A method for modeling natural fractures in tight sandstone reservoirs

Abstract

The invention relates to a modeling method for natural fractures in a compact sandstone reservoir. The modeling method comprises the following steps: 1) identifying single-well fractures and internal structures of fault fracture zones; 2) based on sedimentary facies control and fracture seismic interpretation, and adopting a modeling method combining determinacy and multiple randomness algorithms to establish a geologic model under the lithofacies-construction coupling matrix geologic model; 3) establishing a three-dimensional non-uniform rock mechanical model by adopting a trend modeling method combining sequential indication simulation with a vertical probability body under the constraint of the lithofacies-construction coupling matrix geologic model; 4) performing finite element numerical simulation on the three-dimensional non-uniform rock mechanical model to obtain a three-dimensional space stress field model; 5) establishing a crack model by adopting a discrete crack network modeling method by establishing a relationship between the stress field and the crack parameters. The method can accurately describe the underground space distribution of the natural cracks well, and can be widely applied to the field of unconventional reservoir crack modeling.

Description

technical field [0001] The invention relates to the field of characterization and modeling of unconventional reservoirs, and is a modeling method for natural fractures in tight sandstone reservoirs. Background technique [0002] In tight sandstone reservoirs, the pore-throat radius is small and the pore space is limited, so natural fractures become channels and places for oil and gas migration and storage in such unconventional reservoirs. Therefore, clarifying the spatial distribution of natural fractures in underground reservoirs is the core content. Modeling natural fractures is the most three-dimensional and intuitive means to display the spatial distribution of natural fractures. Model. Natural fracture modeling has always been a difficult problem in the world. Up to now, the identification and modeling of underground natural fractures through geophysical means is the most direct method. However, due to the multi-scale problem of fractures, modeling from geophysical m...

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Problems solved by technology

[0004] In the traditional continuous attribute modeling process, it is often based on the sequential Gaussian simulation algorithm under the control of sedimentary facies, which has the problems of excessive control range of facies boundary conditions and low vertical resolution

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