A horizontal well constrained seismic inversion method and system

Abstract

The present invention belongs to the field of oil and gas geophysical exploration technology and discloses a horizontal well constrained seismic inversion method and system, wherein the method includes: intercepting a horizontal section logging curve; resampling the track spacing of the intercepted horizontal section logging curve; numbering the sample points of the resampled logging curve to construct a horizontal section data set; constructing a target inversion function based on the horizontal section data set; substituting the post-stack seismic data set into the target inversion function, and inverting to obtain the wave impedance prediction value corresponding to each seismic data. The inversion method of the present invention takes into account the characteristics of horizontal wells crossing seismic traces, constructs a horizontal well lateral constraint multi-channel target inversion equation, utilizes the lateral variation of the horizontal well to constrain the seismic lateral inversion, and develops a horizontal well constrained seismic inversion method and device, thereby obtaining high-precision and high-resolution wave impedance inversion results, providing strong technical support for comprehensive evaluation of oil and gas fields and well location deployment.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas geophysical exploration, and in particular relates to a horizontal well constrained seismic inversion method and system. Background Art

[0002] As exploration progresses, oil and gas reservoir targets become more complex and hidden, making the discovery of favorable reservoirs increasingly difficult, increasing exploration costs and drilling risks. In oil and gas field exploration and development, horizontal wells can extend the target layer length, expand the drainage area, and multiply oil and gas production. They have become a drilling method that has been gaining popularity in recent years. Compared to traditional vertical well data, horizontal well data possess lateral extension information, providing high-resolution logging information on lateral reservoir variations over a certain distance. Conventional seismic inversion typically utilizes the high vertical resolution of vertical well logging data to constrain the inversion process and improve vertical resolution. However, the current utilization of horizontal well data makes it difficult to incorporate horizontal well logging data into seismic inversion. This is primarily due to the fact that these horizontal well logging data are not perpendicular to the surface and span multiple seismic traces, making them difficult to integrate with seismic data. Therefore, to fully utilize the lateral resolution advantage of horizontal well data, it is imperative to develop an effective horizontal well constrained seismic inversion solution. Summary of the Invention

[0003] In order to solve at least one problem in the background technology, the present invention proposes a horizontal well constrained seismic inversion method and system.

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

[0005] A horizontal well constrained seismic inversion method comprises the following steps:

[0006] Intercept the horizontal section logging curve;

[0007] Resample the track spacing of the intercepted horizontal section logging curve;

[0008] Number the sample points of the resampled logging curve to construct a horizontal segment data set;

[0009] Construct the target inversion function based on the horizontal segment data set;

[0010] Substitute the post-stack seismic data set into the target inversion function to obtain the wave impedance prediction value corresponding to each seismic data.

[0011] Preferably, intercepting the horizontal section logging curve includes the following steps:

[0012] Intercept the horizontal section logging curve to be involved in seismic inversion, and ensure that the length of the logging curve of the target geological body is more than 1 times the length of the logging curve of the non-target geological body.

[0013] Preferably, resampling the track spacing of the intercepted horizontal section logging curve comprises the following steps:

[0014] The horizontal section logging curve is resampled at every trace spacing to obtain logging curve sample points with equal trace spacing.

[0015] Preferably, numbering the sample points of the resampled logging curve to construct a horizontal segment data set includes the following steps:

[0016] The resampling points are numbered in sequence from the well point to the end of the horizontal section, and recorded as 1, 2, 3...N;

[0017] For multiple horizontal wells, the numbers are accumulated in sequence according to the distance between the wells to construct a horizontal section data set.

[0018] Preferably, the target inversion function is:

[0019]

[0020] Where g ij Represents a post-stack seismic dataset The amplitude value of the jth sample point of the i-th channel data in the dimensionless; Z ij Represents a post-stack seismic dataset The wave impedance value prediction corresponding to the jth sample point of the i-th data channel is expressed in meters per second and kilograms per cubic meter. k represents the number of seismic data channels selected for inversion. m represents the number of sample points in each data channel. q represents the number of horizontal sample points involved in the constraint control. d(g) represents the derivative operation. w represents the seismic wavelet, which is extracted through conventional statistics and is dimensionless. Z p Represents a horizontal segment dataset ￠ The wave impedance earthquake prediction value of the p-th horizontal sample point in Zc, m / s*kg / m3; p Represents a horizontal segment dataset ￠ The wave impedance logging value of the p-th horizontal sample point in is m / s*kg / m3; β is the constraint control coefficient, dimensionless; γ is the variance of the wave impedance of the horizontal segment data set; J is the dependent variable of the wave impedance seismic target inversion function.

[0021] Preferably, substituting the post-stack seismic data set into the target inversion function to invert and obtain the wave impedance prediction value corresponding to each seismic data includes the following steps:

[0022] According to the order of seismic data access, k channels of seismic data are selected and substituted into the target inversion function;

[0023] The target inversion function is optimized using maximum likelihood estimation to obtain the wave impedance prediction value corresponding to each seismic data.

[0024] A horizontal well constrained seismic inversion system, comprising:

[0025] An interception unit is used to intercept the horizontal section logging curve;

[0026] The resampling unit is used to resample the track spacing of the intercepted horizontal section logging curve;

[0027] A numbering unit is used to number the sample points of the resampled logging curve and construct a horizontal segment data set;

[0028] A construction unit, used for constructing a target inversion function based on a horizontal segment data set;

[0029] The calculation unit is used to substitute the post-stack seismic data set into the target inversion function to invert and obtain the wave impedance prediction value corresponding to each seismic data.

[0030] Preferably, the interception unit includes an interception module; the interception module is used to intercept the horizontal section logging curve to be involved in seismic inversion, and the intercepted horizontal section logging curve satisfies that the length of the logging curve of the target geological body encountered is more than 1 times the length of the logging curve of the non-target geological body.

[0031] Preferably, the resampling unit includes:

[0032] The resampling module is used to resample the horizontal section logging curve at every other track spacing to obtain logging curve sample points with equal track spacing.

[0033] Preferably, the numbering unit includes:

[0034] The numbering module is used to number the resampling points in sequence from the well point to the end of the horizontal section, and record them as 1, 2, 3...N;

[0035] The accumulation module is used to accumulate the numbers of multiple horizontal wells in sequence according to the distance of the well distribution to construct a horizontal section data set.

[0036] Preferably, the calculation unit includes:

[0037] The substitution module is used to select k channels of seismic data in sequence and substitute them into the target inversion function according to the order of seismic data access;

[0038] The solution module is used to optimize the target inversion function using maximum likelihood estimation to obtain the wave impedance prediction value corresponding to each seismic data.

[0039] Beneficial effects of the present invention:

[0040] The inversion method of the present invention takes into account the characteristics of horizontal wells crossing seismic traces, constructs a multi-channel target inversion equation for horizontal well lateral constraints, utilizes the lateral changes of horizontal wells to constrain seismic lateral inversion, and develops a horizontal well constrained seismic inversion method and device to obtain high-precision and high-resolution wave impedance inversion results, providing strong technical support for the comprehensive evaluation of oil and gas fields and well deployment.

[0041] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 A flow chart of a horizontal well constrained seismic inversion method according to the present invention is shown;

[0044] Figure 2 The implementation effect diagram of the inversion method is shown;

[0045] Figure 3 A diagram of a horizontal well constrained seismic inversion system of the present invention is shown. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying 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 ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0047] A horizontal well constrained seismic inversion method, such as Figure 1 As shown, the following steps are included:

[0048] S1: intercept the horizontal section logging curve;

[0049] S2: resample the track spacing of the intercepted horizontal section logging curve;

[0050] S3: number the sample points of the resampled logging curve and construct a horizontal segment data set;

[0051] S4: construct the target inversion function based on the horizontal segment dataset;

[0052] S5: Substitute the post-stack seismic data set into the target inversion function to obtain the wave impedance prediction value corresponding to each seismic data.

[0053] like Figure 2 As shown in Figure 1, the wave impedance profile obtained by inversion under the constraint of horizontal wells. It can be seen that the inversion result has obvious changes in the lateral direction, which clearly reflects the lateral change characteristics of the wave impedance of the target layer (dashed box).

[0054] Furthermore, in step S1, the horizontal section logging curve to be involved in seismic inversion is intercepted, and the horizontal section logging curve satisfies that the length of the logging curve of the target geological body encountered is more than 1 times the length of the logging curve of the non-target geological body.

[0055] It should be noted that in step S1, the horizontal well data (horizontal section logging curve) to be used in seismic inversion needs to be intercepted based on the quality of the horizontal section acoustic wave and density logging curve.

[0056] Furthermore, in step S2, the following steps are included:

[0057] S201: resampling the horizontal section logging curve at every trace spacing to obtain logging curve sample points with equal trace spacing.

[0058] It should be noted that, before step S201, the distance between traces of the seismic acquisition observation system needs to be considered.

[0059] Furthermore, in step S3, the following steps are included:

[0060] S301: Number the resampling points in sequence from the well point to the end of the horizontal section, and record them as 1, 2, 3...N; S302: For multiple horizontal wells, accumulate the numbers in sequence according to the distance between the wells to construct a horizontal section data set.

[0061] It should be noted that in steps S301 to S302, the well point is the location of the wellhead on the ground, and the direction from the well point to the end of the horizontal section can be referred to as Figure 2 Curve A in the diagram starts at the well point and extends horizontally from the ground. Furthermore, the distance between wells in the plane represents the distance between the wellheads of multiple wells, with the first well counted being used as a reference. Typically, a key well in the study area is selected as the first well to be counted and numbered, followed by the nearest well, and the numbering continues from nearest to farthest. This invention does not restrict how the first well is selected.

[0062] Furthermore, the target inversion function is:

[0063]

[0064] Where g ij Represents a post-stack seismic dataset The amplitude value of the jth sample point of the i-th channel data in the dimensionless; Z ij Represents a post-stack seismic dataset The wave impedance value prediction corresponding to the jth sample point of the i-th data channel is expressed in meters per second and kilograms per cubic meter. k represents the number of seismic data channels selected for inversion. m represents the number of sample points in each data channel. q represents the number of horizontal sample points involved in the constraint control. d(g) represents the derivative operation. w represents the seismic wavelet, which is extracted through conventional statistics and is dimensionless. Z p Represents a horizontal segment dataset ￠ The wave impedance earthquake prediction value of the p-th horizontal sample point in Zc, m / s*kg / m3; p represents the wave impedance logging value of the p-th horizontal sample point in the horizontal segment data set ￠ (obtained by multiplying the acoustic logging value and the density logging value), m / s*kg / m3; β represents the constraint control coefficient, which is dimensionless; γ represents the variance of the wave impedance of the horizontal segment data set.

[0065] It should be noted that when the selected seismic trace to be inverted includes horizontal well sampling points, the pth horizontal sampling point is the sampling point included in the seismic trace to be inverted, the constraint control coefficient β = 1, and the horizontal segment sampling points play a constraining role. When the selected seismic trace to be inverted does not include horizontal well sampling points, the constraint control coefficient β = 0, and the horizontal segment sampling points do not play a constraining role. In addition, the number of horizontal sampling points participating in the constraint control, q, depends on the number of horizontal well sampling points included in the seismic trace to be inverted and is less than or equal to the number of seismic traces selected for inversion, that is, q ≤ k.

[0066] Furthermore, in step S5, the following steps are included:

[0067] S501: Select k channels of seismic data in sequence and substitute them into the target inversion function. S502: Use maximum likelihood estimation to optimize the target inversion function and obtain the wave impedance prediction value corresponding to each channel of seismic data.

[0068] It should be noted that in step S5, the impedance curve of the study area (obtained by multiplying the acoustic logging and density logging) is used to perform full-area interpolation on the vertical well section to obtain the impedance logging interpolation model as the initial estimation model for maximum likelihood estimation.

[0069] A horizontal well constrained seismic inversion system, such as Figure 3As shown, it includes a truncation unit, a resampling unit, a numbering unit, a construction unit, and a calculation unit. The truncation unit is used to truncate the horizontal segment logging curve; the resampling unit is used to resample the track spacing of the truncated horizontal segment logging curve; the numbering unit is used to number the sample points of the resampled logging curve to construct a horizontal segment data set; the construction unit is used to construct a target inversion function based on the horizontal segment data set; and the calculation unit is used to substitute the post-stack seismic data set into the target inversion function to invert and obtain the wave impedance prediction value corresponding to each seismic data track.

[0070] Furthermore, the interception unit includes an interception module; the interception module is used to intercept the horizontal section logging curve to be involved in seismic inversion, and the intercepted horizontal section logging curve satisfies that the length of the logging curve of the target geological body encountered is more than 1 times the length of the logging curve of the non-target geological body.

[0071] Furthermore, the resampling unit includes a resampling module, which is used to resample the horizontal section logging curve at every other track spacing to obtain logging curve sample points with equal track spacing.

[0072] Furthermore, the numbering unit includes a numbering module and an accumulation module. The numbering module is used to sequentially number the resampled points in the direction from the well point to the end of the horizontal section, recorded as 1, 2, 3...N; the accumulation module is used to accumulate the numbers of multiple horizontal wells in sequence according to the distance between the wells to construct a horizontal section dataset.

[0073] Furthermore, the calculation unit includes a substitution module and a solution module. The substitution module is used to select k channels of seismic data in the order in which the seismic data are accessed and substitute them into the target inversion function. The solution module is used to optimize the target inversion function using maximum likelihood estimation to obtain the wave impedance prediction value corresponding to each channel of seismic data.

[0074] It should be noted that the system embodiments generally correspond to the method embodiments, so for relevant details, please refer to the description of the method embodiments. The various units and modules of the horizontal well constrained seismic inversion system are divided according to functional logic, but are not limited to the above divisions, as long as they can achieve the corresponding functions. In addition, the specific names of the various units are only for the purpose of distinguishing them from each other and are not intended to limit the scope of protection of the present invention.

[0075] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A horizontal well constrained seismic inversion method, characterized in that: The following steps are involved: Intercept the horizontal section logging curve; Resample the track spacing of the intercepted horizontal section logging curve; Number the sample points of the resampled logging curve to construct a horizontal segment data set; A target inversion function is constructed based on the horizontal segment data set; the target inversion function is: ； Where, Represents a post-stack seismic dataset Middle i The first j The amplitude value of each sample point, dimensionless; Represents a post-stack seismic dataset Middle i The first j The wave impedance value prediction corresponding to each sample point is m / s*kg / m3; k Indicates the number of seismic data channels selected for inversion; m Indicates the number of sample points in each data channel; q Indicates the number of horizontal sample points participating in constraint control; represents the derivative operation; represents the seismic wavelet, extracted by conventional statistics, dimensionless; Represents a horizontal segment dataset Middle p The wave impedance earthquake prediction value of each horizontal sample point, m / s*kg / m3; Represents a horizontal segment dataset Middle p Wave impedance logging value of each horizontal sampling point, m / s*kg / m3; represents the constraint control coefficient, dimensionless; γ Indicates the variance of the wave impedance of the horizontal segment data set; J is the dependent variable of the wave impedance seismic target inversion function; Substitute the post-stack seismic data set into the target inversion function to obtain the wave impedance prediction value corresponding to each seismic data.

2. A horizontal well constrained seismic inversion method according to claim 1, characterized in that: Intercepting the horizontal section logging curve includes the following steps: Intercept the horizontal section logging curve to be involved in seismic inversion, and ensure that the length of the logging curve of the target geological body is more than 1 times the length of the logging curve of the non-target geological body.

3. The horizontal well constrained seismic inversion method according to claim 1, characterized in that: Resampling the track spacing of the intercepted horizontal section logging curve includes the following steps: The horizontal section logging curve is resampled at every trace spacing to obtain logging curve sample points with equal trace spacing.

4. The horizontal well constrained seismic inversion method according to claim 1, characterized in that: Numbering the sample points of the resampled logging curve and constructing the horizontal segment dataset includes the following steps: The resampling points are numbered in sequence from the well point to the end of the horizontal section, and recorded as 1, 2, 3...N; For multiple horizontal wells, the numbers are accumulated in sequence according to the distance between the wells to construct a horizontal section data set.

5. A horizontal well constrained seismic inversion method according to any one of claims 1 to 4, characterized in that: Substituting the post-stack seismic data set into the target inversion function, the inversion obtains the wave impedance prediction value corresponding to each seismic data, including the following steps: According to the order of seismic data access, k channels of seismic data are selected and substituted into the target inversion function; The target inversion function is optimized using maximum likelihood estimation to obtain the wave impedance prediction value corresponding to each seismic data.

6. A horizontal well constrained seismic inversion system, characterized in that: include: An interception unit is used to intercept the horizontal section logging curve; The resampling unit is used to resample the track spacing of the intercepted horizontal section logging curve; A numbering unit is used to number the sample points of the resampled logging curve and construct a horizontal segment data set; The construction unit is used to construct a target inversion function based on the horizontal segment data set; the target inversion function is: ； Where, Represents a post-stack seismic dataset Middle i The first j The amplitude value of each sample point, dimensionless; Represents a post-stack seismic dataset Middle i The first j The wave impedance value prediction corresponding to each sample point is m / s*kg / m3; k Indicates the number of seismic data channels selected for inversion; m Indicates the number of sample points in each data channel; q Indicates the number of horizontal sample points participating in constraint control; represents the derivative operation; represents the seismic wavelet, extracted by conventional statistics, dimensionless; Represents a horizontal segment dataset Middle p The wave impedance earthquake prediction value of each horizontal sample point, m / s*kg / m3; Represents a horizontal segment dataset Middle p Wave impedance logging value of each horizontal sampling point, m / s*kg / m3; represents the constraint control coefficient, dimensionless; γ Indicates the variance of the wave impedance of the horizontal segment data set; J is the dependent variable of the wave impedance seismic target inversion function; The calculation unit is used to substitute the post-stack seismic data set into the target inversion function to invert and obtain the wave impedance prediction value corresponding to each seismic data.

7. The horizontal well constrained seismic inversion system according to claim 6, characterized in that: The interception unit includes an interception module; the interception module is used to intercept the horizontal section logging curve to be involved in seismic inversion, and the intercepted horizontal section logging curve meets the requirement that the length of the logging curve of the target geological body encountered is more than 1 times the length of the logging curve of the non-target geological body.

8. The horizontal well constrained seismic inversion system according to claim 6, characterized in that: The resampling unit includes: The resampling module is used to resample the horizontal section logging curve at every other track spacing to obtain logging curve sample points with equal track spacing.

9. The horizontal well constrained seismic inversion system according to claim 6, characterized in that: The numbering unit includes: The numbering module is used to number the resampling points in sequence from the well point to the end of the horizontal section, and record them as 1, 2, 3...N; The accumulation module is used to accumulate the numbers of multiple horizontal wells in sequence according to the distance of the well distribution to construct a horizontal section data set.

10. The horizontal well constrained seismic inversion system according to claim 6, characterized in that: The calculation unit includes: The substitution module is used to select k channels of seismic data in sequence and substitute them into the target inversion function according to the order of seismic data access; The solution module is used to optimize the target inversion function using maximum likelihood estimation to obtain the wave impedance prediction value corresponding to each seismic data.

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