Method for evaluating microstructure of compact reservoir rock

Abstract

The invention discloses a method for evaluating the microstructure of a compact reservoir rock. The method comprises the following steps: soaking a compact reservoir rock sample in a liquid in a self-absorption testing device, wherein only one surface of the sample contacts the liquid; weighing the sample in real time; calculating the volume of the liquid absorbed by the sample according to the initial sample weight, the weighed weight, and liquid density; according to a preset formula, drawing a curve representing the relationship between the volume of the absorbed liquid and the change of the preset values, stopping the self-absorption test, when the expansion section of the curve becomes linear; according to the shape of the curve to determine the absorption time index and diffusion time index, and evaluating the microstructure of the compact reservoir rock sample according to the self-absorption time index and the diffusion time index. The shortage that in the conventional methods, the self-absorption curve is difficult to recognize, is overcome; and the method can be used to carry out quantitative evaluation and research on matrix diffusion effect of compact reservoir rock and clay minerals.

Description

Technical field [0001] The invention relates to the technical field of oil and gas exploration, in particular to a method for evaluating the microstructure of tight reservoir rocks. Background technique [0002] With the rapid development of the world's oil and gas industry, the reserves of conventional oil and gas resources are gradually decreasing, and unconventional oil and gas shale gas as a replacement energy source has become a hot spot for global oil and gas exploration and development. The porosity and permeability of unconventional tight reservoirs are extremely low. At present, there is still a lack of systematic understanding of the microstructure of unconventional tight reservoirs and the mechanism of fluid microscopic seepage. Conventional pressure displacement experiments cannot meet research requirements. The pore thickness of this type of reservoir is generally at the micro-nano level, and the self-absorption caused by capillary force is enhanced. Self-absorption ...

AI Technical Summary

Problems solved by technology

[0013] The present invention provides a method for evaluating the microstructure of tight reservoir rocks, at least to solve the problems in the prior art that the characteristics of self-absorption curves of different tight reservoir rocks are very similar, the identification error is high, and it is difficult to form an intuitive understanding.

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