A resistivity correction method, apparatus, device and medium

Abstract

This invention discloses a resistivity correction method, apparatus, equipment, and medium, including collecting first formation water resistivity and first rock formation resistivity; determining a first correlation and a second correlation; determining the second formation water resistivity of the well to be corrected before drilling fluid invasion based on the target natural gamma difference between the completed well and a typical completed well in the target layer, the first correlation, and the first formation water resistivity; and determining the corrected rock formation resistivity of the well to be corrected before drilling fluid invasion based on the second correlation, the first formation water resistivity, the first rock formation resistivity, and the second formation water resistivity. This invention achieves formation resistivity correction using multiple parameters under drilling fluid invasion conditions. The method is simple, the calculation correction results are highly accurate, and good results have been observed in oil testing. The correction results are more accurate than existing methods.

Description

Technical Field

[0001] This invention relates to the field of well logging technology, and in particular to a resistivity correction method, apparatus, equipment, and medium. Background Technology

[0002] Resistivity logging is widely used in oil and gas exploration and development, and is of great significance for quantitatively identifying formation lithology, reservoirs, and oil and water. Electrical logging is one of the three major logging methods in geophysical logging. Based on the differences in the electrical properties of rock formations, it measures electrical parameters such as resistivity, conductivity, or dielectric constant of the formation. This is used to study geological profiles, determine lithology, and delineate oil, gas, and water layers. Together with other methods, it is used to study the oil-bearing capacity, permeability, and porosity of reservoirs.

[0003] During drilling, because the pressure of the drilling fluid is greater than that of the formation fluid, the drilling fluid, under the action of osmotic pressure difference, drives away the original fluids (oil, gas, and water) in the formation pores around the well wall and enters the formation. This changes the radial distribution of the original formation fluid state near the well wall, thereby changing the radial profile of the formation resistivity, which presents three parts: the flushing zone, the transition zone, and the original formation.

[0004] KCl (potassium chloride) drilling fluid is a measure taken to protect the wellbore, but it reduces the response of logging curves to formation characteristics, adversely affecting logging evaluation. When the resistivity logging response is affected by drilling fluid intrusion, it cannot truly reflect the resistivity characteristics of the formation, causing difficulties for quantitative geological studies.

[0005] Conventional methods utilize sonic transit-time logging to standardize and correct logging curves. However, resistivity logging is significantly affected by lithology, physical properties, and oil-water relationships. Conventional standardization formulas do not consider these factors, resulting in large correction errors that fail to meet research requirements. Therefore, reducing the correction error of logging curves is a pressing issue that needs to be addressed. Summary of the Invention

[0006] This application provides a resistivity correction method, apparatus, device, and medium, which solves the technical problem of large correction errors in existing resistivity logging methods, and achieves the technical effect of reducing correction errors and improving the accuracy of resistivity logging methods.

[0007] In a first aspect, this application provides a resistivity correction method, the method comprising:

[0008] Collect the first formation water resistivity and the first rock formation resistivity of the well to be corrected after drilling fluid invasion.

[0009] Determine the first correlation between the natural gamma difference before and after drilling fluid invasion in a typical completed well and the corresponding formation water resistivity; and determine the second correlation between the formation water resistivity and rock formation resistivity before and after drilling fluid invasion in the typical completed well.

[0010] Based on the target natural gamma difference between the well to be corrected and the typical well to be corrected in the target layer, the first correlation, and the first formation water resistivity, the second formation water resistivity of the well to be corrected before drilling fluid invasion is determined.

[0011] Based on the second correlation, the first formation water resistivity, the first rock formation resistivity, and the second formation water resistivity, the corrected rock formation resistivity corresponding to the well to be corrected before drilling fluid invasion is determined.

[0012] Furthermore, the acquisition of the first formation water resistivity and the first rock formation resistivity corresponding to the drilling fluid invasion after the well to be corrected includes:

[0013] Core samples of the target layer and formation water samples of the target layer were collected from the well to be calibrated.

[0014] The resistivity of the first rock formation corresponding to the drilling fluid invasion of the well to be corrected was collected from the core sample.

[0015] The first formation water resistivity corresponding to the drilling fluid invasion of the well to be calibrated was collected from the formation water sample to be calibrated.

[0016] Furthermore, determining the first correlation between the natural gamma difference before and after drilling fluid invasion in a typical completed well and the corresponding formation water resistivity includes:

[0017] Obtain typical formation water samples from the target layer in the typical completed well;

[0018] Determine the typical natural gamma and typical formation water resistivity of the typical formation water sample;

[0019] The typical formation water sample was divided into N equal parts, and drilling fluid of different concentrations was added to each part to obtain N mixed formation water samples; N is a positive integer.

[0020] Determine the mixed natural gamma and mixed formation water resistivity corresponding to each of the aforementioned mixed formation water samples;

[0021] Based on the typical natural gamma, the typical formation water resistivity, and the mixed natural gamma and mixed formation water resistivity corresponding to each of the mixed formation water samples, the first correlation between the natural gamma difference and formation water resistivity before and after drilling fluid invasion in a typical completed well is determined.

[0022] Further, determining the second correlation between the formation water resistivity and rock formation resistivity of the typical completed well before and after drilling fluid invasion includes:

[0023] In the typical completed well, based on the third correlation between rock porosity, oil and gas saturation, formation water resistivity, rock formation resistivity and rock skeleton resistivity, and the fourth correlation between rock skeleton resistivity, formation water resistivity and rock formation resistivity, a fifth correlation between rock porosity, oil and gas saturation, formation water resistivity and rock formation resistivity is determined.

[0024] Based on the changes in rock porosity and oil and gas saturation before and after drilling fluid invasion in a completed well, and the fifth correlation, the second correlation between formation water resistivity and rock formation resistivity before and after drilling fluid invasion is determined.

[0025] Further, determining the second formation water resistivity of the well to be corrected before drilling fluid invasion, based on the target natural gamma difference between the well to be corrected and the typical well to be corrected at the target layer, the first correlation, and the first formation water resistivity, includes:

[0026] Obtain the first natural gamma curve corresponding to the well to be corrected and the second natural gamma curve corresponding to the typical well completed;

[0027] Determine the target natural gamma difference between the first natural gamma curve and the second natural gamma curve at the target layer;

[0028] Substituting the target natural gamma difference and the first formation water resistivity into the first correlation, the second formation water resistivity corresponding to the well to be corrected before drilling fluid invasion is obtained.

[0029] Furthermore, the first association relationship is as follows:

[0030]

[0031] Wherein, ΔGR is the natural gamma difference of the typical completed well before and after drilling fluid invasion, and R w侵入后 R represents the formation water resistivity of the typical completed well after drilling fluid invasion. w侵入前The formation water resistivity of the typical completed well before drilling fluid invasion is given, where a and b are coefficients.

[0032] Furthermore, the second association is as follows:

[0033]

[0034] Among them, R t侵入前 R represents the rock formation resistivity of the typical completed well before drilling fluid invasion. w侵入前 R represents the formation water resistivity of the typical completed well before drilling fluid invasion; w侵入后 R represents the formation water resistivity of the typical completed well after drilling fluid invasion. t侵入后 The resistivity of the rock formation after drilling fluid invasion in the typical completed well is given.

[0035] Secondly, this application provides a resistivity correction device, the device comprising:

[0036] The acquisition module is used to acquire the first formation water resistivity and the first rock formation resistivity of the well to be corrected after drilling fluid invasion.

[0037] The relationship determination module is used to determine a first correlation between the natural gamma difference before and after drilling fluid invasion in a typical completed well and the corresponding formation water resistivity; and to determine a second correlation between the formation water resistivity and rock formation resistivity before and after drilling fluid invasion in the typical completed well.

[0038] The resistivity determination module is used to determine the second formation water resistivity of the well to be corrected before drilling fluid invasion, based on the target natural gamma difference between the well to be corrected and the typical well to be corrected in the target layer, the first correlation relationship, and the first formation water resistivity.

[0039] The resistivity correction module is used to determine the corrected rock formation resistivity of the well to be corrected before drilling fluid invasion, based on the second correlation, the first formation water resistivity, the first rock formation resistivity, and the second formation water resistivity.

[0040] Furthermore, the data acquisition module is used for:

[0041] Core samples of the target layer and formation water samples of the target layer were collected from the well to be calibrated.

[0042] The resistivity of the first rock formation corresponding to the drilling fluid invasion of the well to be corrected was collected from the core sample.

[0043] The first formation water resistivity corresponding to the drilling fluid invasion of the well to be calibrated was collected from the formation water sample to be calibrated.

[0044] Furthermore, the relationship determination module is used for:

[0045] Obtain typical formation water samples from the target layer in the typical completed well;

[0046] Determine the typical natural gamma and typical formation water resistivity of the typical formation water sample;

[0047] The typical formation water sample was divided into N equal parts, and drilling fluid of different concentrations was added to each part to obtain N mixed formation water samples; N is a positive integer.

[0048] Determine the mixed natural gamma and mixed formation water resistivity corresponding to each of the aforementioned mixed formation water samples;

[0049] Based on the typical natural gamma, the typical formation water resistivity, and the mixed natural gamma and mixed formation water resistivity corresponding to each of the mixed formation water samples, the first correlation between the natural gamma difference and formation water resistivity before and after drilling fluid invasion in a typical completed well is determined.

[0050] Furthermore, the relationship determination module is used for:

[0051] In the typical completed well, based on the third correlation between rock porosity, oil and gas saturation, formation water resistivity, rock formation resistivity and rock skeleton resistivity, and the fourth correlation between rock skeleton resistivity, formation water resistivity and rock formation resistivity, a fifth correlation between rock porosity, oil and gas saturation, formation water resistivity and rock formation resistivity is determined.

[0052] Based on the changes in rock porosity and oil and gas saturation before and after drilling fluid invasion in a completed well, and the fifth correlation, the second correlation between formation water resistivity and rock formation resistivity before and after drilling fluid invasion is determined.

[0053] Furthermore, the resistivity determination module is used for:

[0054] Obtain the first natural gamma curve corresponding to the well to be corrected and the second natural gamma curve corresponding to the typical well completed;

[0055] Determine the target natural gamma difference between the first natural gamma curve and the second natural gamma curve at the target layer;

[0056] Substituting the target natural gamma difference and the first formation water resistivity into the first correlation, the second formation water resistivity corresponding to the well to be corrected before drilling fluid invasion is obtained.

[0057] Furthermore, the first association relationship is as follows:

[0058]

[0059] Wherein, ΔGR is the natural gamma difference of the typical completed well before and after drilling fluid invasion, and R w侵入后 R represents the formation water resistivity of the typical completed well after drilling fluid invasion. w侵入前 The formation water resistivity of the typical completed well before drilling fluid invasion is given, where a and b are coefficients.

[0060] Furthermore, the second association is as follows:

[0061]

[0062] Among them, R t侵入前 R represents the rock formation resistivity of the typical completed well before drilling fluid invasion. w侵入前 R represents the formation water resistivity of the typical completed well before drilling fluid invasion; w侵入后 R represents the formation water resistivity of the typical completed well after drilling fluid invasion. t侵入后 The resistivity of the rock formation after drilling fluid invasion in the typical completed well is given.

[0063] Thirdly, this application provides an electronic device, comprising:

[0064] processor;

[0065] Memory used to store the processor's executable instructions;

[0066] The processor is configured to execute a resistivity correction method as provided in the first aspect.

[0067] Fourthly, this application provides a non-transitory computer-readable storage medium that, when the instructions in the storage medium are executed by a processor of an electronic device, enables the electronic device to perform a resistivity correction method as provided in the first aspect.

[0068] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0069] This application embodiment collects the first formation water resistivity and the first rock formation resistivity of the well to be calibrated after drilling fluid invasion; determines a first correlation between the natural gamma difference and the corresponding formation water resistivity of a typical well before and after drilling fluid invasion; and determines a second correlation between the formation water resistivity and the corresponding rock formation resistivity of the typical well before and after drilling fluid invasion. Based on the target natural gamma difference between the well to be calibrated and the typical well in the target layer, the first correlation, and the first formation water resistivity, the second formation water resistivity of the well to be calibrated before drilling fluid invasion is determined. Based on the second correlation, the first formation water resistivity, the first rock formation resistivity, and the second formation water resistivity, the corrected rock formation resistivity of the well to be calibrated before drilling fluid invasion is determined. As can be seen, the embodiments of this application dissect the effects of pre-drilling fluid (saline-water drilling fluid) on formation radioactivity and resistivity, establish a rock physics model, study the influence of drilling fluid on resistivity curves and energy spectrum curves on natural gamma ray, and explore methods for correcting natural gamma ray curves, providing a basis for KCl drilling fluid logging evaluation. The embodiments of this application realize multi-parameter correction of formation resistivity in drilling fluid invasion environments. This method is simple, has high accuracy in calculation and correction results, and shows good results in oil testing. The correction results are more accurate than existing methods, proving the effectiveness of this method. It is of great significance for oil and gas reservoir interpretation, decision-making on production well sections, and improving single-well production. Attached Figure Description

[0070] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0071] Figure 1 The statistical relationship between the concentration and resistivity of potassium chloride drilling fluid is shown.

[0072] Figure 2 A schematic flowchart of a resistivity correction method provided in an embodiment of this application;

[0073] Figure 3 A schematic diagram of the resistivity curve of a rock formation provided in this application embodiment;

[0074] Figure 4 This is a schematic diagram of the resistivity curves of rock formations before and after correction using the resistivity correction method provided in the embodiments of this application;

[0075] Figure 5This is a schematic diagram of the structure of a resistivity correction device provided in an embodiment of this application;

[0076] Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0077] This application provides a resistivity correction method, which solves the technical problem of large correction errors in existing resistivity logging methods.

[0078] The technical solution of this application embodiment is to solve the above-mentioned technical problems, and the general idea is as follows:

[0079] This application embodiment collects the first formation water resistivity and the first rock formation resistivity of the well to be calibrated after drilling fluid invasion; determines a first correlation between the natural gamma difference and the corresponding formation water resistivity of a typical well before and after drilling fluid invasion; and determines a second correlation between the formation water resistivity and the corresponding rock formation resistivity of the typical well before and after drilling fluid invasion. Based on the target natural gamma difference between the well to be calibrated and the typical well in the target layer, the first correlation, and the first formation water resistivity, the second formation water resistivity of the well to be calibrated before drilling fluid invasion is determined. Based on the second correlation, the first formation water resistivity, the first rock formation resistivity, and the second formation water resistivity, the corrected rock formation resistivity of the well to be calibrated before drilling fluid invasion is determined. As can be seen, the embodiments of this application dissect the effects of pre-drilling fluid (saline-water drilling fluid) on formation radioactivity and resistivity, establish a rock physics model, study the influence of drilling fluid on resistivity curves and energy spectrum curves on natural gamma ray, and explore methods for correcting natural gamma ray curves, providing a basis for KCl drilling fluid logging evaluation. The embodiments of this application realize multi-parameter correction of formation resistivity in drilling fluid invasion environments. This method is simple, has high accuracy in calculation and correction results, and shows good results in oil testing. The correction results are more accurate than existing methods, proving the effectiveness of this method. It is of great significance for oil and gas reservoir interpretation, decision-making on production well sections, and improving single-well production.

[0080] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0081] First, it should be clarified that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0082] To protect the wellbore, KCl brine drilling fluid systems are extensively used during drilling. However, in cases of brine leakage or prolonged soaking time, ion exchange within the brine system can cause various logging series to fail to fully reflect the geological characteristics of the formation. Among these, the resistivity logging curve is most significantly affected by the brine, leading to the most severe consequences: difficulty in identifying fluid properties and an increased risk of errors in interpreting and determining oil and gas reservoirs. Figure 1 The figure shows the statistical relationship between the concentration and resistivity of potassium chloride drilling fluid. The horizontal axis represents the concentration of potassium ions (K ions) in the potassium chloride (KCl) drilling fluid (in %), and the vertical axis represents the resistivity R (in Ωm). Figure 1 It can be seen that the higher the K ion concentration, the lower the resistivity of the drilling fluid.

[0083] Therefore, it is necessary to correct the resistivity curve. Conventional methods can use sonic transit time logging to standardize and correct the logging curve. However, resistivity logging is greatly affected by lithology, physical properties, and oil-water relationships. Conventional standardization formulas do not take these factors into account, resulting in large correction errors that cannot meet research requirements. Therefore, how to reduce the correction error of the logging curve is an urgent problem to be solved.

[0084] To address the aforementioned problems, this application provides a resistivity correction method that can be applied to electronic devices related to resistivity correction. The method is as follows: Figure 2 As shown, it includes steps S21-S24.

[0085] Step S21: Collect the first formation water resistivity and the first rock formation resistivity of the well to be corrected after the drilling fluid invasion.

[0086] Step S22: Determine the first correlation between the natural gamma difference before and after drilling fluid invasion in a typical completed well and the corresponding formation water resistivity; and determine the second correlation between the formation water resistivity and rock formation resistivity before and after drilling fluid invasion in the typical completed well.

[0087] Step S23: Based on the target natural gamma difference between the well to be corrected and the typical well to be corrected in the target layer, the first correlation relationship, and the first formation water resistivity, determine the second formation water resistivity of the well to be corrected before the drilling fluid invasion.

[0088] Step S24: Based on the second correlation, the first formation water resistivity, the first rock formation resistivity, and the second formation water resistivity, determine the corrected rock formation resistivity of the well to be corrected before drilling fluid invasion.

[0089] Regarding step S21, the first formation water resistivity and the first rock formation resistivity are collected after the drilling fluid invasion of the well to be corrected.

[0090] Wells requiring correction are those that need to have their rock formation resistivity corrected. The opposite of wells requiring correction are typical wells, or standard wells, which specifically refer to wells that do not require rock formation resistivity correction or have already undergone rock formation resistivity correction.

[0091] There are various types of drilling fluids; this application only uses KCL (potassium chloride) drilling fluid as an example. It should be noted that the drilling fluid concentration is the same in both typical completed wells and wells requiring calibration.

[0092] In step S21, it is necessary to collect the first formation water resistivity and the first rock formation resistivity of the well to be corrected after the drilling fluid has invaded.

[0093] First, core samples of the target layer and formation water samples of the well to be calibrated are collected from the well to be calibrated.

[0094] Then, the first rock formation resistivity corresponding to the drilling fluid invasion after the well to be calibrated is collected from the core sample. Also, the first formation water resistivity corresponding to the drilling fluid invasion after the drilling fluid invasion is collected from the formation water sample.

[0095] It should be noted that when collecting the first formation water resistivity from the formation water sample to be calibrated, the formation water sample to be calibrated needs to be heated to the temperature corresponding to the target layer in the well to be calibrated, and the formation water resistivity is measured at this temperature to obtain the first formation water resistivity.

[0096] Regarding step S22, a first correlation is determined between the natural gamma difference before and after drilling fluid invasion in a typical completed well and the corresponding formation water resistivity; and a second correlation is determined between the formation water resistivity and rock formation resistivity before and after drilling fluid invasion in the typical completed well.

[0097] The determination of the first correlation between the natural gamma difference before and after drilling fluid invasion in a typical completed well and the corresponding formation water resistivity includes steps S2211-S2215.

[0098] Step S2211: Obtain a typical formation water sample from the target layer in the typical completed well.

[0099] Step S2212: Determine the typical natural gamma and typical formation water resistivity of the typical formation water sample;

[0100] Step S2213: Divide the typical formation water sample into N equal parts, and add drilling fluid of different concentrations to each part to obtain N mixed formation water samples; N is a positive integer;

[0101] Step S2214: Determine the mixed natural gamma and mixed formation water resistivity corresponding to each of the mixed formation water samples;

[0102] Step S2215: Based on the typical natural gamma, the typical formation water resistivity, and the mixed natural gamma and mixed formation water resistivity corresponding to each of the mixed formation water samples, determine the first correlation between the difference in natural gamma and formation water resistivity before and after drilling fluid invasion in the typical completed well.

[0103] Natural gamma logging can provide a good indication of lithology based on the intensity of gamma rays from reflective thorium, uranium, and potassium elements in the formation. Within the same block, reservoir conditions are basically the same, and the natural gamma values ​​of sandstone and mudstone are generally consistent. The standard natural gamma for a block can be obtained statistically from the natural gamma measurements taken during drilling in the absence of invasion.

[0104] After KCl polymer drilling fluid intrusion, KCl plasma enters the formation, leading to an overall increase in natural gamma logging values. Core samples were taken and the natural gamma correction value ΔGR and the resistivity R of the mixed fluid were measured in the laboratory after adding KCl polymer to the formation water under formation temperature and pressure conditions. w侵入后 The relationship between them.

[0105] The target layer of a typical well completion and the target layer of a well to be corrected are mutually corresponding. The target layer of a typical well completion can be determined based on the target layer of the well to be corrected, relying on the natural gamma ray curves corresponding to the typical and the well to be corrected, respectively. The natural gamma ray curves are as follows: Figure 3 As shown, Figure 3 The abbreviations in the text are as follows: GR represents natural gamma, SP represents spontaneous potential, AC represents time difference (the reciprocal of velocity), DEN represents rock density, RT represents deep lateral resistivity, and RS represents shallow lateral resistivity.

[0106] Typical formation water samples were collected from the target layer in the typical completed well, and the typical natural gamma and typical formation water resistivity of the typical formation water samples were determined.

[0107] The typical formation water sample was divided into N equal parts, and drilling fluid of different concentrations was added to each part to obtain N mixed formation water samples, thus obtaining samples after drilling fluid intrusion into the formation water sample. The mixed natural gamma and mixed formation water resistivity of each mixed formation water sample were then examined.

[0108] Based on relevant experimental measurements, the inventors obtained the following formula (1).

[0109]

[0110] Wherein, ΔGR is the natural gamma difference of the typical completed well before and after drilling fluid invasion, and R w侵入后 R represents the formation water resistivity of the typical completed well after drilling fluid invasion. w侵入前 The formation water resistivity of the typical completed well before drilling fluid invasion is given, where a and b are coefficients.

[0111] Substituting the typical natural gamma, the typical formation water resistivity, the mixed natural gamma and the mixed formation water resistivity corresponding to each of the mixed formation water samples into the above formula (1), coefficients a and b can be calculated, and then the first correlation between the difference in natural gamma and formation water resistivity before and after drilling fluid invasion in a typical completed well can be obtained.

[0112] The determination of the second correlation between the formation water resistivity and the rock formation resistivity before and after the drilling fluid invasion in the typical completed well includes steps S2221-S2222.

[0113] Step S2221: In the typical completed well, based on the third correlation between rock porosity, oil and gas saturation, formation water resistivity, rock formation resistivity and rock skeleton resistivity, and the fourth correlation between rock skeleton resistivity, formation water resistivity and rock formation resistivity, a fifth correlation between rock porosity, oil and gas saturation, formation water resistivity and rock formation resistivity is determined.

[0114] Step S2222: Based on the relationship between the changes in rock porosity and oil and gas saturation before and after drilling fluid invasion in the completed well, and the fifth correlation relationship, determine the second correlation relationship between formation water resistivity and rock formation resistivity before and after drilling fluid invasion.

[0115] Assuming that the rock skeleton is uniformly dispersed in continuous pores in a discontinuous spherical form, the inventors derived a third correlation between rock porosity, oil and gas saturation, formation water resistivity, rock formation resistivity and rock skeleton resistivity by combining the formula, as shown in formula (2).

[0116]

[0117] Where φ is the rock porosity; S w R represents the hydrocarbon saturation in the pore fluid of the rock; w R represents the resistivity of formation water. t R represents the resistivity of the rock formation. m The resistivity of the rock skeleton is given; the parameter m is empirically taken as 1.5 when the skeleton particles are spherical.

[0118] The fourth correlation between rock skeleton resistivity, formation water resistivity, and rock formation resistivity refers to: rock skeleton resistivity R m Much greater than the resistivity R of formation water w and the resistivity R of rock formations t Based on this, formula (2) can be simplified to obtain the fifth correlation between rock porosity, oil and gas saturation, formation water resistivity and rock formation resistivity, as shown in formula (3).

[0119]

[0120] Where φ is the rock porosity; S w R represents the hydrocarbon saturation in the pore fluid of the rock; w R represents the resistivity of formation water. t The resistivity of the rock formation is given; the parameter m is empirically taken as 1.5 when the skeletal particles are spherical.

[0121] The relationship between rock porosity and oil and gas saturation before and after drilling fluid invasion after well completion refers to the following: formation porosity did not change before and after drilling fluid invasion, and oil saturation did not change much. Based on this, the following formula (4) can be obtained.

[0122]

[0123] Among them, R t侵入前 R represents the rock formation resistivity of the typical completed well before drilling fluid invasion. w侵入前 R represents the formation water resistivity of the typical completed well before drilling fluid invasion; w侵入后 R represents the formation water resistivity of the typical completed well after drilling fluid invasion. t侵入后 The resistivity of the rock formation after drilling fluid invasion in the typical completed well is given.

[0124] By transforming formula (4), we can obtain the following formula (5), which is the second correlation relationship.

[0125]

[0126] Among them, R t侵入前 R represents the rock formation resistivity of the typical completed well before drilling fluid invasion. w侵入前 R represents the formation water resistivity of the typical completed well before drilling fluid invasion; w侵入后 R represents the formation water resistivity of the typical completed well after drilling fluid invasion. t侵入后 The resistivity of the rock formation after drilling fluid invasion in the typical completed well is given.

[0127] Regarding step S23, based on the target natural gamma difference between the well to be corrected and the typical well in the target layer, the first correlation, and the first formation water resistivity, the second formation water resistivity of the well to be corrected before drilling fluid invasion is determined.

[0128] First, obtain the first natural gamma curve corresponding to the well to be corrected and the second natural gamma curve corresponding to the typical well completion. Then, determine the target natural gamma difference between the first and second natural gamma curves at the target formation. Finally, substitute the target natural gamma difference and the first formation water resistivity into the first correlation to obtain the second formation water resistivity R of the well to be corrected before drilling fluid invasion. w侵入前 .

[0129] Among them, the natural gamma curve is as follows Figure 3 As shown, Figure 3 The abbreviations in the text are as follows: GR represents natural gamma, SP represents spontaneous potential, AC represents time difference (the reciprocal of velocity), DEN represents rock density, RT represents deep lateral resistivity, and RS represents shallow lateral resistivity.

[0130] After determining the target natural gamma difference and the corresponding first formation water resistivity after intrusion, the corresponding second formation water resistivity before intrusion can be determined by combining the aforementioned formula (1).

[0131] Regarding step S24, based on the second correlation, the first formation water resistivity, the first rock formation resistivity, and the second formation water resistivity, the corrected rock formation resistivity corresponding to the well to be corrected before drilling fluid invasion is determined.

[0132] The resistivity R of the first formation water t侵入后The resistivity R of the first rock formation w侵入后 and the second formation water resistivity R w侵入前 Substituting into the second correlation, that is, into the aforementioned formula (5), we can determine the corrected rock formation resistivity R of the well to be corrected before the drilling fluid invasion. t侵入前 R t侵入后 This refers to the final modified rock formation resistivity in the embodiments of this application.

[0133] like Figure 4 As shown, this is the difference between the rock resistivity curves of a well to be corrected and those of the rock formation before and after correction. The rock formation resistivity curve before correction is the original GR curve, and the rock formation resistivity curve after correction is the corrected GR curve.

[0134] In summary, this application embodiment collects the first formation water resistivity and the first rock formation resistivity of the well to be calibrated after drilling fluid invasion; determines a first correlation between the natural gamma difference and the corresponding formation water resistivity of a typical well before and after drilling fluid invasion; and determines a second correlation between the formation water resistivity and the corresponding rock formation resistivity of the typical well before and after drilling fluid invasion; determines a second formation water resistivity of the well to be calibrated before drilling fluid invasion based on the target natural gamma difference between the well to be calibrated and the typical well in the target layer, the first correlation, and the first formation water resistivity; and determines the corrected rock formation resistivity of the well to be calibrated before drilling fluid invasion based on the second correlation, the first formation water resistivity, the first rock formation resistivity, and the second formation water resistivity. As can be seen, the embodiments of this application dissect the effects of pre-drilling fluid (saline-water drilling fluid) on formation radioactivity and resistivity, establish a rock physics model, study the influence of drilling fluid on resistivity curves and energy spectrum curves on natural gamma ray, and explore methods for correcting natural gamma ray curves, providing a basis for KCl drilling fluid logging evaluation. The embodiments of this application realize multi-parameter correction of formation resistivity in drilling fluid invasion environments. This method is simple, has high accuracy in calculation and correction results, and shows good results in oil testing. The correction results are more accurate than existing methods, proving the effectiveness of this method. It is of great significance for oil and gas reservoir interpretation, decision-making on production well sections, and improving single-well production.

[0135] Based on the same inventive concept, the embodiments of this application provide, as follows: Figure 5 The resistivity correction device shown includes:

[0136] The acquisition module 51 is used to acquire the first formation water resistivity and the first rock formation resistivity of the well to be corrected after the drilling fluid has invaded.

[0137] The relationship determination module 52 is used to determine the first correlation between the natural gamma difference before and after drilling fluid invasion in a typical completed well and the corresponding formation water resistivity; and to determine the second correlation between the formation water resistivity and rock formation resistivity before and after drilling fluid invasion in the typical completed well.

[0138] The resistivity determination module 53 is used to determine the second formation water resistivity of the well to be corrected before drilling fluid invasion, based on the target natural gamma difference between the well to be corrected and the typical well to be corrected in the target layer, the first correlation relationship, and the first formation water resistivity.

[0139] The resistivity correction module 54 is used to determine the corrected rock formation resistivity of the well to be corrected before the drilling fluid invades, based on the second correlation, the first formation water resistivity, the first rock formation resistivity, and the second formation water resistivity.

[0140] Furthermore, the acquisition module 51 is used for:

[0141] Core samples of the target layer and formation water samples of the target layer were collected from the well to be calibrated.

[0142] The resistivity of the first rock formation corresponding to the drilling fluid invasion of the well to be corrected was collected from the core sample.

[0143] The first formation water resistivity corresponding to the drilling fluid invasion of the well to be calibrated was collected from the formation water sample to be calibrated.

[0144] Furthermore, the relationship determination module 52 is used for:

[0145] Obtain typical formation water samples from the target layer in the typical completed well;

[0146] Determine the typical natural gamma and typical formation water resistivity of the typical formation water sample;

[0147] The typical formation water sample was divided into N equal parts, and drilling fluid of different concentrations was added to each part to obtain N mixed formation water samples; N is a positive integer.

[0148] Determine the mixed natural gamma and mixed formation water resistivity corresponding to each of the aforementioned mixed formation water samples;

[0149] Based on the typical natural gamma, the typical formation water resistivity, and the mixed natural gamma and mixed formation water resistivity corresponding to each of the mixed formation water samples, the first correlation between the natural gamma difference and formation water resistivity before and after drilling fluid invasion in a typical completed well is determined.

[0150] Furthermore, the relationship determination module 52 is used for:

[0151] In the typical completed well, based on the third correlation between rock porosity, oil and gas saturation, formation water resistivity, rock formation resistivity and rock skeleton resistivity, and the fourth correlation between rock skeleton resistivity, formation water resistivity and rock formation resistivity, a fifth correlation between rock porosity, oil and gas saturation, formation water resistivity and rock formation resistivity is determined.

[0152] Based on the changes in rock porosity and oil and gas saturation before and after drilling fluid invasion in a completed well, and the fifth correlation, the second correlation between formation water resistivity and rock formation resistivity before and after drilling fluid invasion is determined.

[0153] Furthermore, the resistivity determination module 53 is used for:

[0154] Obtain the first natural gamma curve corresponding to the well to be corrected and the second natural gamma curve corresponding to the typical well completed;

[0155] Determine the target natural gamma difference between the first natural gamma curve and the second natural gamma curve at the target layer;

[0156] Substituting the target natural gamma difference and the first formation water resistivity into the first correlation, the second formation water resistivity corresponding to the well to be corrected before drilling fluid invasion is obtained.

[0157] Furthermore, the first association relationship is as follows:

[0158]

[0159] Wherein, ΔGR is the natural gamma difference of the typical completed well before and after drilling fluid invasion, and R w侵入后 R represents the formation water resistivity of the typical completed well after drilling fluid invasion. w侵入前 The formation water resistivity of the typical completed well before drilling fluid invasion is given, where a and b are coefficients.

[0160] Furthermore, the second association is as follows:

[0161]

[0162] Among them, R t侵入前 R represents the rock formation resistivity of the typical completed well before drilling fluid invasion. w侵入前R represents the formation water resistivity of the typical completed well before drilling fluid invasion; w侵入后 R represents the formation water resistivity of the typical completed well after drilling fluid invasion. t侵入后 The resistivity of the rock formation after drilling fluid invasion in the typical completed well is given.

[0163] Based on the same inventive concept, the embodiments of this application provide, as follows: Figure 6 An electronic device shown includes:

[0164] Processor 61;

[0165] Memory 62 is used to store executable instructions of the processor 61;

[0166] The processor 61 is configured to execute a resistivity correction method as described above.

[0167] Based on the same inventive concept, embodiments of this application provide a non-transitory computer-readable storage medium, which, when the instructions in the storage medium are executed by the processor 61 of an electronic device, enables the electronic device to perform a resistivity correction method as described above.

[0168] Since the electronic device described in this embodiment is an electronic device used to implement the information processing method in the embodiments of this application, those skilled in the art can understand the specific implementation methods and various variations of the electronic device in this embodiment based on the information processing method described in the embodiments of this application. Therefore, how the electronic device implements the method in the embodiments of this application will not be described in detail here. Any electronic device used by those skilled in the art to implement the information processing method in the embodiments of this application falls within the scope of protection of this application.

[0169] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0170] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0171] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0172] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0173] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0174] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A resistivity correction method, characterized in that, The method includes: Collect the first formation water resistivity and the first rock formation resistivity of the well to be corrected after drilling fluid invasion. Determine the first correlation between the natural gamma difference before and after drilling fluid invasion in a typical completed well and the corresponding formation water resistivity; and determine the second correlation between the formation water resistivity and rock formation resistivity before and after drilling fluid invasion in the typical completed well. Based on the target natural gamma difference between the well to be corrected and the typical well to be corrected in the target layer, the first correlation, and the first formation water resistivity, the second formation water resistivity of the well to be corrected before drilling fluid invasion is determined. Based on the second correlation, the first formation water resistivity, the first rock formation resistivity, and the second formation water resistivity, the corrected rock formation resistivity corresponding to the well to be corrected before drilling fluid invasion is determined.

2. The method as described in claim 1, characterized in that, The acquisition of the first formation water resistivity and the first rock formation resistivity after drilling fluid invasion in the well to be corrected includes: Core samples of the target layer and formation water samples of the target layer were collected from the well to be calibrated. The resistivity of the first rock formation corresponding to the drilling fluid invasion of the well to be corrected was collected from the core sample. The first formation water resistivity corresponding to the drilling fluid invasion of the well to be calibrated was collected from the formation water sample to be calibrated.

3. The method as described in claim 1, characterized in that, The determination of the first correlation between the natural gamma difference before and after drilling fluid invasion in a typical completed well and the corresponding formation water resistivity includes: Obtain typical formation water samples from the target layer in the typical completed well; Determine the typical natural gamma and typical formation water resistivity of the typical formation water sample; The typical formation water sample was divided into N equal parts, and drilling fluid of different concentrations was added to each part to obtain N mixed formation water samples; N is a positive integer. Determine the mixed natural gamma and mixed formation water resistivity corresponding to each of the aforementioned mixed formation water samples; Based on the typical natural gamma, the typical formation water resistivity, and the mixed natural gamma and mixed formation water resistivity corresponding to each of the mixed formation water samples, the first correlation between the natural gamma difference and formation water resistivity before and after drilling fluid invasion in a typical completed well is determined.

4. The method as described in claim 1, characterized in that, The determination of the second correlation between the formation water resistivity and rock formation resistivity of the typical completed well before and after drilling fluid invasion includes: In the typical completed well, based on the third correlation between rock porosity, oil and gas saturation, formation water resistivity, rock formation resistivity and rock skeleton resistivity, and the fourth correlation between rock skeleton resistivity, formation water resistivity and rock formation resistivity, a fifth correlation between rock porosity, oil and gas saturation, formation water resistivity and rock formation resistivity is determined. Based on the changes in rock porosity and oil and gas saturation before and after drilling fluid invasion in a completed well, and the fifth correlation, the second correlation between formation water resistivity and rock formation resistivity before and after drilling fluid invasion is determined.

5. The method as described in claim 1, characterized in that, The step of determining the second formation water resistivity of the well to be corrected before drilling fluid invasion, based on the target natural gamma difference between the well to be corrected and the typical well to be corrected in the target layer, the first correlation, and the first formation water resistivity, includes: Obtain the first natural gamma curve corresponding to the well to be corrected and the second natural gamma curve corresponding to the typical well completed; Determine the target natural gamma difference between the first natural gamma curve and the second natural gamma curve at the target layer; Substituting the target natural gamma difference and the first formation water resistivity into the first correlation, the second formation water resistivity corresponding to the well to be corrected before drilling fluid invasion is obtained.

6. The method as described in claim 1, characterized in that, The first association is: Wherein, ΔGR is the natural gamma difference of the typical completed well before and after drilling fluid invasion, and R w侵入后 R represents the formation water resistivity of the typical completed well after drilling fluid invasion. w侵入前 The formation water resistivity of the typical completed well before drilling fluid invasion is given, where a and b are coefficients.

7. The method as described in claim 1, characterized in that, The second association is: Among them, R t侵入前 R represents the rock formation resistivity of the typical completed well before drilling fluid invasion. w侵入前 R represents the formation water resistivity of the typical completed well before drilling fluid invasion; w侵入后 R represents the formation water resistivity of the typical completed well after drilling fluid invasion. t侵入后 The resistivity of the rock formation after drilling fluid invasion in the typical completed well is given.

8. A resistivity correction device, characterized in that, The device includes: The acquisition module is used to acquire the first formation water resistivity and the first rock formation resistivity of the well to be corrected after drilling fluid invasion. The relationship determination module is used to determine a first correlation between the natural gamma difference before and after drilling fluid invasion in a typical completed well and the corresponding formation water resistivity; and to determine a second correlation between the formation water resistivity and rock formation resistivity before and after drilling fluid invasion in the typical completed well. The resistivity determination module is used to determine the second formation water resistivity of the well to be corrected before drilling fluid invasion, based on the target natural gamma difference between the well to be corrected and the typical well to be corrected in the target layer, the first correlation relationship, and the first formation water resistivity. The resistivity correction module is used to determine the corrected rock formation resistivity of the well to be corrected before drilling fluid invasion, based on the second correlation, the first formation water resistivity, the first rock formation resistivity, and the second formation water resistivity.

9. An electronic device, characterized in that, include: processor; Memory used to store the processor's executable instructions; The processor is configured to execute a resistivity correction method as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium, wherein instructions in the storage medium, when executed by a processor of an electronic device, enable the electronic device to perform a resistivity correction method as described in any one of claims 1 to 7.

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