An efficient interpretation method based on the target fracture sensitivity attribute

Abstract

The present invention discloses an efficient interpretation method based on target fracture sensitive attributes, which includes: Step 1, based on the interpretive result data, calculate the likelihood and in-situ stress attributes using DSG and Openfracture, and perform resampling; Step 2, use DSG to automatically trace faults for the resampled result data, optimize the parameter threshold values, retain the target fractures, and define the fracture contact relationships; Step 3, export the interpreted fractures, perform multi-attribute plane superposition and fusion using the in-situ stress and curvature attributes, supplement and verify each other spatially, make local manual modifications and improvements to the target fractures, and finely depict the internal structural features of the target fractures. The present invention can quickly and effectively perform fine interpretation of target fractures, contribute to rapid and efficient fracture interpretation in areas with a relatively fast rolling exploration process, provide strong technical support for the optimization of exploration targets and the optimal deployment of well positions, which is of great significance for the overall orderly rolling development of the oilfield and has broad prospects.

Description

Technical Field

[0001] The present invention relates to an efficient interpretation method based on target fracture sensitive attributes, belonging to the technical field of seismic exploration. Background Art

[0002] The interpretation of faults is the key to the interpretation of the entire 3D seismic work area. Whether the interpretation is correct or not will affect the changes in the structural characteristics of the area and the evaluation of traps. Therefore, on the basis of regional geological research, it is necessary to reasonably and scientifically interpret the faults in the work area in combination with tectonic stress and geological models. In the past, fracture interpretation mainly relied on manual work. The first step was to determine the fault mode, and the second step was to carry out fault interpretation. The fault interpretation was carried out simultaneously with the horizon correlation interpretation. It mainly relied on the dislocation, disconnection, faulting, and bending of reflection wave groups on seismic profiles, and at the same time referred to the amplitude change patterns linearly distributed on time slices, fine AFE, coherence bodies, discontinuity and other attribute bodies, and the changes of non-correlated parameters linearly distributed on the slices to trace and interpret faults. When using coherence bodies for interpretation, it should be noted that incoherent data anomalies are not necessarily caused by faults, but may also be caused by lithology changes or other geological phenomena. Traditional methods can accurately and scientifically carry out fine fracture interpretation, but the speed for specific target fractures is slow, and the current advanced interpretation mode of human-computer interaction is not fully utilized, resulting in low efficiency. Since it is mainly based on humans, it has high requirements for fracture interpretation technicians and cannot meet the needs of rapid, efficient and fine interpretation of short-term target fractures. Especially in areas with a relatively fast rolling exploration process, there is an urgent need for a fast and effective method to carry out fine interpretation of target faults. Summary of the Invention

[0003] The purpose of the present invention is to provide an efficient interpretation method based on target fracture sensitive attributes. This method mainly adopts automatic interpretation based on target fracture sensitive attributes, and artificially selects target fractures through parameter optimization and threshold determination, and can quickly and effectively carry out fine interpretation of target fractures.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is: an efficient interpretation method based on target fracture sensitive attributes, which includes the following steps:

[0005] Step 1: Based on the interpretive result data, use DSG and Openfracture to calculate likelihood and in-situ stress attributes, and perform resampling;

[0006] Step 2: Use DSG to automatically trace faults in the resampled result data, optimize the parameter threshold value, retain the target fractures, and define the fracture contact relationship;

[0007] Step 3: Export the well-explained fractures, and use the plane superposition and fusion of multi-attributes of in-situ stress and curvature to complement and verify each other spatially, perform local manual modification and improvement of the target fractures, and finely depict the internal structural characteristics of the target fractures.

[0008] As a further optimization of this solution, the specific steps of Step 1 are as follows:

[0009] (1) Use DSG to calculate the likelihood attribute, set the calculation parameters of the horizontal time window and the longitudinal time window, and perform resampling to focus on strengthening the longitudinal characteristics of the target fractures and the integrity of the regional laws.

[0010] (2) Use Openfracture to calculate the maximum and minimum principal stresses in the fractures and their vicinity, and combine the positive and negative curvature attributes to depict the internal characteristics of the fractures.

[0011] As a further optimization of this solution, the calculation parameters of the horizontal time window and the longitudinal time window are 16 and 32 respectively, and 4m resampling is performed.

[0012] As a further optimization of this solution, the specific steps of Step 2 are as follows:

[0013] (1) Use the DSG fracture automatic tracking function module to perform automatic tracking and interpretation of the target fractures on the resampled likelihood data.

[0014] (2) Sort the fractures after automatic tracking according to the fracture dip angle, fracture length, and fracture width, and select the parameter threshold values of the minimum attribute value, fracture dip angle, fracture length, and fracture width according to the characteristics of the target fractures.

[0015] (3) Define the fault contact and attribution relationship for the retained target fractures.

[0016] As a further optimization of this solution, in the automatic tracking and interpretation of the target fractures, the minimum attribute value is 0.2, the tracking grid is 20, and as much fracture information as possible is involved in the calculation.

[0017] As a further optimization of this solution, in the YL area of the study area, the dip angle of the Ordovician main fractures is greater than 60 degrees, and the fracture length is greater than 0.8 Km.

[0018] As a further optimization of this solution, the specific steps of Step 3 are as follows:

[0019] (1) Combine the plane attributes with the profile and fracture surface to complete the fine interpretation of the fracture system in the study area.

[0020] (2) Combine the plane profile with Geoprobe to describe the three-dimensional spatial structure and variation law of the fractures, and comprehensively determine the active periods based on the deformation differences and distribution characteristics of the upper and lower tectonic layers.

[0021] (3) Comprehensive analysis of the response characteristics and distribution laws of faults in seismic data and various attributes to complete the spatial analysis of faults.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: The method of the present invention mainly adopts automatic interpretation based on the target fault-sensitive attributes, and selects the target faults artificially through parameter optimization and threshold determination, which can quickly and effectively perform fine interpretation of the target faults. The time is shortened to 1 / 7 of the original. The fault interpretation results are accurate and reliable, and the operation is simple with strong popularization. It has very important significance. The improvement and popularization of this method can quickly and effectively perform fine interpretation of the target faults, contribute to the rapid and efficient fault interpretation in areas with a relatively fast rolling exploration process, provide strong technical support for the optimization of exploration targets and the optimal deployment of well positions, which has very important significance for the overall orderly rolling development of the oilfield and broad prospects.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0024] Figure 1 is the flow chart of the efficient interpretation method for target fault-sensitive attributes;

[0025] Figure 2 is the typical seismic profile of the resampled Likelihood attribute in the study area;

[0026] Figure 3 is the test and comparison chart of fault parameters with different time windows of Likelihood in the typical profile and DSG in the study area;

[0027] Figure 4 is the fault unit map generated by automatic fault interpretation;

[0028] Figure 5 is the schematic diagram for determining the threshold value of the target fault;

[0029] Figure 6 is the schematic diagram for determining the contact and attribution relationships of the target fault;

[0030] Figure 7 is the typical seismic profile and the maximum principal stress profile of the key part in the study area;

[0031] Figure 8 is the fusion map of the likelihood attribute and the in-situ stress in the target fault;

[0032] Figure 9 is the comparison map of the original amplitude, negative amplitude curvature, and positive amplitude curvature plane profiles;

[0033] Figure 10It is the superposition carving map of the curvature fracture-vug body and the tectonic stress body (tensile) of the NE strike-slip fault zone in the study area. Specific implementation manners

[0034] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] As Figure 1 shown, an efficient interpretation method based on target fracture sensitive attributes is as follows:

[0036] Step 1, based on the interpretive result data, use DSG and Openfracture to calculate likelihood and in-situ stress attributes, and perform resampling. The specific steps are as follows:

[0037] 1. Use DSG to calculate the likelihood attribute. The calculation parameters of the horizontal time window and the vertical time window are 16 and 32 respectively, and 4m resampling is performed to strengthen the longitudinal characteristics of the target fracture and the integrity of the regional law ( Figure 2 and Figure 3 ).

[0038] 2. Use Openfracture to calculate the maximum and minimum principal stresses in and near the fracture, and combine the positive and negative curvature attributes to characterize the internal characteristics of the target fracture.

[0039] Step 2, use DSG to automatically trace the faults for the resampled result data, optimize the threshold values of parameters such as the minimum value of the attribute, fracture dip angle, fracture length, and fracture width, retain the target fracture, and define the fracture contact relationship. Specifically:

[0040] 1. Use the DSG fracture automatic tracing function module to automatically trace and interpret the target fracture for the resampled 4m likelihood data. The minimum value of the attribute is 0.2, and the tracing grid is 20, allowing as much fracture information as possible to participate in the calculation ( Figure 4 ).

[0041] 2. Sort the fractures after automatic tracing according to the fracture dip angle, fracture length, and fracture width, select the threshold values according to the characteristics of the target fracture. In the YL area of the study area, the dip angle of the Ordovician main fault is greater than 60 degrees, and the fracture length is greater than 0.8Km, etc. ( Figure 5 and Figure 6 ).

[0042] 3. Define the fault contact and attribution relationship for the retained target fracture.

[0043] Step 3, export the interpreted fractures, use the multi-attribute plane superposition and fusion of in-situ stress and curvature attributes, supplement and verify each other spatially, perform local manual modification and improvement of the target fracture, and finely depict the internal branch fractures and structural characteristics.

[0044] Specifically:

[0045] 1. Combine the multi-attribute plane of in-situ stress and curvature attributes with the profile and fault plane to complete the fine interpretation of the fault system in the study area ( Figure 7 ).

[0046] 2. Describe the three-dimensional spatial structure and variation law of faults by combining plane and profile with Geoprobe. Based on the deformation differences and distribution characteristics of the upper and lower tectonic layers, comprehensively determine the active periods ( Figure 8 ).

[0047] 3. Comprehensively analyze the response characteristics and distribution laws of faults in seismic data and various attributes to complete the spatial analysis of faults.

[0048] In the above embodiments, DSG is the abbreviation of DecisionSpace GeoSciences, and DSG is the upgraded version of the Blue Horse decision space geoscience software for existing applications; geoprobe is the geophysical exploration module of the upgraded version of the Blue Horse decision space geoscience software; OpenFracture is the integrated post-stack and pre-stack fracture detection and analysis software; likelihood is the maximum likelihood, which is a sensitive attribute for faults.

[0049] The application implementation effect of the present invention: Since fault interpretation is the key to the interpretation of the entire 3D seismic work area, whether the interpretation is correct or not will affect the change of the tectonic pattern in this area and the evaluation of traps. In the past, fault interpretation mainly relied on humans, with strong subjective factors and low efficiency. Generally, it took several months to finely interpret the faults in a work area with an area of more than 300 square meters. Using the efficient interpretation method based on the sensitive attributes of target faults in the present invention, the interpretation time of target faults is shortened from several months in the past to within one or two weeks. It not only meets the technical requirements of the client, but also has a high fault interpretation accuracy. Figure 9 It shows the typical seismic profile of the local fault dissolution body in the LW area and the comparison of positive and negative curvatures. It can also be seen from it that negative curvature has a good effect on internal faults, and the fault plane and reflection characteristics can be seen. Positive curvature is sensitive to the lateral distribution characteristics of faults and internal fracture-vug anomalies. Figure 10 It shows the three-dimensional display map of the combination of faults and in-situ stress attributes after being interpreted by the method based on the invention in the LW area. It only takes 5 days and has good consistency, providing strong guidance for the subsequent comprehensive reservoir prediction in this area.

[0050] The above shows and describes the basic principles, main features and advantages of the present invention. Those of ordinary skill in the art should understand that the above embodiments do not limit the protection scope of the present invention in any form. Any technical solutions obtained by means of equivalent replacement and the like fall within the protection scope of the present invention.

[0051] Parts not involved in the present invention are the same as or can be implemented by using the prior art.

Claims

1. An efficient interpretation method based on target fracture sensitivity attributes, characterized in that The following steps are involved: Step 1: Based on the explanatory results data, DSG and Openfracture are used to calculate likelihood and ground stress attributes, and resample; Step 2: Use DSG to automatically track the faults in the resampled data, select parameter thresholds, retain the target fractures, and define the fracture contact relationships; specifically, (1) Use the DSG fracture automatic tracking function module to automatically track and interpret the target fractures based on the resampled likelihood data; (2) Sort the automatically tracked faults by fracture inclination, fracture length, and fracture width, and select the minimum attribute value, fracture inclination, fracture length, and fracture width parameter threshold values according to the characteristics of the target fault; (3) Define the fault contact and attribution relationship of the retained target fault; Step 3: Export the interpreted faults, use the multi-attribute plane superposition and fusion of ground stress and curvature attributes, complement and verify each other in space, perform local manual modification and improvement of the target fault, and finely characterize the internal structural characteristics of the target fault.

2. The efficient interpretation method based on target fracture sensitive attributes according to claim 1 is characterized in that: The specific steps of step one are: (1) Use DSG to calculate the likelihood attribute, set the horizontal time window and vertical time window calculation parameters, and perform resampling, focusing on strengthening the longitudinal characteristics of the target fault and the integrity of the regional regularity; (2) Openfracture is used to calculate the maximum and minimum principal stresses in and near the fracture, and the internal characteristics of the fracture are characterized by combining positive and negative curvature attributes.

3. An efficient interpretation method based on the target fracture sensitivity attribute according to claim 2, characterized in that The calculation parameters of the horizontal time window and the vertical time window are 16 and 32 respectively, and 4m resampling is performed.

4. The efficient interpretation method based on target fracture sensitive attributes according to claim 1 is characterized in that: In the automatic tracking interpretation of the target fracture, the minimum attribute value is 0.2 and the tracking grid is 20, so that as much fracture information as possible can be involved in the calculation.

5. The efficient interpretation method based on target fracture sensitive attributes according to claim 1 is characterized in that: In the YL area of the study area, the main fault of the Ordovician system has a dip angle greater than 60 degrees and a fault length greater than 0.8 km.

6. The efficient interpretation method based on the target fracture sensitivity attribute according to claim 1, characterized in that, The specific steps of step three are: (1) Combine plane attributes with cross sections and fracture surfaces to complete a detailed interpretation of the fracture system in the study area; (2) By combining horizontal sectioning with Geoprobe, the three-dimensional spatial structure and variation of the fault are described, and the activity period is comprehensively determined based on the deformation differences and distribution characteristics of the upper and lower structural layers; (3) Comprehensively analyze the response characteristics and distribution patterns of faults in seismic data and various attributes to complete the spatial analysis of faults.

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