A method for prestack fracture prediction in the co-offset co-azimuth domain

Abstract

The invention provides a method for predicating a pre-stack fracture within common offset and common azimuth domains, and belongs to the technical field of oil exploration fracture prediction. The method comprises the following steps: collecting seismic data; performing independent pre-stack migration on all of the common offset and common azimuth domains obtained from the seismic data; carrying out horizon interpretation, wherein obtained CRP (Common Reflection Point) gathers are stacked to obtain a result data body, and the top and the bottom of a target zone are subjected to horizon interpretation; segmenting the CRP gathers, wherein a position partition scheme is determined according to a development direction of a main fracture in a work area, and the CRP gathers are segmented into n groups of sub-CRP gathers according to azimuth information in the CRP gathers; stacking sub-positions, wherein all of the CRP gathers are stacked to obtain n seismic traces, and the n stacked seismic traces are merged together to form a new CRP position gather; converting residual interval moveout to a root-mean-square velocity; converting the new root-mean-square velocity to an interval velocity; performing ellipse fitting to obtain velocities and directions of fast and slow waves; calculating the fracture density.

Description

technical field [0001] The invention relates to a method for predicting pre-stack fractures in the field of common offset and common azimuth, and belongs to the technical field of oil exploration fracture prediction. Background technique [0002] The proportion of fractured oil and gas reservoirs is increasing, and a key point for successful development and production of fractured oil and gas reservoirs is to prove the distribution of fractures. Especially in tight sandstone gas, shale gas and carbonate reservoirs, the density and direction information of fractures is crucial for drilling and subsequent development strategies. In these oil and gas reservoirs, fractures can not only provide effective percolation channels and storage spaces, but also become the main factor to communicate carbonate pores, improve productivity and develop efficiently. Therefore, there is an urgent need for high-precision fracture description . [0003] Traditional fracture research methods are...

AI Technical Summary

Problems solved by technology

However, this method has a huge workload and requires high data requirements.

Often due to the limited number of coverage in the sector, the imaging is very poor. If the sector is enlarged, the analysis of anisotropic parameters will be inaccurate. If the bins are expanded to form a super gather, the accuracy will be affected.

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