Method for calculating effective thickness of thick-layered block oil / gas reservoirs

Abstract

The application provides a method for calculating effective thickness of thick block oil / gas reservoirs, which jointly restricts the effective thickness of thick block oil / gas reservoirs according to geological structure, oil / gas filling ratio and storage ratio of the oil / gas reservoirs; wherein the oil / gas filling ratio comprehensively represents the influence of geological structure and oil / gas water interface on the reservoir; the storage ratio representing the change of the reservoir plane is introduced to be restricted by the seismic attribute; and then, the joint restriction of the geological structure, the oil / gas filling ratio and the storage ratio on the effective thickness of the thick block oil / gas reservoirs is realized, and the determination precision of the effective thickness of the thick block oil / gas reservoirs is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil and gas field exploitation, and relates to a method for calculating effective thickness of an oil reservoir, in particular to a method for calculating effective thickness of a thick blocky oil / gas reservoir. BACKGROUND

[0002] In conventional oil and gas field reserve evaluation, the average effective thickness of the calculation unit is determined by using the isopleth area weighting method, well point area weighting method and arithmetic mean method according to the effective thickness drilled by the well point. The effective thickness is a key core parameter of an oil and gas field, which determines the distribution and size of the oil and gas field. Therefore, the prediction and evaluation of the effective thickness are of great significance to the researches such as oil and gas field reserve evaluation, development plan and development layer perforation.

[0003] CN113850007A discloses a method and system for predicting effective oil layer thickness of an oil reservoir based on finite element analysis, which comprises: constructing a finite element analysis model of the oil reservoir according to the dimensionless size on the spatial domain of the oil reservoir and the dimensionless time on the time domain, taking the dimensionless pressure as the boundary condition of the model; calculating the effective oil layer thickness H m of any oil reservoir under the condition that the dimensionless predicted pressure corresponding to each applied time is operated with the measured pressure at the inlet of the oil extraction equipment corresponding to each actual time point to obtain the total deviation value of the actual pressure corresponding to the effective oil layer thickness H m of the oil reservoir under the condition that the dimensionless predicted pressure corresponding to each applied time is operated with the measured pressure at the inlet of the oil extraction equipment corresponding to each actual time point to obtain the total deviation value of the actual pressure corresponding to the effective oil layer thickness H

[0004] CN101937108A discloses a method for determining the reserves of a low-permeability clastic rock oil and gas reservoir, which comprises: determining the lower limit values of the oil and gas layer material, oiliness and electrical property corresponding to the industrial oil and gas flow by statistically regressing the existing oil and gas test well daily oil and gas production, water data and corresponding oil layer material, oiliness and electrical property data; determining the minimum value of the sand body thickness of the yield according to the relationship between the effective thickness and the oil test yield and the relationship between the sand body thickness and the test yield; and determining the area boundary of the oil and gas reservoir by using the sandstone thickness isopleth method and the effective thickness isopleth method.

[0005] As described above, in the conventional oil and gas field reserve evaluation process, the average effective thickness of the calculation unit is determined by using the contour area weighting method, the well point area weighting method and the arithmetic mean method according to the effective thickness drilled by the well point. However, when the number of wells in the oil field is small, and the exploratory well and the evaluation well are located at the high position of the oil and gas field, the limited drilling cannot represent the real situation of the whole oil and gas reservoir. For example, the effective thickness determined by using the well point arithmetic mean method or the well point area weighting method has a large error. Moreover, for the thick blocky oil reservoir, it has a large oil-water transition zone, and the effective thickness is affected by multiple parameters such as the oil-water interface, the gas-water interface, the structure change, the formation thickness and the reserve-production ratio. In the process of drawing the effective thickness contour, there is a large error, especially in the oil-water transition zone and the gas-water transition zone, and there is a defect that the effective thickness is larger than the actual formation thickness.

[0006] Therefore, for the thick blocky oil / gas reservoir, it is necessary to provide a calculation method of the effective thickness with higher precision. SUMMARY

[0007] The purpose of the present application is to provide a calculation method of the effective thickness of the thick blocky oil / gas reservoir, which can overcome the defect that the transition zone range is large in the thick blocky oil / gas reservoir, and the effective thickness of the oil and gas reservoir cannot be accurately measured, and improve the precision of the determination of the effective thickness of the thick blocky oil / gas reservoir. The "thick layer" in the present application generally refers to the oil layer thickness ≥ 50 m.

[0008] In order to achieve the purpose of the present application, the following technical scheme is adopted:

[0009] The present application provides a calculation method of the effective thickness of the thick blocky oil / gas reservoir, which comprises the following steps:

[0010] (1) The grid of the top and bottom structure surface of the oil / gas reservoir is obtained according to the processing and interpretation of the seismic data, and the formation thickness data H(x, y) of the oil / gas bearing position is calculated;

[0011] (2) The grid data S(x, y) of the oil / gas and water interface is determined according to the well drilling data, the formation pressure analysis and the fluid sample analysis;

[0012] (3) The oil / gas containing boundary and the outer oil / gas containing boundary are determined according to the grid data S(x, y) of the top and bottom structure surface of the oil / gas reservoir and the oil / gas and water interface, and the distribution range of the transition zone between the oil / gas containing boundary and the outer oil / gas containing boundary is determined;

[0013] (4) The contour distribution of the oil / gas fullness ratio in the transition zone is determined according to the distribution range of the transition zone;

[0014] (5) According to the isopleth distribution of the oil / gas filling ratio of the inner oil / gas boundary, the outer oil / gas boundary and the transition zone, the isopleth distribution function F(x, y) of the oil / gas filling ratio of the oil / gas reservoir is obtained;

[0015] (6) According to the storage-to-area ratio of the oil / gas bearing layer of the single well, the plane function RTG(x, y) of the storage-to-area ratio is calculated;

[0016] (7) According to the isopleth distribution function F(x, y) of the oil / gas filling ratio of the oil / gas reservoir and the plane function RTG(x, y) of the storage-to-area ratio, the grid data OTG(x, y) of the oil-to-area ratio is calculated;

[0017] (8) According to the stratum thickness data H(x, y) of the oil / gas bearing layer and the grid data OTG(x, y) of the oil-to-area ratio, the plane distribution data of the effective thickness of the thick block-shaped oil / gas reservoir is calculated;

[0018] The step (1) and the step (2) are not in the order.

[0019] The plane distribution data of the effective thickness of the thick block-shaped oil / gas reservoir finally calculated by the method can calculate the average effective thickness of each plane calculation unit.

[0020] The "oil / gas" in the method is "oil or gas", and the "oil / gas water boundary" is "oil water boundary" or "gas water boundary". The specific concept is determined according to the object of determining the effective thickness, that is, the method can not only determine the effective thickness of the thick block-shaped oil reservoir, but also determine the effective thickness of the thick block-shaped gas reservoir.

[0021] The method introduces the constraints of the geological structure, the oil / gas filling ratio and the storage-to-area ratio on the effective thickness. The oil / gas filling ratio comprehensively represents the influence of the geological structure and the oil / gas water interface on the reservoir, and the storage-to-area ratio constrained by the seismic attribute represents the change of the reservoir plane, so that the common constraints of the geological structure, the oil / gas filling ratio and the storage-to-area ratio on the effective thickness of the thick block-shaped oil / gas reservoir are realized, and the determination accuracy of the effective thickness of the thick block-shaped oil / gas reservoir is improved.

[0022] Preferably, the stratum thickness data H(x, y) of the oil / gas bearing layer calculated in the step (1) is calculated according to the top surface data T(x, y) of the oil / gas reservoir structure surface grid and the bottom surface data B(x, y) of the oil / gas reservoir structure surface grid.

[0023] The H(x, y) = T(x, y) - B(x, y).

[0024] The thickness data H(x, y) of the stratum is in meter; and x and y are the longitudinal and lateral coordinate values in the geodetic coordinate system.

[0025] Preferably, the oil / gas filling ratio P(x, y) of the inner oil / gas boundary in step (3) is 1.

[0026] The oil / gas filling ratio P(x, y) of the outer oil / gas boundary in step (3) is 0.

[0027] Preferably, the oil / gas filling ratio P(x, y) is calculated by the following formula:

[0028] P(x, y) = [H(x, y) - S(x, y)] / [T(x, y) - B(x, y)];

[0029] Wherein S(x, y) is the grid data of the oil / water or gas / water interface.

[0030] Preferably, the contour distribution of the oil / gas filling ratio in the transition zone is determined by P(x, y).

[0031] Preferably, the reservoir-to-formation ratio RTG of the single-well oil / gas bearing zone in step (6) is:

[0032] RTG = H Res / H Str ;

[0033] The H Res is the reservoir thickness at the single well, H Str is the stratum thickness at the single well; and the H Res and H Str are in meter.

[0034] Preferably, the plane function RTG(x, y) of the reservoir-to-formation ratio calculated in step (6) means that the reservoir-to-formation ratio RTG of the single-well oil / gas bearing zone is taken as the input data, the seismic attribute plane data with better correlation with the reservoir-to-formation ratio is taken as the constraint plane data, a suitable algorithm is selected, and the plane function RTG(x, y) of the reservoir-to-formation ratio is obtained.

[0035] The suitable algorithm includes but is not limited to any one of the methods such as convergence interpolation, contour interpolation, minimum curvature difference, Kriging interpolation, sequential Gaussian simulation or moving average, and a person skilled in the art can reasonably select according to the data richness, and the present application does not make too many limitations here.

[0036] For example, the calculation of the plane function RTG(x, y) of the reservoir-to-formation ratio in the present application is performed by using the Make Surface function of the Stratigraphy module under the Peterl E&P Software Platform platform.

[0037] Preferably, the oil-to-ground ratio grid data OTG(x, y) in step (7) is:

[0038] OTG(x, y) = F(x, y) x RTG(x, y).

[0039] For example, the calculation of the oil-to-ground ratio grid data OTG(x, y) in the present application is performed by using the calculator function under the Peterl E&P Software Platform.

[0040] Preferably, the planar distribution data of the effective thickness of the thick block oil / gas reservoir obtained in step (8) is the product of the formation thickness data H(x, y) and the oil-to-ground ratio grid data OTG(x, y).

[0041] As a preferred technical solution of the calculation method in the present application, the calculation method comprises the following steps:

[0042] (1) Calculating the formation thickness data H(x, y) of the oil / gas bearing horizon according to the top and bottom structure surface grid of the oil / gas reservoir; the H(x, y) = T(x, y) - B(x, y); wherein T(x, y) is the top surface data of the structure surface grid of the oil / gas reservoir, and B(x, y) is the bottom surface data of the structure surface grid of the oil / gas reservoir;

[0043] (2) Determining the grid data S(x, y) of the oil / gas water interface according to the comprehensive analysis of the well actual drilling data, formation pressure analysis, fluid sample analysis, etc.

[0044] (3) Determining the inner oil / gas boundary and the outer oil / gas boundary according to the top and bottom structure surface grid of the oil / gas reservoir and the grid data S(x, y) of the oil / gas water interface; the oil / gas fullness ratio P(x, y) of the inner oil / gas boundary is 1, the oil / gas fullness ratio P(x, y) of the outer oil / gas boundary is 0, and the distribution range of the transition zone is between the inner oil / gas boundary and the outer oil / gas boundary;

[0045] The oil / gas fullness ratio is P(x, y) = [H(x, y) - S(x, y)] / [T(x, y) - B(x, y)]; and the S(x, y) is the grid data of the oil / water-gas water interface;

[0046] (4) Determining the contour distribution of the oil / gas fullness ratio in the transition zone according to the distribution range of the transition zone;

[0047] (5) Obtaining the oil / gas fullness ratio contour distribution function F(x, y) of the oil / gas reservoir according to the inner oil / gas boundary, the outer oil / gas boundary, and the contour distribution of the oil / gas fullness ratio in the transition zone;

[0048] (6) The planar function RTG(x,y) of the reservoir ratio is calculated based on the reservoir ratio of the oil / gas-bearing layers in a single well.

[0049] The reservoir ratio of the oil / gas-bearing strata in the single well is RTG = H. Res / H Str The H Res H represents the reservoir thickness at a single well. Str The formation thickness at a single well; the H Res With H Str The unit of measurement is the meter;

[0050] The calculated planar function RTG(x,y) of the reservoir-to-land ratio refers to: using the reservoir-to-land ratio RTG of the oil / gas-bearing layer in a single well as the seismic attribute surface data that is well correlated with the reservoir-to-land ratio as the constraint surface data, and selecting an appropriate algorithm to obtain the planar function RTG(x,y) of the reservoir-to-land ratio.

[0051] (7) The grid data OTG(x,y) of the oil / gas reservoir is calculated based on the contour distribution function F(x,y) of the oil and gas filling ratio and the plane function RTG(x,y) of the reservoir-to-land ratio.

[0052] The grid data for the oil-to-land ratio is: OTG(x,y)=F(x,y)×RTG(x,y);

[0053] (8) The planar distribution data of the effective thickness of thick blocky oil / gas reservoirs is calculated by multiplying the formation thickness data H(x,y) of oil / gas strata with the grid data OTG(x,y) of oil-land ratio.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] The calculation method provided by this invention incorporates geological structure, oil / gas filling ratio, and reservoir-to-land ratio to constrain the effective thickness. The oil / gas filling ratio comprehensively characterizes the influence of geological structure and oil / gas-water interface on the reservoir, while the reservoir-to-land ratio, constrained by seismic attributes, characterizes the changes in the reservoir plane. This achieves a joint constraint on the effective thickness of thick blocky oil / gas reservoirs by geological structure, oil / gas filling ratio, and reservoir-to-land ratio, thereby improving the accuracy of determining the effective thickness of thick blocky oil / gas reservoirs. Attached Figure Description

[0056] Figure 1 This is a thickness distribution map of the oil-bearing strata in Example 1;

[0057] Figure 2 This is a contour map showing the oil-filling ratio in Example 1;

[0058] Figure 3 This is a contour map of the oil-to-land ratio in Example 1;

[0059] Figure 4 Fig. 1 is a contour map of effective thickness of a thick block oil / gas reservoir in Example 1. DETAILED DESCRIPTION

[0060] The technical solutions of the present application are further illustrated by the following specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations to the present application.

[0061] The present application provides a method for calculating effective thickness of a thick block oil / gas reservoir, which comprises the following steps:

[0062] (1) calculating stratum thickness data H(x, y) of oil / gas bearing layers according to the grid of top and bottom structure surfaces of the oil / gas reservoir;

[0063] (2) determining grid data S(x, y) of oil / gas water interface according to comprehensive analysis of well drilling data, stratum pressure analysis, fluid sample analysis, etc;

[0064] (3) determining the inner oil / gas bearing boundary and the outer oil / gas bearing boundary and the distribution range of the transition zone between the inner oil / gas bearing boundary and the outer oil / gas bearing boundary according to the grid data S(x, y) of the oil / gas water interface and the grid of top and bottom structure surfaces of the oil / gas reservoir;

[0065] (4) determining the contour distribution of oil / gas filling ratio in the transition zone according to the distribution range of the transition zone;

[0066] (5) obtaining the contour distribution function F(x, y) of oil / gas filling ratio of the oil / gas reservoir according to the inner oil / gas bearing boundary, the outer oil / gas bearing boundary and the contour distribution of oil / gas filling ratio in the transition zone;

[0067] (6) calculating the planar function RTG(x, y) of the ratio of oil / gas bearing stratum thickness to the total stratum thickness according to the ratio of oil / gas bearing stratum thickness to the total stratum thickness of single well oil / gas bearing layers;

[0068] (7) calculating the grid data OTG(x, y) of the ratio of oil / gas bearing stratum thickness to the total stratum thickness according to the contour distribution function F(x, y) of oil / gas filling ratio of the oil / gas reservoir and the planar function RTG(x, y) of the ratio of oil / gas bearing stratum thickness to the total stratum thickness;

[0069] (8) calculating the planar distribution data of effective thickness of the thick block oil / gas reservoir according to the stratum thickness data H(x, y) of oil / gas bearing layers and the grid data OTG(x, y) of the ratio of oil / gas bearing stratum thickness to the total stratum thickness;

[0070] Step (1) and step (2) are not in a specific order.

[0071] The planar distribution data of the effective thickness of the thick blocky oil / gas reservoir finally calculated by this invention can be used to calculate the average effective thickness of each planar calculation unit.

[0072] In this invention, "oil / gas" refers to "oil or gas"; taking "oil / gas-water boundary" as an example, it is represented as "oil-water boundary" or "gas-water boundary". The specific concept is determined based on whether the object of the effective thickness measurement is an "oil reservoir" or a "gas reservoir". That is, the calculation method described in this invention can not only measure the effective thickness of thick massive oil reservoirs, but also the effective thickness of thick massive gas reservoirs.

[0073] In some embodiments, the formation thickness data H(x,y) of the oil / gas reservoir in step (1) is calculated as follows: the formation thickness data H(x,y) is calculated based on the top surface data T(x,y) of the oil / gas reservoir structural surface grid and the bottom surface data B(x,y) of the oil / gas reservoir structural surface grid.

[0074] The H(x,y)=T(x,y)-B(x,y);

[0075] The unit of measurement for the stratum thickness data H(x,y) is meters; x and y are the longitudinal and transverse coordinates in the geodetic coordinate system.

[0076] In some embodiments, the oil / gas filling ratio P(x,y) of the inner oil / gas boundary in step (3) is 1;

[0077] In step (3), the oil / gas filling ratio P(x,y) of the outer oil / gas boundary is 0.

[0078] In some embodiments, the oil / gas filling ratio P(x,y) is calculated by the following formula:

[0079] P(x,y)=[H(x,y)-S(x,y)] / [T(x,y)–B(x,y)];

[0080] Where S(x,y) represents the oil-water / gas-water interface mesh data.

[0081] In some embodiments, the contour distribution of the oil / gas filling ratio within the transition zone is determined by P(x,y).

[0082] In some embodiments, the reservoir-to-gas ratio (RTG) of the single well oil / gas-bearing formation in step (6) is:

[0083] RTG=H Res / H Str ;

[0084] The H Res H represents the reservoir thickness at a single well. Str The formation thickness at a single well; the HRes H Str The unit of measurement is meter.

[0085] In some embodiments, the planar function RTG(x, y) of the net-to-gross ratio calculated in step (6) refers to: taking the net-to-gross ratio RTG of a single well oil / gas layer as input data, taking the seismic attribute surface data with better correlation with the net-to-gross ratio as constraint surface data, selecting a suitable algorithm, and obtaining the planar function RTG(x, y) of the net-to-gross ratio.

[0086] Illustratively, the calculation of the planar function RTG(x, y) of the net-to-gross ratio in the present application is carried out by using the Make Surface function of the Stratigraphy module under the Peterl E&P Software Platform platform.

[0087] In some embodiments, the grid data OTG(x, y) of the oil-to-gross ratio in step (7) is:

[0088] OTG(x, y) = F(x, y) x RTG(x, y).

[0089] Illustratively, the calculation of the grid data OTG(x, y) of the oil-to-gross ratio in the present application is carried out by using the calculator function under the Peterl E&P Software Platform platform.

[0090] In some embodiments, the planar distribution data of the effective thickness of the thick block oil / gas reservoir obtained in step (8) is the product of the grid data OTG(x, y) of the oil-to-gross ratio and the grid data H(x, y) of the formation thickness.

[0091] Embodiment 1

[0092] The present embodiment provides a method for calculating the effective thickness of a thick block oil reservoir. The oil reservoir is A oilfield in deep sea area of Brazil, which is 180 km offshore, with a water depth of 1800-2000 m, and a target layer buried at a depth of 3070-3800 m. The oilfield has drilled 15 exploratory wells and evaluation wells. The target layer B is widely distributed, and the average reservoir thickness drilled by the well is 212.6 m. The average porosity of the carbonate reservoir is 12.9%, and the average permeability is 124 mD. Through the analysis of the actual drilling and formation pressure of the exploratory well, the B oil reservoir has a unified oil-water interface of -5700 m TVDSS. The B oil reservoir is a thick block oil reservoir.

[0093] The calculation method comprises the following steps:

[0094] (1) According to the grid of the top and bottom structure surface of the reservoir, the formation thickness data H(x, y) of the oil-bearing layer is calculated, and the obtained formation thickness distribution map is as shown in Figure 1H(x, y) = T(x, y) - B(x, y); wherein T(x, y) is top surface data of a grid of reservoir structure surfaces, and B(x, y) is bottom surface data of the grid of reservoir structure surfaces;

[0095] (2) determining grid data S(x, y) of an oil / gas / water interface according to comprehensive analysis of well drilling data, formation pressure analysis, fluid sample analysis, etc.;

[0096] (3) determining an inner oil-containing boundary and an outer oil-containing boundary according to the grid data of the reservoir top and bottom structure surfaces and the grid data S(x, y) of the oil / water interface; the oil fill proportion P(x, y) of the inner oil-containing boundary is 1, the oil fill proportion P(x, y) of the outer oil-containing boundary is 0, and the distribution range of a transition zone is between the inner oil-containing boundary and the outer oil-containing boundary;

[0097] the oil fill proportion is P(x, y) = [H(x, y) - S(x, y)] / [T(x, y) - B(x, y)]; and S(x, y) is grid data of an oil / water / gas interface;

[0098] (4) determining contour distribution of the oil fill proportion in the transition zone according to the distribution range of the transition zone, and the obtained contour distribution of the oil fill proportion is as shown in Figure 2 ;

[0099] (5) obtaining an oil / gas fill proportion contour distribution function F(x, y) of a reservoir by comprehensively considering the inner oil-containing boundary, the outer oil-containing boundary, and the contour distribution of the oil fill proportion in the transition zone;

[0100] (6) calculating a plane function RTG(x, y) of a reservoir thickness to formation thickness ratio according to the reservoir thickness to formation thickness ratio of a single well oil-bearing horizon;

[0101] the reservoir thickness to formation thickness ratio of the single well oil-bearing horizon is RTG = H Res / H Str ; H Res is reservoir thickness at a single well, and H Str is formation thickness at the single well; and H Res and H Str have a unit of meter;

[0102] the plane function RTG(x, y) of the reservoir thickness to formation thickness ratio is that: taking the reservoir thickness to formation thickness ratio RTG of a single well oil-bearing horizon as input data, taking seismic attribute surface data related to the reservoir thickness to formation thickness ratio as constraint surface data, and selecting a suitable algorithm to obtain the plane function RTG(x, y) of the reservoir thickness to formation thickness ratio;

[0103] (7) calculating grid data OTG(x, y) of an oil / formation thickness ratio according to the oil / gas fill proportion contour distribution function F(x, y) of a reservoir and the plane function RTG(x, y) of the reservoir thickness to formation thickness ratio;

[0104] The grid data of the oil-to-ground ratio is OTG(x, y) = F(x, y) x RTG(x, y);

[0105] The contour distribution map of the obtained oil-to-ground ratio is shown in Figure 3

[0106] (8) The planar distribution data of the effective thickness of the thick block-shaped reservoir is calculated from the product of the formation thickness data H(x, y) of the oil-bearing interval and the grid data OTG(x, y) of the oil-to-ground ratio; the contour distribution map of the obtained effective thickness of the thick block-shaped reservoir is shown in Figure 4

[0107] The step (1) and the step (2) are not in the order.

[0108] The planar distribution data of the effective thickness of the thick block-shaped reservoir finally calculated can be used to calculate the average effective thickness of each planar calculation unit.

[0109] In summary, the calculation method provided by the present application introduces the constraints of the geological structure, the oil / gas filling ratio and the storage-to-ground ratio on the effective thickness; the oil / gas filling ratio comprehensively represents the influence of the geological structure and the oil / gas water interface on the reservoir, the storage-to-ground ratio constrained by the seismic attribute represents the change of the reservoir plane, and thus the common constraints of the geological structure, the oil / gas filling ratio and the storage-to-ground ratio on the effective thickness of the thick block-shaped oil / gas reservoir are realized, and the determination precision of the effective thickness of the thick block-shaped oil / gas reservoir is improved.

[0110] The above merely describes specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and those skilled in the art should understand that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and all of them fall within the protection scope and disclosure scope of the present application.​​

Claims

1. A method for calculating the effective thickness of a thick-layered oil / gas reservoir, characterized in that, The calculation method comprises the following steps: (1) obtaining the grid data of the top and bottom structural surfaces of the oil / gas reservoir according to seismic data processing and interpretation, and calculating the stratum thickness data H(x, y) of the oil / gas bearing horizon; (2) determining the grid data S(x, y) of the oil / gas water interface according to comprehensive analysis of well drilling data, stratum pressure analysis and fluid sample analysis; (3) determining the inner oil / gas bearing boundary and the outer oil / gas bearing boundary according to the grid data of the top and bottom structural surfaces of the oil / gas reservoir and the grid data S(x, y) of the oil / gas water interface, and determining the distribution range of the transition zone between the inner oil / gas bearing boundary and the outer oil / gas bearing boundary; (4) determining the contour distribution of the oil / gas filling ratio in the transition zone according to the distribution range of the transition zone; (5) obtaining the contour distribution function F(x, y) of the oil / gas filling ratio of the oil / gas reservoir according to the inner oil / gas bearing boundary, the outer oil / gas bearing boundary and the contour distribution of the oil / gas filling ratio in the transition zone; (6) calculating the plane function RTG(x, y) of the reservoir-to-stratum ratio according to the reservoir-to-stratum ratio of the oil / gas bearing horizon of a single well; (7) calculating the grid data OTG(x, y) of the oil-to-stratum ratio according to the contour distribution function F(x, y) of the oil / gas filling ratio of the oil / gas reservoir and the plane function RTG(x, y) of the reservoir-to-stratum ratio; (8) calculating the plane distribution data of the effective thickness of the thick block-shaped oil / gas reservoir according to the stratum thickness data H(x, y) of the oil / gas bearing horizon and the grid data OTG(x, y) of the oil-to-stratum ratio. The steps (1) and (2) are not in a specific order.

2. The computational method of claim 1, wherein, The stratum thickness data H(x, y) of the oil / gas bearing horizon is calculated according to the top surface data T(x, y) of the oil / gas reservoir structural surface grid and the bottom surface data B(x, y) of the oil / gas reservoir structural surface grid; The H(x, y) = T(x, y) - B(x, y); The unit of the stratum thickness data H(x, y) is meter; and x and y are the longitudinal and transverse coordinate values in the geodetic coordinate system.

3. The computational method of claim 2, wherein, The oil / gas filling ratio P(x, y) of the inner oil / gas bearing boundary is 1. The oil / gas filling ratio P(x, y) of the outer oil / gas bearing boundary is 0.

4. The computational method of claim 3, wherein, The oil / gas filling ratio P(x, y) is calculated by the following formula: P(x, y) = [H(x, y) - S(x, y)] / [T(x, y) - B(x, y)]; Wherein, S(x, y) is the grid data of the oil / water or gas / water interface.

5. The computational method of claim 4, wherein, The contour distribution of the oil / gas filling ratio in the transition zone is determined by P(x, y).

6. The calculation method according to any one of claims 1 to 5, characterized in that, The reservoir-to-stratum ratio RTG of the oil / gas bearing horizon of a single well is: RTG = H Res / H Str ; The H Res is the reservoir thickness at a single well, H Str is the formation thickness at a single well; the H Res is the H Str is measured in meters.

7. The computational method of claim 6, wherein, The plane function RTG(x, y) of the reservoir-to-stratum ratio is obtained by taking the reservoir-to-stratum ratio RTG of the oil / gas bearing horizon of a single well as the input data, taking the seismic attribute surface data related to the reservoir-to-stratum ratio as the constraint surface data, selecting a suitable algorithm, and obtaining the plane function RTG(x, y) of the reservoir-to-stratum ratio.

8. The computational method according to any one of claims 1-7, characterized in that, The grid data OTG(x, y) of the oil-to-stratum ratio is: OTG(x, y) = F(x, y) x RTG(x, y).

9. The computational method according to any one of claims 1-8, characterized in that, The planar distribution data of the effective thickness of the thick blocky oil / gas reservoir obtained in step (8) is the product of the formation thickness data H(x,y) and the grid data OTG(x,y) of the oil-to-land ratio.

10. The computational method according to any one of claims 1-9, characterized in that, The calculation method includes the following steps: (1) Calculate the formation thickness data H(x,y) of the oil / gas strata based on the top and bottom structural surface grid of the oil / gas reservoir; H(x,y) = T(x,y) - B(x,y); where T(x,y) is the top surface data of the structural surface grid of the oil / gas reservoir, and B(x,y) is the bottom surface data of the structural surface grid of the oil / gas reservoir. (2) The grid data S(x,y) of the oil / gas-water interface is determined by comprehensive analysis based on actual well drilling data, formation pressure analysis, fluid sample analysis, etc. (3) Based on the grid of the top and bottom structural surfaces of the oil / gas reservoir and the grid data of the oil / gas-water interface S(x,y), determine the inner oil / gas boundary and the outer oil / gas boundary; the oil / gas filling ratio P(x,y) of the inner oil / gas boundary is 1, the oil / gas filling ratio P(x,y) of the outer oil / gas boundary is 0, and the distribution range of the transition zone between the inner oil / gas boundary and the outer oil / gas boundary is ; The oil / gas filling ratio is P(x,y)=[H(x,y)-S(x,y)] / [T(x,y)–B(x,y)]; where S(x,y) is the oil-water / gas-water interface grid data; (4) Determine the contour lines of the oil / gas filling ratio within the transition zone based on the distribution range of the transition zone; (5) Based on the contour distribution of the oil / gas filling ratio of the inner oil / gas boundary, the outer oil / gas boundary and the transition zone, the contour distribution function F(x,y) of the oil / gas filling ratio of the oil / gas reservoir is obtained. (6) The planar function RTG(x,y) of the reservoir ratio is calculated based on the reservoir ratio of the oil / gas-bearing layers in a single well. The reservoir thickness at the single well is H Res / H Str ; the H Res is the reservoir thickness at the single well, H Str is the formation thickness at the single well; the H Res and H Str are measured in meters; The calculated planar function RTG(x,y) of the reservoir-to-land ratio refers to: using the reservoir-to-land ratio RTG of the oil / gas-bearing layer in a single well as the seismic attribute surface data that is well correlated with the reservoir-to-land ratio as the constraint surface data, and selecting an appropriate algorithm to obtain the planar function RTG(x,y) of the reservoir-to-land ratio. (7) The grid data OTG(x,y) of the oil / gas reservoir is calculated based on the contour distribution function F(x,y) of the oil and gas filling ratio and the plane function RTG(x,y) of the reservoir-to-land ratio. The grid data for the oil-to-land ratio is: OTG(x,y)=F(x,y)×RTG(x,y); (8) The planar distribution data of the effective thickness of thick blocky oil / gas reservoirs is calculated by multiplying the formation thickness data H(x,y) of oil / gas strata with the grid data OTG(x,y) of oil-land ratio. Steps (1) and (2) are not in any particular order.

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