Strike-slip breaking control carbonate rock fracture-cavity reservoir fluid discrimination method and application thereof

Abstract

The invention provides a strike-slip breaking control carbonate rock fracture-cavity reservoir fluid discrimination method and application thereof, and relates to the field of oil exploration and development. The distinguishing method comprises the following steps: S1, collecting gas logging display data and an oil testing result; s2, classifying the gas logging display data according to the type of the oil testing result; s3, processing the gas logging display data according to the type of the oil testing result; s4, calculating and obtaining two fluid discrimination parameters delta WH and delta lg; s5, establishing a logarithmic coordinate system according to the two fluid discrimination parameters, and establishing a gas logging chart according to the distribution condition of various data points in the logarithmic coordinate system; and projecting a new well to be explained to the gas logging plate to judge the fluid property. According to the judgment method, reservoir fluid properties can be judged in advance, the interpretation accuracy of an oil and gas reservoir is improved, and the oil and gas discovery rate of a new area and a new horizon is increased.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas exploration and development, and specifically relates to a method for distinguishing fluid in a strike-slip fault-controlled carbonate fracture-vuggy reservoir and an application thereof. Background Art

[0002] During oil and gas exploration, the main production layers of some oil and gas fields are ultra-deep strike-slip fault-controlled carbonate fracture-cave reservoirs, which have strong vertical and horizontal porosity and permeability heterogeneity, complex and changeable oil, gas and water layers, and various types of oil and gas reservoirs. In order to uncover more reservoirs to build high-yield wells, people often design high-yield wells as large-angle inclined wells or horizontal wells, and use mixed oil mud or oil-based mud during the drilling of the target layer, resulting in high and unstable gas logging background values.

[0003] At present, the commonly used gas logging interpretation system for comprehensive logging instruments in oil and gas fields for strike-slip fault-controlled carbonate fracture-cavity reservoirs is an empirical gas logging interpretation chart for sandstone oil and gas reservoirs. However, it is not applicable to the interpretation of carbonate oil and gas reservoirs, the gas logging display level does not correspond to the oil test results and industrial production capacity, and there are many shortcomings such as single gas logging interpretation evaluation method, scattered parameters, and rough accuracy in oil and gas fields. It cannot provide new technical evaluation basis and suggestions in drilling production and completion plan decision-making.

[0004] In addition, among the related technologies, gas logging technology is an indirect technology for evaluating reservoirs, which mainly determines the properties of formation fluids by measuring the composition and content of hydrocarbons in drilling fluids. At present, the commonly used gas logging interpretation charts are Pixler charts, triangle charts, and 3H charts. Although the above-mentioned technologies and charts have good application effects in oil and gas interpretation of clastic oil and gas reservoirs, they are very inadequate in identifying oil, gas and water in carbonate reservoirs. For example, there are data points of different fluid properties that are mixed and difficult to distinguish; there are many shortcomings such as poor practicality in judging fluids in mixed oil mud or oil-based mud.

[0005] Chinese invention patent 202011154813.8 discloses a normalization method, device, computer equipment and storage medium for wave impedance curves, wherein the method includes: obtaining the lithology data of the drilling, dividing the lithology types in the lithology data; assigning a grade to each lithology type, calibrating the grade assignment of each lithology type, and obtaining a lithology curve; normalizing the wave impedance curve by absolute value; adding the wave impedance curve after absolute value normalization and the lithology curve at the corresponding depth to obtain a normalized wave impedance curve. This scheme realizes the use of lithology curves in the process of normalizing the wave impedance curve, realizes the normalization of the wave impedance curve according to the lithology grade, so that the normalized wave impedance curve takes into account the sedimentary phase and sedimentary cycle, which is conducive to improving the lithology sensitivity of the normalized wave impedance curve, and then helps to improve the accuracy of the normalized wave impedance curve.

[0006] Chinese invention patent 201811038729.2 discloses a method for judging reservoir fluid properties by using the gas logging peak morphology, including the following steps: a. Selecting abnormal gas logging sections; b. Calculating the skewness coefficient and kurtosis coefficient of the abnormal gas logging sections; c. Establishing a peak type chart based on the skewness coefficient and kurtosis coefficient; d. Judging the reservoir fluid properties based on the established peak type chart. The peak type chart established by the invention can effectively distinguish between gas layers and non-gas layers, and the accuracy of gas layer determination reaches 80%. However, the invention focuses on the automatic identification, morphological description and chart implementation of single gas logging display peaks, and focuses on the openness of automatic calculation and chart discrimination by face computer, and does not provide a record of judging the fluid properties of strike-slip fault-controlled carbonate fracture-cave reservoirs based on charts drawn based on gas logging peak values ​​and gas logging base values ​​of total alkanes and various combustible gases.

[0007] Therefore, there is an urgent need for a method to identify fluids in strike-slip fault-controlled carbonate fracture-vuggy reservoirs and to provide new gas logging maps to determine reservoir fluid properties in advance, improve the accuracy of oil and gas layer interpretation, and increase the oil and gas discovery rate in new areas and new strata. Summary of the invention

[0008] In view of the problems existing in the prior art, the present invention provides a method for identifying fluid in strike-slip fault-controlled carbonate fracture-vuggy reservoirs and its application, which solves the problems that commonly used gas logging interpretation plates are not applicable to carbonate oil and gas reservoirs, the fluid identification in carbonate reservoirs is difficult, and the fluid identification in the case of mixed oil mud or oil-based mud is poor in practicality, provides a supporting basis for the formulation of completion plans, improves the accuracy of oil and gas layer interpretation, and increases the oil and gas discovery rate in new areas and new layers.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0010] First, the present invention provides a method for identifying fluid in a strike-slip fault-controlled carbonate fracture-vuggy reservoir, comprising the following steps:

[0011] S1. Collect gas test display data and oil test results;

[0012] S2. Classify the gas test display data according to the category of oil test results;

[0013] S3. Process the gas test display data according to the type of oil test results;

[0014] S4, calculate and obtain two fluid discrimination parameters, humidity coefficient ΔWH and dryness coefficient Δlg;

[0015] S5. A logarithmic coordinate system is established according to the two fluid discrimination parameters, and a gas logging map is established according to the distribution of various data points in the logarithmic coordinate system; the new well to be interpreted is projected onto the gas logging map to determine the fluid properties.

[0016] Preferably, in step S1, the gas logging display data and oil test results are collected from the logging oil and gas display segments of each well test, and are the gas logging display data and oil test results of the logging oil and gas display segments.

[0017] Preferably, in step S2, the classification is specifically: according to the category of the oil test result, the gas testing display data of the logging oil and gas display sections of each well test with the same oil test result category are classified.

[0018] Further preferably, the categories of the oil test results are oil layer, water layer and gas layer.

[0019] Preferably, in step S3, the gas logging display data is processed, specifically: obtaining the total alkane gas logging peak value, the gas logging peak value of each combustible gas, the total alkane gas logging base value and the gas logging base value of each combustible gas in the logging display segment of the logging oil and gas logging display data, and performing difference calculations to obtain the difference between the total alkane gas logging peak value and the gas logging base value, and the difference between the gas logging peak value and the gas logging base value of each combustible gas.

[0020] Further preferably, the gas measurement peak value of the total alkanes is TG; the gas measurement peak values ​​of the combustible gases are respectively: C1, C2, C3, iC4, nC4, iC5, nC5; the gas measurement base value of the total alkanes is TG'; the gas measurement base values ​​of the combustible gases are respectively: C1', C2', C3', iC4', nC4', iC5', nC5'; TG represents the gas measurement peak value of the total alkanes, TG' represents the gas measurement base value of the total alkanes; C1 represents the gas measurement peak value of methane, C1' represents the methane gas measurement base value, C2 represents the ethane gas measurement peak value, C2' represents the ethane gas measurement base value, C3 represents the propane gas measurement peak value, C3' represents the propane gas measurement base value, iC4 represents the isobutane gas measurement peak value, iC4' represents the isobutane gas measurement base value, nC4 represents the normal butane gas measurement peak value, nC4' represents the normal butane gas measurement base value, iC5 represents the isopentane gas measurement peak value, iC5' represents the isopentane gas measurement base value, nC5 represents the normal pentane gas measurement peak value, and nC5' represents the normal pentane gas measurement base value.

[0021] Further preferably, the difference between the gas-measured peak value and the gas-measured base value of total alkanes is ΔTG; the differences between the gas-measured peak value and the gas-measured base value of each combustible gas are: ΔC1, ΔC2, ΔC3, ΔiC4, ΔnC4, ΔiC5, ΔnC5, respectively.

[0022] Further preferably, the formula for calculating the difference is:

[0023] The difference between the gas measurement peak value and the gas measurement base value of total alkanes is calculated as follows: ΔTG = TG-TG', where TG represents the gas measurement peak value of total alkanes and TG' represents the gas measurement base value of total alkanes;

[0024] The difference calculation formula between the gas measurement peak value and the gas measurement base value of each combustible gas is as follows: ΔC1=C1-C1', ΔC2=C2-C2', ΔC3=C3-C3', ΔiC4=iC4-iC4', ΔnC4=nC4-nC4', ΔiC5=iC5-iC5', ΔnC5=nC5-nC5'; C1 represents the methane gas measurement peak value, C1' represents the methane gas measurement base value, and C2 represents the ethane gas measurement peak value. value, C2' represents the ethane gas measurement base value, C3 represents the propane gas measurement peak value, C3' represents the propane gas measurement base value, iC4 represents the isobutane gas measurement peak value, iC4' represents the isobutane gas measurement base value, nC4 represents the normal butane gas measurement peak value, nC4' represents the normal butane gas measurement base value, iC5 represents the isopentane gas measurement peak value, iC5' represents the isopentane gas measurement base value, nC5 represents the normal pentane gas measurement peak value, and nC5' represents the normal pentane gas measurement base value.

[0025] Preferably, in step S4, the calculation formula of ΔWH is: ΔWH=[(ΔC2+ΔC3+ΔiC4+ΔnC4+ΔiC5+ΔnC5) / (ΔC1+ΔC2+ΔC3+ΔiC4+ΔnC4+ΔiC5+ΔnC5)].

[0026] Preferably, in step S4, the calculation formula of Δlg is: Δlg=lg(ΔC1 / ΔC2).

[0027] In the present invention, the ΔWH is the humidity coefficient, reflecting the relative abundance of heavy hydrocarbons; and the Δlg is the dryness coefficient, reflecting the relative abundance of light hydrocarbons.

[0028] Preferably, in step S5, the fluid property is determined by projecting the new well to be interpreted onto the gas logging map, and determining the fluid property according to the landing area.

[0029] Then, the present invention provides a gas measurement chart established by the above-mentioned identification method.

[0030] Finally, the present invention provides the application of the above-mentioned gas survey chart in oil and gas exploration and development.

[0031] Preferably, the application is: using the gas logging map established by the discrimination method to judge carbonate oil and gas reservoirs, judge the fluid properties of carbonate reservoirs, and judge oil, gas and water layers.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The discrimination method provided by the present invention can effectively solve the problems that the commonly used gas logging interpretation chart is not applicable to carbonate oil and gas reservoirs, the fluid judgment of carbonate reservoirs is difficult, and the fluid judgment in the case of mixed oil mud or oil-based mud is poor in practicality. The new oil-water identification chart has a good recognition application effect and a high accuracy rate.

[0034] 2. The identification method provided by the present invention can determine the reservoir fluid properties in advance, improve the accuracy of oil and gas layer interpretation, and increase the oil and gas discovery rate in new areas and new strata.

[0035] 3. The gas measurement chart established by the discrimination method of the present invention is also applicable to carbonate oil and gas reservoirs, and solves the difficult problems of difficult fluid judgment in carbonate reservoirs and poor practicality of fluid judgment in mixed oil mud or oil-based mud. It has good application effect and high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is an overall flow chart of the discrimination method described in the embodiment of the present invention.

[0037] Figure 2 It is a detailed flow chart of step S2 of the embodiment of the present invention.

[0038] Figure 3 It is a schematic diagram of gas logging display data of a part of the oil and gas display section of the logging in step S3 of the embodiment of the present invention.

[0039] Figure 4 It is the gas measurement chart of the embodiment of the present invention.

[0040] Figure 5 This is a plate obtained using traditional methods. DETAILED DESCRIPTION

[0041] The following non-limiting examples can make those of ordinary skill in the art understand the present invention more comprehensively, but do not limit the present invention in any way. The following content is merely an exemplary description of the scope of the present invention, and those skilled in the art can make various changes and modifications to the present invention according to the disclosed content, and it should also belong to the scope of the present invention. When the embodiment gives a numerical range, it should be understood that, unless otherwise specified in the present invention, the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those of ordinary skill in the technical field to which the present invention belongs.

[0042] The present invention will be further described below by way of specific embodiments.

[0043] Example 1

[0044] A method for identifying fluid in strike-slip fault-controlled carbonate fracture-vuggy reservoirs. Figure 1 The overall flow chart for fluid identification is as follows:

[0045] S1. Collect the gas test display data and oil test results of the oil and gas display section of each well test;

[0046] S2. Classifying the gas logging display data of the oil and gas display sections of each well logging test having the same oil testing result category according to the category of the oil testing result;

[0047] Figure 2 The detailed flowchart of step S2 of the discrimination method of the embodiment of the present invention is further detailed; specifically, in step 2, the gas test display data of the logging oil and gas display sections of each well test of the same category are classified according to the oil test results as oil layer, water layer, and gas layer;

[0048] S3. According to the category of the oil test result, the logging oil and gas display data of the logging oil and gas display section is processed. The specific steps are as follows:

[0049] The total alkane gas measurement peak value, the gas measurement peak value of each combustible gas, the total alkane gas measurement base value and the gas measurement base value of each combustible gas in the logging oil and gas measurement display data of the logging display section are obtained, and the difference calculation is performed respectively to obtain the difference between the total alkane gas measurement peak value and the gas measurement base value, and the difference between the gas measurement peak value and the gas measurement base value of each combustible gas.

[0050] The gas-measured peak value of the total alkanes is TG; the gas-measured peak values ​​of the combustible gases are C1, C2, C3, iC4, nC4, iC5, and nC5; the gas-measured base value of the total alkanes is TG'; the gas-measured base values ​​of the combustible gases are C1', C2', C3', iC4', nC4', iC5', and nC5'. The difference between the gas-measured peak value and the gas-measured base value of the total alkanes is ΔTG; the difference between the gas-measured peak value and the gas-measured base value of the combustible gases is ΔC1, ΔC2, ΔC3, ΔiC4, ΔnC4, ΔiC5, and ΔnC5.

[0051] The difference between the gas measurement peak value and the gas measurement base value of total alkanes is calculated as follows: ΔTG = TG-TG', where TG represents the gas measurement peak value of total alkanes and TG' represents the gas measurement base value of total alkanes;

[0052] The difference calculation formula between the gas measurement peak value and the gas measurement base value of each combustible gas is as follows: ΔC1=C1-C1', ΔC2=C2-C2', ΔC3=C3-C3', ΔiC4=iC4-iC4', ΔnC4=nC4-nC4', ΔiC5=iC5-iC5', ΔnC5=nC5-nC5'; C1 represents the methane gas measurement peak value, C1' represents the methane gas measurement base value, and C2 represents the ethane gas measurement peak value. value, C2' represents the ethane gas measurement base value, C3 represents the propane gas measurement peak value, C3' represents the propane gas measurement base value, iC4 represents the isobutane gas measurement peak value, iC4' represents the isobutane gas measurement base value, nC4 represents the normal butane gas measurement peak value, nC4' represents the normal butane gas measurement base value, iC5 represents the isopentane gas measurement peak value, iC5' represents the isopentane gas measurement base value, nC5 represents the normal pentane gas measurement peak value, and nC5' represents the normal pentane gas measurement base value.

[0053] in, Figure 3 A schematic diagram of gas logging display data of a part of the oil and gas display section of the well logging in step S3 of the discrimination method of the embodiment of the present invention is given. Figure 3 As shown, specifically, step 3 mainly includes two steps:

[0054] (1) Obtain the gas logging peak value and gas logging base value of total alkanes and each combustible gas in the logging oil and gas logging display data of the logging display section; the gas logging peak value is the value at which the gas logging values ​​of total alkanes and each combustible gas reach the maximum value when the logging oil and gas is displayed; the gas logging base value is the value at which the gas logging values ​​of total alkanes and each combustible gas are relatively stable before the logging oil and gas is displayed; the logging oil and gas logging display data can be understood as Figure 3 The gas measurement curve in Figure 3 The gas test curves of total alkanes and some components in all gas test curves of various combustible gases are shown in FIG.

[0055] (2) Calculate and obtain the difference between the gas measurement peak value and the gas measurement base value of the total alkane and each combustible gas;

[0056] S4. Calculate and obtain two fluid discrimination parameters, ΔWH and Δlg, by the following formula;

[0057] in,

[0058] ΔWH=[(ΔC2+ΔC3+ΔiC4+ΔnC4+ΔiC5+ΔnC5 / (ΔC1+ΔC2+ΔC3+ΔiC4+ΔnC4+ΔiC5+ΔnC5)]; Δlg=lg(ΔC1 / ΔC2), where the meaning of each letter is the same as that of the letters in step S3.

[0059] S5. A logarithmic coordinate system is established based on the two fluid discrimination parameters, and a gas logging chart is established based on the distribution of various data points in the logarithmic coordinate system. Then, the new well to be interpreted is projected onto the gas logging chart, and the fluid properties are determined based on the landing area.

[0060] Figure 4 This is the gas measurement chart obtained according to the above embodiment of the present invention.

[0061] The above discrimination method was used to judge 11 new wells, and the judgment results were as follows: 8 wells in the oil layer all met the requirements; 1 well in the gas layer met the requirements; 1 well in the oil-bearing water-bearing layer did not meet the requirements; and 1 well in the water layer did not meet the requirements. This shows that the discrimination method of the present invention has a good application effect in the new oil-water identification chart. Among the 11 wells, 9 wells met the requirements for the judgment of fluid properties, with a compliance rate of more than 75%.

[0062] The gas measurement chart established by traditional methods includes Figure 5The triangle chart, ratio chart, logarithmic chart, and 3H chart shown. Figure 5 It can be seen that, compared with the discrimination method described in the present invention, the gas logging chart of the traditional method does not perform statistical analysis on the correspondence between a large number of logging oil and gas display sections and oil test results in the work area, does not consider the mixed oil mud or oil-based mud, and does not consider the strong vertical and horizontal porosity and permeability heterogeneity of carbonate oil and gas reservoirs, resulting in large differences or complete differences in the interpretation conclusions of different traditional methods in judging fluids. It is not applicable to the interpretation of carbonate oil and gas reservoirs, does not correspond to the oil test results, has poor practicability, and has poor effects.

[0063] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for identifying fluid in strike-slip fault-controlled carbonate fracture-vuggy reservoirs. It is characterized in that Includes steps: S1. Collect gas test display data and oil test results; S2. Classify the gas test display data according to the category of oil test results; S3. Process the gas test display data according to the category of the oil test result; S4, calculate and obtain two fluid discrimination parameters ΔWH and Δlg; S5. Establish a logarithmic coordinate system according to the above two fluid discrimination parameters, and establish a gas measurement chart according to the distribution of various data points in the logarithmic coordinate system; Project the new well to be interpreted onto the above-mentioned gas logging chart to determine the fluid properties.

2. The determination method according to claim 1, It is characterized in that In step S1, the gas logging display data and oil test results are collected from the logging oil and gas display segments of each well test, and are the gas logging display data and oil test results of the logging oil and gas display segments.

3. The identification method according to claim 1, It is characterized in that In step S2, the classification is specifically: according to the category of the oil test result, the gas testing display data of the logging oil and gas display section of each test well with the same oil test result category are classified.

4. The determination method according to claim 3, It is characterized in that The categories of the oil test results are oil layer, water layer and gas layer.

5. The identification method according to claim 1, It is characterized in that In step S3, the gas logging display data is processed, specifically: obtaining the total alkane gas logging peak value, the gas logging peak value of each combustible gas, the total alkane gas logging base value and the gas logging base value of each combustible gas in the logging display segment of the logging oil and gas logging display data, and performing difference calculations to obtain the difference between the total alkane gas logging peak value and the gas logging base value, and the difference between the gas logging peak value and the gas logging base value of each combustible gas.

6. The determination method according to claim 5, It is characterized in that The gas measurement peak value of the total alkanes is TG; the gas measurement peak values ​​of the combustible gases are: C1, C2, C3, iC4, nC4, iC5, nC5; the gas measurement base value of the total alkanes is TG'; the gas measurement base values ​​of the combustible gases are: C1', C2', C3', iC4', nC4', iC5', nC5'; TG represents the total alkane gas measurement peak value, TG' represents the total alkane gas measurement base value; C1 represents the methane gas measurement peak value, C1' represents the methane gas measurement base value, C2 represents the ethane gas measurement peak value, C2' represents the ethane gas measurement base value, C3 represents the propane gas measurement peak value, C3' represents the propane gas measurement base value, iC4 represents the isobutane gas measurement peak value, iC4' represents the isobutane gas measurement base value, nC4 represents the normal butane gas measurement peak value, nC4' represents the normal butane gas measurement base value, iC5 represents the isopentane gas measurement peak value, iC5' represents the isopentane gas measurement base value, nC5 represents the normal pentane gas measurement peak value, and nC5' represents the normal pentane gas measurement base value.

7. The determination method according to claim 5, It is characterized in that The difference between the gas-measured peak value and the gas-measured base value of the total alkanes is ΔTG; the differences between the gas-measured peak value and the gas-measured base value of each combustible gas are: ΔC1, ΔC2, ΔC3, ΔiC4, ΔnC4, ΔiC5, ΔnC5 respectively.

8. The determination method according to claim 7, It is characterized in that The formula for calculating the difference is: The difference between the gas measurement peak value and the gas measurement base value of total alkanes is calculated by the formula: ΔTG = TG-TG'; The calculation formula for the difference between the gas measurement peak value and the gas measurement base value of each combustible gas is: ΔC1=C1-C1', ΔC2=C2-C2', ΔC3=C3-C3', ΔiC4=iC4-iC4', ΔnC4=nC4-nC4', ΔiC5=iC5-iC5', ΔnC5=nC5-nC5'.

9. The identification method according to claim 1, It is characterized in that In step S4, the calculation formula of ΔWH is: ΔWH=[(ΔC2+ΔC3+ΔiC4+ΔnC4+ΔiC5+ΔnC5) / (ΔC1+ΔC2+ΔC3+ΔiC4+ΔnC4+ΔiC5+ΔnC5)].

10. The identification method according to claim 1, It is characterized in that In step S4, the calculation formula of Δlg is: Δlg=lg(ΔC1 / ΔC2).

11. The determination method according to claim 1, It is characterized in that In step S5, the fluid properties are determined by projecting the new well to be interpreted onto the gas logging map and determining the fluid properties according to the landing area.

12. A gas measurement chart established by the identification method according to any one of claims 1 to 11.

13. Use of the gas mapping chart according to claim 12 in oil and gas exploration and development.

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