the field of high temperature and high pressure, has good application effect and is easy to operate. It can be promoted and applied to other buried-hill natural gas exploration areas, especially to predict the accumulation of buried-hill gas reservoirs, and can provide a basis for exploration direction and zone prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 is a flow chart of the steps of the method of the present invention;

[0061] Figure 2 The statistical table of characteristic parameters of each typical buried hill structure transport system in the Qiongdongnan Basin in Example 3;

[0062] Figure 3 The quantitative evaluation table of typical structural transport systems in the Qiongdongnan Basin in Example 3;

[0063] Figure 4 This is a quantitative evaluation standard table for the transportation system in the Qiongdongnan Basin in Example 3.

[0064] The illustrations are as follows: DETAILED DESCRIPTION

[0065] The present invention is further described below in conjunction with specific implementation methods. The accompanying drawings are only used for exemplary descriptions and are only schematic diagrams, not actual drawings, and cannot be understood as limiting this patent; in order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the accompanying drawings may be omitted.

[0066] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0067] Example 1

[0068] like Figure 1 As shown, a method for predicting the target buried-hill reservoir formation based on the evaluation of the transport system specifically includes the following steps:

[0069] S1: Describe the distribution of structural characteristics of the target buried hill and identify the type of transport system;

[0070] S2: Establish a transport system evaluation parameter system based on the distribution of target buried-hill structural characteristics and the type of transport system;

[0071] S3: Determine the weight of each evaluation parameter of the transport system evaluation parameter system;

[0072] S4: Establish quantitative evaluation criteria for the target buried-hill transport system and obtain the evaluation conclusion of the corresponding target buried-hill;

[0073] S5: The corresponding relationship between the preset evaluation conclusion and the reservoir formation situation is determined, and the reservoir formation situation of the target buried hill is determined according to the evaluation conclusion of the target buried hill.

[0074] The method of the present application can be applied to target buried hills with a relatively recent formation time, fast sedimentation rate, and generally developed high temperature and high pressure characteristics. The source rocks of these buried hills have the characteristics of high maturity, high pressure coefficient, and sufficient charging power, and therefore contribute greatly to the comprehensive performance of the transport system. The present invention is based on the distribution of the structural characteristics of the target buried hill and the type of the transport system, and integrates various transport system influencing factors, divides the elements of the transport system, establishes a transport system evaluation parameter system, clarifies and quantifies the quantitative evaluation standards of the transport system, so as to achieve the prediction of the distribution law of the target buried hill oil and gas reservoir by integrating the elements of each transport system. The method of the present application can meet the quantitative evaluation of the transport system of buried hill gas reservoirs, especially in the field of high temperature and high pressure, has good application effect, and is easy to operate. It can be promoted and applied to other buried hill natural gas exploration areas, especially for predicting the accumulation of buried hill gas reservoirs, and can provide a basis for exploration direction and zone prediction.

[0075] Specifically, the structural features in step S1 include one or more combinations of gully-source faults, sand bodies, structural ridges, unconformity surfaces, buried-hill fractures and step faults.

[0076] Specifically, the distribution characterization method of the structural features in step S1 is as follows: based on the three-dimensional seismic data body of the target buried-hill gas reservoir, the top interface seismic strata and fault system of the target buried-hill are interpreted and tracked, the top interface strata and fault interpretation data of the target buried-hill are obtained, and the structural feature distribution of the top interface of the target buried-hill is formed according to the top interface strata and fault interpretation data.

[0077] Specifically, the method for identifying the type of the conduction system in step S1 is as follows: based on the distribution of structural characteristics of the top interface of the target buried hill, the conduction system type of the target buried hill is identified according to the main conduction system types in petroleum geology, and then according to the spatial combination relationship of different conduction system types and their relationship with source rocks, the combination pattern of the conduction system type of the target buried hill is determined.

[0078] It should be noted that based on the three-dimensional seismic data body, the three-dimensional seismic data body work area of ​​the target buried hill can be established through seismic processing software (such as DSG, Petrel, etc.), and the two-dimensional profile interception function of the software can be used to intercept representative seismic profile reflection maps of the target buried hill and the surrounding source area in the seismic work area. Through the seismic profile reflection map of the target buried hill in the study area, the distribution of gully source faults, sand bodies and unconformity surfaces can be identified; based on the three-dimensional seismic data body, the seismic horizons and fault systems of the buried hill top interface are interpreted and tracked, and the horizons and faults of the buried hill top interface are obtained. According to the top interface horizon and fault interpretation data, the structural contour map of the buried hill top interface (i.e., the depth structural map without faults and the depth structural map with faults) is drawn. Based on the structural contour map of the buried hill top interface, the structural characteristics and structural ridges of the buried hill can be further identified. According to the main types of transport systems in petroleum geology (such as faults, unconformities, sand bodies, structural ridges, fractures, etc.), the target buried-hill transport system is identified, and then the combination style of the buried-hill transport system types is determined according to the spatial combination relationship of each transport system type and its relationship with the source rock, such as: the combination type of high-pressure injection of source rocks and long-distance composite transport of faults-sand bodies-unconformities-structural ridges, and the transport type dominated by high-pressure injection of source rocks and source-reservoir contact transport.

[0079] Specifically, the evaluation parameters of the transport system in step S2 include hydrocarbon supply power parameters and transport performance parameters of the transport system itself;

[0080] The hydrocarbon supply dynamic parameters include source rock maturity and pressure coefficient;

[0081] The transport performance parameters of the transport system itself include transport efficiency parameters and hydrocarbon supply efficiency parameters; the transport efficiency parameters include the area of ​​the unconformity surface, the fault throw and dip angle of the channel source fault, and the area and thickness of the sand body; the hydrocarbon supply efficiency includes the length of the structural ridge and the distance of natural gas migration.

[0082] The present application comprehensively considers two aspects: the hydrocarbon source rock hydrocarbon supply dynamic parameters and the conduction performance parameters of the conduction system itself: the source rock will show the characteristics of hydrocarbon generation and pressure increase during the hydrocarbon generation process, and this characteristic has reached a general consensus in the petroleum geology community. Therefore, for hydrocarbon generation depressions, after entering the hydrocarbon generation window, the maturity of the source rock and the pressure coefficient in the depression have a positive correlation, and it is generally believed that the residual pressure of the source rock in the depression can be used as the original power for oil and gas injection. Therefore, the present invention believes that the maturity of the source rock and the pressure coefficient are used to reflect the hydrocarbon supply dynamic parameters; for the conduction system transport performance parameters, the maturity of the source rock and the pressure coefficient are used to reflect the hydrocarbon supply dynamic parameters. In terms of conductivity, faults are the main channels for vertical migration of oil and gas, and unconformities and sand bodies are the main channels for lateral migration of oil and gas. These understandings have reached a consensus in the industry. Therefore, this application measures the vertical migration capacity of oil and gas by the fault distance and dip angle of the ditch source fault, and measures the lateral migration capacity of oil and gas by the unconformity surface. At present, most studies have mentioned that structural ridges are the dominant path for long-distance migration of oil and gas, and believe that the closer to the hydrocarbon-generating depression, the higher the conductivity of the structural ridge. Therefore, this application measures the hydrocarbon supply efficiency of oil and gas transportation by the length of the structural ridge and the distance of natural gas migration.

[0083] Therefore, the characteristic parameters of the transportation system evaluation parameters are determined based on the hydrocarbon supply dynamics (i.e., maturity of source rocks and pressure coefficient), transportation efficiency of the transportation system (i.e., fault throw and dip of the channel source fault, sand body area and thickness, unconformity surface area) and hydrocarbon supply efficiency (i.e., length of structural ridge and natural gas migration distance).

[0084] Specifically, the method for determining the weight of each evaluation parameter of the transport system evaluation parameter system in step S3 is: determining the contribution weight of each evaluation parameter of the transport system evaluation parameter system of the target buried hill to the migration and charging of natural gas according to the geological characteristics of the target buried hill.

[0085] Based on the reservoir formation of the drilled wells and the corresponding natural gas transportation conditions, the influence of each transportation system evaluation parameter is determined; based on the evaluation parameters of each transportation system and combined with the geological characteristics of the known buried-hill gas reservoirs, the weight of each transportation system evaluation parameter is determined.

[0086] Specifically, the pressure intensity of each source rock is divided according to the pressure measurement data of the wells drilled in the area where the target buried hill is located or the pressure coefficient is calculated by basin simulation, and the weights corresponding to the hydrocarbon dynamic parameters are determined by the pressure intensity zoning; there is large-scale abnormally high pressure in the deep hydrocarbon-generating depressions of the target buried hill, which is caused by undercompaction and hydrocarbon generation pressurization and is the main power source for natural gas migration. Therefore, the pressure measurement data of the wells drilled in the area where the target buried hill is located can be integrated or the pressure coefficient is calculated by basin simulation, and the pressure intensity of each source rock can be divided, and the weights corresponding to the hydrocarbon dynamic parameters can be determined by the pressure intensity zoning.

[0087] The weights corresponding to the fault throw and dip of the gully source fault are determined by the zoning, staging and corresponding characteristics of the target buried hill. If there are many faults, small fault throw, unclear cross-section ridge, large dip and weak activity, the fault transport capacity is weak, and the amount of oil and gas migrating to the target buried hill is small. If there are few faults, large fault throw, developed cross-section ridge, small dip and strong activity, the fault transport capacity is strong, and the amount of oil and gas migrating to the target buried hill is large.

[0088] The weights corresponding to the area and thickness of the sand body are comprehensively determined by the scale and physical properties of the sand body. The sand body related to the migration of buried hill natural gas is obviously affected by the paleogeographic pattern of the sedimentary period. If the paleo-geomorphology is high, the burial time is early, and the material source is rich, it is easy to form a large number of sand body deposits with large areas. Therefore, the weights corresponding to the area and thickness of the sand body can be comprehensively determined by the scale and physical properties of the sand body.

[0089] The weight corresponding to the area of ​​the unconformity surface is comprehensively determined according to the scale and number of the unconformity surface;

[0090] The weight corresponding to the hydrocarbon supply efficiency is determined by the distance from the hydrocarbon generation center to the target buried hill.

[0091] Specifically, the method for establishing the quantitative evaluation standard of the target buried hill conduction system in step S4 is:

[0092] S41: according to the effectiveness of each evaluation parameter of the transport system evaluation parameter system on the target buried hill reservoir formation, the evaluation parameters are divided into different zones and quantitatively weighted;

[0093] S42: determining actual values ​​of the evaluation parameters according to the actual values ​​of the evaluation parameters of the target buried hill;

[0094] S43: Calculating the weights of the evaluation parameters of the target buried hill and the actual values ​​of the parameters to obtain the score values ​​of the evaluation parameters of the target buried hill;

[0095] S44: Add the score values ​​of each evaluation parameter of the target buried hill to obtain an evaluation conclusion.

[0096] Specifically, the partition quantitative weighting method in step S41 is:

[0097] Assign a score of 0-10 to each evaluation parameter of each target buried hill, and divide the score of 0-10 into 5 equal assignment intervals;

[0098] According to the effectiveness of the known actual statistical values ​​of each evaluation parameter on the target buried-hill reservoir formation, the actual statistical values ​​of each evaluation parameter are divided into corresponding assignment intervals.

[0099] It should be noted that the actual statistical values ​​of each evaluation parameter reflect the effectiveness of the target buried-hill reservoir, which is derived from the industry evaluation standards of the corresponding evaluation parameters. For example, the maturity of source rocks is determined by the boundaries of immature, mature, high maturity, and overmature, and different maturity levels have corresponding numerical critical points in the industry. Therefore, the division of each assignment interval can refer to the industry evaluation standards; such as the pressure coefficient is determined by the boundaries of no pressure, normal pressure, low-amplitude overpressure, overpressure, and strong overpressure; in addition, the relationship between the corresponding parameters and their conductivity can be determined. For example, by analyzing the relationship between parameters such as fault dip, sand body area, thickness, hydrocarbon supply distance and oil and gas conductivity, it is comprehensively determined to determine which assignment interval the actual statistical values ​​of each evaluation parameter should be divided into.

[0100] Specifically, the correspondence between the preset evaluation conclusion and the reservoir formation situation in step S5 is: when the evaluation conclusion is greater than 6, the target buried hill has formed reservoirs; when the evaluation conclusion is between 5 and 6, the target buried hill has a certain migration; when the evaluation conclusion is less than 5, the target buried hill has not formed reservoirs.

[0101] It should be noted that certain migration means that the target buried hill has a certain oil and gas response, but it does not reach the scale of reservoir formation. The well logging interpretation is that the target buried hill has a gas-water layer or a gas-water layer.

[0102] The comprehensive evaluation conclusion of this application is presented in the form of numerical scores of various evaluation parameters of the target buried hill. The comprehensive score ranges from 0 to 10 points. The higher the comprehensive score, the more conducive it is to oil and gas transportation and accumulation.

[0103] Example 2

[0104] This embodiment is similar to Embodiment 1, except that in this embodiment:

[0105] The evaluation parameters of the transport system in step S2 include hydrocarbon supply power parameters and transport performance parameters of the transport system itself;

[0106] The hydrocarbon supply dynamic parameters include source rock maturity and pressure coefficient;

[0107] The transport performance parameters of the transport system itself include transport efficiency parameters and hydrocarbon supply efficiency parameters; the transport efficiency parameters include the area of ​​the unconformity surface, the fault throw and dip angle of the channel source fault, and the area and thickness of the sand body; the hydrocarbon supply efficiency includes the length of the structural ridge and the distance of natural gas migration.

[0108] Specifically, the specific method for determining each parameter is as follows:

[0109] (1) Maturity and pressure coefficient of source rocks: When drilling data is available, the maturity and pressure coefficient of source rocks can be directly obtained through the vitrinite reflectance of source rocks and the formation pressure measurement data of drilling cables. When there is no drilling data in hydrocarbon-generating depressions, the maturity Ro and pore fluid pressure Pf of different types of source rocks (such as type III organic matter, or type III + part of type II) can be obtained through basin simulation to establish virtual wells, and then the formation pressure coefficient C can be calculated.

[0110] The formation pressure coefficient is calculated as shown in Formula 1:

[0111] C=Pf / ρgh (Formula 1)

[0112] Where: ρ is the density of water, kg / m 3 ; g is the acceleration due to gravity, m / s 2 ; h is the burial depth, m; Pf is the pore fluid pressure, MPa.

[0113] (2) Distance and dip of the gully source fault: Based on the three-dimensional seismic data volume in the work area, a seismic section perpendicular to the fault strike direction is intercepted in the seismic volume by intercepting the two-dimensional seismic section, and the two-way reflection time xline and inline values ​​in the software are read to calculate the distance L (Formula 2) and dip α (Expression 3) of each part of the section.

[0114] L = f(t 上 )-f(t 下 ) (Formula 2)

[0115] Where: L is the fault throw, m; f(t) is the time-depth conversion function of the study area, obtained based on the seismic velocity body or the wellbore seismic velocity body; t 上 is the round trip time of the upper plate breakpoint, ms; t 下 is the round trip time of the lower plate breakpoint, ms.

[0116] α=arctan (Δy / Δx) (Formula 3)

[0117] Among them, α represents the fault dip, Δy is the vertical distance between two points on the cross section (m), and Δx is the lateral distance between two points on the cross section (m).

[0118] (3) Area and thickness of sand bodies: Based on the three-dimensional seismic data in the work area, the distribution range and thickness of the sand bodies are determined through seismic sand body tracking.

[0119] Through the top and bottom envelope of the sand body, the corresponding sand body area is delineated, and the sand body thickness H 砂 Depth H through the top of the envelope 砂包络顶 and the depth H of the bottom of the envelope 砂包络底 , predicted or actual drilling sand content and other parameters are calculated as follows:

[0120] H 砂 =(H 砂包络底 -H 砂包络顶 )*Sand content (Formula 4)

[0121] (4) Unconformity surface area: The distribution range of unconformity surface can be determined by tracking the unconformity surface in the 3D seismic volume.

[0122] (5) Length of structural ridge: It is determined by measuring the structural contour map of the buried hill top.

[0123] (6) Distance of natural gas migration: refers to the horizontal distance from the gas generation center to the target trap in the buried hill. It can be calculated based on the hydrocarbon generation intensity results map of the main source rock (generally based on a relative scale gas generation intensity of 2 billion cubic meters / km2). 2 The boundary is determined) and the relationship between the buried hill target area is obtained together.

[0124] Example 3

[0125] This embodiment is similar to the embodiment 1, except that this embodiment is specifically applied to the deepwater buried hill area in the Qiongdongnan Basin in the northern South China Sea, and is used to evaluate the exploration and transportation conditions and reservoir formation of buried hill natural gas in the area:

[0126] The method for establishing the quantitative evaluation standard of the target buried hill conduction system in step S4 is as follows:

[0127] Specifically, all evaluation parameters in the deepwater buried hill area of ​​the Qiongdongnan Basin in the northern South China Sea are assigned scores of 0-10, and the higher the score, the better the conductivity. The evaluation parameters of the conductivity system evaluation parameter system are assigned values ​​according to their different assignment intervals. The assignment standard is formulated based on the effectiveness of the key parameters of each conductivity system on the target structure reservoir, such as Figure 4 As shown in the figure, the comprehensive evaluation of the transport system of the buried hill gas reservoir is finally obtained by combining the weight proportion of the target buried hill structural transport system and the actual score of each evaluation parameter. The comprehensive evaluation result is presented in the form of the numerical value of the target structural transport comprehensive score. The comprehensive score value is in the range of 0 to 10 points. The higher the comprehensive score, the more conducive it is to oil and gas transport and accumulation.

[0128] Based on the three-dimensional seismic data volume of the Qiongdongnan Basin, the seismic horizon and fault system of the target buried hill top interface T100 are interpreted and tracked, and the top interface horizon and fault interpretation data of the target buried hill are obtained. According to the top interface horizon and fault interpretation data, the structural characteristic distribution of the top interface of the target buried hill is formed. According to the top interface horizon and fault interpretation data, the structural contour map of the top interface of the buried hill is drawn (i.e., the deep structural map without faults and the deep structural map with faults), and then the migration channel type of the buried hill natural gas reservoir is identified, and it is determined that this embodiment includes a certain type or a combination of several types of "ditch source faults, sand bodies, structural ridges, unconformities, and buried hill fractures" in the transport system, and it is found that the transport conditions of the buried hills in different areas of the Qiongdongnan Basin are quite different.

[0129] Among them, the Songnan low uplift is characterized by high-pressure charging and strong charging power, with long-distance composite transport of fault-sand-unconformity-structural ridge, and various types of transport channels, with sand body transport being the dominant one; the Lingnan low uplift is adjacent to the Ledong sag, which has a large scale, high maturity, and sufficient gas source. The natural gas migration distance is relatively short, and it belongs to the transport type dominated by source-reservoir contact transport. The transport channel types are relatively single, with fault transport being the dominant one.

[0130] like Figure 2 As shown in the figure, the evaluation parameters of the transport system evaluation parameter system corresponding to the relevant drilling statistics include the maturity and pressure coefficient of source rocks, the fault throw and dip of source faults, the area and thickness of sand bodies, the area of ​​unconformity surfaces, the length of structural ridges and the distance from source rocks.

[0131] like Figure 3 As shown in the figure, corresponding to the evaluation results of the typical structures of the drilled wells, the comprehensive score of the transport system is consistent with the reservoir formation. The sand body in the Y8 area of ​​the Songnan Low Uplift has a large contribution and a high comprehensive score. Therefore, it can be known that the target buried hill has formed reservoirs. The L32 well in the Lingnan Low Uplift has sufficient hydrocarbon supply power. Combined with the moderate fault throw and dip angle of the ditch source fault and the structural ridge, the comprehensive score is high and the reservoir has formed. Under the background of sufficient hydrocarbon supply power, the dip angle of the ditch source fault is large, resulting in a small lateral migration component of the buried hill, and the comprehensive score is relatively low. Therefore, it can be known that there is a certain migration in the target buried hill. The other failed wells have a limited scale of the transport system or lack of one or several types of transport elements, resulting in low comprehensive scores and no reservoir formation in the buried hill section.

[0132] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for predicting target buried-hill reservoir formation based on transport system evaluation, characterized in that: The specific steps include: S1: Describe the distribution of structural features of the target buried hill and identify the type of transport system; the structural features include one or more combinations of gully source faults, sand bodies, structural ridges, unconformity surfaces, buried hill fractures and step faults; S2: Establish a transport system evaluation parameter system according to the distribution of the target buried hill structural characteristics and the type of transport system; the transport system evaluation parameters include hydrocarbon supply dynamic parameters and transport performance parameters of the transport system itself; the hydrocarbon supply dynamic parameters include the maturity and pressure coefficient of the source rock; the transport performance parameters of the transport system itself include transport efficiency parameters and hydrocarbon supply efficiency parameters; the transport efficiency parameters include the area of ​​the unconformity surface, the fault throw and dip of the channel source fault, and the area and thickness of the sand body; the hydrocarbon supply efficiency includes the length of the structural ridge and the distance of natural gas migration; S3: Determine the weight of each evaluation parameter of the transport system evaluation parameter system; S4: establishing a quantitative evaluation standard for the target buried-hill conduction system and obtaining an evaluation conclusion of the corresponding target buried-hill; the method for establishing the quantitative evaluation standard for the target buried-hill conduction system is as follows: S41: partitioning and quantitatively weighting each evaluation parameter of the conduction system evaluation parameter system according to its effectiveness on the target buried-hill reservoir formation; S42: determining actual values ​​of the evaluation parameters according to the actual values ​​of the evaluation parameters of the target buried hill; S43: Calculate the weights of the evaluation parameters of the target buried hill and the actual values ​​of the parameters to obtain the score values ​​of the evaluation parameters of the target buried hill; S44: Add the score values ​​of the evaluation parameters of the target buried hill to obtain the evaluation conclusion; S5: The corresponding relationship between the evaluation conclusion and the reservoir formation situation is preset, and the reservoir formation situation of the target buried-hill is predicted according to the evaluation conclusion of the target buried-hill.

2. The method for predicting target buried hill reservoir formation based on transport system evaluation according to claim 1, characterized in that: The distribution characterization method of the structural features in step S1 is specifically as follows: based on the three-dimensional seismic data body of the target buried-hill gas reservoir, the top interface seismic horizon and the fault system of the target buried-hill are interpreted and tracked, the top interface horizon and fault interpretation data of the target buried-hill are obtained, and the structural feature distribution of the top interface of the target buried-hill is formed according to the top interface horizon and fault interpretation data.

3. The method for predicting target buried hill reservoir formation based on transport system evaluation according to claim 2, characterized in that: The method for identifying the type of the conduction system in step S1 is specifically as follows: based on the distribution of structural characteristics of the top interface of the target buried hill, the conduction system type of the target buried hill is identified according to the main conduction system types in petroleum geology, and then according to the spatial combination relationship of different conduction system types and their relationship with source rocks, the combination pattern of the conduction system type of the target buried hill is determined.

4. The method for predicting target buried hill reservoir formation based on transport system evaluation according to claim 1, characterized in that: The method for determining the weight of each evaluation parameter of the transport system evaluation parameter system in step S3 is specifically: determining the contribution weight of each evaluation parameter of the transport system evaluation parameter system of the target buried hill to the migration and charging of natural gas according to the geological characteristics of the target buried hill.

5. The method for predicting target buried-hill reservoir formation based on transport system evaluation according to claim 4, characterized in that: Based on the pressure measurement data of the wells drilled in the target buried hill area or the pressure coefficient calculated by basin simulation, the pressure intensity of each source rock is divided, and the weight corresponding to the hydrocarbon dynamic parameter is determined based on the pressure intensity division; Determine the weights corresponding to the fault throw and dip of the gully source fault through the zoning, staging and corresponding characteristics of the gully source fault of the target buried hill; Comprehensively determine the weights corresponding to the area and thickness of the sand body according to the sand body scale and sand body physical property conditions; The weight corresponding to the area of ​​the unconformity surface is comprehensively determined according to the scale and number of the unconformity surface; The weight corresponding to the hydrocarbon supply efficiency is determined by the distance from the hydrocarbon generation center to the target buried hill.

6. The method for predicting target buried hill reservoir formation based on transport system evaluation according to claim 1, characterized in that: The partition quantitative weighting method in step S41 is: Assign a score of 0-10 to each evaluation parameter of each target buried hill, and divide the score of 0-10 into 5 equal assignment intervals; According to the effectiveness of the known actual statistical values ​​of each evaluation parameter on the target buried-hill reservoir formation, the actual statistical values ​​of each evaluation parameter are divided into corresponding assignment intervals.

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