Formation fluid interpretation method, device and equipment based on core chlorine salt content and storage medium

Abstract

The invention discloses a formation fluid interpretation method, device and equipment based on core chlorine salt content and a storage medium, and relates to the technical field of geological evaluation while drilling, and the method comprises the following steps: collecting well logging and logging data and oil testing data of a tested oil well in a research area, and screening out water analysis data corresponding to gas testing display in a test section; further screening out chloride ion test well section data from the re-screened test section, and dividing the test section into a water layer and a gas layer according to an oil test result; obtaining the relationship between the content of chlorate in the core test and the salt concentration of the stratum matrix and the salt concentration of the stratum water through the reservoir rock model; fitting the research area to obtain the salt concentration of the stratum matrix and the salt concentration of the stratum water; and a water and gas reservoir discrimination function is established for judging the properties of other reservoirs in the research area, so that the problems of difficulty in fluid evaluation of the reservoir while drilling and low evaluation accuracy in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of geological evaluation while drilling, and particularly relates to a formation fluid interpretation method, device, equipment and storage medium based on the chloride salt content of core samples. Background Art

[0002] Currently, there are many studies on reservoir fluid interpretation methods in China, mainly including chart methods, curve methods, nuclear magnetic resonance, spectrum methods, etc. The chart method mainly establishes charts for gas logging parameters and water saturation. The curve method uses drilling fluid logging parameters such as outlet temperature, conductivity, and density to judge fluid properties. Light hydrocarbons, geochemistry, quantitative fluorescence, etc. can indirectly judge the water content of the reservoir. In the prior art, no scheme for establishing a mathematical model for reservoir fluid interpretation using the chloride salt test content of core samples has been found.

[0003] The evaluation of reservoir fluids while drilling mainly uses logging parameters such as gas logging and drilling time during logging, which have a certain response to the reservoir, and corrects the influence of these response parameters by combining engineering parameters such as drilling pressure, rotation speed, and displacement. Fluid interpretation is carried out based on the change of curve morphology or by using reservoir fluid evaluation techniques based on these parameters. However, due to characteristics such as difficult reservoir division and complex reservoir parameter calculation, fluid interpretation while drilling faces many problems and often relies on research experience and adjacent well data in actual production.

[0004] In recent years, a fluid interpretation method using core chloride salts has often been adopted in single well tracking work. This method is more suitable for the needs of actual production compared with traditional fluid interpretation methods. However, at present, single well tracking evaluation mainly relies on the matching of big data statistics of the structure in the study area and the oil testing conclusion, and establishes a fluid interpretation standard based on production experience, that is, a quantitative baseline of greater than 600 mg / kg for water-based mud and a quantitative baseline of greater than 700 mg / kg for oil-based mud are used as the gas-water layer discrimination standard. The disadvantage of this method is that the critical value is uncertain, highly dependent on the test results of a single chloride salt content and the experience of single well tracking personnel, and often cannot accurately reflect the true situation of the formation. For example, in the technical solution of the application with the application number "CN201410082190.6" and the name "Method for discriminating reservoir fluid types using drilling fluid logging data while drilling" proposed by applicants such as China National Petroleum Corporation in 2014, drilling fluid parameters are used to interpret reservoir fluids. Since drilling fluid parameters are greatly affected by engineering factors, the effect of this method in actual application is not good.

[0005] Therefore, it is very important to innovate in the fluid interpretation method based on chloride salt content and study new methods. Summary of the Invention

[0006] The object of the present invention is to provide a formation fluid interpretation method based on the chloride salt content of core samples, which solves the problems of difficult evaluation of reservoir fluids during drilling and low evaluation accuracy in the prior art.

[0007] In the present invention, a reservoir chloride salt content equation is established by calculating the chloride salt content in the pore space and the chloride salt content in the reservoir rock matrix. Based on the core chloride salt test data, the chloride salt concentration of formation water and the chloride salt concentration of reservoir matrix are fitted through a mathematical model, and then a reservoir gas-water discrimination method is established through this model.

[0008] Specifically, it is realized through the following technical solutions:

[0009] A formation fluid interpretation method based on the chloride salt content of core samples, characterized by comprising the following steps:

[0010] S1. Collect the logging, well logging data and oil testing data of the oil-tested wells in the study area, and screen out the water analysis data corresponding to the gas logging display in the test section;

[0011] S2. Further screen out the chloride ion test well section data from the test section screened in step S1, and divide it into water layer and gas layer according to the oil testing results;

[0012] S3. Then, through the reservoir rock model, obtain the relationship between the chloride salt content measured in the core, the salt concentration in the formation matrix, and the salt concentration in the formation water;

[0013] S4. According to step S3, use the big data of the chloride salt content measured in the cores in the study area to fit the salt concentration in the formation matrix and the salt concentration in the formation water in the study area;

[0014] S5. Through the oil testing results, divide the chloride ion content test data into water layer and gas layer respectively, establish a water-gas layer discrimination function, and then use it to judge the properties of other reservoirs in the study area.

[0015] Further, in step S3, according to the reservoir characteristics, the relationship between the chloride salt content measured in the core, the salt concentration in the formation matrix, and the salt concentration in the formation water satisfies the following relationship of formula (Ⅰ)

[0016]

[0017] where C is the chloride salt content measured in the core, with the unit of mg / kg;

[0018] C 1 is the salt concentration in the formation matrix, with the unit of mg / kg;

[0019] C 2 is the salt concentration in the formation water, with the unit of mg / kg;

[0020] is the formation porosity;

[0021] V is the volume of the core sample, cm 3 .

[0022] Further, in step S4, it is derived according to formula (I) that the relationship between the chloride salt content measured in the core test, the salt concentration in the formation matrix, and the salt concentration in the formation water satisfies the relationship of the following formula (II),

[0023]

[0024] Further, in step S4, the large data of the chloride salt content measured in the cores of the known wells in the study area is used to fit C 1 、C 2 . According to the water layer and gas layer divided in step S2, the two demarcation point values of C 21 、C 22 are obtained. C 21 < C 22 . The salt concentration in the formation water of the reservoir to be evaluated is denoted as C 2 ':

[0025] When C 2 '≥ C 22 , it is a gas layer;

[0026] When C 2 '≤ C 21 , it is a water layer;

[0027] When C 21 < C 2 '< C 22 , it is a gas-water layer.

[0028] Further, in step S4, according to the characteristics that the matrix chloride salt is difficult to change during the formation sedimentation process and the chloride salt in the fluid in the pore space is greatly increased due to the inflow of formation water, the two values of C 2 in C 21 、C 22 are determined as the demarcation point values for gas, water, and gas-water layers.

[0029] Further, in step S4, when the reservoir to be studied is a carbonate rock sedimentary reservoir, C 22 is 170 and C 21 is 27.

[0030] A discriminant device for formation fluids based on the chloride salt content in cores, which is used to implement the above-mentioned formation fluid interpretation method based on the chloride salt content in cores. The device includes: a data acquisition module, a data analysis module, and a discriminant evaluation module;

[0031] The data acquisition module is used to obtain the logging, well logging data and well testing information of the oil-tested wells in the study area, and obtain the big data of the chloride salt content in the core test of the study area;

[0032] The data analysis module is used to screen out the water analysis data corresponding to the gas logging display in the test section, divide it into water layers and gas layers according to the well testing results, fit the formation matrix salt concentration and formation water salt concentration in the study area, establish a discrimination function for water and gas layers, and obtain the relationship between the chloride salt content in the core test and the formation matrix salt concentration and formation water salt concentration;

[0033] The discrimination and evaluation module is used to evaluate the reservoir properties of the wells to be tested in the study area according to the relationship between the chloride salt content in the core test and the formation matrix salt concentration and formation water salt concentration of the oil-tested wells in the study area.

[0034] A computer device includes a memory, a processor, and a computer program stored on the memory and executable in the processor. When the processor executes the computer program, the above method steps are implemented.

[0035] A computer-readable storage medium stores a computer program, and when the computer program is executed in a computer processor, the above method is implemented.

[0036] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0037] First, in the present invention, a mathematical model for interpreting reservoir fluids by using the chloride salt test content of cores is innovatively proposed. Previously, the drilling fluid parameters used for fluid interpretation were often interfered by various engineering factors, making it impossible to accurately reflect the true situation of the formation fluid properties when using the curve method for fluid interpretation. The chloride salt content in the core is the most direct reaction of the formation fluid on the core. Therefore, the present invention greatly improves the accuracy of fluid interpretation by establishing a formation fluid interpretation model based on the chloride salt content in the core. In actual tracking work, according to production experience, establishing a fluid interpretation standard can, to a certain extent, divide water and gas layers. However, due to the heterogeneity of the study area and the uncertainty of experience, there are errors in its standard. Therefore, the present invention establishes a discrimination function through mathematical model derivation, quantitatively distinguishes gas and water layers through the chloride salt content, and greatly improves the efficiency of fluid interpretation.

[0038] Second, it is innovatively proposed to calculate the chloride salt content in the pore space and the chloride salt content in the reservoir rock matrix by using the chloride salt test content of cores.

[0039] During the formation sedimentation process, with the compaction of the overlying formation, the chloride salt content in the formation water entering the formation matrix of the tight formation is relatively stable at 100 - 200 mg / kg. With the occurrence of dissolution during the late stage of formation sedimentation, during the dissolution process, the formation water enters the pore space, significantly increasing the chloride salt content of the formation. The greater the intensity of the dissolution, the greater the chloride salt content. Therefore, simply considering the chloride salt content to explain formation fluids ignores the influence of porosity. The present invention establishes an equation for the chloride salt content of the reservoir through a reservoir rock model, fully considering the influence of pore space on chloride salt. Using the measured chloride salt content of the core to calculate the chloride salt content in the pore space and the chloride salt content in the reservoir rock matrix, such a reservoir fluid interpretation model can better reflect the true fluid properties of the formation. Brief Description of the Drawings

[0040] Figure 1 It is the logging interpretation profile of Well A in Example 1.

[0041] Figure 2 It is the gas-water discrimination chart obtained by simulation in Example 1. Detailed Embodiments

[0042] The present invention will be further described in detail below in conjunction with embodiments, but the implementation manners of the present invention are not limited thereto.

[0043] Example 1

[0044] To facilitate public understanding of the solution, this example takes the oil-tested wells in a certain research area as an example to further illustrate the formation fluid interpretation method based on core chloride salt content in the present invention, belonging to the technical field of geological evaluation while drilling.

[0045] Specifically, it includes the following steps:

[0046] Step 1: Collect the logging, well logging data and oil testing data of the oil-tested wells in the research area, and screen out the water analysis data corresponding to the gas logging shows in the test section.

[0047] Step 2: Further screen out the data of the chloride ion test well sections from the test sections screened in Step 1, and divide them into water layers and gas layers according to the oil testing results.

[0048] Reference Figure 1 , Figure 1 is the logging interpretation profile of Well A in this research area.

[0049] Step 3: Further obtain the relationship between the chloride salt content measured in the core, the salt concentration in the formation matrix, and the salt concentration in the formation water through the reservoir rock model.

[0050] In this example, the relationship between the chloride salt content measured in the core, the salt concentration in the formation matrix, and the salt concentration in the formation water satisfies the relationship of the following formula (Ⅰ),

[0051]

[0052] Among them, C is the chloride salt content measured by core testing, with the unit of mg / kg;

[0053] C 1 is the salt concentration in the formation matrix, with the unit of mg / kg;

[0054] C 2 is the salt concentration in the formation water, with the unit of mg / kg;

[0055] is the porosity of the formation;

[0056] V is the volume of the core sample, in cm 3 .

[0057] Step Four: According to Step S3, using the big data of chloride salt content measured by cores in the study area, fit the formation matrix salt concentration and formation water salt concentration in the study area.

[0058] In this step, it is deduced according to Equation (Ⅰ) that the relationship between the chloride salt content measured by core testing and the formation matrix salt concentration and formation water salt concentration satisfies the relationship of the following Equation (Ⅱ),

[0059]

[0060] In this embodiment, since the chloride salt content in the matrix is basically unchanged during the deposition process, as the formation water flows into the pore space, the chloride salt content in the water layer and the gas layer is different, and the chloride salt content in the water layer is significantly higher than that in the gas layer. Through the analysis of the oil testing data in the study area and referring to Appendix Figure 1 , the C 1 , C 2 is obtained by fitting the core data in the study area.

[0061] According to Step Two, combined with the water layer and gas layer divided according to the oil testing results, according to Appendix Figure 1 , the respectively fitted relational expressions (Ⅲ) and (Ⅳ)

[0062] y = 178.51x + 118 (Ⅲ);

[0063] y = 27.19x + 120 (Ⅳ).

[0064] Step Five: Through the oil testing results, divide the water layer and gas layer respectively to obtain the chloride ion content test data. Use the formation matrix salt concentration and formation water salt concentration obtained in the above Steps One to Three to establish a water and gas layer discrimination function, and then judge the nature of the reservoir.

[0065] In this embodiment, based on the analysis results of the oil testing data in the study area and the relationships (III) and (IV) calculated in Step 4, combined with the actual production situation and the geological understanding of the study area, the discrimination accuracy and reliability of gas layers and water layers are improved as much as possible. In this embodiment, the gas line and water line standards are set at 170 and 27, respectively. The specific discrimination method is as follows:

[0066] That is, when C 2 ≥ 170, it is a gas layer;

[0067] When C 2 ≤ 27, it is a water layer;

[0068] When 27 < C 2 < 170, it is a gas-water interlayer.

[0069] Then, according to the gas-water discrimination equation, the D layer section of Well A in the P well area is evaluated. The results are shown in Table 1. It can be seen from Table 1 that the logging interpretation results obtained by using this scheme are consistent with the oil testing results.

[0070] Table 1: Comparison table of logging interpretation results and oil testing results

[0071]

[0072] It can be seen from Table 1 that among the logging interpretation results obtained by using this method, the interpretation results of Well Sections 1-4 of this well are consistent with the oil testing results.

[0073] After multiple tests, the inventor of this scheme found that when the evaluation results of the reservoir obtained by using this scheme are compared with the oil testing results, the coincidence rate can reach 85%, which is significantly higher than the results obtained by using conventional logging evaluation methods for formation fluids while drilling, such as the chart method, curve method, nuclear magnetic resonance, and spectrogram method.

[0074] Furthermore, the present invention also provides a discrimination device for formation fluids based on the chloride salt content of cores. The device is used to implement the above-mentioned formation fluid interpretation method based on the chloride salt content of cores. The device includes: a data acquisition module, a data analysis module, and a discrimination and evaluation module;

[0075] The data acquisition module is used to obtain the logging, well logging data, and oil testing data of the wells that have been oil tested in the study area, and obtain the big data of the chloride salt content tested on the cores in the study area;

[0076] The data analysis module is used to screen out the water analysis data corresponding to the gas logging shows in the test section, divide them into water layers and gas layers according to the oil testing results, fit the formation matrix salt concentration and formation water salt concentration in the study area, establish a water and gas layer discrimination function, and obtain the relationship between the chloride salt content tested on the cores and the formation matrix salt concentration and formation water salt concentration;

[0077] The discrimination and evaluation module is used to evaluate the reservoir properties of the wells to be tested in the study area according to the relationship between the chloride salt content measured from the cores of the wells with known oil test results in the study area, the salt concentration of the formation matrix, and the salt concentration of the formation water, and quickly determine whether they are gas layers, water layers or gas-water layers.

[0078] Furthermore, the present invention also provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above method steps are implemented.

[0079] Furthermore, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a computer processor, implements the above method.

[0080] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modification or equivalent change made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A formation fluid interpretation method based on core chloride content, characterized in that: The steps include: S1. Collect the logging data, well logging data and oil test data of the tested wells in the study area, and select the water analysis data corresponding to the gas test display in the test section; S2, further filtering out chloride ion test well section data from the test section screened out in step S1, and dividing it into water layer and gas layer according to the oil test results; S3, then using the reservoir rock model, obtain the relationship between the chloride content in the core test and the salt concentration of the formation matrix and the salt concentration of the formation water; S4, according to step S3, using the big data of chloride content in the core test of the study area, fitting the salt concentration of the formation matrix and the salt concentration of the formation water in the study area; S5. The water layer and gas layer are divided into different layers through oil test results to obtain chloride ion content test data, and the water and gas layer discriminant functions are established, which are then used to judge the properties of other reservoirs in the study area.

2. The formation fluid interpretation method based on core chloride content according to claim 1, characterized in that: In step S3, according to the reservoir characteristics, it is found that the relationship between the chloride content in the core test and the salt concentration of the formation matrix and the salt concentration of the formation water satisfies the following formula (I): C=V×φ×C1+ V×(1-φ)×C2 (Ⅰ), Wherein, C is the chloride content of the core test, in mg / kg; C1 is the salt concentration of the formation matrix, in mg / kg; C2 is the salt concentration of formation water, in mg / kg; φ is the formation porosity; V is the core sample volume, cm 3 .

3. The formation fluid interpretation method based on core chloride content according to claim 2, characterized in that: In step S4, it is deduced according to formula (I) that the relationship between the chloride content in the core test and the salt concentration of the formation matrix and the salt concentration of the formation water satisfies the relationship of the following formula (II): C / V=C1+(1-φ) / φ×C2(II).

4. The formation fluid interpretation method based on core chloride content according to claim 3, characterized in that: In step S4, the core test chloride content big data of known wells in the study area is used to fit C1 and C2, and C is obtained according to the water layer and gas layer divided in step S2. 21 , C 22 Two cut-off values, C 21 <C 22 , the formation water salt concentration of the reservoir to be evaluated is recorded as C2': when C2' ≥ C 22 When , it is the gas layer; When C2'≤C 21 When , it is the water layer; When C 21 <C2'<C 22 When , the air and water are in the same layer.

5. The formation fluid interpretation method based on core chloride content according to claim 4, characterized in that: In step S4, according to the characteristics that the matrix chloride salt is difficult to change during the formation deposition process, and the fluid in the void space has a significant increase in chloride salt due to the influx of formation water, the C in C2 is determined. 21 , C 22 The two values ​​serve as the dividing point values ​​of gas, water and gas-water layers.

6. The formation fluid interpretation method based on core chloride content according to claim 5, characterized in that: When the area to be studied is a carbonate sedimentary reservoir, C 22 170, C 21 is 27.

7. A device for distinguishing formation fluid based on the chloride content of core, characterized in that: The device is used to implement the formation fluid interpretation method based on core chloride content as described in any one of claims 1 to 6, and the device comprises: a data acquisition module, a data analysis module and a discrimination and evaluation module; The data acquisition module is used to obtain the logging data, well logging data and oil testing information of the tested wells in the study area, and obtain the big data of chloride salt content in the core test of the study area; The data analysis module is used to filter out the water analysis data corresponding to the gas test display in the test section, and divide it into water layer and gas layer according to the oil test results, fit the study area to obtain the formation matrix salt concentration and formation water salt concentration, establish the water and gas layer discriminant function, and obtain the relationship between the core test chloride content and the formation matrix salt concentration and formation water salt concentration; The discrimination and evaluation module is used to evaluate the reservoir properties of the wells to be tested in the study area according to the relationship between the chloride content of the core test of the tested oil wells in the study area and the salt concentration of the formation matrix and the salt concentration of the formation water.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable in the processor, characterized in that: When the processor executes the computer program, the method steps described in any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed in a computer processor, the method according to any one of claims 1 to 6 is implemented.

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