Quantitative identification method for sand body dominant transport path in reservoir forming period of mature exploration area

Abstract

The invention belongs to the technical field of oil and gas geological exploration, and particularly relates to a mature exploration area reservoir-forming period sand body dominant conduction path quantitative identification method. The quantitative identification method can meet the identification requirements of the dominant transport path of the sand body in the exploration area, recovers the top surface form, porosity and permeability, sand body thickness (connectivity) and oil-gas migration dynamic conditions of the sand layer in the main reservoir forming period, is widely applied to quantitative identification of dominant transport paths of sand bodies in other mature exploration areas, and provides effective guidance for oil-gas exploration. The path quantification identification method comprises the following steps: drawing a skeleton sand body thickness contour map; determining an oil-gas main reservoir forming period; constructing a reservoir period backbone sand body transport capacity porosity and permeability evaluation model; constructing a reservoir period backbone sand body top surface structure form evaluation model; constructing a reservoir period backbone sand body transport capability evaluation model; constructing a backbone sand body oil-gas migration dynamic evaluation model; constructing a quantitative evaluation model of the dominant migration path of the backbone sand body; and determining an effective transport path of the backbone sand body.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas geological exploration, and in particular relates to a method for quantitatively identifying advantageous transport paths of sand bodies in a mature exploration area during the reservoir formation period. Background Art

[0002] Oil and gas reservoirs are formed by the accumulation of oil and gas along migration pathways throughout geological history. Exploration has confirmed that over 70% of oil and gas reservoirs are located along dominant oil and gas migration pathways. Specifically, oil and gas transport pathways include sand bodies, faults, and unconformities; large sand bodies are the primary pathways for the lateral migration of oil and gas. Fan deltas, braided river deltas, meandering river deltas, braided rivers, meandering rivers, and shallow lakes are all favorable areas for the development of large sand bodies. Therefore, accurately identifying the dominant migration pathways of sand bodies and finding new trap targets along these pathways is of great guiding significance for filling "blank areas" in mature exploration areas, discovering new reserves, and improving the success rate of oil and gas exploration.

[0003] It's worth noting that the study of sand bodies as transport pathways focuses on evaluating their transport capacity, focusing on their development and reservoir properties. If a sand body develops in a certain area (or interval) and exhibits good porosity and permeability, it is generally considered to possess good transport properties and thus serve as a pathway for oil and gas migration. Statistically, oil and gas migrate underground along the path of least resistance, thus defining the characteristics of effective pathway space and a dominant direction. Domestic and international researchers have conducted extensive simulations and numerical studies on the secondary migration of oil and gas within transporting layers, demonstrating that secondary migration occurs exclusively through limited, dominant pathways, occupying only 1% to 10% of the total transporting layer. Macroscopically, oil and gas exhibit a source-oriented pattern, from fine to coarse, along sedimentary facies zones, and exhibit selective migration along structural highs. Accurately identifying and characterizing dominant migration pathways is key to efficient exploration, employing the principle of "following the vine to find the melon." Domestic and international scholars have proposed various methods for evaluating sand body transport pathways. Cha Ming (1996) proposed using the fluid potential field of a compacted flow basin to analyze oil and gas migration trends. Hindle (1997) established different models based on the structural morphology of the sand body top surface to evaluate sand body transport capacity. Li Mingcheng (2004) proposed a structural ridge geological analysis method to identify the direction of dominant oil and gas migration pathways. Xiong Wei (2009) used the sand body high porosity and permeability zone method to identify dominant oil and gas transport pathways. With the development of organic geochemical analysis and testing technology, an organic geochemical method has been proposed to trace migration pathways using biomarker compounds and nitrogen-containing compound parameters based on the principle of oil and gas migration fractionation.

[0004] However, after further research, the inventors found that the dominant pathway only reflects the preferred migration route of oil and gas, but not the migration trend, nor the potential tendency of oil and gas migration represented by the fluid potential field. Oil and gas generated by source rocks enter the sandstone under the action of buoyancy, hydrodynamics and capillary forces. The migration in the sand body is affected by many factors such as the geometry, connectivity, porosity and permeability of the conducting layer itself and fluid dynamic conditions. Moreover, the evaluation methods proposed in the prior art are mostly fuzzy or semi-quantitative in identifying and locating the dominant migration pathway, and only consider the single factor of the current structural morphology or reservoir properties of the top surface of the sand body. It does not consider the possible differences between the current structural morphology and reservoir properties of the top surface of the sand body and the main accumulation period. The evaluation method has obvious deficiencies. Therefore, in order to meet the needs of fine exploration in more mature exploration areas, it is urgent for those skilled in the art to explore a new quantitative evaluation method to finely identify the dominant migration pathways of oil and gas, so as to better guide oil and gas exploration. Summary of the Invention

[0005] The present invention provides a method for quantitatively identifying the dominant transport paths of sand bodies in mature exploration areas during the reservoir formation period. This quantitative identification method can meet the requirements for identifying the dominant transport paths of sand bodies in higher exploration areas, and restore the top surface morphology, porosity and permeability, sand body thickness (connectivity) and oil and gas migration dynamics of the sand layer during the main reservoir formation period. It considers factors more comprehensively and objectively, establishes a quantitative evaluation model for the dominant migration paths of backbone sand bodies, and has higher evaluation accuracy. It has a good application effect in the work area and can be widely used in the quantitative identification of the dominant migration paths of sand bodies in other mature exploration areas, providing effective guidance for efficient oil and gas exploration.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for quantitatively identifying the dominant transport pathways of sand bodies in a mature exploration area during the reservoir formation period includes the following steps: Step 1: Draw a contour map of the thickness of the backbone sand body based on the statistical thickness of the sand body revealed in the target layer of drilling; Step 2: Determine the main oil and gas accumulation period based on the homogenization temperature of the target layer reservoir and the brine inclusions associated with oil and gas; Step 3: Construct a porosity and permeability evaluation model for the transport capacity of the backbone sand body during the reservoir formation period; Step 4: Construct a structural morphology evaluation model for the top surface of the backbone sand body during the reservoir formation period; Step 5: Construct a model to evaluate the conductivity of the backbone sand body during the reservoir formation period; Step 6: Construct a backbone sand body oil and gas migration dynamics evaluation model; Step 7: Construct a quantitative evaluation model for the dominant migration path of the backbone sand body; Step 8: Determine the effective transport path of the backbone sand body.

[0007] Preferably, the step 3 can be specifically described as: Step 301: Obtain porosity and permeability characteristics of the backbone sand body; Step 302: Establish a relationship model between the porosity, permeability and burial depth of the backbone sand body; Step 303: restoring the top burial depth of the backbone sand body during the main reservoir formation period; Step 304: Obtain the porosity and permeability of the backbone sand body during the main reservoir formation period; Step 305: Construct a physical property evaluation factor model for the conductivity of the backbone sand body during the reservoir formation period.

[0008] Preferably, the relationship model between porosity, permeability and burial depth of the backbone sand body established in step 302 satisfies: The relationship between the porosity of the backbone sand body and the burial depth is: φ = e -ah The relationship between the permeability of the backbone sand body and the burial depth is: K = e -bh ; Among them, φ is the present porosity of the backbone sand, K is the present permeability of the backbone sand, h is the present burial depth of the backbone sand, a is the fitting coefficient of the present porosity of the backbone sand and the burial depth, and b is the fitting coefficient of the present permeability of the backbone sand and the burial depth.

[0009] Preferably, step 303 can be specifically described as: Based on the fine calibration of the drilled backbone sand body, the seismic reflection axis corresponding to the top surface of the backbone sand body is determined; the fine seismic tracking interpretation of the structural layer is carried out to obtain the current structural map of the top surface of the backbone sand body; through data gridding, the scattered point data of the structural morphology of the top surface of the backbone sand body is obtained; Based on the fine calibration of the drilled core sand bodies, the seismic reflection axis of the bottom of the sedimentary strata after the main accumulation period is determined; the fine tracking and interpretation of the sedimentary strata seismic data is performed to obtain the bottom structural map of the sedimentary strata after the main accumulation period; through data gridding, the scattered point data of the structural morphology of the bottom of the sedimentary strata after the main accumulation period are obtained; If there is no denudation of the strata during the main reservoir formation period, the top burial depth of the backbone sand body during the main reservoir formation period shall be restored to meet the following requirements: H 古 =H 砂 -H 上覆 Among them, H 古 H is the top burial depth of the backbone sand body during the main accumulation period; 砂 H is the current burial depth of the top surface of the backbone sand body; 上覆 The burial depth of the bottom of the sedimentary strata after the main accumulation period; If the overlying strata during the main reservoir formation period are eroded, the stratum erosion thickness is first restored; a contour map of the stratum erosion thickness during this period is drawn, and scattered data of the stratum erosion thickness are obtained through data gridding; then the top burial depth of the backbone sand body formed during the main reservoir formation period is restored to meet the following requirements: H 古’ =H 砂 -H 上覆 +h剥 Among them, H 古 H is the top burial depth of the backbone sand body during the main accumulation period when there is no erosion; 古’ H is the top burial depth of the backbone sand body during the main reservoir formation period when there is stratum denudation; 砂 H is the current burial depth of the top surface of the backbone sand body; 上覆 The burial depth of the bottom of the sedimentary strata after the main accumulation period; h 剥 The erosion thickness of the strata during the main reservoir-forming period.

[0010] Preferably, step 304 can be specifically described as: Based on the current models of the relationship between the porosity and burial depth of the backbone sand bodies and the relationship between the permeability and burial depth, combined with the burial depth of the backbone sand bodies during the main reservoir formation period, the equivalent depth method was used to determine the relationship between the porosity and permeability of the backbone sand bodies during the main reservoir formation period and obtain the scattered data of the porosity and permeability of the backbone sand bodies during the main reservoir formation period. Among them, the relationship between porosity and burial depth during the main accumulation period satisfies: Φ a =e -aH古 ; The relationship between permeability and burial depth during the main accumulation period satisfies: K a =e -bH古’ Φ a K is the porosity of the backbone sand body during the main reservoir formation period; a is the permeability of the backbone sand body during the main reservoir formation period; H 古 H is the burial depth of the main sand body during the main accumulation period without stratum erosion; 古 ' is the burial depth of the backbone sand body during the main accumulation period with stratum denudation; a is the fitting coefficient of the relationship between the present porosity of the backbone sand body and the burial depth; b is the fitting coefficient of the relationship between the present permeability of the backbone sand body and the burial depth.

[0011] Preferably, the step 305 can be specifically described as: Different depth intervals were selected to determine the lower limits of porosity and permeability of the backbone sand body. The porosity and permeability lower limit data point fitting regression method was used to obtain the functional relationship between the lower limit of porosity and depth, and the lower limit of permeability and depth of the conducting sand body. Among them, the functional relationship between the lower limit of porosity of the conducting sand body and depth satisfies: Φ s =c*lnH+d; The functional relationship between the lower limit of permeability and depth satisfies: K s =m*e nH Φ s is the lower limit of the porosity of the backbone sand body; K s is the lower limit of the permeability of the backbone sand body; H is the burial depth of the backbone sand body; c, d, m, n are the regression coefficients of the fitting formula, and ln is the logarithmic function; According to the burial depth of the backbone sand body during the main reservoir formation period and its corresponding sand body porosity and permeability, the evaluation factors of the conductivity porosity and permeability of the backbone sand body during the reservoir formation period were constructed respectively, specifically: When Φ a <Φ s When I φp =0; When Φ a >Φ s When I φp =Φ a / Φ s ; When K a <K s When I φp =0; When K a >K s When I Kp =lg(K a / K s ); Among them, I φp is the porosity evaluation factor for the conductivity of the backbone sand body during the reservoir formation period; Φ a Porosity of the backbone sand body during the main reservoir formation period; Φ s is the lower limit of the porosity of the current backbone sand body; I Kp K is the evaluation factor of the conductivity and permeability of the backbone sand body; a Permeability of the backbone sand body during the main reservoir formation period; K s is the lower limit of the current backbone sand body permeability; lg is the logarithmic function.

[0012] Preferably, the step 4 can be specifically described as: Step 401: Based on the well seismic calibration of the drilled backbone sand body, the seismic reflection axis corresponding to the top surface of the backbone sand body is determined; a detailed seismic interpretation of the structural layer is performed to obtain a structural map of the top surface of the backbone sand body; and scattered point data of the structural morphology of the top surface of the backbone sand body is obtained by data gridding. Step 402: Restoring the top structural morphology of the backbone sand body during the main reservoir formation period; Step 403: Construct an ideal oil and gas migration surface. Based on the restoration of the structural morphology of the top surface of the backbone sand body during the main accumulation period, the structural morphology is modified according to the overall structural stratigraphic trend, and an ideal slope for oil and gas migration along the backbone sand body is constructed and mapped. By gridding the data, scattered point data of the ideal structural morphology is obtained. Step 404: Based on the scattered data of the structural morphology of the backbone sand body during the main accumulation period and the ideal structural morphology, a structural morphology factor of the backbone sand body migration capacity is established; the structural morphology factor of the backbone sand body migration capacity satisfies: Among them, I smThe structural morphological factor of the migration capacity of the backbone sand body during the main accumulation period; Indicates that the top surface of the backbone sand body is a structural ridge. Indicates that the top surface of the backbone sand body is a slope. Indicates that the top surface of the backbone sand body is a structural groove; SM t Scattered data of structural morphology of a grid point during the main reservoir formation period; SM i Ideally construct morphological scattered data corresponding to grid points.

[0013] Preferably, the evaluation model for the conductivity of the backbone sand body during the reservoir formation period constructed in step 5 satisfies the following requirements: M =I h *I φp *I Kp *I SM ; Among them, I M I is the evaluation index of the conductivity of the backbone sand body; h is the evaluation factor of the thickness of the backbone sand body; I φp I is the porosity evaluation factor for the conductivity of the backbone sand body; Kp I is the evaluation factor of the conductivity and permeability of the backbone sand body; SM It is a structural morphological evaluation factor for the conductivity of the backbone sand body.

[0014] Preferably, the backbone sand body oil and gas migration dynamics evaluation model constructed in step 6 satisfies: Among them, I p I is the evaluation index of oil and gas migration momentum in the backbone sand body; F is the dip index of the backbone sand body formation; Pc is the formation fluid pressure coefficient; ρ o is the density of crude oil; ρ w is the average density of formation water; g is the acceleration due to gravity; Pf is the formation fluid pressure, Ph is the hydrostatic pressure; and h is the height of the water column.

[0015] Preferably, the quantitative evaluation model of the backbone sand body dominant migration path constructed in step 7 satisfies: M p =I M *I p ; Among them, M p is the identification index of the dominant migration path of the backbone sand body, I M I is the evaluation index of the conductivity of the backbone sand body; p It is an evaluation index of oil and gas migration momentum.

[0016] The present invention provides a quantitative identification method for the advantageous transport paths of sand bodies in a mature exploration area during the oil and gas accumulation period, comprising the following steps: Step 1: drawing a contour map of the thickness of a backbone sand body according to the statistical thickness of the sand bodies revealed by drilling in a target layer; Step 2: determining the main oil and gas accumulation period according to the homogenized temperature of the target layer reservoir and the brine inclusions associated with the oil and gas; Step 3: constructing a porosity and permeability evaluation model for the transport capacity of the backbone sand bodies during the oil and gas accumulation period; Step 4: constructing a structural morphology evaluation model for the top surface of the backbone sand bodies during the oil and gas accumulation period; Step 5: constructing a transport capacity evaluation model for the backbone sand bodies during the oil and gas accumulation period; Step 6: constructing an oil and gas migration dynamics evaluation model for the backbone sand bodies; Step 7: constructing a quantitative evaluation model for the advantageous migration paths of the backbone sand bodies; and Step 8: determining the effective transport paths of the backbone sand bodies. The quantitative identification method for the dominant transport pathways of sand bodies in mature exploration areas during the reservoir formation period, characterized by the above steps, comprehensively considers multiple factors influencing oil and gas migration, including the thickness, porosity and permeability, structural morphology, occurrence, and migration dynamics of the core sand body. Based on the porosity and permeability of the core sand body during the reservoir formation period and the restoration of the structural morphology of the top surface of the sand layer, a porosity and permeability evaluation model for the core sand body's transport capacity, a structural morphology evaluation model for the core sand body's transport capacity, and an oil and gas migration dynamics evaluation model are constructed to evaluate its transport capacity during the reservoir formation period. The evaluation results are more objective and reliable. Furthermore, by analyzing the relationship between the oil, gas, and water distribution and the oil and gas transport pathways along the sand body in drilled and discovered oil and gas reservoirs, a lower limit for the evaluation of the dominant transport pathways of the core sand body is determined, achieving quantitative identification of dominant migration pathways and predicting favorable exploration areas. Compared with the existing technology, the quantitative identification method of the dominant transport paths of sand bodies in the reservoir-forming period of mature exploration areas proposed in the present invention can meet the requirements of identifying the dominant transport paths of sand bodies in different strata in relatively mature to mature exploration areas. It takes into account factors more comprehensively, has higher evaluation accuracy, and has good application effects in work areas. It can be widely used in the evaluation of dominant oil and gas transport paths in other similar areas, and can provide effective guidance for improving the success rate of exploration. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the following drawings: Figure 1 A schematic flow chart of a method for quantitatively identifying the dominant transport pathways of sand bodies in a mature exploration area during the reservoir formation period provided by the present invention; Figure 2 A set of example maps of the study area locations provided by the present invention; Figure 3a Graph showing the relationship between porosity and burial depth of the backbone sandstone in an embodiment of the present invention; Figure 3b Graph showing the relationship between the permeability of the backbone sandstone and the burial depth in an embodiment of the present invention; Figure 4a This is a relationship diagram between the lower limit of porosity and burial depth of the backbone sandstone during the reservoir formation period in the embodiment of the present invention; Figure 4b 2. This is a relationship diagram between the lower limit of permeability and burial depth of the backbone sandstone during the reservoir formation period in the embodiment of the present invention; Figure 5 This is a schematic diagram of the idealized structural morphology during the reservoir formation period in an embodiment of the present invention; Figure 6 This is a schematic diagram of crude oil density distribution in an embodiment of the present invention; Figure 7 Schematic diagram of the distribution of the dip angle of the backbone sand body stratum in the embodiment of the present invention; Figure 8 Schematic diagram of identification of dominant migration path of backbone sand body in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The present invention provides a method for quantitatively identifying the dominant transport paths of sand bodies in mature exploration areas during the reservoir formation period. This quantitative identification method can meet the requirements for identifying the dominant transport paths of sand bodies in higher exploration areas, and restore the top surface morphology, porosity and permeability, sand body thickness (connectivity) and oil and gas migration dynamics of the sand layer during the main reservoir formation period. It considers factors more comprehensively and objectively, establishes a quantitative evaluation model for the dominant migration paths of backbone sand bodies, and has higher evaluation accuracy. It has a good application effect in the work area and can be widely used in the quantitative identification of the dominant migration paths of sand bodies in other mature exploration areas, providing effective guidance for efficient oil and gas exploration.

[0019] like Figure 1 As shown, the present invention provides a method for quantitatively identifying the dominant transport pathway of sand bodies in the reservoir formation period of a mature exploration area, which includes the following eight step features from step 1 to step 8: It is necessary to add that, in order to facilitate those skilled in the art to understand the quantitative identification method of the conduction path of the present invention, Figure 2 The identification process of the dominant migration path of the backbone sand body of the 3rd member 3rd sand group of the Shahejie Formation (abbreviated as Sha 3rd member 3rd sand group) in the Qudi Oilfield in the southern slope zone of Huimin Sag in Jiyang Depression in Bohai Bay Basin is illustrated as an example.

[0020] Step 1: Draw a contour map of the backbone sand body thickness based on the statistical thickness of the sand body revealed in the drilling target layer.

[0021] Step 1 is used to conduct a preliminary study of the distribution characteristics of the backbone sand bodies. Specifically, to ensure good conductivity, the backbone sand bodies are first defined as those with thick single sand layers, good continuity, and good reservoir properties. The lithology and single-layer thickness of the backbone sand bodies are determined based on the sand body types developed in the target strata of the study area. Then, to ensure good connectivity and extension, the single-layer thickness of the backbone sand bodies should not be too thin. Specifically, the lower limit of the single-layer thickness of the corresponding sedimentary sand bodies should be determined based on the genetic type of the backbone sand bodies of different sedimentary facies. For example, the lower limit of the single-layer thickness of the backbone sand bodies in alluvial fan facies is 4 meters, and the lower limit of the single-layer thickness of the backbone sand bodies in fan delta, braided river, meandering river, and shallow lake facies is 2 meters. Generally speaking, muddy and limy sandstones have relatively poor physical properties and do not fall into the category of backbone sand bodies. The lithology of backbone sand bodies mainly includes siltstone, fine sandstone, medium sandstone, coarse sandstone, gravelly sandstone, and sandstone (conglomerate) rock.

[0022] correspond Figure 2 In the example shown, based on the core sand body thickness statistics of 272 wells drilled in the study area that encountered the third sand formation of the third member of the Shahejie Formation, a core sand body thickness contour map was constructed using the Double Arc software, using the sedimentary facies distribution as a constraint. The study area is (493000, 4100000), (493000, 4114000), (519000, 4114000), and (519000, 4100000). To meet the research accuracy requirements, a 100-meter gridding step was selected. The core sand body thickness data was gridded using the Surfer software, resulting in scatter plots of core sand body thickness (a total of 36,801 data points).

[0023] Step 2: Determine the main oil and gas accumulation period based on the homogenized temperature of the target layer reservoir and the oil and gas associated brine inclusions. Specifically, this step 2 is used to determine the main oil and gas accumulation period. Figure 2 In the example shown, based on the homogenization temperature test analysis of the reservoir and the oil and gas associated brine inclusions in the 3rd sand group of the 3rd member of the Shahejie Formation in the study area, combined with the burial history, it is determined that the main oil and gas accumulation period is the Minghuazhen period (since 5 Ma).

[0024] Step 3: Construct a porosity and permeability evaluation model for the conductivity of the backbone sand body during the reservoir formation period.

[0025] It is important to note that to quantitatively evaluate oil and gas migration based on sandbody physical properties, a model for evaluating the conductivity and porosity of the core sandbody during the reservoir formation period must be constructed. The specific process for constructing this model can be described as follows: Step 301: Obtain the porosity and permeability characteristics of the backbone sand body.

[0026] The process can be described as follows: First, based on core testing, conventional logging interpretation, and nuclear magnetic resonance logging, the porosity and permeability data for each well are compiled, and the arithmetic mean is taken as the porosity and permeability values of the core sand body at the corresponding well point. Then, using software such as Double Arc, the current porosity and permeability contour maps of the core sand body are drawn. Based on this, an appropriate grid step size is selected based on the research accuracy requirements, and the current porosity and permeability contour maps of the core sand body are gridded using software such as Surfer. This results in the porosity and permeability characteristics of the core sand body, including the scattered porosity and permeability data of the core sand body.

[0027] correspond Figure 2 In the example shown, based on the actual data from the study area, core porosity and permeability test data, and conventional well logging interpretation, the porosity and permeability values of over 2,100 core sand bodies in the third member of the Shahejie Formation (Shahejie Formation) were calculated from 162 wells. The average values were used as the porosity and permeability values at the corresponding well points. Using the thickness distribution of the core sand bodies as a constraint, the present-day porosity and permeability contour maps of the core sand bodies were plotted using the Double Arc software. Based on this, the present-day porosity and permeability contour maps of the core sand bodies were gridded using the Surfer software, selecting a 100-meter gridding step size. This yielded scattered porosity and permeability data for the core sand bodies.

[0028] Step 302: Establish a relationship model between the porosity, permeability and burial depth of the backbone sand body.

[0029] On the basis of completing step 301, a porosity and burial depth relationship model and a permeability and burial depth relationship model are further established. Among them, as a more preferred embodiment of the present invention, step 302 establishes the relationship model of the porosity, permeability and burial depth of the formed backbone sand body, which respectively satisfies the following formulas: That is, the relationship between the porosity of the backbone sand body and the burial depth is: φ = e -ah The relationship between the permeability of the backbone sand body and the burial depth is: K = e -bh ; Among them, the relationship between the porosity of the backbone sand body and the burial depth can be referred to Figure 3a For an example of the relationship between the permeability of the backbone sand body and the burial depth, please refer to Figure 3b , φ is the present porosity of the backbone sand, K is the present permeability of the backbone sand, h is the present burial depth of the backbone sand, a is the fitting coefficient of the relationship between the present porosity of the backbone sand and the burial depth, and b is the fitting coefficient of the relationship between the present permeability of the backbone sand and the burial depth.

[0030] correspond Figure 2 In the example shown, based on the porosity and permeability data of the core measured in the core of the 3rd sand body of the 3rd member of the Shahejie Formation in the study area and the interpretation of the physical properties of conventional well logging, the fitting formula of the relationship model between porosity, permeability and burial depth is established as follows: The relationship between porosity and burial depth is: Φ = 52.116e -0.0004h , R 2 =0.87; The relationship between permeability and burial depth is: K = 31632e -0.003h , R 2 =0.93; Step 303: Restore the top burial depth of the backbone sand body during the main reservoir formation period.

[0031] Specifically, as a preferred embodiment of the present invention, step 303 can be specifically described as follows: Based on the fine seismic calibration of the drilled backbone sand body, the seismic reflection axis corresponding to the top surface of the backbone sand body is determined; the seismic fine tracking interpretation of the structural layer is carried out to obtain the current structural map of the top surface of the backbone sand body; and through data gridding, the scattered point data of the structural morphology of the top surface of the backbone sand body are obtained.

[0032] It is worth noting that in the process of data gridding processing of the current backbone sand body top surface structural map, it is preferable to use software similar to Surfer to achieve the purpose of obtaining the scattered point data of the backbone sand body top surface structural morphology.

[0033] Based on the fine calibration of the drilled backbone sand bodies, the seismic reflection axis of the bottom of the sedimentary strata after the main accumulation period is determined; fine seismic tracking and interpretation of the sedimentary strata are carried out to obtain the bottom structural map of the sedimentary strata after the main accumulation period; and through data gridding, scattered point data of the structural morphology of the bottom of the sedimentary strata after the main accumulation period are obtained.

[0034] This step is similar to the previous one. You can choose to use software like Surfer to complete the data gridding process. For the structural layer map (the bottom surface structural map of the sedimentary strata after the main accumulation period), you can use the double arc software to complete it.

[0035] If there is no denudation of the strata during the main reservoir formation period, the top burial depth of the backbone sand body during the main reservoir formation period shall be restored to meet the following requirements: H 古 =H 砂 -H 上覆 Among them, H 古 H is the top burial depth of the backbone sand body during the main accumulation period; 砂 H is the current burial depth of the top surface of the backbone sand body; 上覆 The burial depth of the bottom of the sedimentary strata after the main accumulation period; If the overlying strata during the main reservoir formation period are eroded, the stratum erosion thickness is first restored; a contour map of the stratum erosion thickness during this period is drawn, and scattered data of the stratum erosion thickness are obtained through data gridding; then the top burial depth of the backbone sand body formed during the main reservoir formation period is restored to meet the following requirements: H 古’ =H 砂 -H 上覆 +h 剥Among them, H 古 H is the top burial depth of the backbone sand body during the main accumulation period when there is no erosion; 古’ H is the top burial depth of the backbone sand body during the main reservoir formation period when there is stratum denudation; 砂 H is the current burial depth of the top surface of the backbone sand body; 上覆 The burial depth of the bottom of the sedimentary strata after the main accumulation period; h 剥 The erosion thickness of the strata during the main reservoir-forming period.

[0036] It is important to note that if the overlying strata were eroded during the primary accumulation period, the erosion thickness must first be restored. This process requires the use of stratigraphic trend and acoustic transit time methods, and the optional use of dual-arc software to create contour maps of erosion thickness during this period.

[0037] correspond Figure 2 In the example shown, since the main accumulation period in the study area is the Minghuazhen period, and the Minghuazhen and Guantao formations are continuously deposited, there is no stratum erosion during the accumulation period. Therefore, the formula for the main accumulation period without stratum erosion can be directly applied to calculate the paleo-burial depth of the top surface of the backbone sand body during the accumulation period (H 古 ) to recover and obtain the scattered data of the top surface depth of the 3rd sand group of the 3rd section of the Minghua Town Shaheqi. For details, please refer to: H a =H p -H l ; Among them, H a H is the top burial depth of the backbone sand body in the Minghuazhen period; p H is the current burial depth of the top surface of the backbone sand body; l It is the sum of the thickness of the Guantao Formation and the Pingyuan Formation deposited after the Minghuazhen period.

[0038] Step 304: Obtain the porosity and permeability of the backbone sand body during the main reservoir formation period.

[0039] After completing step 303, step 304 is further implemented. Specifically, as a preferred embodiment of the present invention, step 304 can be specifically described as: Based on the current relationship models of the porosity and burial depth of the backbone sand bodies and the relationship models of the permeability and burial depth, combined with the burial depth of the backbone sand bodies during the main accumulation period, the equivalent depth method was used to determine the relationship between the porosity and permeability of the backbone sand bodies and the burial depth during the main accumulation period, and the scattered data of the porosity and permeability of the backbone sand bodies during the main accumulation period were obtained.

[0040] Among them, the relationship between porosity and burial depth during the main accumulation period satisfies: Φ a =e -aH古 ; The relationship between permeability and burial depth during the main accumulation period satisfies: K a =e -bH古’ Φ aK is the porosity of the backbone sand body during the main reservoir formation period; a is the permeability of the backbone sand body during the main reservoir formation period; H 古 H is the burial depth of the main sand body during the main accumulation period without stratum erosion; 古 ' is the burial depth of the backbone sand body during the main accumulation period with stratum denudation; a is the fitting coefficient of the relationship between the present porosity of the backbone sand body and the burial depth; b is the fitting coefficient of the relationship between the present permeability of the backbone sand body and the burial depth.

[0041] correspond Figure 2 In the example shown, based on the current relationship models of the porosity and burial depth of the backbone sand body and the relationship models of the permeability and burial depth, combined with the burial depth of the 3rd sand group of the 3rd member of the Shahejie Formation in the Minghuazhen period, the porosity and permeability of the backbone sand body during the reservoir formation period were determined using the equivalent depth method. The porosity and permeability scatter data of the backbone sand body of the 3rd sand group of the 3rd member of the Shahejie Formation in the Minghuazhen period were obtained. The specific reference is as follows: R 2 =0.87; K a =31632e -0.003Ha , R 2 =0.93; Where, Φ a is the paleo-porosity of the backbone sand body in the Minghuazhen period; K a is the paleo-permeability of the backbone sand body in the Minghuazhen period; H a This is the burial depth of the backbone sand body of the Minghuazhen period.

[0042] Step 305: Construct a physical property evaluation factor model for the conductivity of the backbone sand body during the reservoir formation period.

[0043] It should be noted that physical properties are important factors controlling sand body conductivity, and their quality affects whether the sand body can transport oil and gas and the efficiency of transporting oil and gas.

[0044] Under the same or similar conditions, the better the sandbody's physical properties, the more conducive it is to transporting oil and gas; as the physical properties deteriorate, the sandbody's transport capacity weakens. When the physical properties fall below a certain value, the sandbody is unable to transport oil and gas. Therefore, this physical property value is the lower limit of the sandbody's transport properties, generally measured by a certain value of porosity or permeability. Specifically, the minimum flow pore throat radius method and distribution function method proposed by Shen Pu (2015) can be used to determine the lower limit of the sandbody's transport properties. Alternatively, the lower limit of the sandbody's transport properties can be determined based on the interpretation of well logging properties. Specifically, if the sand layer is interpreted as dry by well logging, and there are no oil and gas indications in the mud log or no trace of oil and gas migration in the particle quantitative fluorescence analysis, the corresponding porosity and permeability values are the lower limit of the transport properties.

[0045] Specifically, as a preferred embodiment of the present invention, step 305 can be specifically described as follows: Select different depth intervals and determine the lower limit of porosity and permeability of the backbone sand body. The relationship between the lower limit of porosity and depth of the backbone sand body can be referred to Figure 4a The relationship between the lower limit of permeability of the backbone sand body and its depth can be referred to Figure 4b The porosity and permeability lower limit data point fitting regression method was used to obtain the functional relationships between the porosity lower limit and depth, and the permeability lower limit and depth of the conducting sand body, respectively.

[0046] Among them, the functional relationship between the lower limit of porosity of the conducting sand body and depth satisfies: Φ s =c*lnH+d; The functional relationship between the lower limit of permeability and depth satisfies: K s =m*e nH Φ s is the lower limit of the porosity of the backbone sand body; K s is the lower limit of the permeability of the backbone sand body; H is the burial depth of the backbone sand body; c, d, m, n are the regression coefficients of the fitting formula, and ln is the logarithmic function.

[0047] correspond Figure 2 In the example shown, based on the actual data in the study area, the results of well logging physical property interpretation were used to determine the lower limits of porosity and permeability. Specifically, for sand bodies interpreted as dry layers with no oil or gas indications and no traces of oil and gas migration (QGF < 2.0) by well logging, the corresponding physical property values are the lower limits of porosity and permeability. By fitting over 900 porosity and permeability data points at different depths in the study area, the functional relationships between the lower limit of porosity (Φs) and the burial depth, and the lower limit of permeability (Ks) and the burial depth of the backbone sand bodies were obtained, respectively. The specific formulas are as follows: Φ s =-12.247ln(h)+110.398, R2=0.79; K s =547.11e -0.002h , R2=0.85; Among them, Φ s is the lower limit of the porosity of the backbone sand body; K s is the lower limit of the permeability of the backbone sand body; h is the burial depth of the backbone sand body; ln is the logarithmic function with base e.

[0048] According to the burial depth of the backbone sand body during the main reservoir formation period and its corresponding sand body porosity and permeability, the evaluation factors of the conductivity porosity and permeability of the backbone sand body during the reservoir formation period were constructed respectively, specifically: When Φ a <Φ s When I φp =0; When Φ a >Φ s When I φp =Φa / Φ s ; When K a <K s When I φp =0; When K a >K s When I Kp =lg(K a / K s ); Among them, I φp is the porosity evaluation factor for the conductivity of the backbone sand body during the reservoir formation period; Φ a Porosity of the backbone sand body during the main reservoir formation period; Φ s is the lower limit of the porosity of the current backbone sand body; I Kp K is the evaluation factor of the conductivity and permeability of the backbone sand body; a Permeability of the backbone sand body during the main reservoir formation period; K s is the lower limit of the current backbone sand body permeability; lg is the logarithmic function. After completing step 3 above, proceed to step 4.

[0049] Step 4: Construct a structural morphology evaluation model for the top surface of the backbone sand body during the reservoir formation period.

[0050] It should be noted that for the out-of-source oil and gas reservoir system in the basin margin slope area, buoyancy is the main driving force for oil and gas migration; for the in-source or near-source oil and gas reservoir system in the hydrocarbon-generating center area of the basin, abnormal overpressure and buoyancy are the main driving forces for oil and gas migration. Therefore, the structural morphology of the top surface of the sand body has a very important control effect on oil and gas migration. According to different structural morphologies, units such as uplifts (nose bulges), slopes and depressions (grooves) can be divided. Here, in order to quantitatively characterize the impact of structural morphology on oil and gas migration capacity, an evaluation model of the structural morphology of the top surface of the backbone sand body during the accumulation period is introduced to reflect the impact of structural morphology differences on oil and gas migration capacity. Combined with Figure 2 As shown in the example, the Qudi area is located in the southern slope of the Huimin Sag and belongs to an external oil and gas reservoir system. Buoyancy is the main driving force for oil and gas migration. Based on the structural morphology of the top surface of the backbone sand body of the 3rd sand group of the 3rd member of the Minghuazhen period and the structural morphology of the ideal migration surface, a model for evaluating the transport capacity of the top surface structural morphology of the backbone sand body during the reservoir formation period is constructed as follows. Among them, the schematic diagram of the ideal structural morphology during the reservoir formation period can be referred to Figure 5 shown.

[0051] Specifically, as a preferred embodiment of the present invention, step 4 can be specifically described as: Step 401: Based on the well seismic calibration of the drilled backbone sand body, determine the seismic reflection axis corresponding to the top surface of the backbone sand body; conduct detailed seismic interpretation of the structural layer to obtain the current structural map of the top surface of the backbone sand body; and obtain scattered point data of the structural morphology of the top surface of the backbone sand body through data gridding.

[0052] Step 402: Restore the top structural morphology of the backbone sand body during the main reservoir formation period.

[0053] For example, the restoration process of the top structural morphology of the backbone sand body during the main accumulation period can be carried out by the impression method, that is, the morphology of the top structural morphology of the sand body is represented according to the burial depth of the top structural morphology of the backbone sand body during the main accumulation period.

[0054] Specifically, this step can be described as follows: First, restore the structure of the target sand layer during the main accumulation period. Based on this, measure the distance D between two adjacent contour lines on the structural map of the top surface of the target sand layer during the main accumulation period, and read the elevation difference Δh between the two adjacent contour lines. Then, based on the scale s of the structural map, the dip angle θ of the sand layer at that point can be calculated using the formula: θ=180*artgΔh / D h π D h =100*D / s Where Δh is the elevation difference between two adjacent structural contour lines; D is the distance between two adjacent contour lines; s is the scale of the structural map of the top surface of the sand layer; θ is the dip angle of the sand layer, and D h is the actual distance between two adjacent contour lines; artg is the inverse tangent trigonometric function; π is the circumference of a circle, which is 3.14.

[0055] Then, based on the top surface structure map of the target layer backbone sand body, draw the sand layer dip contour map. On this basis, perform data gridding processing to obtain dip angle scatter data. And based on the physical property data of the target layer drilled crude oil, draw the crude oil density contour map. On this basis, perform data gridding processing to obtain density scatter data. Figure 2 The example shown uses the layer flattening method to restore the top structural morphology of the backbone sandbody of the 3rd Member of the Shahejie Formation in the Minghua Zhenqi period. The present-day structural contour line grid data for the top of the backbone sandbody are subtracted from the structural contour line grid data for the bottom of the Guantao Formation to obtain the structural contour line scatter data for the top of the backbone sandbody of the 3rd Member of the Shahejie Formation in the Minghua Zhenqi period.

[0056] Step 403: Construct an ideal oil and gas migration surface. Based on the restoration of the structural morphology of the top surface of the backbone sand body during the main accumulation period, the structural morphology is corrected according to the overall structural stratigraphic trend, and an ideal slope for oil and gas migration along the backbone sand body is constructed and mapped. By gridding the data, scattered point data of the ideal structural morphology is obtained.

[0057] It should be noted that both step 401 and step 403 can be implemented using software such as Double Arc to generate structural layer maps (respectively obtaining the structural map of the top surface of the backbone sand body and the ideal slope structural map of oil and gas migration along the backbone sand body). On this basis, software such as Surfer is used to complete the data gridding process.

[0058] Step 404: Based on the scattered data of the structural morphology of the backbone sand body during the main accumulation period and the ideal structural morphology, a structural morphology factor of the backbone sand body migration capacity is established; the structural morphology factor of the backbone sand body migration capacity satisfies: Among them, I sm The structural morphological factor of the migration capacity of the backbone sand body during the main accumulation period; Indicates that the top surface of the backbone sand body is a structural ridge. Indicates that the top surface of the backbone sand body is a slope. Indicates that the top surface of the backbone sand body is a structural groove; SM t Scattered data of structural morphology of a grid point during the main reservoir formation period; SM i Ideally construct morphological scattered data corresponding to the gridded points.

[0059] After completing step 4 above, proceed to step 5. Step 5: Construct a model to evaluate the conductivity of the backbone sand body during the reservoir formation period.

[0060] It is worth noting that, as a preferred embodiment of the present invention, the evaluation model for the conductivity of the backbone sand body during the reservoir formation period constructed in step 5 satisfies the following requirements: M =I h *I φp *I Kp *I SM ; Among them, I M I is the evaluation index of the conductivity of the backbone sand body; h is the evaluation factor of the thickness of the backbone sand body (the evaluation factor of the thickness of the backbone sand body is specifically determined by the thickness of the backbone sand body); I φp I is the porosity evaluation factor for the conductivity of the backbone sand body; Kp I is the evaluation factor of the conductivity and permeability of the backbone sand body; SM It is a structural morphological evaluation factor for the conductivity of the backbone sand body.

[0061] After completing step 5 above, proceed to step 6. Step 6: Construct a backbone sand body oil and gas migration dynamics evaluation model.

[0062] Here, it is necessary to add that, generally speaking, the basin margin slope area and shallow formations are under normal pressure, while the depression area and deep formations of the hydrocarbon generation center are overpressured. Considering the differences in the driving force conditions of oil and gas migration in the specific research target area (layer segment) (the driving force of oil and gas migration in the normal pressure area mentioned above is mainly buoyancy, and the driving force of oil and gas migration in the overpressure area is abnormal overpressure and buoyancy of the formation), since the buoyancy component to which oil and gas are subjected during migration is positively correlated with the inclination of the transporting layer, the occurrence (inclination) of the sand body can indirectly reflect the size of the buoyancy of oil and gas migration. At the same time, the physical properties of crude oil (density, viscosity) also have an important influence on the migration of oil and gas in the sand body. Therefore, with the help of the backbone sand body oil and gas migration dynamics index (I p ), and a backbone sand body oil and gas migration dynamics evaluation model was constructed to realize the differential evaluation of oil and gas migration dynamics.

[0063] Combined with the Figure 2 As can be seen from the example shown, the Qudi area is located in a slope tectonic setting, so it exhibits normal pressure. The formation pressure coefficient is generally 0.96 to 1.03, and buoyancy is the main driving force for oil and gas migration. The inclination of the sand layer and the density of crude oil have an important influence on buoyancy. The buoyancy component is positively correlated with the inclination of the backbone sand layer. The occurrence (inclination) of the sand body can indirectly reflect the magnitude of the buoyancy of oil and gas migration. The greater the difference between the crude oil density and the formation water density, the greater the buoyancy effect. Among them, the distribution diagram of crude oil density can be referred to as follows Figure 6 As shown in the figure, the schematic diagram of the dip angle distribution of the backbone sand body formation can be referred to as follows Figure 7 shown.

[0064] Specifically, as a preferred embodiment of the present invention, the backbone sand body oil and gas migration dynamics evaluation model constructed in step 6 satisfies: Among them, I p I is the evaluation index of oil and gas migration momentum in the backbone sand body; F is the dip index of the backbone sand body formation; Pc is the formation fluid pressure coefficient; ρ o is the density of crude oil; ρ w is the average density of formation water; g is the acceleration due to gravity; Pf is the formation fluid pressure, Ph is the hydrostatic pressure; and h is the height of the water column.

[0065] correspond Figure 2 In the example shown, the implementation process of step 6 can be referred to as follows: First, determine the dip index of the backbone sand body formation during the accumulation period.

[0066] In order to quantitatively evaluate the influence of formation dip on oil and gas migration capacity, a backbone sand body formation dip index model is proposed. First, the structural contour line scatter data of the top surface of the backbone sand body of the third sand group of the third section of the Minghua Town period are obtained by using the above steps, and the contour line is mapped using the double arc software. On this basis, the distance D between two adjacent contour lines is measured on the top surface structural map of the third sand group of the third section of the Minghua Town period period. According to the structural map scale S (1:100,000), the actual distance (D h ), read the altitude difference Δh between two adjacent contour lines on the structural map, and the tangent value of the formation dip and the corresponding formation dip at that point can be obtained.

[0067] On this basis, the formation dip contour map is further drawn. F ) specifically meet the following requirements: When θ≤1, I F =0; When θ>1, I F =lnθ; Where, I F is the dip index of the backbone sand body; Δh is the elevation difference between two adjacent structural contour lines; D is the distance between two adjacent contour lines; S is the scale of the contour line map of the top surface of the backbone sand body; D h is the actual distance between two adjacent contour lines; θ is the dip angle of the backbone sand body formation; artg is the inverse tangent trigonometric function; π is the value of pi, which is 3.14; tg is the tangent trigonometric function; and ln is the logarithmic function.

[0068] Based on the top structural map of the Minghuazhen period of the backbone sand body of the third sand group of the third member of the Shahejie Formation, the above formula can be used to obtain stratigraphic dip data. On this basis, a sand layer dip contour map was further drawn. The data was then gridded using software such as Sufer with a 100-meter step size to obtain scattered dip data.

[0069] Then, the buoyancy dynamic conditions of the fluid density difference are evaluated. The relative size reflects the relative size of the buoyancy. According to the physical properties of crude oil from the drilling of the 3rd sand group of the third section of Shahejie Formation (0.8731~0.9545g / cm 3 ) and draw crude oil density contour maps. On this basis, the crude oil density contour data are gridded using software such as Sufer with a step size of 100m to obtain crude oil density scatter point data.

[0070] Specifically, the mineralization of the formation water in the third sand group of the third section of Shahejie Formation is 13227-23618 mg / L, the water type is CaCl2 type, and the density of the formation water taken this time is 1.05 g / cm 3 , thereby obtaining the ratio of formation water density to crude oil density in the target layer.

[0071] Finally, the formation fluid dynamic conditions were evaluated. Based on measured or converted formation fluid pressures from drilling in the third sand group of the third member of the Shahejie Formation, the formation fluid pressure coefficient was calculated using the aforementioned formula. Formation fluid pressures generally ranged from 0.96 to 1.03. Based on this, contour maps of the abnormal formation fluid pressure coefficient were drawn. The contour data was then gridded using Sufer software with a 100-meter step size to generate scattered data for the abnormal formation fluid pressure coefficient.

[0072] After completing step 6 above, proceed to step 7. Step 7: Construct a quantitative evaluation model for the dominant migration path of the backbone sand body.

[0073] Specifically, as a more preferred embodiment of the present invention, the quantitative evaluation model of the backbone sand body dominant migration path formed in step 7 satisfies: M p =I M *I p ; Among them, M p is the identification index of the dominant migration path of the backbone sand body, I M I is the evaluation index of the conductivity of the backbone sand body; p It is an evaluation index of oil and gas migration momentum.

[0074] correspond Figure 2 In the example shown, by implementing step 7, the dominant migration path identification index (M p ) Corresponding to the scattered data, the dual arc software can be used to further draw the contour map of the identification index of the backbone sand body's dominant migration path.

[0075] After completing step 7 above, proceed to step 8. Step 8: Determine the effective transport path of the backbone sand body.

[0076] Finally, it should be noted that based on the oil and gas displays and oil and gas distribution in the drilled wells, the evaluation threshold value of the dominant transport path of the backbone sand body can be determined, and thus the effective transport path of the backbone sand body can be finally determined.

[0077] Specifically, according to the oil and gas display and oil and gas distribution of the drilled wells, the evaluation threshold value of the backbone sand body's advantageous transport path is determined, thereby determining the effective oil and gas transport path. Figure 2The example shown shows that the threshold value (Mp) of the dominant transport path of the backbone sand body of the 3rd sand group of the Shahejie Formation in the study area is 8. Mp>8 indicates that the sand body can serve as a transport layer for oil and gas; Mp<8 indicates that the sand body cannot serve as a transport layer for oil and gas. Finally, the dominant migration path of the backbone sand body was identified as the Xia223-Xia22-Qu15-Qu102 well area and the Xiaxie61-Qu6 well area as the dominant migration path of the 3rd sand group of the Shahejie Formation. The results can be referred to as follows Figure 8 shown.

[0078] Thus, the present invention provides a method for quantitatively identifying the advantageous transport paths of sand bodies in the reservoir-forming period of mature exploration areas, which comprehensively considers various factors and realizes the quantitative identification process of the effective transport paths of the backbone sand bodies.

[0079] The present invention provides a quantitative identification method for the advantageous transport paths of sand bodies in a mature exploration area during the oil and gas accumulation period, comprising the following steps: Step 1: drawing a contour map of the thickness of a backbone sand body according to the statistical thickness of the sand bodies revealed by drilling in a target layer; Step 2: determining the main oil and gas accumulation period according to the homogenized temperature of the target layer reservoir and the brine inclusions associated with the oil and gas; Step 3: constructing a porosity and permeability evaluation model for the transport capacity of the backbone sand bodies during the oil and gas accumulation period; Step 4: constructing a structural morphology evaluation model for the top surface of the backbone sand bodies during the oil and gas accumulation period; Step 5: constructing a transport capacity evaluation model for the backbone sand bodies during the oil and gas accumulation period; Step 6: constructing an oil and gas migration dynamics evaluation model for the backbone sand bodies; Step 7: constructing a quantitative evaluation model for the advantageous migration paths of the backbone sand bodies; and Step 8: determining the effective transport paths of the backbone sand bodies. The quantitative identification method for the dominant transport pathways of sand bodies in mature exploration areas during the reservoir formation period, characterized by the above steps, comprehensively considers multiple factors influencing oil and gas migration, including the thickness, porosity and permeability, structural morphology, occurrence, and migration dynamics of the core sand body. Based on the porosity and permeability of the core sand body during the reservoir formation period and the restoration of the structural morphology of the top surface of the sand layer, a porosity and permeability evaluation model for the core sand body's transport capacity, a structural morphology evaluation model for the core sand body's transport capacity, and an oil and gas migration dynamics evaluation model are constructed to evaluate its transport capacity during the reservoir formation period. The evaluation results are more objective and reliable. Furthermore, by analyzing the relationship between the oil, gas, and water distribution and the oil and gas transport pathways along the sand body in drilled and discovered oil and gas reservoirs, a lower limit for the evaluation of the dominant transport pathways of the core sand body is determined, achieving quantitative identification of dominant migration pathways and predicting favorable exploration areas. Compared with the existing technology, the quantitative identification method of the dominant transport paths of sand bodies in the reservoir-forming period of mature exploration areas proposed in the present invention can meet the requirements of identifying the dominant transport paths of sand bodies in different strata in relatively mature to mature exploration areas. It takes into account factors more comprehensively, has higher evaluation accuracy, and has good application effects in work areas. It can be widely used in the evaluation of dominant oil and gas transport paths in other similar areas, and can provide effective guidance for improving the success rate of exploration.

[0080] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for quantitatively identifying the dominant transport pathway of sand bodies in a mature exploration area during the reservoir formation period, characterized in that: The following steps are included: Step 1: Draw a contour map of the thickness of the backbone sand body based on the statistical thickness of the sand body revealed in the target layer of drilling; Step 2: Determine the main oil and gas accumulation period based on the homogenization temperature of the target layer reservoir and the brine inclusions associated with oil and gas; Step 3: Construct a porosity and permeability evaluation model for the transport capacity of the backbone sand body during the reservoir formation period; Step 4: Construct a structural morphology evaluation model for the top surface of the backbone sand body during the reservoir formation period; Step 5: Construct a model to evaluate the conductivity of the backbone sand body during the reservoir formation period; Step 6: Construct a backbone sand body oil and gas migration dynamics evaluation model; Step 7: Construct a quantitative evaluation model for the dominant migration path of the backbone sand body; Step 8: Determine the effective transport path of the backbone sand body.

2. The method for quantitatively identifying the dominant transport path of sand bodies in the reservoir-forming period of a mature exploration area according to claim 1, characterized in that: The step 3 can be specifically described as: Step 301: Obtain porosity and permeability characteristics of the backbone sand body; Step 302: Establish a relationship model between the porosity, permeability and burial depth of the backbone sand body; Step 303: restoring the top burial depth of the backbone sand body during the main reservoir formation period; Step 304: Obtain the porosity and permeability of the backbone sand body during the main reservoir formation period; Step 305: Construct a physical property evaluation factor model for the conductivity of the backbone sand body during the reservoir formation period.

3. The method for quantitatively identifying the dominant transport path of sand bodies in the reservoir-forming period of a mature exploration area according to claim 1, characterized in that: Step 302 establishes a relationship model between the porosity, permeability and burial depth of the formed backbone sand body, which satisfies: The relationship between the porosity of the backbone sand body and the burial depth is: φ = e -ah The relationship between the permeability of the backbone sand body and the burial depth is: K = e -bh ; Among them, φ is the present porosity of the backbone sand, K is the present permeability of the backbone sand, h is the present burial depth of the backbone sand, a is the fitting coefficient of the present porosity of the backbone sand and the burial depth, and b is the fitting coefficient of the present permeability of the backbone sand and the burial depth.

4. The method for quantitatively identifying the dominant transport path of sand bodies in the reservoir-forming period of a mature exploration area according to claim 2, characterized in that: The step 303 can be specifically described as: Based on the fine calibration of the drilled backbone sand body, the seismic reflection axis corresponding to the top surface of the backbone sand body is determined; the fine seismic tracking interpretation of the structural layer is carried out to obtain the current structural map of the top surface of the backbone sand body; through data gridding, the scattered point data of the structural morphology of the top surface of the backbone sand body is obtained; Based on the fine calibration of the drilled core sand bodies, the seismic reflection axis of the bottom of the sedimentary strata after the main accumulation period is determined; the fine tracking and interpretation of the sedimentary strata seismic data is performed to obtain the bottom structural map of the sedimentary strata after the main accumulation period; through data gridding, the scattered point data of the structural morphology of the bottom of the sedimentary strata after the main accumulation period are obtained; If there is no erosion in the main reservoir formation period, the top burial depth of the backbone sand body formed during the main reservoir formation period shall be restored to meet the following requirements: H 古 =H 砂 -H 上覆 Among them, H 古 H is the top burial depth of the backbone sand body during the main accumulation period; 砂 H is the current burial depth of the top surface of the backbone sand body; 上覆 The burial depth of the bottom of the sedimentary strata after the main accumulation period; If the overlying strata during the main reservoir formation period are eroded, the stratum erosion thickness is first restored; a contour map of the stratum erosion thickness during this period is drawn, and scattered data of the stratum erosion thickness are obtained through data gridding; then the top burial depth of the backbone sand body formed during the main reservoir formation period is restored to meet the following requirements: H 古’ =H 砂 -H 上覆 +h 剥 Among them, H 古 H is the top burial depth of the backbone sand body during the main accumulation period when there is no erosion; 古’ H is the top burial depth of the backbone sand body during the main reservoir formation period when there is stratum denudation; 砂 H is the current burial depth of the top surface of the backbone sand body; 上覆 The burial depth of the bottom of the sedimentary strata after the main accumulation period; h 剥 The erosion thickness of the strata during the main reservoir-forming period.

5. The method for quantitatively identifying the dominant transport path of sand bodies in the reservoir-forming period of a mature exploration area according to claim 4, characterized in that: The step 304 can be specifically described as: Based on the current models of the relationship between the porosity and burial depth of the backbone sand bodies and the relationship between the permeability and burial depth, combined with the burial depth of the backbone sand bodies during the main reservoir formation period, the equivalent depth method was used to determine the relationship between the porosity and permeability of the backbone sand bodies during the main reservoir formation period and obtain the scattered data of the porosity and permeability of the backbone sand bodies during the main reservoir formation period. Among them, the relationship between porosity and burial depth during the main accumulation period satisfies: Φ a =e -aH古 ; The relationship between permeability and burial depth during the main accumulation period satisfies: K a =e -bH古’ Φ a K is the porosity of the backbone sand body during the main reservoir formation period; a is the permeability of the backbone sand body during the main reservoir formation period; H 古 H is the burial depth of the main sand body during the main accumulation period without stratum erosion; 古 ’ is the burial depth of the backbone sand body during the main accumulation period with stratum denudation; a is the fitting coefficient of the relationship between the present porosity of the backbone sand body and the burial depth; b is the fitting coefficient of the relationship between the present permeability of the backbone sand body and the burial depth.

6. The method for quantitatively identifying the dominant transport path of sand bodies in the reservoir-forming period of a mature exploration area according to claim 5, characterized in that: The step 305 can be specifically described as: Different depth intervals were selected to determine the lower limits of porosity and permeability of the backbone sand body. The porosity and permeability lower limit data point fitting regression method was used to obtain the functional relationship between the lower limit of porosity and depth, and the lower limit of permeability and depth of the conducting sand body. Among them, the functional relationship between the lower limit of porosity of the conducting sand body and depth satisfies: Φ s =c*lnH+d; The functional relationship between the lower limit of permeability and depth satisfies: K s =m*e nH Φ s is the lower limit of the porosity of the backbone sand body; K s is the lower limit of the permeability of the backbone sand body; H is the burial depth of the backbone sand body; c, d, m, n are the regression coefficients of the fitting formula, and ln is the logarithmic function; According to the burial depth of the backbone sand body during the main reservoir formation period and its corresponding sand body porosity and permeability, the evaluation factors of the conductivity porosity and permeability of the backbone sand body during the reservoir formation period were constructed respectively, specifically: When Φ a <Φ s When I φp =0; When Φ a > Φ s then I φp = Φ a / Φ s ; When K a <K s When I φp =0; When K a >K s When I Kp =lg(K a / K s ); Among them, I φp is the porosity evaluation factor for the conductivity of the backbone sand body during the reservoir formation period; Φ a Porosity of the backbone sand body during the main reservoir formation period; Φ s is the lower limit of the porosity of the current backbone sand body; I Kp K is the evaluation factor of the conductivity and permeability of the backbone sand body; a Permeability of backbone sand bodies during the main reservoir formation period; K s is the lower limit of the current backbone sand body permeability; lg is the logarithmic function.

7. The method for quantitatively identifying the dominant transport path of sand bodies in the reservoir-forming period of a mature exploration area according to claim 1, characterized in that: The step 4 can be specifically described as: Step 401: Based on the well seismic calibration of the drilled backbone sand body, the seismic reflection axis corresponding to the top surface of the backbone sand body is determined; a detailed seismic interpretation of the structural layer is performed to obtain a structural map of the top surface of the backbone sand body; and scattered point data of the structural morphology of the top surface of the backbone sand body is obtained by data gridding. Step 402: Restoring the top structural morphology of the backbone sand body during the main reservoir formation period; Step 403: Construct an ideal oil and gas migration surface. Based on the restoration of the structural morphology of the top surface of the backbone sand body during the main accumulation period, the structural morphology is modified according to the overall structural stratigraphic trend, and an ideal slope for oil and gas migration along the backbone sand body is constructed and mapped. By gridding the data, scattered point data of the ideal structural morphology is obtained. Step 404: Based on the scattered data of the structural morphology of the backbone sand body during the main accumulation period and the ideal structural morphology, a structural morphology factor of the backbone sand body migration capacity is established; the structural morphology factor of the backbone sand body migration capacity satisfies: Among them, I sm The structural morphological factor of the migration capacity of the backbone sand body during the main accumulation period; Indicates that the top surface of the backbone sand body is a structural ridge. Indicates that the top surface of the backbone sand body is a slope. Indicates that the top surface of the backbone sand body is a structural groove; SM t Scattered data of structural morphology of a grid point during the main reservoir formation period; SM i Ideally construct morphological scattered data corresponding to grid points.

8. The method for quantitatively identifying the dominant transport path of sand bodies in a mature exploration area during the reservoir formation period according to claim 1, characterized in that: Step 5: The evaluation model of the transport capacity of the backbone sand body during the reservoir formation period is constructed to meet the following requirements: M =I h *I φp *I Kp *I SM ; Among them, I M I is the evaluation index of the conductivity of the backbone sand body; h is the evaluation factor of the thickness of the backbone sand body; I φp I is the porosity evaluation factor for the conductivity of the backbone sand body; Kp I is the evaluation factor of the conductivity and permeability of the backbone sand body; SM It is a structural morphological evaluation factor for the conductivity of the backbone sand body.

9. The method for quantitatively identifying the dominant transport path of sand bodies in the reservoir-forming period of a mature exploration area according to claim 1, characterized in that: The backbone sand body oil and gas migration dynamics evaluation model constructed in step 6 satisfies the following requirements: Among them, I p I is the evaluation index of oil and gas migration momentum in the backbone sand body; F is the dip index of the backbone sand body formation; Pc is the formation fluid pressure coefficient; ρ o is the density of crude oil; ρ w is the average density of formation water; g is the acceleration due to gravity; Pf is the formation fluid pressure, Ph is the hydrostatic pressure; and h is the height of the water column.

10. The method for quantitatively identifying the dominant transport path of sand bodies in the reservoir-forming period of a mature exploration area according to claim 1, characterized in that: Step 7: The quantitative evaluation model of the backbone sand body's dominant migration path is constructed to meet the following requirements: p =I M *I p ; Among them, M p is the identification index of the dominant migration path of the backbone sand body, I M I is the evaluation index of the conductivity of the backbone sand body; p It is an evaluation index of oil and gas migration momentum.

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