Method for inversion of properties of fracture

Abstract

The invention proposes a method for inversion of properties of a fracture. The method comprises: establishing an inversion objective function based on frequency-variant amplitude versus offset and azimuth (AVAZ) features; according to a calculation result of the inversion objective function, establishing a likelihood function of a fracture parameter; combining prior distribution of the fracture parameter with the likelihood function of the fracture parameter and calculating a posterior probability distribution function of the fracture parameter; and with a statistic method, displaying an inversion result visually. Compared with the existing method, the novel method has the following beneficial effects: the result of the novel method is close to the real situation in terms of medium hypothesis presupposition; more fracture properties are predicted in terms of results and fluid identification can be performed; and the effective and reasonable fusion process of balancing geology, logging,and seismic information is realized.

Description

technical field [0001] The invention relates to the technical field of oil and gas geophysics, in particular to a method for retrieving fracture properties. Background technique [0002] With the development and utilization of oil and natural gas resources, the reserves of conventional porous oil and gas reservoirs are decreasing day by day, and the difficulty of development is gradually increasing. The direction of oil and gas exploration is gradually shifting from shallow to deep, and from conventional oil and gas reservoirs to special oil and gas reservoirs, especially fractured reservoirs. (tight sandstone, carbonate rock and shale reservoir, etc.). The study of fracture prediction is of great significance. [0003] Almost all oil and gas reservoirs are affected to some degree by natural fractures. Fractures developed underground are often important places for oil and gas storage, and as a common phenomenon, fractures widely exist in various rock formations. In carbon...

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Problems solved by technology

Neither of the above two inversion methods can be used for fluid identification, and the former relies heavily on the prior information obtained from geology and well logging, while the latter does not consider how to reasonably integrate the fracture prediction results of geology and well logging

[0007] However, in fact, the complexity of fractures requires a reasonable combination of geological, logging and seismic data to predict fracture properties more accurately, and the prediction results of these information often have certain errors, that is, inconsistencies. Therefore, it is necessary to Physical theory research can balance the use of geological, logging and seismic information to invert the method of fracture properties

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