Pre-stack OVT domain fluid prediction method based on AVO forward modeling

Abstract

The invention provides a pre-stack OVT domain fluid prediction method based on AVO forward modeling. The prediction method comprises the steps that 1, amplitude response characteristics of an oil layer are determined through single-well AVO forward modeling; 2, carrying out anisotropy analysis on a target layer of a pre-stack OVT domain gather; 3, optimally dividing the azimuth angle and the offset distance, and establishing a superposition template; 4, extracting AVO class attributes of a target layer according to the superposition template; and 5, analyzing and determining an oil and gas distribution rule according to the AVO class attributes. On the basis of anisotropy analysis of the OVT domain prestack gather data, logging and other data are fully utilized, the established superposition template is reliable, and oiliness prediction carried out on the basis is objective and reliable.

Description

Technical Field

[0001] The present invention relates to the field of exploration geophysics, and in particular to a pre-stack OVT domain fluid prediction method based on AVO forward simulation. Background Art

[0002] Prestack seismic data contains more frequency information and has better resolution. People have developed prestack elastic inversion technology, prestack seismic inversion technology and quantitative AVO technology using prestack seismic data. They all use prestack CRP gather data (or partial stacking data), velocity data (generally offset velocity) and well data (S-wave velocity, P-wave velocity, density and other elastic parameter data) to obtain various elastic parameters related to lithology and oil and gas content by using different approximate inversion solutions, and further use them to predict reservoir lithology, reservoir physical properties and oil and gas content.

[0003] With the continuous advancement of exploration technology, more and more OVT domain wide azimuth and large offset pre-stack gather data have appeared and are used in production. Compared with conventional pre-stack gather seismic, OVT domain pre-stack gather retains more azimuth information. During the seismic propagation process, the information of underground geological bodies recorded at different azimuths and offsets is different. Therefore, using OVT domain pre-stack gathers to carry out lithology or fluid prediction is an important direction for future seismic exploration. Summary of the invention

[0004] In view of the above problems, the present invention is proposed to provide a pre-stack OVT domain fluid prediction method based on AVO forward modeling, which overcomes the above problems or at least partially solves the above problems.

[0005] According to one aspect of the present invention, a pre-stack OVT domain fluid prediction method based on AVO forward simulation is provided, the prediction method comprising:

[0006] Step 1: Use single-well AVO forward simulation to clarify the amplitude response characteristics of the reservoir;

[0007] Step 2: Carry out anisotropy analysis of the target layer in the pre-stack OVT domain gathers;

[0008] Step 3: Optimize the division of azimuth and offset, and establish a superposition template;

[0009] Step 4: extracting the AVO class attributes of the target layer according to the overlay template;

[0010] Step 5: Clarify the oil and gas distribution pattern based on the AVO attribute analysis.

[0011] Optionally, the step 1: using a single-well AVO forward simulation to clarify the amplitude response characteristics of the oil layer specifically includes:

[0012] Select typical oil reservoir wells by integrating the drilling data of multipole array acoustic waves;

[0013] Conduct AVO forward modeling of a single well;

[0014] Clarify the variation characteristics of seismic amplitude with offset distance at the oil layer development location.

[0015] Optionally, the drilling data includes: well logging, mud logging and drilling data.

[0016] Optionally, the step 2: conducting anisotropy analysis of the target layer in the pre-stack OVT domain gather specifically includes:

[0017] Conduct anisotropy analysis of the target layer of the actual OVT domain pre-stack gathers in the work area;

[0018] It is clarified that the target layer has anisotropy, and anisotropy research is conducted.

[0019] Optionally, the step 3: preferably dividing the azimuth angle and the offset distance to establish the overlay template specifically includes:

[0020] By changing the range in the OVT domain pre-stack gather stacking template view, a sector is found that makes the pre-stack gather amplitude response at the typical oil layer well position in the work area have the same amplitude response characteristics as the single well AVO forward simulation;

[0021] The blind wells in the work area were used for verification to clarify the sector range that can reflect oil content in the OVT domain pre-stack gathers and obtain the pre-stack sector range;

[0022] The azimuth and offset range of the pre-stack sector range are recorded to establish a stacking template.

[0023] Optionally, the changing of the range in the OVT domain pre-stack gather overlay template view specifically includes: changing the azimuth angle and offset sector range in the OVT domain pre-stack gather overlay template view

[0024] Optionally, the blind wells in the work area specifically include: oil layer wells and water layer wells.

[0025] Optionally, the step 4: extracting the AVO class attributes of the target layer according to the overlay template specifically includes:

[0026] According to the stacking template, the AVO attribute class analysis of the target layer in the work area is carried out on the OVT domain pre-stack gather within the template range to obtain the AVO attribute class map.

[0027] Optionally, the step 5: clarifying the oil and gas distribution pattern according to the AVO attribute analysis specifically includes:

[0028] By using geological statistics to analyze the differences in different attributes, we can obtain an attribute map that is highly consistent with the actual oil content in drilling and clarify the oil and gas distribution pattern in the work area.

[0029] Optionally, the step 5: after clarifying the oil and gas distribution pattern according to the AVO-type attribute analysis, further comprises: obtaining an oil-bearing plane distribution pattern map according to the oil and gas distribution pattern of the work area.

[0030] The present invention provides a pre-stack OVT domain fluid prediction method based on AVO forward simulation, the prediction method comprising: step 1: using single well AVO forward simulation to clarify the amplitude response characteristics of the oil layer; step 2: conducting pre-stack OVT domain gather target layer anisotropy analysis; step 3: preferably dividing azimuth and offset distance, and establishing a stacking template; step 4: extracting the target layer AVO class attributes according to the stacking template; step 5: clarifying the oil and gas distribution law according to the AVO class attribute analysis. Based on the anisotropy analysis of the OVT domain pre-stack gather data, the well logging, mud logging and other data are fully utilized, the established stacking template is reliable, and the oil content prediction based on this is objective and reliable.

[0031] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0033] Figure 1 A flowchart of a specific embodiment of a pre-stack OVT domain fluid prediction method based on AVO forward simulation provided by an embodiment of the present invention;

[0034] Figure 2 This is a forward simulation diagram of AVO for a single well in Shengli 1 work area in a specific embodiment of the present invention;

[0035] Figure 3 It is a graph of the intersection of oil layer amplitude and offset distance in Shengli 1 work area in a specific embodiment of the present invention;

[0036] Figure 4 This is an anisotropy analysis diagram of the pre-stack gathers in the OVT domain of Shengli 1 work area in a specific embodiment of the present invention;

[0037] Figure 5It is a template view of the oil content prediction sector of Shengli 1 work area in a specific embodiment of the present invention;

[0038] Figure 6 It is an intersection diagram of seismic response amplitude and offset distance of the target oil layer of the OVT domain pre-stack gather in Shengli 1 work area in a specific embodiment of the present invention;

[0039] Figure 7 It is an intersection diagram of seismic response amplitude and offset distance of the target layer water layer of the OVT domain pre-stack gather in Shengli 1 work area in a specific embodiment of the present invention;

[0040] Figure 8 It is a pseudo-Poisson's ratio attribute map of a certain target layer in Shengli 1 work area in a specific embodiment of the present invention;

[0041] Fig. 9 This is a plan view of the oil and gas distribution pattern of a certain target layer in Shengli 1 work area in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0042] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0043] The terms "comprises" and "having" and any variations thereof in the description embodiments, claims and drawings of the present invention are intended to cover non-exclusive inclusions, for example, including a series of steps or units.

[0044] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0045] Example 1

[0046] A specific embodiment 1 of the present invention is applied, Figure 1 The flowchart of the pre-stack OVT domain fluid prediction method based on AVO forward simulation of the present invention is as follows. The pre-stack OVT domain fluid prediction method based on AVO forward simulation of the present invention comprises the following steps:

[0047] Step 101, selecting typical oil layer wells based on well logging, mud logging and drilling data such as integrated multipole array acoustic waves to perform AVO forward simulation of single wells, and clarifying the variation characteristics of seismic amplitude at the oil layer development position with offset distance. Figure 2 This is an AVO forward modeling diagram of a typical oil well in Shengli 1 work area in a specific embodiment of the present invention. Figure 3This is an intersection diagram of oil layer amplitude and offset distance in Shengli 1 work area in a specific embodiment of the present invention. It is found that when the reservoir contains oil, the seismic amplitude decreases as the offset distance increases; the process enters step 102.

[0048] Step 102, conduct anisotropy analysis of the actual OVT domain pre-stack gathers in the work area to confirm that the target layer has anisotropy and conduct anisotropy research. Figure 4 This is an anisotropy analysis diagram of the OVT domain pre-stack gathers in Shengli 1 area. The amplitude slices show that anisotropy exists in different directions and at different offsets. The process enters step 103.

[0049] Step 103, by changing the azimuth and offset sector ranges in the OVT domain pre-stack gather stacking template view, find the sector that makes the pre-stack gather amplitude response of the typical oil layer well position in the work area have the same amplitude response characteristics as the single well AVO forward simulation in step 1, and verify it with other blind wells in the work area (including oil layer wells and water layer wells), clarify the sector range that can reflect the oil content in the OVT domain pre-stack gather, record the azimuth and offset range of the sector, and establish the stacking template. Figure 5 This is the template view of the oil content prediction sector in Shengli No. 1 work area. Figure 6 This is the intersection diagram of the seismic response amplitude of the target oil layer in the OVT domain pre-stack gather and the offset distance. The seismic amplitude of the oil layer decreases with the increase of the offset distance. Figure 7 This is an intersection diagram of the seismic response amplitude of the water layer in the OVT domain pre-stack gather of the Shengli 1 work area and the offset distance in a specific embodiment of the present invention. The seismic amplitude of the water layer does not change substantially with the increase of the offset distance. Figure 6 and Figure 7 The comparison shows Figure 5 The amplitude response characteristics of the oil layer and the water layer in the template are different. The process proceeds to step 104.

[0050] In step 104, based on the stacking template established in step 103, the AVO attribute class analysis of the target layer in the work area is carried out on the pre-stack gathers within the template range to obtain the AVO attribute class map. Figure 8 It is a pseudo-Poisson's ratio attribute map of a target layer in Shengli 1 work area in a specific embodiment of the present invention. The process enters step 105.

[0051] In step 105, the differences in different attributes are analyzed by using geological statistics to find an attribute map with a high consistency with the actual drilling oil content, and to clarify the oil and gas distribution pattern in the work area. Fig. 9 This is a plan view of the oil and gas distribution pattern of a target layer in Shengli No. 1 work area. The process ends.

[0052] This embodiment provides a pre-stack OVT domain fluid prediction method based on AVO forward simulation. By combining the AVO forward simulation of a single well (oil layer well) in the work area with the anisotropy analysis of the OVT domain pre-stack gathers, a stacking template with oil and gas pointing significance is established. The attribute prediction performed on this template can better predict the plane distribution law of oil and gas.

[0053] Beneficial effects: The pre-stack OVT domain fluid prediction method based on AVO forward simulation of the present invention can conveniently use the anisotropic characteristics of the OVT domain pre-stack gather data to detect the oil and gas content of the region, and guide the comprehensive evaluation and exploration deployment of the exploration area.

[0054] The present invention is based on anisotropy analysis of pre-stack gather data in the OVT domain, makes full use of logging, mud logging and other data, and establishes a reliable stacking template. The oil content prediction based on this is objective and reliable.

[0055] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A pre-stack OVT domain fluid prediction method based on AVO forward simulation, characterized in that: The prediction method comprises: Step 1: Use single-well AVO forward simulation to clarify the amplitude response characteristics of the reservoir; Step 2: Carry out anisotropy analysis of the target layer in the pre-stack OVT domain gathers; Step 3: Optimize the division of azimuth and offset, and establish a superposition template; Step 4: extracting the AVO class attributes of the target layer according to the overlay template; Step 5: Clarify the oil and gas distribution pattern based on the AVO attribute analysis.

2. A pre-stack OVT domain fluid prediction method based on AVO forward simulation according to claim 1, characterized in that: The step 1: using single-well AVO forward simulation to clarify the amplitude response characteristics of the oil layer specifically includes: Select typical oil reservoir wells by integrating the drilling data of multipole array acoustic waves; Conduct AVO forward modeling of a single well; Clarify the variation characteristics of seismic amplitude with offset distance at the oil layer development location.

3. The pre-stack OVT domain fluid prediction method based on AVO forward simulation according to claim 2 is characterized in that: The drilling data includes well logging, well logging and drilling data.

4. A pre-stack OVT domain fluid prediction method based on AVO forward simulation according to claim 1, characterized in that: The step 2: carrying out anisotropy analysis of the target layer in the pre-stack OVT domain gather specifically includes: Carry out anisotropy analysis of the target layer of the actual OVT domain pre-stack gather in the work area; It is clarified that the target layer has anisotropy, and anisotropy research is conducted.

5. A pre-stack OVT domain fluid prediction method based on AVO forward simulation according to claim 1, characterized in that: The step 3: preferably dividing the azimuth and offset to establish the overlay template specifically includes: By changing the range in the OVT domain pre-stack gather stacking template view, a sector is found that makes the pre-stack gather amplitude response at the typical oil layer well position in the work area have the same amplitude response characteristics as the single well AVO forward simulation; The blind wells in the work area were used for verification to clarify the sector range that can reflect the oil content in the OVT domain pre-stack gathers and obtain the pre-stack sector range; The azimuth and offset range of the pre-stack sector range are recorded to establish a stacking template.

6. A pre-stack OVT domain fluid prediction method based on AVO forward simulation according to claim 5, characterized in that: The changing of the range in the OVT domain pre-stack gather overlay template view specifically includes: changing the azimuth angle and offset sector range in the OVT domain pre-stack gather overlay template view.

7. A pre-stack OVT domain fluid prediction method based on AVO forward simulation according to claim 5, characterized in that: The blind wells in the work area specifically include: oil layer wells and water layer wells.

8. A pre-stack OVT domain fluid prediction method based on AVO forward simulation according to claim 1, characterized in that: The step 4: extracting the AVO attributes of the target layer according to the overlay template specifically includes: According to the stacking template, the AVO attribute class analysis of the target layer in the work area is carried out on the OVT domain pre-stack gather within the template range to obtain the AVO attribute class map.

9. A pre-stack OVT domain fluid prediction method based on AVO forward simulation according to claim 1, characterized in that: The step 5: clarifying the oil and gas distribution law according to the AVO attribute analysis specifically includes: By using geological statistics to analyze the differences in different attributes, we can obtain an attribute map that is highly consistent with the actual oil content in drilling and clarify the oil and gas distribution pattern in the work area.

10. A pre-stack OVT domain fluid prediction method based on AVO forward simulation according to claim 1, characterized in that: The step 5: after clarifying the oil and gas distribution law according to the AVO attribute analysis, it also includes: obtaining an oil-bearing plane distribution law map according to the oil and gas distribution law of the work area.

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