Horizontal well constrained seismic inversion method and system

Abstract

The invention belongs to the technical field of oil and gas geophysical exploration, and discloses a horizontal well constrained seismic inversion method and system, and the method comprises the steps: intercepting a logging curve of a horizontal section; channel spacing resampling is carried out on the intercepted horizontal section logging curve; numbering sampling points of the resampled logging curve, and constructing a horizontal section data set; constructing a target inversion function based on the horizontal segment data set; and substituting the post-stack seismic data set into the target inversion function, and performing inversion to obtain a wave impedance prediction value corresponding to each channel of seismic data. According to the inversion method, the characteristic that the horizontal well crosses a seismic channel is considered, a horizontal well transverse constraint multi-channel target inversion equation is constructed, the horizontal well transverse change constraint seismic transverse inversion is utilized, the horizontal well constraint seismic inversion method and device are researched and developed, a high-precision and high-resolution wave impedance inversion result is obtained, and the method and the device are suitable for large-scale popularization and application. And powerful technical support is provided for comprehensive evaluation of oil and gas fields and well location deployment.

Description

Technical Field

[0001] The 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] With the advancement of exploration, the exploration targets of oil and gas reservoirs are more complex and hidden, which makes it increasingly difficult to discover new favorable oil and gas reservoirs, and the exploration investment cost becomes higher and the drilling risk increases. In the exploration and development of oil and gas fields, horizontal wells can increase the length of the target layer, increase the oil leakage area, and increase the oil and gas production several times. It is a drilling mode that has been gradually promoted in recent years. Compared with traditional vertical well data, horizontal well data has lateral extension information and can provide high-resolution logging information of lateral changes of reservoirs at a certain distance. In the conventional seismic inversion process, the high-resolution advantage of vertical well logging data in the vertical direction is generally used to constrain the seismic inversion process and improve the vertical resolution of seismic. However, in terms of the current status of the use of horizontal well data, the horizontal section logging data of horizontal wells is difficult to be used in the seismic inversion process. The main reason is that the horizontal section logging data is not perpendicular to the ground, spans multiple seismic traces, and is difficult to combine with seismic data. Therefore, in order to make full use of the lateral resolution advantage of horizontal well data, it is particularly urgent 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 provides 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] Constructing the target inversion function based on the horizontal segment data set;

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

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

[0012] The horizontal section logging curve to be involved in seismic inversion is intercepted, and 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.

[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 interval to obtain logging curve sample points with equal intervals.

[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 of well distribution to construct a horizontal section data set.

[0018] Preferably, the target inversion function is:

[0019]

[0020] In the formula, g ij Represents a post-stack seismic dataset The amplitude value of the jth sample point of the i-th channel data in Z is dimensionless; ij Represents a post-stack seismic dataset The wave impedance value prediction corresponding to the jth sample point of the i-th data is m / s*kg / m3; 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 constraint control; d(g) represents the derivative operation; w represents the seismic wavelet, extracted through conventional statistics, dimensionless; Z p Represents a horizontal segment dataset ￠ The wave impedance earthquake prediction value of the p-th horizontal sample point in, m / s*kg / m3; Zc 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 represents the constraint control coefficient, dimensionless; γ represents 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 in sequence;

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

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

[0025] An interception unit, used for intercepting the horizontal section logging curve;

[0026] A 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 to 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 comprises:

[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 comprises:

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

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

[0036] Preferably, the calculation unit comprises:

[0037] A substitution module is used to select k channels of seismic data in sequence and simultaneously 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 by using the 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 the horizontal well to constrain the lateral seismic 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 site deployment.

[0041] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing 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 briefly introduces 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 creative work.

[0043] Figure 1 A flow chart of a horizontal well constrained seismic inversion method of 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] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[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 to construct a horizontal segment data set;

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

[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 FIG. 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 the 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 involved in the seismic inversion needs to be intercepted according to the quality of the horizontal section acoustic wave and density logging curve.

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

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

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

[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, the numbers are accumulated in sequence according to the distance of the well distribution to construct a horizontal section data set.

[0061] It should be noted that in step S301 to step S302, the well point is the position 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 figure starts from the well point and extends from the ground to the horizontal direction. In addition, the distance of well distribution is that there is a certain distance between the wellheads of multiple wells on the plane, and the first well counted is used as a reference. Generally, the key well in the study area is selected as the first well for statistical numbering, and then the nearest well is selected for the next numbering, and the numbers are numbered from near to far in sequence. The present invention does not limit how to select the first well.

[0062] Furthermore, the target inversion function is:

[0063]

[0064] In the formula, g ij Represents a post-stack seismic dataset The amplitude value of the jth sample point of the i-th channel data in Z is dimensionless; ij Represents a post-stack seismic dataset The wave impedance value prediction corresponding to the jth sample point of the i-th data is m / s*kg / m3; 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 constraint control; d(g) represents the derivative operation; w represents the seismic wavelet, extracted through conventional statistics, dimensionless; Z p Represents a horizontal segment dataset ￠ The wave impedance earthquake prediction value of the p-th horizontal sample point in, m / s*kg / m3; Zc p It represents the wave impedance logging value of the pth horizontal sample point in the horizontal segment data set ￠ (obtained by multiplying the acoustic logging and the density logging), m / s*kg / m3; β represents the constraint control coefficient, 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 contains horizontal well sample points, the pth horizontal sample point is the sample point contained in the seismic trace to be inverted, the constraint control coefficient β=1, and the horizontal segment sample point plays a constraint role. When the selected seismic trace to be inverted does not contain horizontal well sample points, the constraint control coefficient β=0, and the horizontal segment sample point does not play a constraint role. In addition, the number of horizontal sample points q participating in the constraint control depends on the number of horizontal well sample points contained in the seismic trace to be inverted, which is less than or equal to the number of seismic traces selected to be inverted, that is, q≤k.

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

[0067] S501: According to the order of seismic data access, k seismic data are selected in sequence and substituted into the target inversion function; S502: The target inversion function is optimized by maximum likelihood estimation to obtain the wave impedance prediction value corresponding to each seismic data.

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

[0069] A horizontal well constrained seismic inversion system, such as Figure 3As shown, it includes an interception unit, a resampling unit, a numbering unit, a construction unit and a calculation unit. The 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; the numbering unit is used to number the sample points of the resampled logging curve to construct a horizontal section data set; the construction unit is used to construct a target inversion function based on the horizontal section data set; 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.

[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 number the resampling points in sequence according to 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 of the well distribution to construct a horizontal section data set.

[0073] Furthermore, the calculation unit includes a substitution module and a solution module. The substitution module is used to select k seismic data in sequence and simultaneously 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 by using maximum likelihood estimation to obtain the wave impedance prediction value corresponding to each seismic data.

[0074] It should be noted that, for the system embodiment, since it basically corresponds to the method embodiment, the relevant parts can refer to the partial description of the method embodiment. The various units and modules of the horizontal well constrained seismic inversion system are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of the units are only for the convenience of distinguishing each other, and are not used 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 substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions 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; Constructing the target inversion function based on the horizontal segment data set; Substitute the post-stack seismic data set into the target inversion function and invert 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: The interception of the horizontal section logging curve includes the following steps: The horizontal section logging curve to be involved in seismic inversion is intercepted, and 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.

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

4. A horizontal well constrained seismic inversion method according to claim 1, characterized in that: The sample points of the resampled logging curve are numbered to construct a horizontal segment data set, including 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 of well distribution to construct a horizontal section data set.

5. The horizontal well constrained seismic inversion method according to claim 1, characterized in that: The target inversion function is: In the formula, g ij Represents a post-stack seismic dataset The amplitude value of the jth sample point of the i-th channel data in is 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 is m / s*kg / m3; 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 constraint control; d(g) represents the derivative operation; w represents the seismic wavelet, extracted through conventional statistics, dimensionless; Z p Represents a horizontal segment dataset ￠ The wave impedance earthquake prediction value of the p-th horizontal sample point in, m / s*kg / m3; Zc 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 represents the constraint control coefficient, dimensionless; γ represents 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.

6. A horizontal well constrained seismic inversion method according to any one of claims 1 to 5, 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 in sequence; The target inversion function is optimized by using the maximum likelihood estimation method to obtain the predicted wave impedance value corresponding to each seismic data.

7. A horizontal well constrained seismic inversion system, characterized in that: include: An interception unit, used for intercepting the horizontal section logging curve; A 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 to construct a horizontal segment data set; A construction unit, used for constructing a target inversion function based on a horizontal segment data set; 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.

8. A horizontal well constrained seismic inversion system according to claim 7, 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 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.

9. A horizontal well constrained seismic inversion system according to claim 7, characterized in that: The resampling unit comprises: 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.

10. The horizontal well constrained seismic inversion system according to claim 7, 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, recorded as 1, 2, 3...N; The accumulation module is used to accumulate the numbers of multiple horizontal wells in order according to the distance of the well distribution to construct a horizontal section data set.

11. A horizontal well constrained seismic inversion system according to claim 7, characterized in that: The computing unit comprises: A substitution module is used to select k channels of seismic data in sequence and simultaneously 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 by using the maximum likelihood estimation to obtain the wave impedance prediction value corresponding to each seismic data.

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