Resistivity logging inversion initial value selection method, system, equipment and medium

Abstract

The invention discloses a resistivity logging inversion initial value selection method, system and device and a medium. The method comprises the steps that a three-parameter radial step inversion model is established; substituting the pump-pumped slurry filtrate volume into the inversion model to calculate the radius initial value of the intrusive zone; calculating a formation resistivity inversion initial value according to the pumping formation water volume and the pumping formation oil gas volume through an Archie formula; and according to the initial value of the radius of the intrusive zone and the initial value of the resistivity of the intrusive zone, calculating an initial inversion value of the resistivity of the intrusive zone through the pseudo-geometric factor. The method can effectively reduce the deviation between the initial value and the true value of the inversion, can prevent the inversion algorithm from falling into a local optimal solution, improves the inversion precision, can reduce the number of inversion iterations, and accelerates the inversion processing speed.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas exploration and development, and in particular relates to a resistivity logging inversion initial value selection method, system, equipment and medium. Background Art

[0002] Accurate resistivity measurement is key to evaluating reservoir oil and gas content. Resistivity logging (such as dual laterolog, dual induction logging, array laterolog, and array induction logging) is a common technique for measuring formation resistivity. However, its results represent a comprehensive response to reservoir and environmental factors (such as the wellbore, surrounding rock, and mud invasion). Inversion processing is often required to obtain resistivity information that reflects the reservoir's inherent characteristics. The accuracy and speed of resistivity logging inversion are closely related to the appropriate selection of initial inversion values. Inappropriate initial values ​​can lead to a high number of iterations and a long inversion time, and may even cause the inversion algorithm to fail to converge and become trapped in a local optimum, resulting in inversion failure. In practical applications, the wellbore radius, the shallowest resistivity curve value at the shallowest depth, and the deepest resistivity curve value at the deepest depth are generally used as the initial values ​​for the invasion zone radius, invasion zone resistivity, and formation resistivity, respectively. These initial values ​​deviate significantly from the true values, resulting in slow inversion speed and low accuracy.

[0003] The patent publication number is CN111305834B, and its name is a patent application for a method and system for constructing a three-dimensional inversion initial model based on multi-detection mode resistivity logging. First, the logging curve is obtained, and the target layer is stratified based on the logging curve. Then, based on the stratification results, the apparent resistivity in the logging curve is corrected to obtain the true resistivity. Finally, the true resistivity is kriging interpolated, and based on the results of the kriging interpolation, the resistivity of the finite element grid required for the forward model is assigned. By correcting the apparent resistivity in the logging curve, a true resistivity that is closer to the actual formation can be obtained and used as the resistivity of the three-dimensional inversion initial model based on multi-detection mode resistivity logging. This patent application can correct the apparent resistivity to reduce the number of inversion iterations, but this patent application cannot select an initial value that is closer to the actual value. Summary of the Invention

[0004] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a method, system, equipment and medium for selecting initial values ​​for resistivity logging inversion, and propose a method for selecting initial values ​​for resistivity logging inversion, which improves the accuracy and speed of resistivity logging inversion by obtaining more realistic initial values.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for selecting initial values ​​for resistivity logging inversion includes the following steps:

[0007] S1: Establish a three-parameter radial step inversion model;

[0008] S2: Substitute the volume of pumped mud filtrate into the inversion model to calculate the initial value of the invasion zone radius;

[0009] S3: Calculate the initial value of formation resistivity inversion based on the volume of pumped formation water and the volume of pumped formation oil and gas using Archie's formula;

[0010] S4: Based on the initial values ​​of the intrusion zone radius and the initial values ​​of the intrusion zone resistivity, the initial value of the intrusion zone resistivity is calculated through the pseudo-geometric factor.

[0011] Optionally, after step S4, the initial value of the invasion zone radius, the invasion zone resistivity, and the formation resistivity are substituted into the inversion algorithm to obtain an inversion value.

[0012] Optionally, before step S1, the volume of pumped mud filtrate, the volume of pumped formation water, and the volume of pumped formation oil and gas are collected corresponding to the cable formation.

[0013] Optionally, in step S1, the calculation formula for the initial value of the intrusion zone radius is: Where r i is the initial value of the intrusion zone radius; V ly is the volume of pumped mud filtrate; H is the thickness of the inversion horizon; d is the wellbore radius; φ is the formation porosity.

[0014] Optionally, in step S3, the calculation formula for the initial value of formation resistivity inversion is:

[0015] Where R t is the initial value of formation resistivity; R w is the resistivity of formation water; a, b, m, and n are all lithology coefficients.

[0016] Optionally, in step S4, the calculation formula for the initial value of the intrusion zone resistivity inversion is: Where R i is the initial resistivity of the intrusion zone; R amin The apparent resistivity at the shallowest detection depth; R amax G is the apparent resistivity at the deepest detection depth; amin It is the pseudo-geometric factor corresponding to the apparent resistivity at the shallowest detection depth.

[0017] Optionally, in step S1, the independent variable of the three-parameter radial step inversion model is radius, and the dependent variable is resistivity.

[0018] A resistivity logging inversion initial value selection system, comprising:

[0019] Model building module, used to build a three-parameter radial step inversion model;

[0020] The first calculation module is used to bring the volume of the pumped mud filtrate into the inversion model to calculate the initial value of the invasion zone radius;

[0021] The second calculation module is used to calculate the initial value of formation resistivity inversion based on the volume of pumped formation water and the volume of pumped formation oil and gas using Archie's formula;

[0022] The third calculation module is used to calculate the initial value of the intrusion zone resistivity inversion through the pseudo-geometric factor according to the initial value of the intrusion zone radius and the initial value of the intrusion zone resistivity.

[0023] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the resistivity logging inversion initial value selection method are implemented.

[0024] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a resistivity logging inversion initial value selection method.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] This paper proposes a method for selecting initial values ​​for resistivity logging inversion based on wireline formation test data. The method's innovations are embodied in the following aspects: Based on a three-parameter radial step inversion model, the initial inversion value for the invasion zone radius is calculated using the volume of mud filtrate pumped by the wireline formation test; based on the Archie formula, the initial inversion value for formation resistivity is calculated using the volumes of formation water and oil and gas pumped by the wireline formation test; and based on a pseudo-geometric factor, the initial inversion value for the invasion zone resistivity is calculated using the invasion zone radius and the initial inversion value for formation resistivity. This method can effectively reduce the deviation between the initial inversion value and the true value, prevent the inversion algorithm from falling into a local optimal solution, improve inversion accuracy, and reduce the number of inversion iterations, thereby accelerating the inversion processing speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

[0028] In the attached figure:

[0029] Figure 1 This is a three-parameter inversion radial step inversion model diagram of the present invention;

[0030] Figure 2 This is a flow chart of a method for selecting initial values ​​for resistivity logging inversion according to the present invention. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solutions of the present invention, 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 only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts should fall within the scope of protection of the present invention.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] It should be noted that in the claims, any reference signs placed between brackets shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claim. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The present application may be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, and third etc. does not indicate any order. These words may be interpreted as names.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0035] The present invention will be described in detail below with reference to the accompanying drawings.

[0036] A resistivity logging inversion initial value selection method of the present invention comprises the following steps:

[0037] Step 1: For the layer that needs resistivity logging inversion processing, collect the corresponding cable formation test sampling data, including the volume V of the mud filtrate pumped from the layer ly , pumped formation water volume V w , pumped formation oil and gas volume V o .

[0038] Step 2: Based on the three-parameter radial step inversion model, the pumped formation water volume V ly Calculate the initial value of the intrusion zone radius:

[0039] like Figure 1 As shown in the figure, the independent variable of the three-parameter radial step inversion model is the radius, and the dependent variable is the resistivity. When the radius is smaller than the wellbore radius d, the resistivity value is the mud resistivity R mc ; When the radius is larger than the wellbore radius d and smaller than the initial value of the invasion zone radius r i When the resistivity is the initial resistivity value of the intrusion zone R i ; When the radius is greater than the initial value of the intrusion zone radius r i When the resistivity is the initial value of formation resistivity R t .

[0040] V ly =(πr i 2 -πd 2 )Hφ (1)

[0041] From formula (1), we can get:

[0042]

[0043] In formula (2), r i is the initial value of the intrusion zone radius, in m; V ly is the volume of pumped mud filtrate, in m 3 ; H is the thickness of the inversion horizon, in m; d is the wellbore radius, in m; φ is the formation porosity, in %, where r is removed from formula (2). i All other values ​​are known.

[0044] Step 3: Based on Archie's formula, use V w and V o Calculate the initial value of formation resistivity inversion:

[0045]

[0046]

[0047] From equations (3) and (4), we can get:

[0048]

[0049] In formula (5), R t is the initial value of formation resistivity, in Ω.m; R w is the formation water resistivity, in Ω.m; a, b, m, n are all lithologic coefficients, dimensionless. In formula (5), except for R t All other values ​​are known;

[0050] Step 4: Based on the pseudo-geometric factor, use r i and R t Calculate the initial value of resistivity inversion in the intrusion zone:

[0051]

[0052] In formula (6), R i is the initial value of the resistivity of the intrusion zone, in Ω.m; R amin The apparent resistivity at the shallowest detection depth, in Ω.m; R amax The apparent resistivity at the deepest detection depth, in Ω.m; G amin G is the pseudo-geometric factor corresponding to the shallowest apparent resistivity, dimensionless. When the initial resistivity of the intrusion zone and the instrument structure are known, G amin is a known value.

[0053] Step 5: r i 、R t 、R i Substitute the initial values ​​of the three resistivity parameters into the inversion algorithm to obtain the inversion value.

[0054] Example

[0055] The specific embodiments of the present invention are further described below.

[0056] In this embodiment, taking the radial step formation model (theoretical model) as an example, a method for selecting initial values ​​for resistivity logging inversion includes the following steps:

[0057] Step 1: Collect the pumping and apparent resistivity data of the cable formation test corresponding to the theoretical model, as shown in Table 1 below. Specifically, the pumped mud filtrate volume V ly , pumped formation water volume V w , pumped formation oil and gas volume V o , apparent resistivity data HDIL1-HDIL5.

[0058] Table 1

[0059]

[0060]

[0061] Step 2: Based on the three-parameter radial step inversion model, use V ly Calculate the initial value of the intrusion zone radius;

[0062] Step 3: Based on Al's formula, use V w and V o Calculate the initial value of formation resistivity inversion;

[0063] Step 4: Based on the pseudo-geometric factor, use r i and R t Calculate the initial value of resistivity inversion of the intrusion zone;

[0064] Step 5: Compare the initial inversion values ​​with the actual formation parameters to evaluate the effectiveness of the selected method.

[0065] Table 2

[0066]

[0067] Table 2 is a comparison between the initial inversion values ​​and the actual formation parameters. It can be seen from Table 2 that the results of the present invention can effectively reduce the deviation between the initial inversion values ​​and the true values. Compared with the conventional method, the deviation between the initial inversion values ​​and the true values ​​is reduced by 26.41%, and can be applied to the field.

[0068] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0069] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0070] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0071] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0072] Unless otherwise specified, the working modes or control modes involved in the above embodiments are all conventional working modes or control modes in the art.

[0073] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limiting. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for selecting initial values ​​for resistivity logging inversion, characterized in that: The following steps are involved: S1: Establish a three-parameter radial step inversion model; S2: Substitute the volume of pumped mud filtrate into the inversion model to calculate the initial value of the invasion zone radius; S3: Calculate the initial value of formation resistivity inversion based on the volume of pumped formation water and the volume of pumped formation oil and gas using Archie's formula; S4: Based on the initial values ​​of the intrusion zone radius and the initial values ​​of the intrusion zone resistivity, the initial value of the intrusion zone resistivity is calculated through the pseudo-geometric factor.

2. The method for selecting initial values ​​for resistivity logging inversion according to claim 1, wherein: After step S4, the initial value of the invasion zone radius, the invasion zone resistivity and the formation resistivity are substituted into the inversion algorithm to obtain the inversion value.

3. The method for selecting initial values ​​for resistivity logging inversion according to claim 1, wherein: Before step S1, the volume of pumped mud filtrate, the volume of pumped formation water, and the volume of pumped formation oil and gas are collected from the corresponding cable formation.

4. The method for selecting initial values ​​for resistivity logging inversion according to claim 1, wherein: In step S1, the initial value calculation formula of the intrusion zone radius is: Where ri is the initial value of the invasion zone radius; Vly is the volume of pumped mud filtrate; H is the formation thickness of the inversion horizon; d is the wellbore radius; and φ is the formation porosity.

5. The method for selecting initial values ​​for resistivity logging inversion according to claim 1, wherein: In step S3, the calculation formula for the initial value of formation resistivity inversion is: Where, Rt is the initial value of formation resistivity; Rw is the formation water resistivity; a, b, m, and n are all lithology coefficients.

6. The method for selecting initial values ​​for resistivity logging inversion according to claim 1, wherein: In step S4, the calculation formula for the initial value of the intrusion zone resistivity inversion is: Where Ri is the initial resistivity of the intrusion zone; Ramin is the apparent resistivity at the shallowest detection depth; Ramax is the apparent resistivity at the deepest detection depth; Gamin is the pseudo-geometric factor corresponding to the apparent resistivity at the shallowest detection depth.

7. The method for selecting initial values ​​for resistivity logging inversion according to claim 1, wherein: In step S1, the independent variable of the three-parameter radial step inversion model is the radius, and the dependent variable is the resistivity.

8. A resistivity logging inversion initial value selection system, characterized in that: include: Model building module, used to build a three-parameter radial step inversion model; The first calculation module is used to bring the volume of the pumped mud filtrate into the inversion model to calculate the initial value of the invasion zone radius; The second calculation module is used to calculate the initial value of formation resistivity inversion based on the volume of pumped formation water and the volume of pumped formation oil and gas using Archie's formula; The third calculation module is used to calculate the initial value of the intrusion zone resistivity inversion through the pseudo-geometric factor according to the initial value of the intrusion zone radius and the initial value of the intrusion zone resistivity.

9. An electronic device comprising 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 method for selecting initial values ​​for resistivity logging inversion according to any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the computer program implements the steps of the resistivity logging inversion initial value selection method according to any one of claims 1 to 7.

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