Formation water resistivity obtaining method, system and device capable of eliminating residual hydrocarbon influence and medium

Abstract

The invention discloses a formation water resistivity obtaining method, system and device for eliminating residual hydrocarbon influence and a medium, and the method comprises the steps: carrying out the reverse calibration of a sound wave time difference curve and a density curve based on the sound wave time difference curve, the density curve and the neutron logging principle difference, and obtaining a macroporosity index SI; the compensated neutrons and the density curve are subjected to reverse calibration, the macroporosity index SI2 influenced by the residual hydrocarbon is obtained, and the difference H between the two is in direct proportion to the content of the residual hydrocarbon in the reservoir; calibration is carried out through a plurality of oil-water testing layers, so that correction coefficients K under different formation water resistivity can be obtained; and correcting the conventional resistivity-porosity plate by using the correction coefficient, and obtaining the formation water resistivity on the corrected plate by using a bottom water layer method. According to the method, the problem that the formation water resistivity value calculated by a conventional chart is too large due to high resistivity of the water layer is solved, and accurate calculation of the formation water resistivity is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of well logging reservoir evaluation, and relates to a formation water resistivity acquisition method, system, device and medium for eliminating the influence of residual hydrocarbons. Background Art

[0002] Formation water resistivity is a key parameter for obtaining water saturation in logging interpretation. The accuracy of its calculation directly affects the quantitative interpretation of oil and gas. At present, there are three main methods for obtaining formation water resistivity: chemical analysis method, natural potential method and formation resistivity and porosity intersection method. Among them, the chemical analysis method is the most direct and accurate method based on formation water samples, but due to the limited number of samples and representativeness problems, it does not meet the actual interpretation needs. The other two methods are back-calculated based on logging data. The results are continuous and can be widely used, but the accuracy is different. According to the research of Li Xia et al., the calculation results of the resistivity-porosity intersection method are closest to the formation water resistivity determined by laboratory water analysis. This method is also called the bottom water layer method, that is, the resistivity and porosity readings of the pure water layer in the interpretation interval are projected onto a series of resistivity-porosity plates corresponding to the formation water resistivity. The formation water resistivity corresponding to the bottom of these points is the formation water resistivity of the well section. The current formation water resistivity calculation method is not suitable for reservoirs with complex oil-water relationships and the presence of organic complexes. The calculated formation water resistivity is often quite different from that obtained from water analysis. Summary of the invention

[0003] The purpose of the present invention is to solve the problems that the methods for obtaining formation water resistivity in the prior art are not suitable for reservoirs with complex oil-water relationships and the presence of organic complexes; the calculated formation water resistivity is often quite different from the formation water resistivity obtained by water analysis, and to provide a formation water resistivity acquisition method, system, device and medium that eliminates the influence of residual hydrocarbons.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for obtaining formation water resistivity by eliminating the influence of residual hydrocarbons, comprising:

[0006] Based on the acoustic time difference curve and density curve measured by well logging, the macropore index SI is obtained;

[0007] Based on the well logging measurement compensation neutron curve and density curve, the macropore index SI2 affected by residual hydrocarbons is obtained;

[0008] Based on the macropore index SI and the macropore index SI2 affected by residual hydrocarbons, the heavy hydrocarbon index H is obtained;

[0009] Combined with regional oil testing data, the resistivity R is obtained through multiple water layer scales and heavy hydrocarbon index H.0校 ; Pure water layer resistivity R calculated based on Archie formula and regional rock electrical parameters 0 ; R 0校 With R 0 Compare and obtain the correction coefficient K;

[0010] Through the correction coefficient chart, based on the heavy hydrocarbon index H of the water layer in the formation water resistivity interval to be obtained, a series of correction coefficients K under formation water resistivity are obtained, and the conventional resistivity-porosity chart is corrected to obtain the corrected chart;

[0011] The water layer of the well section where the formation water resistivity is to be obtained is projected, and the formation water resistivity of the well section is obtained by the bottom water layer method.

[0012] A further improvement of the present invention is:

[0013] Furthermore, based on the acoustic time difference curve and density curve measured by well logging, the macropore index SI is obtained, which is:

[0014]

[0015] Wherein, Δt is the acoustic time difference value measured by well logging; den is the density value measured by well logging; a is the minimum value of the acoustic scale, b is the maximum value of the acoustic scale, c is the minimum value of the density scale, and d is the maximum value of the density scale.

[0016] Furthermore, based on the well logging measurement compensation neutron curve and density curve, the macropore index SI2 affected by residual hydrocarbons is obtained, which is specifically:

[0017]

[0018] Wherein, den and cnl are the density and compensated neutron values ​​measured by logging, respectively; SI2 is the difference between the neutron and density curves, e is the minimum value of the compensated neutron scale, and f is the maximum value of the compensated neutron scale.

[0019] At the same time, the density den measured by logging is

[0020]

[0021] Among them, den f is the fluid density value; den ma is the skeleton density value; is the porosity.

[0022] Furthermore, based on the macropore index SI and the macropore index SI2 affected by residual hydrocarbons, the heavy hydrocarbon index H is obtained, specifically:

[0023] H=SI2-SI (4)

[0024] Furthermore, combined with regional oil testing data, the resistivity R is obtained through multiple water layer scales and heavy hydrocarbon index H. 0校 , specifically:

[0025] R 0校 =10 A×H+B (5)

[0026] Where A and B are both constants.

[0027] Furthermore, the pure water layer resistivity R is calculated based on Archie's formula and regional rock electrical parameters. 0 ; R 0校 With R 0 By comparison, the correction coefficient K is obtained, which is specifically:

[0028]

[0029]

[0030] Among them, Rw is the formation water resistivity obtained by water analysis of the test oil layer; a' and m are rock electrical parameters, which are constants within the block.

[0031] A formation water resistivity acquisition system for eliminating the influence of residual hydrocarbons, comprising:

[0032] A first acquisition module, wherein the first acquisition module obtains a macropore index SI based on an acoustic time difference curve and a density curve measured by well logging;

[0033] A second acquisition module, wherein the second acquisition module obtains a macropore index SI2 affected by residual hydrocarbons based on a well logging measurement compensated neutron curve and a density curve;

[0034] A heavy hydrocarbon index acquisition module, wherein the heavy hydrocarbon index acquisition module obtains a heavy hydrocarbon index H based on the macropore index SI and the macropore index SI2 affected by residual hydrocarbons;

[0035] The comparison module combines regional oil testing data, obtains the resistivity R through multiple water layer scales and heavy hydrocarbon index H. 0校 ; Pure water layer resistivity R calculated based on Archie formula and regional rock electrical parameters 0 ; R 0校 With R 0 Compare and obtain the correction coefficient K;

[0036] A correction module, wherein the correction module obtains a series of correction coefficients K under formation water resistivity based on the heavy hydrocarbon index H of the water layer in the formation water resistivity layer section to be obtained through a correction coefficient plate, and corrects the conventional resistivity-porosity plate to obtain a corrected plate;

[0037] The formation water resistivity acquisition module projects the water layer of the well section for which the formation water resistivity is to be obtained, and obtains the formation water resistivity of the well section by a bottom water layer method.

[0038] A terminal device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0039] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] Based on the differences in the acoustic time difference curve, density curve, and neutron logging principles, the present invention reversely scales the acoustic time difference curve and the density curve to obtain the macropore index SI; reversely scales the compensated neutron and density curves to obtain the macropore index SI2 affected by residual hydrocarbons, and the difference H between the two is proportional to the content of residual hydrocarbons in the reservoir; calibrates multiple oil test water layers to obtain the correction coefficient K under different formation water resistivities; uses the correction coefficient to correct the conventional resistivity-porosity chart, and applies the bottom water layer method on the corrected chart to obtain the formation water resistivity. The present invention overcomes the problem that the formation water resistivity value calculated by the conventional chart is too large due to the high resistivity of such water layers, and realizes the accurate calculation of the formation water resistivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 A schematic flow chart of a method for obtaining formation water resistivity by eliminating the influence of residual hydrocarbons according to the present invention;

[0044] Figure 2 This is a schematic diagram of the structure of the formation water resistivity acquisition system for eliminating the influence of residual hydrocarbons of the present invention;

[0045] Figure 3 Another schematic flow chart of the method for obtaining formation water resistivity by eliminating the influence of residual hydrocarbons according to the present invention;

[0046] Figure 4 It is a schematic diagram of the correction coefficient plate of the present invention;

[0047] Figure 5 It is a schematic diagram of the corrected resistivity-porosity plate (H=0.14) of the present invention;

[0048] Figure 6 This is a schematic diagram of an example of obtaining formation water resistivity according to the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0050] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0052] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0053] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0054] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0056] See also Figure 1 The present invention discloses a method for obtaining formation water resistivity by eliminating the influence of residual hydrocarbons, comprising:

[0057] S101, based on the acoustic time difference curve and density curve measured by well logging, the macropore index SI is obtained.

[0058] The acoustic time difference mainly propagates between contacting particles, reflecting the interconnected intergranular pores in the rock, i.e., macropores; the density curve measures the volume density of the rock, reflecting the total porosity of the rock; the smaller the density, the larger the total porosity, and the larger the sound wave, the more macropores. Both the acoustic time difference and density curves use linear scales, and the acoustic time difference curve and the density curve are overlapped. The two basically overlap in reservoir sections with pure lithology and good physical properties, and there will be an envelope in other well sections, so as to determine the appropriate left and right scale values ​​for the study area. The overlapping envelope area of ​​the two can reflect the macropores in the reservoir and the proportion they occupy, which is called the macropore index SI. The specific formula is:

[0059]

[0060] Wherein, Δt is the acoustic time difference value measured by well logging; den is the density value measured by well logging; a is the minimum value of the acoustic scale, b is the maximum value of the acoustic scale, c is the minimum value of the density scale, and d is the maximum value of the density scale.

[0061] S102, obtaining a macropore index SI2 affected by residual hydrocarbons based on the compensated neutron curve and density curve measured by well logging.

[0062] Compensated neutron logging measures the hydrogen content in the reservoir and has a good indication effect on mud or micropores. Mudstone has high neutron and high density characteristics, while reservoirs have low neutron and low density characteristics. Reversely scaling the two has a good mud indication and stratification effect. Due to the advantages of resolution and indication of physical properties, its stratification effect is even better than the commonly used natural potential and natural gamma curves. The compensated neutron and density curves both use linear scales, and the two are reversely overlapped so that the stratification boundaries of the two are the same as the natural gamma, so as to determine the left and right scale values ​​suitable for the study area. The larger the envelope area of ​​the two, the more macropores (total pores-micropores) there are in the reservoir. The residual hydrocarbons present in the macropores after the reservoir is destroyed have the characteristics of heavy carbon and light hydrocarbons, which will cause the compensated neutron logging value of the reservoir to decrease. That is, the influence of residual hydrocarbons will cause the neutron-density envelope area to increase, which is called the macropore index SI2 affected by residual hydrocarbons. The specific formula is

[0063]

[0064] Wherein, den and cnl are the density and compensated neutron values ​​measured by logging, respectively; SI2 is the difference between the neutron and density curves, e is the minimum value of the compensated neutron scale, and f is the maximum value of the compensated neutron scale.

[0065] At the same time, the density den measured by logging is

[0066]

[0067] Among them, den f is the fluid density value; den ma is the skeleton density value; is the porosity.

[0068] S103, obtaining a heavy hydrocarbon index H based on the macropore index SI and the macropore index SI2 affected by residual hydrocarbons.

[0069] Subtract SI2 from SI, and the difference is the effect of residual hydrocarbons in the macropores on the logging value. This difference is called the heavy hydrocarbon index H, which is proportional to the residual oil content in the reservoir. The specific formula is:

[0070] H=SI2-SI (4)

[0071] S104, combined with regional oil testing data, through multiple water layer scales and heavy hydrocarbon index H, the resistivity R is obtained 0校 ; Pure water layer resistivity R calculated based on Archie formula and regional rock electrical parameters 0 ; R 0校 With R 0 By comparison, the correction coefficient K is obtained.

[0072]

[0073]

[0074] Among them, Rw is the formation water resistivity obtained by water analysis of the test oil layer; a' and m are rock electrical parameters, which are constants within the block.

[0075] S105, obtaining a series of correction coefficients K under formation water resistivity based on the heavy hydrocarbon index H of the water layer in the formation water resistivity interval to be obtained through the correction coefficient chart, and correcting the conventional resistivity-porosity chart to obtain a corrected chart.

[0076] S106, projecting the water layer of the well section for which the formation water resistivity is to be obtained, and obtaining the formation water resistivity of the well section by the bottom water layer method.

[0077] See also Figure 2 The present invention discloses a formation water resistivity acquisition system for eliminating the influence of residual hydrocarbons, comprising:

[0078] A first acquisition module, wherein the first acquisition module obtains a macropore index SI based on an acoustic time difference curve and a density curve measured by well logging;

[0079] A second acquisition module, wherein the second acquisition module obtains a macropore index SI2 affected by residual hydrocarbons based on a well logging measurement compensated neutron curve and a density curve;

[0080] A heavy hydrocarbon index acquisition module, wherein the heavy hydrocarbon index acquisition module obtains a heavy hydrocarbon index H based on the macropore index SI and the macropore index SI2 affected by residual hydrocarbons;

[0081] The comparison module combines regional oil testing data, obtains the resistivity R through multiple water layer scales and heavy hydrocarbon index H. 0校 ; Pure water layer resistivity R calculated based on Archie formula and regional rock electrical parameters 0 ; R 0校 With R 0 Compare and obtain the correction coefficient K;

[0082] A correction module, wherein the correction module obtains a series of correction coefficients K under formation water resistivity based on the heavy hydrocarbon index H of the water layer in the formation water resistivity layer section to be obtained through a correction coefficient plate, and corrects the conventional resistivity-porosity plate to obtain a corrected plate;

[0083] The formation water resistivity acquisition module projects the water layer of the well section for which the formation water resistivity is to be obtained, and obtains the formation water resistivity of the well section by a bottom water layer method.

[0084] Example:

[0085] See also Figure 3 The present invention discloses a method for obtaining formation water resistivity by eliminating the influence of residual hydrocarbons, comprising the following steps:

[0086] S100, overlapping the acoustic time difference curve and the density curve, and using the overlapping envelope area of ​​the two to obtain the macropore index SI;

[0087] Specifically, the acoustic time difference curve and the density curve are overlapped. The two basically overlap in the reservoir section with pure lithology and good physical properties, and have an envelope in other well sections, so as to determine the left and right scale values ​​suitable for the study area. The distance between the two curves is SI, called macropore index, and the formula is:

[0088]

[0089] Where Δt is the acoustic time difference value measured by well logging, in units of us / m; den is the density value measured by well logging, in units of g / cm 3 ;

[0090] S200, overlay the compensated neutron and density curves in reverse scale to obtain the macropore index SI2 affected by residual heavy hydrocarbons;

[0091] Specifically, the compensated neutron and density curves are both linearly scaled, and the two are reversely overlapped so that their stratification boundaries are the same as the natural gamma, so as to determine the left and right scale values ​​suitable for the study area. The envelope area of ​​the two is the macropore index SI2 affected by residual heavy hydrocarbons, and the formula is:

[0092]

[0093] Where, den and cnl are the density and compensated neutron value measured by well logging, respectively, and the units are g / cm 3 , %; SI2 is the difference between neutron and density curves, no unit;

[0094] S300, subtract SI2 from SI to obtain the heavy hydrocarbon index H, the specific formula is:

[0095] H=SI2-SI

[0096] S400, combined with regional oil testing data, obtains resistivity correction value R through multiple water layer calibrations 0校 ; Use density to obtain total porosity through volume model; Use Archie formula and regional rock electrical parameters to obtain pure water layer resistivity R 0 ; R 0校 With R 0 Ratio, get the correction factor K plate, see Figure 4 :

[0097] Specifically, the resistivity R 0校The calculation formula is as follows:

[0098] R 0校 =10 2.7×H+1.0664

[0099]

[0100]

[0101]

[0102] Where, Rw is the formation water resistivity obtained by water analysis at the test oil layer, in Ω.m; H is the residual index obtained in S300, without unit; den, den f 、den ma They are respectively the density measured by well logging, fluid density value, and skeleton density value, in g / cm 3 ; is the porosity, a decimal.

[0103] S600, using the correction coefficient to correct the conventional resistivity-porosity chart to obtain the corrected resistivity-porosity chart, and using the bottom water layer method to obtain the formation water resistivity of the high resistivity water layer;

[0104] Specifically, through the correction coefficient chart, according to the heavy hydrocarbon index H of the water layer in the formation water resistivity layer section to be obtained, a series of R w The correction coefficient K under the condition is used to correct the conventional resistivity-porosity chart (solid line) to obtain the corrected chart (dashed line), see Figure 5 The water layer of the well section where the formation water resistivity is to be obtained is projected on this plate, and the formation water resistivity of this well section is obtained using the bottom water layer method.

[0105] Figure 6 This is an example of water layer interpretation using this method. The first channel is the resistivity curve channel, the second channel is the three-pore curve channel, the third channel is the depth channel, the fourth channel is the logging display channel, the fifth channel is the interpretation conclusion channel, the sixth channel is the lithology logging channel, the seventh channel is the porosity channel; the eighth channel is the permeability channel, the ninth channel is the macropore index channel, the tenth channel is the residual index channel, and the eleventh channel is the logging interpretation lithology profile channel. From the logging curve, the density of the 51st layer is 2.53g / cm 3 , the acoustic time difference is 218us / m, the analyzed porosity is 10.7%, the resistivity is 67.7Ω.m, and it is a high resistivity water layer. The heavy hydrocarbon index H calculated for this layer is 0.14. Figure 4 The correction coefficient plate shows R w A series of correction coefficients ranging from 0.04Ω.m to 0.5Ω.m are shown in Table 1. The conventional porosity-resistivity chart is corrected to obtain a corrected chart. Figure 6The porosity and resistivity values ​​of the 51st layer in the figure are projected onto this plate, see Figure 5 The bottom value of this layer segment corresponds to R w It is about 0.42Ω.m, which corresponds to R on the calibration plate. w The resistivity of the formation water R is calculated based on the produced water analysis data (Table 2). w It is 0.32Ω.m, which shows that the corrected plate can obtain more accurate calculation results. By comparing the corrected plate with the original plate, it can be seen that when R w When the correction amount is small, the correction amount of both is large. w Increasing the correction amount makes it smaller, which is consistent with geological laws.

[0106] Table 1

[0107] <![CDATA[R w / Ω.m]]> 0.04 0.06 0.08 0.1 0.12 0.15 0.2 0.3 0.4 0.5 K 2.3 2.25 2.15 2.1 2 1.9 1.82 1.5 1.24 1.04

[0108] Table 2

[0109]

[0110] The water layer formed after the ancient oil reservoir was destroyed has heavy components such as asphaltene attached to the surface of rock particles, combined with clay film to form an organic complex, blocking the rock conductive network and forming a high-resistivity water layer. It is inaccurate to use the conventional porosity-resistivity chart to obtain the formation water resistivity. The present invention realizes the quantitative characterization of residual hydrocarbons in the reservoir through the difference in the principles of different logging curves. On this basis, the resistivity is corrected to obtain the resistivity-porosity cross-section chart corrected for residual heavy hydrocarbons. On this basis, the bottom water layer method is used to improve the accuracy of formation water resistivity calculation.

[0111] The quantitative characterization technology in the present invention can not only be applied to the calculation of formation water resistivity, but also can be used to identify the fluid properties of complex reservoirs, on this basis, reservoir capacity classification and other work can be carried out.

[0112] A terminal device is provided in one embodiment of the present invention. The terminal device of this embodiment includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above-mentioned method embodiments are implemented. Alternatively, when the processor executes the computer program, the functions of the modules / units in the above-mentioned device embodiments are implemented.

[0113] The computer program may be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to accomplish the present invention.

[0114] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0115] The processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0116] The memory may be used to store the computer programs and / or modules, and the processor implements various functions of the terminal device by running or executing the computer programs and / or modules stored in the memory and calling the data stored in the memory.

[0117] If the module / unit integrated in the terminal device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0118] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for obtaining formation water resistivity by eliminating the influence of residual hydrocarbons, characterized in that: include: Based on the acoustic time difference curve and density curve measured by well logging, the macropore index SI is obtained; Based on the well logging measurement compensation neutron curve and density curve, the macropore index SI2 affected by residual hydrocarbons is obtained; Based on the macropore index SI and the macropore index SI2 affected by residual hydrocarbons, the heavy hydrocarbon index H is obtained; Combined with regional oil testing data, the resistivity R is obtained through multiple water layer scales and heavy hydrocarbon index H. 0校 ; The pure water layer resistivity R0 is calculated based on Archie's formula and regional rock electrical parameters; R 0校 Compare with R0 to obtain the correction coefficient K; Through the correction coefficient chart, based on the heavy hydrocarbon index H of the water layer in the formation water resistivity interval to be obtained, a series of correction coefficients K under formation water resistivity are obtained, and the conventional resistivity-porosity chart is corrected to obtain the corrected chart; The water layer of the well section where the formation water resistivity is to be obtained is projected, and the formation water resistivity of the well section is obtained by the bottom water layer method.

2. The method for obtaining formation water resistivity by eliminating the influence of residual hydrocarbons according to claim 1, characterized in that: The macropore index SI is obtained based on the acoustic time difference curve and density curve measured by well logging, which is specifically: Wherein, Δt is the acoustic time difference value measured by well logging; den is the density value measured by well logging; a is the minimum value of the acoustic scale, b is the maximum value of the acoustic scale, c is the minimum value of the density scale, and d is the maximum value of the density scale.

3. The method for obtaining formation water resistivity by eliminating the influence of residual hydrocarbons according to claim 2, characterized in that: The macropore index SI2 affected by residual hydrocarbons is obtained by compensating the neutron curve and the density curve based on the well logging measurement, specifically: Wherein, den and cnl are the density and compensated neutron values ​​measured by well logging, respectively; SI2 is the difference between neutron and density curves, e is the minimum value of compensated neutron scale, and f is the maximum value of compensated neutron scale; At the same time, the density den measured by logging is Among them, den f is the fluid density value; den ma is the skeleton density value; is the porosity.

4. The method for obtaining formation water resistivity by eliminating the influence of residual hydrocarbons according to claim 3, characterized in that: The heavy hydrocarbon index H is obtained based on the macropore index SI and the macropore index SI2 affected by residual hydrocarbons, specifically: H = SI2 - SI (4).

5. The method for obtaining formation water resistivity by eliminating the influence of residual hydrocarbons according to claim 4, characterized in that: The resistivity R is obtained by combining regional oil test data with multiple water layer scales and heavy hydrocarbon index H. 0校 , specifically: R 0校 ＝10 A×H+B (5) Where A and B are both constants.

6. The method for obtaining formation water resistivity by eliminating the influence of residual hydrocarbons according to claim 5, characterized in that: The pure water layer resistivity R0 calculated based on Archie's formula and regional rock electrical parameters; R 0校 Compared with R0, the correction coefficient K is obtained, which is: Among them, Rw is the formation water resistivity obtained by water analysis of the test oil layer; a' and m are rock electrical parameters, which are constants within the block.

7. A formation water resistivity acquisition system for eliminating the influence of residual hydrocarbons, characterized in that: include: A first acquisition module, wherein the first acquisition module obtains a macropore index SI based on an acoustic time difference curve and a density curve measured by well logging; A second acquisition module, wherein the second acquisition module obtains a macropore index SI2 affected by residual hydrocarbons based on a well logging measurement compensated neutron curve and a density curve; A heavy hydrocarbon index acquisition module, wherein the heavy hydrocarbon index acquisition module obtains a heavy hydrocarbon index H based on the macropore index SI and the macropore index SI2 affected by residual hydrocarbons; The comparison module combines regional oil testing data, obtains the resistivity R through multiple water layer scales and heavy hydrocarbon index H. 0校 ; The pure water layer resistivity R0 is calculated based on Archie's formula and regional rock electrical parameters; R 0校 Compare with R0 to obtain the correction coefficient K; A correction module, wherein the correction module obtains a series of correction coefficients K under formation water resistivity based on the heavy hydrocarbon index H of the water layer in the formation water resistivity layer section to be obtained through a correction coefficient plate, and corrects the conventional resistivity-porosity plate to obtain a corrected plate; The formation water resistivity acquisition module projects the water layer of the well section for which the formation water resistivity is to be obtained, and obtains the formation water resistivity of the well section by a bottom water layer method.

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

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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