Method and system for interpreting apparent permeability of low-permeability reservoir in formation

Abstract

The invention discloses a method and a system for interpreting apparent permeability of a low-permeability reservoir in a formation. The method comprises the steps of firstly, determining a curve that the permeability measured value of a test sample changes along with gas pressure, secondly, determining the Knudsen numbers of the test sample under different pressures, converting the curve that the permeability measured value of the test sample changes along with the gas pressure into a curve that the permeability measured value of the test sample changes along with the Knudsen numbers, determining the intrinsic permeability of the test sample, the wall influence parameter of the test sample and the ratio of the slippage distance of the test sample to the molecular average free path by performing least square method data fitting on the curve that the permeability measured value of the test sample changes along with the Knudsen numbers, and finally, for determining the apparent permeability of the low-permeability reservoir in the formation, correcting the wall slippage effect by use of the wall influence parameter of the test sample and the ratio of the slippage distance of the test sample to the molecular average free path so as to interpret the apparent permeability of the low-permeability reservoir in the formation more accurately.

Description

technical field [0001] The invention belongs to the technical field of reservoir development, and in particular relates to an interpretation method and system for apparent permeability of low-permeability reservoirs in formations. Background technique [0002] At present, one of the important methods for understanding and modeling oil and gas reservoirs in low-permeability reservoirs (such as tight core or shale) in the formation is to conduct core testing, and core permeability testing is to understand the flow capacity of the reservoir. , and the most basic and most important analysis and testing means for reservoir evaluation. [0003] According to the different fluids used, the permeability test methods can be divided into liquid permeability test and gas permeability test. At present, gas permeability measurement is mostly used for low permeability reservoirs. The testing principle of permeability is usually based on Darcy's law, that is, the flow rate of porous media ...

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Problems solved by technology

[0005] However, the applicant found that the accuracy of the apparent permeability of low-permeability reservoirs determined based on existing methods is low, which will have adverse effects on subsequent reservoir evaluation and development

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