Prediction method for vertical oil and gas transmission efficiency of fault

Abstract

The invention provides a method for predicting the vertical oil and gas transmission efficiency of a fault. The prediction method comprises the following steps: determining the fullness degree of a drilled oil and gas-containing trap in a research area; establishing a function relationship between the fullness degree of the drilled oil-gas-bearing traps and a single geological parameter or a combined geological parameter of a migration fault of each drilled oil-gas-bearing trap through fitting, and obtaining a function relationship with the best correlation with the fullness degree of the drilled oil-gas-bearing traps; and substituting the corresponding geological parameters of the migration fault of the undrilled trap into the optimal function relationship, and calculating to obtain the fullness of the undrilled trap. According to the prediction method, the combined action of various factors is comprehensively considered, the correlation between the factors and the conduction efficiency is comprehensively evaluated before prediction, the factors which have the most remarkable influence on the conduction efficiency in the region are determined, and the vertical oil and gas conduction efficiency of the fault can be accurately and quantitatively predicted.

Description

Technical Field

[0001] The present invention belongs to the field of oil and gas exploration and relates to a method for predicting the vertical oil and gas conduction efficiency of faults. Background Art

[0002] The hydrocarbon source rock that generates oil and gas and the reservoir that stores oil and gas are usually different strata, formed in different geological epochs and buried at different depths underground. After the oil and gas are generated in the hydrocarbon source rock, they need to be transported through migration channels to the reservoir to form an oil and gas reservoir. Faults can connect hydrocarbon source rocks and reservoirs of different epochs and are one of the main channels for oil and gas conduction. The vertical conduction of oil and gas along the fault plane is the main way for faults to conduct oil and gas. Quantitatively predicting the efficiency of the vertical oil and gas conduction of faults is of great significance for oil and gas exploration. However, there are many factors affecting the vertical conduction efficiency of faults, including the geometric shape of the fault plane, the contact area between the fault and the reservoir sand body, the thickness of the mudstone penetrated during the oil and gas migration process, the activity intensity of the fault during the conduction period, etc. In different study areas, the control effects of these factors on the fault conduction efficiency are also different.

[0003] At present, the methods for predicting the fault conduction efficiency adopted by the academic community mainly include qualitative prediction, prediction based on the geometric shape of the fault plane, and prediction based on the activity intensity of the fault. When these methods are applied to a certain study area, they often only consider one or several influencing factors and lack an assessment of the combined effects of all factors, so accurate quantitative prediction cannot be carried out. At present, there is no technical method for comprehensively and systematically evaluating the influencing factors of the vertical fault conduction efficiency and quantitatively predicting the conduction efficiency. Summary of the Invention

[0004] To solve the problems existing in the prior art, the present invention provides a method for predicting the vertical oil and gas conduction efficiency of faults. This prediction method comprehensively considers the combined effects of various factors, comprehensively evaluates the correlation between these factors and the conduction efficiency before prediction, determines the factors that have the most significant influence on the conduction efficiency in this area, and can accurately quantitatively predict the vertical oil and gas conduction efficiency of faults.

[0005] To achieve the above technical effects, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for predicting the vertical oil and gas conduction efficiency of faults, which includes:

[0007] Determine the filling degree of the drilled hydrocarbon-bearing traps in the study area;

[0008] Establish a functional relationship between the filling degree of the drilled hydrocarbon-bearing traps and the single geological parameter or combined geological parameters of the migration faults of each drilled hydrocarbon-bearing trap by fitting, and obtain the functional relationship with the best correlation with the filling degree of the drilled hydrocarbon-bearing traps;

[0009] Substitute the corresponding geological parameters of the migration faults of the un-drilled traps into the optimal functional relationship to calculate the filling degree of the un-drilled traps.

[0010] As a preferred technical solution of the present invention, the number of drilled hydrocarbon-bearing traps in the study area is not less than 3.

[0011] As a preferred technical solution of the present invention, the geological parameters of the migration faults of the drilled hydrocarbon-bearing traps are obtained through seismic interpretation and structural evolution analysis.

[0012] As a preferred technical solution of the present invention, the geological parameters of the migration faults of the drilled hydrocarbon-bearing traps include the included angle between the section ridge and the fault plane, the dip angle of the fault plane, the contact area with the reservoir sand body, the vertical thickness of the mudstone passed through during hydrocarbon migration, and the throw generated by fault activity during the hydrocarbon migration period.

[0013] As a preferred technical solution of the present invention, the combined geological parameters are obtained through mathematical operations on different single geological parameters.

[0014] As a preferred technical solution of the present invention, the mathematical operations used to obtain the combined geological parameters include any one or a combination of at least two of addition operation, subtraction operation, multiplication operation, division operation, power operation, square root operation, or trigonometric function operation.

[0015] As a preferred technical solution of the present invention, the fitting method includes regression analysis.

[0016] As a preferred technical solution of the present invention, through the determination coefficient R of the functional relationship 2 Judge the correlation between the filling degree of the drilled hydrocarbon-bearing traps and the single geological parameter or combined geological parameter of the migration faults.

[0017] As a preferred technical solution of the present invention, the determination coefficient R of the functional relationship with the best correlation with the filling degree of the drilled hydrocarbon-bearing traps 2 is not less than 0.7.

[0018] As a preferred technical solution of the present invention, the corresponding geological parameters of the migration faults of the un-drilled traps are obtained using the same seismic interpretation and structural evolution analysis as the geological parameters of the migration faults of the drilled hydrocarbon-bearing traps.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects:

[0020] The present invention provides a method for predicting the vertical hydrocarbon conduction efficiency of faults. Compared with the existing fault conduction efficiency prediction methods that only consider one or several influencing factors commonly used in the academic community, this prediction method comprehensively considers the combined effects of multiple factors, and comprehensively evaluates the correlation between these factors and the conduction efficiency before prediction to determine the factors that have the most significant impact on the conduction efficiency in this area, and can accurately quantitatively predict the vertical hydrocarbon conduction efficiency of faults. Description of the Drawings

[0021] Figure 1 It is a schematic diagram of geological parameters of the migration fault.

[0022] Figure 2 It is a regression analysis diagram of the influencing factor X1 and the closed-loop filling degree P in Example 1.

[0023] Figure 3 It is a regression analysis diagram of the influencing factor X2 and the closed-loop filling degree P in Example 1.

[0024] Figure 4 It is a regression analysis diagram of the influencing factor X3 and the closed-loop filling degree P in Example 1.

[0025] Figure 5 It is a regression analysis diagram of the influencing factor X4 and the closed-loop filling degree P in Example 1.

[0026] Figure 6 It is a regression analysis diagram of the influencing factor X5 and the closed-loop filling degree P in Example 1.

[0027] Figure 7 It is a regression analysis diagram of the influencing factor X6 and the closed-loop filling degree P in Example 1.

[0028] Figure 8 It is a regression analysis diagram of the influencing factor X7 and the closed-loop filling degree P in Example 1.

[0029] Figure 9 It is a regression analysis diagram of the influencing factor X8 and the closed-loop filling degree P in Example 1.

[0030] Figure 10 It is a regression analysis diagram of the influencing factor X9 and the closed-loop filling degree P in Example 1.

[0031] Figure 11 It is a regression analysis diagram of the influencing factor X 10 and the closed-loop filling degree P.

[0032] Figure 12 It is a regression analysis diagram of the influencing factor X 11 and the closed-loop filling degree P.

[0033] Figure 13 It is a regression analysis diagram of the influencing factor X 12 and the closed-loop filling degree P.

[0034] Figure 14 It is a regression analysis diagram of the influencing factor X 13 and the closed-loop filling degree P.

[0035] Figure 15For influencing factor X in Example 1 14 Regression analysis chart of it and closed-loop fullness P.

[0036] Figure 16 For influencing factor X in Example 1 15 Regression analysis chart of it and closed-loop fullness P.

[0037] Figure 17 For influencing factor X in Example 1 16 Regression analysis chart of it and closed-loop fullness P.

[0038] The present invention will be further described in detail below. However, the following examples are merely simple examples of the present invention and do not represent or limit the scope of the protection of the present invention. The scope of protection of the present invention shall be subject to the claims. Specific embodiments

[0039] The technical solution of the present application will be further described below through specific embodiments.

[0040] The specific embodiment of the present invention provides a method for predicting the vertical oil and gas conduction efficiency of a fault. The prediction method includes:

[0041] Determine the fullness of the drilled oil and gas traps in the study area;

[0042] Establish a functional relationship between the fullness of the drilled oil and gas traps and the single geological parameter or combined geological parameters of the migration faults of each drilled oil and gas trap through fitting, and obtain the functional relationship with the best correlation with the fullness of the drilled oil and gas traps;

[0043] Substitute the corresponding geological parameters of the migration faults of the undrilled traps into the best functional relationship to calculate the fullness of the undrilled traps.

[0044] In a specific embodiment of the present invention, the application of the prediction method has certain requirements for the study area. The drilled oil and gas traps and the predicted traps in the study area have the same and clear oil and gas sources, and the main migration mode of the oil and gas is vertical migration along the fault. The reservoirs in the study area can be accurately characterized by conventional geological methods, geophysical methods, three-dimensional geological modeling methods, dynamic data constraints and other methods.

[0045] In a specific embodiment of the present invention, the number of drilled oil and gas traps in the study area is not less than 3, such as 3, 4, 5, 6, 7, 8, 9 or 10, etc., but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0046] In a specific embodiment of the present invention, the fullness refers to the ratio of the effective pore volume occupied by the oil and gas in the oil and gas trap to the total effective pore volume of the trap. The formula is:

[0047] Degree of filling = (pore volume occupied by oil and gas / total effective pore volume of the trap) × 100%.

[0048] In a specific embodiment of the present invention, the specific measurement method of the degree of filling is a conventional method in the art and will not be further limited herein. For example, the degree of filling can be determined by combining methods such as geological and geophysical analysis, well logging interpretation, core and laboratory analysis, and dynamic data verification.

[0049] In a specific embodiment of the present invention, the geological parameters of the migration faults of the drilled oil and gas traps are obtained through seismic interpretation and tectonic evolution analysis. Among them, seismic interpretation and tectonic evolution analysis are conventional methods in the art for obtaining geological parameters, and the process thereof will not be further limited herein.

[0050] In a specific embodiment of the present invention, the single geological parameters of the migration faults of the drilled oil and gas traps include the cross-sectional ridge angle α, cross-sectional dip angle β, contact area S with the reservoir sand body, vertical thickness T of the mudstone penetrated during oil and gas migration, and fault throw D generated by fault activity during the oil and gas migration period, as Figure 1 shown. Not limited to the above single geological parameters, other parameters that may affect the vertical oil and gas conduction efficiency of the fault are also applicable to this prediction method.

[0051] In a specific embodiment of the present invention, the combined geological parameters are obtained by mathematical operations on different single geological parameters.

[0052] In a specific embodiment of the present invention, the mathematical operations used to obtain the combined geological parameters include any one or a combination of at least two of addition operation, subtraction operation, multiplication operation, division operation, power operation, square root operation, or trigonometric function operation. Not limited to the above mathematical operation methods, other achievable mathematical operation methods are also applicable to this prediction method.

[0053] In a specific embodiment of the present invention, it is assumed that there are n (n≥1) migration faults in the drilled oil and gas trap, and the cross-sectional ridge angle of the jth (1≤j≤n) migration fault is α j (90 < α < 180, unit: °), the cross-sectional dip angle is β j (0 < β < 90, unit: °), the contact area with the reservoir sand body is S j (unit: m 2 ), the vertical thickness of the mudstone penetrated during oil and gas migration is T j (unit: m), and the fault throw generated by fault activity during the oil and gas migration period is D j (unit: m), then the single geological parameters or combined geological parameters of the n migration faults of this oil and gas trap are shown in Table 1.

[0054] Table 1

[0055]

[0056] In a specific embodiment of the present invention, the fitting method includes regression analysis. Among them, regression analysis can be carried out using common calculation software such as EXCEL or MATLAB, and the specific method is not further limited herein.

[0057] In a specific embodiment of the present invention, through the determination coefficient R of the functional relationship 2 Judge the correlation between the filling degree of the drilled hydrocarbon-bearing trap and the single geological parameter or combined geological parameters of the migration fault. Among them, the determination coefficient R 2 Can be obtained synchronously in the regression analysis, and the specific method is not further limited herein.

[0058] In a specific embodiment of the present invention, the determination coefficient R of the functional relationship with the best correlation with the filling degree of the drilled hydrocarbon-bearing trap 2 Is not less than 0.7, such as 0.75, 0.80, 0.85, 0.90 or 0.95, etc., but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0059] In a specific embodiment of the present invention, if the determination coefficient R of the functional relationship with the best correlation with the filling degree of the drilled hydrocarbon-bearing trap 2 Is less than 0.7, it indicates that the prediction method is not applicable to the study area under the current conditions.

[0060] In a specific embodiment of the present invention, the corresponding geological parameters of the migration fault of the undrilled trap are obtained by using the same seismic interpretation and tectonic evolution analysis as those of the migration fault of the drilled hydrocarbon-bearing trap.

[0061] In a specific embodiment of the present invention, if the best functional relationship is set as P = f(X k ), then the corresponding X of the migration fault of the undrilled trap is obtained through seismic interpretation and tectonic evolution analysis k Geological parameters, such as the cross-section ridge angle α, cross-section dip angle β, contact area S with the reservoir sand body, vertical thickness T of the mudstone penetrated during hydrocarbon migration, and fault throw D generated by fault activity during hydrocarbon migration period or a combination of each parameter, and the corresponding X k The parameters are substituted into P = f(X k ) to calculate the filling degree of the undrilled trap.

[0062] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, the typical but non-limiting embodiments of the present invention are as follows:

[0063] Example 1

[0064] This embodiment provides a method for predicting the vertical hydrocarbon conduction efficiency of faults. The prediction method includes:

[0065] The M gas field in a certain basin contains 8 drilled hydrocarbon-bearing traps M① - M⑧. The migration faults and filling degrees of each drilled trap are shown in Table 2.

[0066] Using seismic interpretation and tectonic evolution analysis, the included angle between the fault plane ridge of each migration fault is α j (90 < α < 180, unit: °), the dip angle of the fault plane is β j (0 < β < 90, unit: °), the contact area with the reservoir sand body is S j (unit: m 2 ), the vertical thickness of the mudstone through which the hydrocarbon migrates is T j (unit: m), the fault throw generated by fault activity during the hydrocarbon migration period is D j (unit: m), as specifically shown in Table 2.

[0067] Table 2

[0068]

[0069] Calculate the single geological parameter or combined geological parameters of all migration faults in each drilled trap according to Table 1. The calculation results are shown in Table 3.

[0070] Table 3

[0071]

[0072] Through regression analysis, fit the functional relationship between the filling degree of the drilled traps and the parameters in Table 1, and obtain the determination coefficient R corresponding to each functional relationship 2 , and the results are shown in Table 4 and Figures 2 to 17 .

[0073] Table 4

[0074] Influencing factors Fitting function relationship <![CDATA[Coefficient of determination R 2 > <![CDATA[X1]]> <![CDATA[P = 0.1827ln(X1)-1.082]]> 0.7793 <![CDATA[X2]]> <![CDATA[P = 0.1816ln(X2)-1.1064]]> 0.7783 <![CDATA[X3]]> <![CDATA[P = 0.1853ln(X3)-1.0941]]> 0.7708 <![CDATA[X4]]> <![CDATA[P = 0.2035ln(X4)-2.5813]]> 0.8309 <![CDATA[X5]]> <![CDATA[P = 0.182ln(X5)-0.3867]]> 0.7675 <![CDATA[X6]]> <![CDATA[P = 0.2037ln(X6)-1.8142]]> 0.8224 <![CDATA[X7]]> <![CDATA[P = 0.1805ln(X7)-0.4132]]> 0.7648 <![CDATA[X8]]> <![CDATA[P = 0.185ln(X8)-0.3936]]> 0.765 <![CDATA[X9]]> <![CDATA[P = 0.2023ln(X9)-2.6019]]> 0.8303 <![CDATA[X 10 > <![CDATA[P = 0.2071ln(X 10 ) - 2.626]]> 0.8262 <![CDATA[X 11 > <![CDATA[P = 0.1844ln(X 11 ) - 1.1211]]> 0.7699 <![CDATA[X 12 > <![CDATA[P = 0.202ln(X 12 ) - 1.8331]]> 0.8198 <![CDATA[X 13 > <![CDATA[P = 0.2081ln(X 13 ) - 1.8574]]> 0.8258 <![CDATA[X 14 > <![CDATA[P = 0.1837ln(X 14 ) - 0.4213]]> 0.7622 <![CDATA[X 15 > <![CDATA[P = 0.2063ln(X 15 ) - 2.6532]]> 0.8262 <![CDATA[X 16 > <![CDATA[P = 0.2067ln(X 16 ) - 1.8803]]> 0.8233

[0075] The functional relationship corresponding to the maximum determination coefficient R 2 is P = 0.2035ln(X4) - 2.5813, and R 2 > 0.7.

[0076] The N gas field is about 14 km away from the M gas field. The two have similar source rock conditions and tectonic evolution histories. To test the application effect of the present invention, 4 drilled traps N① - N④ in the N gas field are selected to verify the prediction results. The migration faults and their parameters, predicted trap filling degrees, actual trap filling degrees, and prediction error rates of the 4 traps are shown in Table 5. The prediction error rates of the 4 traps in the N gas field are all below 20%, indicating that the present invention has a good application effect in this research area.

[0077] Table 5

[0078]

[0079] The applicant declares that the detailed structural features of the present invention are illustrated by the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of the components selected for the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

[0080] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0081] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any suitable way. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0082] Furthermore, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A method for predicting the vertical hydrocarbon conduction efficiency of a fault, characterized in that, The prediction method includes: Determining the filling degree of the drilled hydrocarbon-bearing traps in the study area; Establishing a functional relationship between the filling degree of the drilled hydrocarbon-bearing traps and the single geological parameter or combined geological parameters of the migration faults of each drilled hydrocarbon-bearing trap through fitting, and obtaining the functional relationship with the best correlation with the filling degree of the drilled hydrocarbon-bearing traps; Substituting the corresponding geological parameters of the migration faults of the un-drilled traps into the best functional relationship to calculate the filling degree of the un-drilled traps.

2. The prediction method according to claim 1, wherein The number of drilled hydrocarbon-bearing traps in the study area is not less than 3.

3. The prediction method according to claim 1, characterized in that The geological parameters of the migration faults of the drilled hydrocarbon-bearing traps are obtained through seismic interpretation and tectonic evolution analysis.

4. The prediction method according to claim 1, wherein The single geological parameters of the migration faults of the drilled hydrocarbon-bearing traps include the included angle between the section ridge and the fault surface, the dip angle of the fault surface, the contact area with the reservoir sand body, the vertical thickness of the mudstone penetrated during hydrocarbon migration, and the throw generated by fault activity during hydrocarbon migration period.

5. The prediction method according to claim 1, wherein The combined geological parameters are obtained through mathematical operations of different single geological parameters.

6. The prediction method according to claim 5, wherein The mathematical operations used to obtain the combined geological parameters include any one or a combination of at least two of addition operation, subtraction operation, multiplication operation, division operation, power operation, square root operation or trigonometric function operation.

7. The prediction method according to claim 1, wherein The fitting method includes regression analysis.

8. The prediction method according to claim 1, characterized in that Determination coefficient R of the function relationship 2 Judge the correlation between the filling degree of the drilled hydrocarbon-bearing trap and the single geological parameter or combined geological parameters of the migration fault.

9. The prediction method according to claim 8, characterized in that The determination coefficient R of the functional relationship with the best correlation with the fill degree of the drilled hydrocarbon-bearing trap 2 is not less than 0.

7.

10. The prediction method according to claim 1, wherein The corresponding geological parameters of the migration faults of the un-drilled traps are obtained using the same seismic interpretation and tectonic evolution analysis as the geological parameters of the migration faults of the drilled hydrocarbon-bearing traps.

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