Inematic rock seismic fractal recognition and construction method

Abstract

The invention discloses an igneous rock seismic fractal recognition and construction method. The method comprises the steps of well seismic calibration; determining the distribution type of igneous rocks in the research area based on well-seismic calibration; seismic detection of the intrusive rock mass: eliminating strongly reflective sandstone in the intrusive rock mass in the research area to obtain an intrusive rock attribute body; carrying out earthquake detection on the fire body, extracting a variance body of the fire body in the research area, carrying out normalization, and pressing a high-value section by using a target pressing and releasing technology to obtain an indicator of the fire body; carrying out the extraction of the top and bottom enveloping surfaces of the fire body from the attribute body after the target compression, and carrying out the background compression of the fire body through the constraint of the top and bottom enveloping surfaces of the fire body, thereby forming a background shielding reinforcement of the fire body; and performing fractal construction on the igneous rock, and combining the intrusive rock attribute body and the fire body background shielding reinforcement body to obtain a complex of igneous rock space distribution. According to the method, spatial distribution of igneous rocks is comprehensively described through fractal detection and an embedded construction technology, and a geological foundation is laid for well trajectory optimization and well leakage prevention of an igneous rock development area.

Description

Technical Field

[0001] The present invention relates to the technical field of prediction and evaluation before drilling in petroleum exploration and development, and in particular to a method for identifying and constructing igneous rock seismic fractals. Background Art

[0002] Igneous rocks are widely found in Tertiary and older strata. Their distribution is crucial for oil and gas accumulation, lost circulation control, drilling speed and efficiency enhancement, and well trajectory optimization. In recent years, the development of igneous oil and gas resources, drilling speed and efficiency enhancement, and lost circulation prevention have placed a greater demand on the spatial distribution of igneous rocks.

[0003] At present, in the domestic and international oil industry, a variety of technologies with logging, seismic, and geology as the core have been formed in recent years to characterize the distribution of igneous rocks. Due to the complexity and diversity of related results, the application of the results is difficult and non-professionals find it difficult to effectively grasp them. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above technical problems and propose a method for identifying and constructing igneous rock seismic fractals.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] A method for identifying and constructing igneous rock seismic fractals comprises the following steps:

[0007] Well-seismic calibration is performed based on the post-stack 3D seismic data and drilled well data in the study area;

[0008] Based on well-seismic calibration, the distribution types of igneous rocks in the study area are determined, including intrusive rocks and volcanic bodies.

[0009] Seismic detection of intrusive rock mass: eliminating the strongly reflecting sandstone in the intrusive rock mass in the study area and obtaining the intrusive rock attribute volume;

[0010] Volcanic body seismic detection uses variance body attributes and normalization to form an attribute body, and uses target suppression technology to highlight the volcanic body structure and obtain the attribute body after target suppression;

[0011] Extract the top and bottom envelope surfaces of the volcanic body from the attribute body after the target is suppressed, and use the top and bottom envelope surface constraints to suppress the volcanic body background to form a volcanic body background shielding enhancement body;

[0012] Igneous rock fractal construction combines intrusive rock attributes and volcanic background shielding enhancement to obtain a comprehensive spatial distribution of igneous rocks.

[0013] Optionally, the specific steps of seismic detection of intrusive rock mass include:

[0014] Optimize seismic attributes: By comparing attributes, using seismic "sweet spot" attributes and normalizing them, identify igneous rock bodies above 6-7 meters;

[0015] Eliminate strong reflections of sandstone: Superimpose the sweet spot attributes with the seismic amplitude absolute value attributes to eliminate the false strong reflections of sandstone and obtain the intrusive rock attribute volume.

[0016] Optionally, the specific steps of volcanic body earthquake detection include:

[0017] The variance volume attributes are used and normalized to form an attribute volume, and the target suppression technique is used to highlight the volcanic body structure:

[0018]

[0019] Among them, Var normal is the normalized variance volume, dimensionless; Var normal-edit It is the attribute body of the target after compression, dimensionless.

[0020] Optionally, the specific steps of forming the volcanic body background shielding reinforcement body include:

[0021] Extraction of the envelope of a single volcanic body: Using a combination of seismic amplitude profiles and coherence volume profiles, the top and bottom surfaces of the igneous body are extracted separately; the bottom surface of the igneous body is displayed as a fault.

[0022] Meshing of the volcanic body envelope: The top surfaces of the igneous bodies are displayed on a plane by overlaying them. The top surfaces with overlapping areas are classified into different layer files, and polygon sets of the top surface boundaries are generated; and then meshed into the top and bottom surfaces of the igneous body;

[0023] Volcanic background suppression: The volcanic background is suppressed using the top and bottom envelope constraints of the igneous rock body. The process is as follows:

[0024]

[0025] Where top1 represents the top depth of the igneous body numbered 1; bot1 represents the bottom depth of the igneous body numbered 1; top2 represents the top depth of the igneous body numbered 2; bot2 represents the bottom depth of the igneous body numbered 2; Z represents the depth, m; Var normal-FR is the volcanic background shielding enhancement body, dimensionless; Var normal is the normalized variance volume, dimensionless.

[0026] Optionally, the specific steps of constructing the igneous rock fractal include:

[0027] Merge the intrusive rock attribute volume and the volcanic body background shielding enhancement volume:

[0028] FRvol = Sweet normal-edit + Var normal-FR (3)

[0029] Wherein, FR vol is igneous rock three-dimensional complex, dimensionless; Sweet normal-edit is intrusive rock attribute body, dimensionless; Var normal-FR is volcanic body background shielding enhancement body, dimensionless; Wherein, FR vol The low value section with the value less than 0.1 is a background area, FR vol The medium-high value section with the value greater than 0.3 is an indication area of igneous rock.

[0030] In conclusion, the technical effects and advantages of the present application are as follows: the method of the present application comprehensively depicts the spatial distribution of igneous rock by fractal detection and embedded construction technology, and lays a geological foundation for well trajectory optimization and well leakage prevention in igneous rock development area. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments or prior art in the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0032] Figure 1 It is a flowchart of igneous rock seismic fractal identification and construction method in an embodiment of the present application;

[0033] Figure 2 It is a fractal diagram of igneous rock distribution in an embodiment of the present application;

[0034] Figure 3 It is a schematic diagram of the effect of intrusive igneous rock seismic comprehensive detection in an embodiment of the present application;

[0035] Figure 4 It is a schematic diagram of the effect of intrusive igneous rock seismic comprehensive detection in an embodiment of the present application;

[0036] Figure 5 It is a schematic diagram of the effect of intrusive igneous rock seismic comprehensive detection in an embodiment of the present application;

[0037] Figure 6 It is a schematic diagram of the effect of intrusive igneous rock seismic comprehensive detection in an embodiment of the present application;

[0038] Figure 7 It is a schematic diagram of the effect of intrusive igneous rock seismic comprehensive detection in an embodiment of the present application;

[0039] Figure 8Schematic diagram of the comprehensive detection effect of igneous rocks in one embodiment of the present invention (connected well section);

[0040] Figure 9 This is a schematic diagram of the comprehensive detection effect of igneous rocks in one embodiment of the present invention (3D effect). DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 are within the scope of protection of the present invention.

[0042] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] This embodiment addresses the spatial development needs of igneous rocks by providing a method for identifying and constructing igneous rock seismic fractals. This method generates an intuitive, simple, and clear igneous rock spatial development complex, effectively guiding well trajectory optimization, drilling loss reduction, and drilling speed and efficiency enhancement. This application primarily relies on drilled, post-stack 3D seismic data, utilizing fractal detection and spatial embedding techniques to predict the 3D spatial distribution of igneous rocks.

[0044] This embodiment first determines the distribution type of igneous rocks in the study area based on the drilled well and three-dimensional seismic data; then, the seismic "sweet spot" attributes are extracted and normalized, and the influence of high-permeability sandstone, etc. is eliminated by using the dual-track characteristics of layered igneous rocks to obtain the layered igneous intrusive rock attribute volume; secondly, the variance volume is extracted, normalized, and the high-value segments are suppressed to obtain the target attribute volume after suppression; then, the top and bottom envelope surfaces of each igneous rock body are obtained using the amplitude envelope volume; then, the top surfaces of each igneous rock body are superimposed on the plane, and the top surfaces with overlapping areas are respectively classified into different layers, and a set of local polygons of each top surface boundary is generated and gridded into the top and bottom surfaces of the igneous rock body; then, the volcanic body background shielding enhancement volume (local variance volume) is embedded in the igneous intrusive rock attribute volume to obtain the three-dimensional igneous rock complex; finally, the spatial distribution volume of the igneous rock is obtained through screening, and the screening condition is that the value of the three-dimensional igneous rock complex is greater than 0.3, indicating igneous rock.

[0045] like Figure 1 As shown, the specific steps include:

[0046] (1) Basic data preparation

[0047] Collect post-stack 3D seismic data and existing well data, especially well logging lithology data, in the study area. Establish a seismic study area and perform well-to-seismic time-depth calibration to correlate lithologic information with seismic characteristics.

[0048] (2) Igneous rock fractal and type determination

[0049] After the well-seismic calibration, the main distribution of intrusive rock bodies (bedding and through-bedding) and volcanic bodies (hummocky, funnel-shaped, and umbrella-shaped) in the study area was determined through plane and section browsing. Figure 2 That is, the distribution types of igneous rocks in the study area include intrusive bodies and volcanic bodies.

[0050] (3) Seismic detection of intrusive rock masses

[0051] 1) Optimizing earthquake attributes

[0052] By comparing the attributes and using the seismic "sweet spot" attributes and normalizing them, we can better identify igneous rock bodies above 6-7m. normal (See attached Figure 3 ), the compliance of wellbore seismic data for igneous rocks can reach over 80%.

[0053] 2) Eliminate strong reflective sandstone, etc.

[0054] Using the vertical high-resolution root mean square amplitude (RMS) attribute or seismic amplitude absolute value attribute, it can be seen that igneous rocks correspond to the double-track phenomenon of double-strong energy combination, while strong reflections such as sandstone correspond to the single-track strong energy phenomenon (see Appendix Figure 4 ), superimposing the sweet spot attribute with the seismic amplitude absolute value attribute can effectively eliminate the strong reflection false images such as sandstone, effectively improve the reliability of igneous rock seismic detection, and obtain the final intrusive rock attribute body Sweet normal-edit .

[0055] (4) Volcanic body earthquake detection

[0056] Use the variance body attributes and normalize them to form the attribute body Var normal (See attached Figure 5 ) can effectively highlight the characteristics of the volcanic body. It is mainly distributed in the middle value interval segment, and the high value segment is distributed in layered igneous rocks and strong reflective sandstone. The target pressure release technology can highlight the volcanic body structure Var normal-edit :

[0057]

[0058] Among them, Var normal is the normalized variance volume, dimensionless; Var normal-edit It is the attribute body of the target after compression, dimensionless.

[0059] Through the processing, it can be seen that the volcanic body attributes of the new attribute body are highlighted. See the attached Figure 6 .

[0060] 1) The attribute body after the target is released is used to extract the top and bottom envelope surfaces of the volcanic body in the subsequent steps;

[0061] 2) Igneous rock fractal construction is to use the intrusive rock attribute volume obtained in step (3) and the volcanic body background shielding enhancement volume obtained in steps (4) and (5) to weight and form a new igneous rock detection attribute volume.

[0062] (5) Extracting the volcanic envelope

[0063] 1) Extraction of the envelope of a single volcanic body

[0064] Seismic amplitude profiles are combined with coherence volume profiles to extract the top and bottom surfaces of the igneous body. Conventional seismic horizons are difficult to effectively represent the base envelope of the volcanic body due to the large dip angles that may occur on the bottom surface of the igneous body. Therefore, the base of the volcanic body is represented as a fault. Furthermore, additional control points are added for steeper dips to achieve finer control of the volcanic body envelope.

[0065] 2) Meshing of the volcanic envelope

[0066] The top surfaces of the igneous bodies are displayed on the plane. The top surfaces of the overlapping areas are classified into different layer files, and a polygon set of the boundary of each top surface is generated. Secondly, the volcanic channel can be controlled by a small grid (5m×5m), and the grid is formed into the top and bottom surfaces of the igneous body. See the attached figure. Figure 7 .

[0067] 3) Volcanic background suppression

[0068] The volcanic background is suppressed by using the top and bottom surface constraints of the igneous rock body. The process is as follows:

[0069]

[0070] Where top1 represents the top depth of the igneous body numbered 1; bot1 represents the bottom depth of the igneous body numbered 1; top2 represents the top depth of the igneous body numbered 2; bot2 represents the bottom depth of the igneous body numbered 2; Z represents the depth, m; Var normal-FR is the volcanic background shielding enhancement body, dimensionless; Var normal is the normalized variance volume, dimensionless.

[0071] The volcanic bodies in the study area are highlighted by the background suppression of sandstone and mudstone in the igneous rock strata.

[0072] Similarly, a plurality of volcanic body background shielding enhancers can be formed and used for subsequent volcanic rock spatial fractal construction.

[0073] (6) Igneous rock fractal construction

[0074] The normalized sweet spot attribute after the double-track phenomenon test, the normalized coherent body of the target increase, the igneous rock seismic fractal detection body, and the merged multiple normalized fractal bodies are as follows:

[0075] FR vol = Sweet normal-edit + Var normal-FR (3)

[0076] Wherein, FR vol is the igneous rock three-dimensional complex, dimensionless; Sweet normal-edit is the intrusive rock attribute body, dimensionless; Var normal-FR is the volcanic body background shielding enhancer, dimensionless. Wherein, FR vol The low value section with a value less than 0.1 is the background area, FR vol The medium-high value section with a value greater than 0.3 is the indication area of the igneous rock. FR vol The value in the interval of 0.1-0.3 has a certain ambiguity.

[0077] As can be seen from the attached Figure 8 , the interval of 0.5-0.1 in the igneous rock body shows the distribution of layered intrusive rock, the interval of 0.2-0.5 is the attribute distribution interval of the volcanic body, and 0-0.15 is the background sandstone and mudstone distribution interval, which effectively describes the spatial distribution of various igneous rock facies in the same profile (see attached Figure 9 ).

[0078] The method of the embodiment solves the problems that the types of igneous rock facies are various, the seismic characteristics are greatly different, the seismic attributes are difficult to consider and describe, and the conventional igneous rock recognition results are difficult to effectively apply in the field. The spatial distribution of the igneous rock is described by the fractal detection and embedded construction technology, which lays a geological foundation for well trajectory optimization and well leakage prevention in the igneous rock development area. Secondly, the method is not only suitable for the igneous rock development area, but also suitable for the lithology prediction and description of sandstone and mudstone and reef, turbidity channel and other multi-genetic types.

[0079] Each embodiment in the specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same and similar parts between each embodiment can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the related parts can be referred to the method part.

[0080] The principles and implementation manners of the present application are described by using specific examples in the present application, and the above examples are only used to help understand the method of the present application and its core idea; meanwhile, for the general technical personnel in the art, the specific implementation manners and application ranges will be changed according to the idea of the present application. In conclusion, the content of the present specification should not be understood as the limitation of the present application.

Claims

1. A method for identifying and constructing igneous rock seismic fractals, characterized in that: The following steps are involved: Well-seismic calibration is performed based on the post-stack 3D seismic data and drilled well data in the study area; Based on well-seismic calibration, the distribution types of igneous rocks in the study area are determined, including intrusive rocks and volcanic bodies. Seismic detection of intrusive rock mass: eliminating the strongly reflecting sandstone in the intrusive rock mass in the study area and obtaining the intrusive rock attribute volume; Volcanic body seismic detection uses variance body attributes and normalization to form an attribute body, and uses target suppression technology to highlight the volcanic body structure and obtain the attribute body after target suppression; Extract the top and bottom envelope surfaces of the volcanic body from the attribute body after the target is suppressed, and use the top and bottom envelope surface constraints to suppress the volcanic body background to form a volcanic body background shielding enhancement body; Igneous rock fractal construction combines intrusive rock attributes and volcanic background shielding enhancement to obtain a comprehensive spatial distribution of igneous rocks.

2. The igneous rock seismic fractal identification and construction method according to claim 1, characterized in that: The specific steps of seismic detection of intrusive rock mass include: Optimize seismic attributes: By comparing attributes, using seismic "sweet spot" attributes and normalizing them, identify igneous rock bodies larger than 6-7 meters. Eliminate strong reflections of sandstone: Superimpose the sweet spot attributes with the seismic amplitude absolute value attributes to eliminate the false strong reflections of sandstone and obtain the intrusive rock attribute volume.

3. The igneous rock seismic fractal identification and construction method according to claim 1, characterized in that: The specific steps of volcanic body seismic detection include: The variance volume attributes are used and normalized to form an attribute volume, and the target suppression technology is used to highlight the volcanic body structure: Among them, Var normal is the normalized variance volume, dimensionless; Var normal-edit It is the attribute body of the target after compression, dimensionless.

4. The method for identifying and constructing igneous rock seismic fractals according to claim 1, characterized in that: The specific steps to form the volcanic background shielding enhancement body include: Extraction of the envelope of a single volcanic body: Using a combination of seismic amplitude profiles and coherence volume profiles, the top and bottom surfaces of the igneous body are extracted separately; the bottom surface of the igneous body is displayed as a fault. Meshing of the volcanic body envelope: The top surfaces of the igneous bodies are displayed on a plane by overlaying them. The top surfaces with overlapping areas are classified into different layer files, and polygon sets of the top surface boundaries are generated; and then meshed into the top and bottom surfaces of the igneous body; Volcanic background suppression: The volcanic background is suppressed using the top and bottom envelope constraints of the igneous rock body. The process is as follows: Where top1 represents the top depth of the igneous body numbered 1; bot1 represents the bottom depth of the igneous body numbered 1; top2 represents the top depth of the igneous body numbered 2; bot2 represents the bottom depth of the igneous body numbered 2; Z represents the depth, m; Var normal-FR is the volcanic background shielding enhancement body, dimensionless; Var normal is the normalized variance volume, dimensionless.

5. The method for identifying and constructing igneous rock seismic fractals according to claim 4, characterized in that: The specific steps of constructing igneous rock fractals include: Merge the intrusive rock attribute volume and the volcanic body background shielding enhancement volume: FR vol =Sweet normal-edit +Where normal-FR (3) Among them, FR vol It is a three-dimensional complex of igneous rocks, dimensionless; Sweet normal-edit is the intrusive rock attribute, dimensionless; Var normal-FR is the volcanic background shielding enhancement body, dimensionless; where FR vol The low value segment with a value less than 0.1 is the background area, FR vol The medium and high value segments with values ​​greater than 0.3 are indicative areas of igneous rocks.

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