Method for recognizing small fracture through gravity

Abstract

The invention discloses a method for recognizing a small fracture through gravity. The horizontal gradient calculation is carried out on gravity anomaly, horizontal gradient values of mesh points are compared with horizontal gradient values of adjacent points on the two sides in the east-west direction, the north-south direction, the north-west direction and the north-east direction one by one, when the horizontal gradient values of the mesh points are greater than the horizontal gradient values of the adjacent points on the two sides in one or more directions at the same time, the mesh points are determined as points with the maximum horizontal gradient value, the coordinates and gradient values of the mesh points are recorded, the grid points with the maximum horizontal gradient value are drawn to a plane graph, and then the small fracture can be recognized out. Large-scale fracture information can be extracted from gravity data, small-scale fracture information can also be extracted, and particularly when fractures of different sizes exist, fractures of different sizes can be recognized out at the same time.

Description

technical field [0001] The invention belongs to the gravity exploration data processing technology, and is a method for identifying small fractures by gravity. Background technique [0002] Fracture is one of the basic main contents of gravity exploration. As exploration progresses, smaller and smaller fractures are required to be identified. [0003] The fracture appears as an abnormal gravity change belt with a certain extension length in gravity. The conventional method for studying fractures by gravity is to calculate the horizontal derivative of the Bouguer gravity anomaly or residual gravity anomaly to obtain the gravity horizontal gradient value, identify and outline the gradient maximum position on the plane contour map, and obtain the distribution of fractures. Since the plane contour map does not directly reflect the position of the maximum value, it can only be interpreted according to the middle position of the contour closure. Therefore, the interpretation of ...

AI Technical Summary

Problems solved by technology

Since the plane contour map does not directly reflect the position of the maximum value, it can only be interpreted according to the middle position of the contour closure. Therefore, the interpretation of the fracture position is somewhat artificial, especially the existence of fractures of different sizes When , small breaks cannot be reflected on the contour line, resulting in unexplained small breaks

[0004] Previously, in order to improve the accuracy of fracture interpretation and improve the ability to identify small fractures, predecessors have adopted the method of enhancing fracture information on gravity anomalies or gravity horizontal gradients, but this method is still interpreted on the plane contour. The identification ability of gravity data for weak and small fractures has not been fundamentally improved, and there are still problems that the interpretation of fracture positions is not accurate enough, and weak and small fractures cannot be effectively reflected

[0005] Another type of method is to use the image method to make gravity anomaly or horizontal gradient image map, and use the linear shadow position to explain the fracture. It also has the problem of inaccurate fracture location and unrecognizable small fractures.

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