CN117970460A - High-angle fracture information enhancement method - Google Patents

Abstract

The invention relates to a high-angle fracture information enhancement method, which belongs to the technical field of oil-gas field exploration, and comprises the steps of firstly carrying out construction guide filtering on three-dimensional seismic data of a target area, carrying out two-dimensional correlation analysis on filtering results to calculate correlation coefficient arrays of seismic data bodies in different directions, then enhancing high-angle signals of three different planes based on the correlation coefficient arrays, calculating fracture indication factor arrays corresponding to different directions, and finally fusing three groups of high-angle fracture indication factors to obtain a data body with enhanced high-angle fracture information.

Description

High-angle fracture information enhancement method

Technical Field

The invention relates to the technical field of oil and gas field exploration, in particular to a high-angle fracture information enhancement method.

Background

The discovery of the effective reservoir of the inner curtain of the submarine mountain changes the knowledge that the effective reservoir section is only distributed on the top weathering zone in the past, enriches and perfects the development mode of cracks of the submarine mountain, also shows the great potential of the inner curtain of the submarine mountain, and opens a new idea for the oil and gas exploration of the submarine mountain. Compared with a weathering zone, the number of low-angle cracks of the inner zone is reduced, the proportion of high-angle cracks is increased, but the whole of the reservoir of the inner zone is poor, the reservoir of the inner zone in a high-angle fault development area is generally well developed, and how to accurately predict the high-angle fracture information of the inner zone of the submarine mountain becomes one of the important points in the field of oil and gas field exploration. At present, conventional high-angle fracture identification methods include a bulk wave amplitude comparison method, a resonance frequency method, a linear time-frequency analysis method and the like, and conventional enhancement methods include a wavelet threshold denoising algorithm, a structure tensor algorithm, non-local mean filtering and the like.

However, conventional identification and enhancement methods have drawbacks in that the signal-to-noise ratio of the seismic profile imaging can be improved when the low signal-to-noise ratio seismic data is processed, if the frequency band of the seismic data coincides with the formation resonance response frequency band (Huang Dezhi, 2017). The linear time-frequency analysis is to carry out convolution and other operations on signals and other functions, the information leakage problem exists, the accuracy is low (Zhang Hongmao, 2023), the classical wavelet threshold denoising algorithm adopts a mode of setting a global threshold, noise in seismic data has obvious space-time conversion property, and the global threshold denoising method is easy to generate overkill or overstock phenomenon (self dragon, 2021). At present, few studies are conducted on high-angle fracture, and enhancement information is reconstructed by enhancing curvelet coefficients at corresponding positions of a curvelet domain for high-angle reflection formed by large-scale cracks in a buried hill (Zhang Zhijun, 2021). High angle fractures typically develop around high angle fractures, and f-k filtering and high linearity Radon transforms can extract high angle fractures from post-stack seismic data, but with low resolution, with artifacts (Fan Yanen, 2022).

Based on sufficient investigation and practical data application, the invention considers that the existing high-angle fracture signal recognition and enhancement technology has at least the following problems in the aspect of crack prediction:

(1) Limitations of unidirectional identification: the conventional unidirectional fracture identification method only considers a certain direction or specific attribute of the seismic data, ignores information of other directions or attributes, possibly leads to insufficient utilization of multi-source data and global information and influences the integrity and integrity of results, and meanwhile, the conventional unidirectional fracture identification method often depends on a preset threshold value or rule to judge whether the fracture exists or not, but for different seismic data, the selection of the threshold value and rule can bring misjudgment or omission, so that the inaccuracy and the deviation of the identification result are caused;

(2) Limitations in improving resolution: the conventional signal enhancement method often needs to perform operations such as signal filtering and noise reduction, and the operations can limit the frequency range of the signal, and may cause loss of detailed information of the signal, thereby affecting the resolution of the signal, and the conventional method cannot adapt to complex and changeable actual conditions, so that the resolution and definition of the signal are reduced.

Disclosure of Invention

The invention provides a high-angle fracture information enhancement method for solving the problem that the prior art cannot accurately identify high-angle fracture of an inner curtain belt. According to the method, correlation coefficient arrays of seismic data bodies in different directions are calculated through a two-dimensional correlation algorithm, then plane images and inclined extension continuity enhancement processing are carried out according to different plane data bodies and different methods, high-angle signals in the data bodies are enhanced, three groups of high-angle fracture indication factor arrays are obtained, and finally the three groups of high-angle fracture indication factor arrays are fused, so that the data bodies with obviously enhanced high-angle information and clear fracture boundaries are obtained, high-angle cracks around high-angle fractures can be accurately identified, the defects of the prior art are overcome, and a good effect is obtained.

The specific technical scheme is as follows:

(1) Inputting a three-dimensional seismic data array S of a target area, wherein the three-dimensional seismic data array S comprises a line number (X direction), a track number (Y direction) and a time sampling point number (Z direction);

(2) Performing construction guide filtering on the three-dimensional seismic data array S, and recording the filtered array as SP;

(3) The correlation coefficient array of the array SP is calculated in three ways: calculating along the XOY plane, calculating along the XOZ plane and calculating along the YOZ plane, and recording three correlation coefficient arrays as SC_XOY, SC_XOZ and SC_YOZ;

(4) For the correlation coefficient array SC_XOY, performing fault plane continuity enhancement processing on the XOY plane, wherein the processed array is a fracture indication factor array SE_XOY corresponding to the XOY plane;

(5) Aiming at the correlation coefficient array SC_XOZ, performing trend extension continuity enhancement processing, wherein the processed array is a fracture indication factor array SE_XOZ corresponding to the XOZ plane;

(6) Calculating a fracture indication factor array SE_YOZ corresponding to the YOZ plane aiming at the correlation coefficient array SC_YOZ by adopting the same method as the step (5);

(7) The three fracture indication factor arrays SE_XOY, SE_XOZ and SE_YOZ are fused to obtain a fracture indication factor array SN.

Compared with the prior art, the invention can achieve the following positive technical effects:

(1) Accuracy of high angle information extraction: the seismic signals may have different characteristics and information in different directions and angles, and when a single data volume correlation coefficient array is calculated to extract a high-angle signal, comprehensive information may not be obtained.

(2) Resolution of high angle fracture signals is improved: by acquiring the seismic data from multiple directions and fusing the data volumes, the signal-to-noise ratio of the seismic data can be remarkably improved, the seismic signals in different directions are analyzed, the azimuth angle of high-angle fracture can be determined, the data acquired in different directions can be subjected to different interferences and noises, but after fusion, the interferences can be weakened or eliminated, the high-angle fracture signal is enhanced, and the target signal is clearer.

Drawings

FIG. 1 is a technical flow chart of the present invention;

FIG. 2 is a cross-sectional view of three-dimensional seismic data of a target zone;

FIG. 3 is a cross-sectional view of the result of construction-oriented filtering;

FIG. 4 is a randomly extracted front and rear seismic section with high angle signal enhancement, FIG. 4- (a) is a section without high angle signal enhancement, and FIG. 4- (b) is a section after high angle signal enhancement;

Detailed Description

Example 1

A high-angle fracture information enhancement method comprises the following steps:

step 1: inputting three-dimensional seismic data S (x, y, t) of a target area, wherein x represents a line number, y represents a track number and t represents a time sampling point number;

Step 2: the method adopts a construction guide filtering method to carry out construction guide filtering on an array S (x, y, t), the construction guide filtering method adopted by the invention is a published method, zhao Feng is the method of 'application of construction guide filtering technology in fracture identification' published in 2018, and the filtered array is SP (x, y, t);

step 3: the correlation coefficient array of the array SP (x, y, t) is calculated in three ways:

step 3-1: calculating along the XOY plane to obtain a correlation coefficient array SC_XOY (x, y, t),

Wherein X _i represents the ith number in the X direction, Y _i represents the ith number in the Y direction,Mean value in X direction,/>Representing the average value in the Y direction, and N represents the length of a calculation time window, wherein the invention is set to be 5;

Step 3-2: calculating along the XOZ plane and along the YOZ plane by adopting the same method as the step 3-1 to obtain a correlation coefficient array SC_XOZ (x, y, t) and SC_YOZ (x, y, t);

Step 4: aiming at a correlation coefficient array SC_XOY (x, y, t), performing image plane continuity enhancement processing on a XOY plane, wherein the image plane continuity enhancement processing method adopted by the invention is a public method, and the method of paper Anisotropic diffusion in image processing published in 1998 by Weickert J is recorded as a fracture indication factor array SE_XOY (x, y, t) corresponding to the XOY plane;

Step 5: for the correlation coefficient array SC_XOZ (x, y, t), a trend extension continuity enhancement process is performed,

Sx＝e^px(x,y,t),Sz(x,y,t)＝e^pt(x,y,t)，

Wherein P _x (x, y, t) is an inclination array of an array SC_XOZ (x, y, t) in the x direction, P _t (x, y, t) is an inclination array of an array SC_XOZ (x, y, t) in the t direction, and SE_XOZ (x, y, t) is a fracture indication factor array corresponding to the XOZ plane;

Step 6: calculating a fracture indication factor array SE_YOZ (x, y, t) corresponding to the YOZ plane aiming at the correlation coefficient array SC_YOZ (x, y, t) by adopting the same method as the step 5;

Step 7: fusing three fracture indication factor arrays SE_XOY (x, y, t), SE_XOZ (x, y, t) and SE_YOZ (x, y, t),

a(x,y,t)＝SE_XOY(x,y,t)+SE_XOZ(x,y,t)+SE_YOZ(x,y,t)，

b(x,y,t)＝SE_XOY(x,y,t)²+SE_XOZ(x,y,t)²+SE_YOZ(x,y,t)²，

Where SN (x, y, t) is a high angle fracture indicator array.

Example 2

Fig. 2 and fig. 3 are respectively a three-dimensional seismic data of a target interval and a structural guide filtering result sectional view of a certain research area of the Bohai sea, the time range of the target interval is 3000-5000 ms, and after the method is applied, high-angle fracture signals are accurately extracted, horizontal and low-angle fracture signals are eliminated, target fracture is well reserved, the high-angle fracture enhancement effect is obvious, and a foundation is laid for accurately predicting high-angle cracks of an inner curtain band in the follow-up process.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.

Claims (1)

1. The method for enhancing the high-angle fracture information comprises the following specific steps of:

step 1: inputting three-dimensional seismic data S (x, y, t) of a target area, wherein x represents a line number, y represents a track number and t represents a time sampling point number;

Step 2: the method adopts a construction guide filtering method to carry out construction guide filtering on an array S (x, y, t), the construction guide filtering method adopted by the invention is a published method, zhao Feng is the method of 'application of construction guide filtering technology in fracture identification' published in 2018, and the filtered array is SP (x, y, t);

step 3: the correlation coefficient array of the array SP (x, y, t) is calculated in three ways:

step 3-1: calculating along the XOY plane to obtain a correlation coefficient array SC_XOY (x, y, t),

Wherein X _i represents the ith number in the X direction, Y _i represents the ith number in the Y direction,Mean value in X direction,/>Representing the average value in the Y direction, and N represents the length of a calculation time window, wherein the invention is set to be 5;

Step 3-2: calculating along the XOZ plane and along the YOZ plane by adopting the same method as the step 3-1 to obtain a correlation coefficient array SC_XOZ (x, y, t) and SC_YOZ (x, y, t);

Step 4: aiming at a correlation coefficient array SC_XOY (x, y, t), performing image plane continuity enhancement processing on a XOY plane, wherein the image plane continuity enhancement processing method adopted by the invention is a public method, and the method of paper Anisotropic diffusion in image processing published in 1998 by Weickert J is recorded as a fracture indication factor array SE_XOY (x, y, t) corresponding to the XOY plane;

Step 5: for the correlation coefficient array SC_XOZ (x, y, t), a trend extension continuity enhancement process is performed,

Wherein P _x (x, y, t) is an inclination array of an array SC_XOZ (x, y, t) in the x direction, P _t (x, y, t) is an inclination array of an array SC_XOZ (x, y, t) in the t direction, and SE_XOZ (x, y, t) is a fracture indication factor array corresponding to the XOZ plane;

Step 6: calculating a fracture indication factor array SE_YOZ (x, y, t) corresponding to the YOZ plane aiming at the correlation coefficient array SC_YOZ (x, y, t) by adopting the same method as the step 5;

Step 7: fusing three fracture indication factor arrays SE_XOY (x, y, t), SE_XOZ (x, y, t) and SE_YOZ (x, y, t),

a(x,y,t)＝SE_XOY(x,y,t)+SE_XOZ(x,y,t)+SE_YOZ(x,y,t)，

b(x,y,t)＝SE_XOY(x,y,t)²+SE_XOZ(x,y,t)²+SE_YOZ(x,y,t)²，

Where SN (x, y, t) is a high angle fracture indicator array.