Earthquake prediction method and system for igneous rock intrusive fault zone closure

Abstract

The invention belongs to the technical field of exploration and development of fault block oil and gas reservoirs, and particularly relates to a seismic prediction method and system for igneous rock intrusive fault zone sealing performance, and the method comprises the steps: determining the seismic attribute and seismic frequency attribute of a highlight body of a target interval according to petroleum seismic exploration data; determining magma invasion characteristic parameters according to the seismic attribute and the seismic frequency attribute of the highlight body, and determining fracture characteristic parameters of the fracture zone according to an eigenvalue characteristic algorithm operation result in the third-generation coherent attribute of the seismic data; determining an internal structure index of the intrusive fault zone according to the magma invasion characteristic parameters and the fracture characteristic parameters of the fault zone; and comparing the internal structure index of the intrusive fault zone with a closed lower limit threshold of the internal structure index of the known oil reservoir fault zone, and predicting the fault zone closure and the closure capability thereof according to a comparison result, thereby realizing quantitative determination of the oil and gas migration and dredging capability of the fault with magma invasion in the clastic rock stratum.

Description

Technical Field

[0001] The present invention belongs to the technical field of fault block oil and gas reservoir exploration and development, and in particular relates to a seismic prediction method and system for the sealing property of an igneous rock intrusive fault zone. Background Art

[0002] Frequent tectonic activity in faulted lake basins often results in the coexistence of igneous and clastic rocks within fault zones, posing a direct challenge to the exploration of both clastic fault-block and igneous reservoirs. Previous research focused on the closure of clastic fault zones, utilizing methods such as ESGR. However, these methods failed to consider the changes in the internal structure of fault zones and the variations in their closure after magma intrusion. Current information mining using seismic data is far from sufficient. While seismic data contain rich information about fault zones and magma reflections, direct prediction of internal structural changes and closure of fault zones after magma intrusion using seismic data has not yet been achieved. Summary of the Invention

[0003] In response to the above problems, in a first aspect, the present invention proposes a method for earthquake prediction of the sealing property of an igneous intrusive fault zone, comprising the following steps:

[0004] Determine the seismic attributes and seismic frequency attributes of the target layer highlights based on petroleum seismic exploration data;

[0005] Determine the magma intrusion characteristic parameters according to the seismic attributes and seismic frequency attributes of the highlight body, and determine the fracture characteristic parameters of the fault zone according to the result of the eigenvalue characteristic algorithm calculation in the third generation coherent attributes of the seismic data;

[0006] Determine the internal structure index of the intrusive fault zone based on the characteristic parameters of magma intrusion and the fracture characteristic parameters of the fault zone;

[0007] The internal structure index of the intrusive fault zone is compared with the lower closure threshold of the internal structure index of the fault zone in the known reservoir, and the closure of the fault zone is predicted based on the comparison results.

[0008] Furthermore, before determining the seismic attributes of the target layer highlight body, the following steps are also included:

[0009] Acquiring petroleum seismic exploration data, wherein the petroleum seismic exploration data includes fault interpretation data, oil and gas well logging data, and petroleum seismic data;

[0010] The petroleum seismic data includes seismic amplitude and the result of eigenvalue characteristic algorithm calculation in the third generation coherent attributes.

[0011] Furthermore, the seismic attribute of the target layer highlight body is the algebraic difference obtained by subtracting the average seismic amplitude within the specified frequency range from the peak value of the seismic amplitude within the frequency range.

[0012] Furthermore, the magma intrusion characteristic parameters are determined based on the seismic attributes and seismic frequency attributes of the highlight body using the following formula:

[0013]

[0014] Among them, F1 represents the characteristic parameter of magma intrusion, A hlb is the seismic attribute of the highlight body, ln(A hlb ) is the logarithm of the seismic attributes of the highlight body, and f represents the main frequency of the seismic data at a certain location in space.

[0015] Furthermore, the fracture characteristic parameters of the fault zone are determined based on the result of the eigenvalue characteristic algorithm calculation in the third generation coherent attributes of the seismic data using the following formula:

[0016] F2=ln(EIG)

[0017] Where F2 represents the fracture characteristic parameter of the fault zone, EIG is the result of the eigenvalue characteristic algorithm calculation in the third-generation coherent attributes of the publicly available seismic data, and is dimensionless; ln(EIG) is the logarithm of EIG.

[0018] Furthermore, the internal structure index of the intrusive fault zone is determined based on the magma intrusion characteristic parameters and the fault characteristic parameters of the fault zone using the following formula:

[0019] IFIS=w1×F1+w2×F2

[0020] Among them, IFIS is the internal structure index of the intrusive fault zone, F1 is the characteristic parameter of magma intrusion, F2 is the fracture characteristic parameter of the fault zone, w1 and w2 are the weight coefficients of the magma intrusion characteristic parameter and fracture characteristic parameter, respectively, w1+w2=1.

[0021] Furthermore, the internal structure index IFIS of the intrusive fracture zone is compared with the lower closure threshold of the internal structure index of the fracture zone in the known reservoir, and the fracture zone closure is predicted based on the comparison result, specifically including:

[0022] The lower limit threshold of the internal structure index of the reservoir fracture zone in the statistical exploration area has been found;

[0023] Compare the internal structure index IFIS of the intrusive fault zone with the closed lower limit threshold; if IFIS is greater than the closed lower limit threshold, the fault is laterally closed, otherwise the fault is laterally open;

[0024] The sealing ability is characterized by the difference between IFIS and the lower limit of the sealing threshold. The larger the difference, the stronger the fault sealing ability, and vice versa.

[0025] In a second aspect, the present invention provides an earthquake prediction system for the closure of igneous intrusive fault zones, comprising:

[0026] The first determining unit is used to determine the seismic attributes and seismic frequency attributes of the highlight body of the target layer segment based on the data obtained from the petroleum seismic exploration;

[0027] a second determining unit, configured to determine characteristic parameters of magma intrusion according to the seismic attributes and seismic frequency attributes of the highlight body, and to determine fracture characteristic parameters of the fault zone according to the result of an eigenvalue characteristic algorithm calculation in the third generation coherent attributes of the seismic data;

[0028] A third determining unit is used to determine the internal structure index of the intrusive fault zone according to the magma intrusion characteristic parameters and the fault characteristic parameters of the fault zone;

[0029] The prediction unit is used to compare the internal structure index of the intrusive fracture zone with the lower closure threshold of the internal structure index of the fracture zone in the known reservoir, and predict the closure of the fracture zone according to the comparison result.

[0030] In a third aspect, the present invention provides an electronic device, comprising a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus;

[0031] a memory storing a computer program;

[0032] The processor is used to implement the earthquake prediction method of the closure of the igneous intrusive fault zone when executing the program stored in the memory.

[0033] In a fourth aspect, the present invention proposes a computer-readable storage medium storing a computer program, which, when executed, executes the seismic prediction method for the closure of an igneous intrusive fault zone.

[0034] Beneficial effects of the present invention:

[0035] The present invention directly uses seismic data to identify the internal structural changes of the fault zone after magma intrusion, calculates the magma intrusion characteristic parameters and the fracture characteristic parameters respectively, determines the internal structural index of the intrusive fracture zone based on the characteristic parameters, and compares it with the lower closure threshold of the internal structural index of the fracture zone in the known oil reservoir. Based on the comparison results, the closure of the fracture zone and its sealing capacity are predicted, thereby achieving quantitative judgment of the ability of faults in clastic rock formations where magma intrusion occurs to migrate and channel oil and gas.

[0036] 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, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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 any creative work.

[0038] Figure 1 A flow chart showing the earthquake prediction method for the sealing property of an igneous intrusive fault zone proposed by the present invention;

[0039] Figure 2 The distribution diagram of the structural index IFIS of the intrusive fault zone in the southern part of the Wuerxun Sag in the Hailar Basin on the top surface fault of the basement is shown in an embodiment of the present invention;

[0040] Figure 3 A schematic diagram of an earthquake prediction system for the closure of an igneous intrusive fault zone provided in an embodiment of the present invention is shown;

[0041] Figure 4 A schematic diagram of an electronic device provided in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0042] 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.

[0043] Based on the above problems, the present invention proposes a seismic prediction method for the closure of igneous intrusive fault zones, such as Figure 1 As shown, the specific steps include:

[0044] S1: Acquire petroleum seismic exploration data, including petroleum seismic data, oil and gas well logging data, and fault interpretation data; wherein the petroleum seismic data includes seismic amplitude and the result of eigenvalue characteristic algorithm calculation in the third generation coherent attribute;

[0045] S2: Determine the seismic attributes and seismic frequency attributes of the target layer highlight based on the petroleum seismic exploration data;

[0046] The highlight attribute is a post-stack seismic data attribute obtained by performing time-frequency analysis on the post-stack seismic data in a specified frequency range. The highlight attribute is the algebraic difference between the peak amplitude of the seismic spectrum in the specified frequency range and the average amplitude of the seismic spectrum in the frequency range, as shown in Formula 1.

[0047] A hlb =|f(x)-A ave |

[0048] Where A hlb is the seismic attribute of the highlight body; f(x) refers to the seismic amplitude of a certain frequency, and x is between the lower limit frequency and the upper cutoff frequency of the estimated frequency range; A ave It represents the average value of earthquake amplitude within a certain frequency range, that is, the average amplitude;

[0049] If the average amplitude is regarded as the expected value, the process of determining the seismic attributes of the highlight body is equivalent to determining the deviation, where small deviations correspond to normal amplitudes and large deviations correspond to abnormal amplitudes.

[0050] S3: Determine the characteristic parameters of magma intrusion according to the seismic attributes and seismic frequency attributes of the highlight body; specifically, the following formula can be used:

[0051]

[0052] Among them, F1 represents the characteristic parameter of magma intrusion, A hlb is the seismic attribute of the highlight body, ln(A hlb ) is the logarithm of the seismic attribute of the highlight body, f represents the main frequency of the seismic data at a certain location in space, HZ;

[0053] S4: Determine the fracture characteristic parameters of the fault zone based on the results of the eigenvalue characteristic algorithm calculation in the third generation coherent attributes of the seismic data;

[0054] F2=ln(EIG)

[0055] Where F2 refers to the fault characteristic parameter of the fault zone; EIG is the result of the eigenvalue characteristic algorithm calculation in the third-generation coherent attributes of the publicly available seismic data, which is dimensionless; ln(EIG) is the logarithm of EIG.

[0056] It should be noted that the third-generation coherence attribute, EIG, is the ratio of the maximum eigenvalue of the covariance matrix of the target seismic trace and its adjacent channels to the sum of all eigenvalues ​​within the coherence time window. Its calculation requires a dip scan, using the seismic data within the scanned coherence time window to construct the covariance matrix. The coherence value is estimated by calculating the eigenvalues ​​of the covariance matrix. Finally, the ratio of the maximum eigenvalue to the sum of all eigenvalues ​​is calculated, i.e., the EIG eigenvalue. The expression is as follows:

[0057]

[0058] Among them, C3 is the third generation coherence value, also known as EIG; λ max is the maximum eigenvalue; i is the characteristic value of any seismic trace in the time window.

[0059] S5: Determine the internal structure index of the intrusive fault zone based on the magma intrusion characteristic parameters and the fault characteristic parameters of the fault zone. The specific formula is as follows:

[0060] IFIS=w1×F1+w2×F2

[0061] IFIS refers to the structural index of the intrusive fault zone, F1 refers to the magma intrusion characteristic parameter, F2 refers to the fracture characteristic parameter, w1 and w2 are the weight coefficients of the magma intrusion characteristic parameter and the fracture characteristic parameter, respectively, w1 + w2 = 1, which can be obtained through regression calculation based on actual drilling data or expert experience.

[0062] S6: comparing the internal structure index of the intrusive fault zone with the lower closure threshold of the internal structure index of the fault zone in the known reservoir, and predicting the closure of the fault zone based on the comparison result;

[0063] Specifically, the lower limit threshold of the internal structure index of the reservoir fault zone discovered in the statistical area is calculated, and the internal structure index IFIS data of the fault zone within a certain stratum of the predicted fault zone is compared with the lower limit threshold to quantitatively evaluate the fault's oil and gas sealing capacity and determine the favorable location; if IFIS is larger than the lower limit threshold, the fault is laterally closed, otherwise the fault is laterally open; the sealing capacity is characterized by the difference between IFIS and the lower limit threshold; the larger the difference, the stronger the fault sealing capacity, and vice versa.

[0064] In one embodiment of the present invention, the specific process of the seismic prediction method for the sealing property of igneous intrusive fault zones is exemplified by taking the basement fault in the southern part of the Wuerxun Depression in the Hailar Basin as an example;

[0065] S1: Loading petroleum seismic data, oil and gas well logging data, and fault interpretation data;

[0066] S2: Determine the target layer segment based on the data obtained from oil seismic exploration and determine the seismic attributes of the highlight body A hlb and earthquake frequency attribute f;

[0067] A hlb =|f(x)-A ave |

[0068] Where A hlb is the seismic attribute of the highlight body; f(x) refers to the seismic amplitude of a certain frequency, and x is between the lower limit frequency and the upper cutoff frequency of the estimated frequency range; A ave It represents the average value of earthquake amplitude within a certain frequency range;

[0069] S3: Determine the characteristic parameter F1 of magma intrusion. F1 represents the range of magma intrusion. The characteristics of magma are proportional to the highlight and inversely proportional to the frequency of earthquakes.

[0070]

[0071] Among them, F1 represents the characteristic parameter of magma intrusion, A hlb is the seismic attribute of the highlight body, ln(A hlb ) is the logarithm of e for the highlight, f represents the main frequency of the seismic data at a certain location in space, HZ;

[0072] S4: Determine the fracture characteristic parameter F2 of the fracture zone;

[0073] F2=ln(EIG)

[0074] EIG is the result of the eigenvalue characteristic operation in the third generation coherent attributes of the publicly available seismic data. ln(EIG) is the logarithm of EIG.

[0075] S5: Determine the internal structure index IFIS of the intrusive fault zone based on the magma intrusion characteristic parameter F1 and the fault characteristic parameter F2 of the fault zone;

[0076] IFIS=w1×F1+w2×F2

[0077] Among them, the sum of w1 and w2 is 1, and IFIS is a weighted operation of F1 and F2;

[0078] S6: Calculate the lower limit threshold of the internal structure index IFIS of the fault zone of the main fault controlling the oil reservoir in the area where drilling exploration has been carried out, compare the internal structure index IFIS data of the fault zone within a certain formation range of the fault zone to be predicted with the lower limit threshold, quantitatively evaluate the fault's oil and gas sealing capacity and determine the favorable location.

[0079] In this example, the distribution of the internal structure index IFIS of the intrusive fault zone along the fault plane is as follows: Figure 2As shown in the figure, it is found that there are obvious changes within the same fault zone. This change not only reflects the difference in its internal structure, but also reflects its lateral and vertical sealing ability and favorable locations for oil and gas. According to experience, values ​​such as 50 and 42 can be used as the lower limit sealing threshold. In the figure, wu33, wu40, wu49, wu61, and wu45 represent different areas. The left strip in the figure is a strip display card of the internal structure index IFIS of different fault zones. It can be seen from the figure that the location with an IFIS greater than 50 is the most conducive to oil and gas sealing, belonging to the high-value IFIS area, which generally coincides with the location of magma intrusion; IFIS less than 42 represents a low-value area, which is a location with the development of sandstone without magma intrusion and weak sealing; the location with an IFIS between 42 and 50 belongs to the medium-value range of IFIS, which is a location with mixed transition between clastic rocks and igneous rocks and has good sealing. Combined with the results of exploration well drilling and the distribution of oil and gas wells in this area, statistics show that the larger the IFIS index, the more conducive it is to fracture sealing oil and gas, and vice versa; this shows that the prediction method proposed in this invention conforms to geological laws in practical applications and is reliable.

[0080] Based on the same concept of the present invention, another exemplary embodiment of the present invention provides an earthquake prediction system for the closure of an igneous intrusive fault zone, such as Figure 3 Shown, including:

[0081] The first determining unit 301 is used to determine the seismic attributes and seismic frequency attributes of the highlight body of the target layer according to the petroleum seismic exploration data;

[0082] The second determining unit 302 is configured to determine the characteristic parameters of the magma intrusion according to the seismic attributes and the seismic frequency attributes of the highlight body, and determine the fracture characteristic parameters of the fault zone according to the result of the eigenvalue characteristic algorithm calculation in the third generation coherent attributes of the seismic data;

[0083] The third determining unit 303 is configured to determine the internal structure index of the intrusive fault zone according to the magma intrusion characteristic parameters and the fault characteristic parameters of the fault zone;

[0084] The prediction unit 304 is configured to compare the internal structure index of the intrusive fracture zone with the lower closure threshold of the internal structure index of the fracture zone in a known reservoir, and predict the closure of the fracture zone based on the comparison result.

[0085] Based on the same inventive concept, another exemplary embodiment of the present invention provides an electronic device. Figure 4 As shown, the electronic device includes at least one processor 401, at least one communication interface 402, at least one memory 403 and at least one communication bus 404; wherein the processor 401, the communication interface 402 and the memory 403 communicate with each other via the communication bus 404;

[0086] Memory 403, storing computer programs;

[0087] The processor 401 is configured to implement the earthquake prediction method for the sealing property of an igneous intrusive fault zone when executing the program stored in the memory 403 .

[0088] Optionally, the communication interface may be an interface of a communication module, such as an interface of a GSM module; the processor may be a CPU, or an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present invention. The memory may include a high-speed RAM memory, and may also include a non-volatile memory, such as at least one disk storage. The memory stores a program, and the processor calls the program stored in the memory to execute some or all of the above-mentioned method embodiments.

[0089] Based on the same inventive concept, an embodiment of the present application further provides a computer-readable storage medium storing a computer program, wherein when the computer program is executed, some or all of the above-mentioned method embodiments are implemented. Optionally, the storage medium may be a non-transitory computer-readable storage medium, for example, a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc.

[0090] 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 method for earthquake prediction of the sealing property of an igneous intrusive fault zone, characterized in that: The following steps are involved: Determine the seismic attributes and seismic frequency attributes of the target layer highlights based on petroleum seismic exploration data; Determine the magma intrusion characteristic parameters according to the seismic attributes and seismic frequency attributes of the highlight body, and determine the fracture characteristic parameters of the fault zone according to the result of the eigenvalue characteristic algorithm calculation in the third generation coherent attributes of the seismic data; Determine the internal structure index of the intrusive fault zone based on the characteristic parameters of magma intrusion and the fracture characteristic parameters of the fault zone; The internal structure index of the intrusive fault zone is compared with the lower closure threshold of the internal structure index of the fault zone in the known reservoir, and the closure of the fault zone is predicted based on the comparison results.

2. The earthquake prediction method for the sealing property of an igneous intrusive fault zone according to claim 1, characterized in that: Before determining the seismic attributes of the target layer highlight, the following steps are also included: Acquiring petroleum seismic exploration data, wherein the petroleum seismic exploration data includes fault interpretation data, oil and gas well logging data, and petroleum seismic data; The petroleum seismic data includes seismic amplitude and the result of eigenvalue characteristic algorithm calculation in the third generation coherent attributes.

3. The earthquake prediction method for the sealing property of an igneous intrusive fault zone according to claim 1, characterized in that: The seismic attribute of the target layer highlight body is the algebraic difference obtained by subtracting the average seismic amplitude within the specified frequency range from the peak value of the seismic amplitude within the specified frequency range.

4. The earthquake prediction method for the sealing property of an igneous intrusive fault zone according to claim 1, characterized in that: The following formula is used to determine the characteristic parameters of magma intrusion based on the seismic attributes and seismic frequency attributes of the highlight body: Among them, F1 represents the characteristic parameter of magma intrusion, A hlb is the seismic attribute of the highlight body, ln(A hlb ) is the logarithm of the seismic attributes of the highlight body, and f represents the main frequency of the seismic data at a certain location in space.

5. The earthquake prediction method for the sealing property of an igneous intrusive fault zone according to claim 1, characterized in that: The following formula is used to determine the fracture characteristic parameters of the fault zone based on the results of the eigenvalue characteristic algorithm calculation in the third generation coherent attributes of the seismic data: F2=ln(EIG) Where F2 represents the fracture characteristic parameter of the fault zone, EIG is the dimensionless result of the eigenvalue characteristic algorithm in the third-generation coherent attributes of the publicly available seismic data, and ln(EIG) is the logarithm of EIG.

6. The earthquake prediction method for the sealing property of an igneous intrusive fault zone according to claim 1, characterized in that: The internal structure index of the intrusive fault zone is determined based on the magma intrusion characteristic parameters and the fault characteristic parameters of the fault zone using the following formula: IFIS=w1×F1+w2×F2 Among them, IFIS is the internal structure index of the intrusive fault zone, F1 is the characteristic parameter of magma intrusion, F2 is the fracture characteristic parameter of the fault zone, w1 and w2 are the weight coefficients of the magma intrusion characteristic parameter and fracture characteristic parameter, respectively, w1+w2=1.

7. The earthquake prediction method for the sealing property of an igneous intrusive fault zone according to claim 6, characterized in that: Comparing the internal structure index of the intrusive fault zone with the lower closure threshold of the internal structure index of the known reservoir fault zone and predicting the closure of the fault zone based on the comparison result specifically includes: The lower limit threshold of the internal structure index of the reservoir fracture zone in the statistical exploration area has been found; Compare the internal structure index IFIS of the intrusive fault zone with the closed lower limit threshold; if IFIS is greater than the closed lower limit threshold, the fault is laterally closed, otherwise the fault is laterally open; The sealing ability is characterized by the difference between IFIS and the lower limit of the sealing threshold. The larger the difference, the stronger the fault sealing ability, and vice versa.

8. An earthquake prediction system for the closure of igneous intrusive fault zones, characterized by: include: The first determining unit is used to determine the seismic attributes and seismic frequency attributes of the highlight body of the target layer segment based on the data obtained from the petroleum seismic exploration; a second determining unit, configured to determine characteristic parameters of magma intrusion according to the seismic attributes and seismic frequency attributes of the highlight body, and to determine fracture characteristic parameters of the fault zone according to the result of an eigenvalue characteristic algorithm calculation in the third generation coherent attributes of the seismic data; A third determining unit is used to determine the internal structure index of the intrusive fault zone according to the magma intrusion characteristic parameters and the fault characteristic parameters of the fault zone; The prediction unit is used to compare the internal structure index of the intrusive fracture zone with the lower closure threshold of the internal structure index of the fracture zone in the known reservoir, and predict the closure of the fracture zone according to the comparison result.

9. An electronic device, characterized in that: The processor, the communication interface, the memory and the communication bus are connected to each other via the communication bus. a memory storing a computer program; The processor is configured to implement the seismic prediction method for the closure of an igneous intrusive fault zone according to any one of claims 1 to 7 when executing the program stored in the memory.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed, the method for earthquake prediction of the sealing property of an igneous intrusive fault zone according to any one of claims 1 to 7 is executed.

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