Fracture permeability computing method

Abstract

The invention provides a fracture permeability computing method, comprising the steps of obtaining average fracture permeability according to well test permeability, matrix permeability and fracture porosity, wherein the well test permeability is obtained according to open-flow capacity; establishing a first computing model among the average fracture permeability, average fracture porosity and anaverage fluid movement index; calibrating the first computing model according to the well test permeability and establishing a second computing model among the fracture permeability, fracture porosityand the fluid movement index; and obtaining the fracture permeability according to the second computing model. According to the computing method provided by the invention, the fracture permeability and fracture effectiveness can be evaluated relatively accurately, so a fracture permeability computing result achieves well test precision.

Description

technical field [0001] The invention relates to a calculation method for fracture permeability, which belongs to the technical field of well logging evaluation of oil and gas reservoirs in petroleum exploration. Background technique [0002] Reservoir permeability is a measure of the ability of fluid to pass through the effective pores of porous rock under pressure difference. Accurate calculation of reservoir permeability is an important task for reservoir evaluation. The matrix porosity and permeability of low-porosity and low-permeability fractured sandstone gas reservoirs are very low. Fractures are the main seepage channels of reservoirs. Accurate evaluation of fracture seepage capacity is an important task of reservoir evaluation and guides gas reservoir development and measures. [0003] The calculation of fracture permeability has always been a difficult point in the field of reservoir evaluation. According to fractured reservoir engineering, in the case of simplifie...

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Problems solved by technology

The above-mentioned theoretical model of fracture permeability is quite different from the actual formation test conditions. Without well test calibration, it can only be used to estimate the seepage capacity of fractures, and cannot quantitatively calculate fracture permeability. It cannot be used for low porosity and low permeability fractured sandstone gas Accurately evaluate the seepage capacity of reservoir fractures

[0006] On the other hand, the fracture permeability can be qualitatively analyzed by combining the Stoneley wave fluid movement index with the waveform and reflection coefficient of the full dipole acoustic wave. Electrical imaging logging can accurately identify fractures, but cannot effectively evaluate fracture permeability.

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