A Method for Predicting Brittleness of Tight Oil Reservoirs

Abstract

The invention discloses a method for predicting the brittleness of a compact oil reservoir. The method comprises the following steps: S01, adding an ellipsoidal pore with a fixed aspect ratio to a feldspar mineral; S02, calculating a bulk modulus and a shear modulus of a mixed mineral matrix by combining quartz minerals, carbonate minerals, and pyrite minerals; S03, on the basis of an SCA theory, mixing the feldspar mineral with the mixed mineral matrix based on a proportion to form a siltstone rock skeleton; S04, adding a micro crack into the rock skeleton by using a differential equivalent medium (DEM) model; S05, adding clay minerals into the rock skeleton in an inclusion body manner according to different mineral aspect ratios; and S06, calculating a speed, a Young's modulus, a Poisson's ratio and a brittleness index of the rock. According to the disclosed method, for the compact oil reservoir with low porosity, low permeability and internal complex structure, a brittle rock physics model is constructed by combining the SCA with the DEM model, so that the internal structure of the compact oil siltstone reservoir is described well.

Description

technical field [0001] The invention relates to a method for predicting the brittleness of tight oil reservoirs, belonging to the technical field of petrophysical modeling. Background technique [0002] Tight oil is another new hotspot in the field of exploration and development of unconventional oil and gas reservoirs after shale gas. Tight oil is widely distributed in my country and has great potential. Due to the tightness and complex lithology of reservoirs, fracturing is required to obtain industrial production capacity. The success of fracturing is closely related to the brittleness of the rock mass. The higher the degree of brittleness, the more favorable it is to generate a large number of fracturing fractures and keep them open for a long time. Therefore, accurate prediction of reservoir brittleness is of great significance for tight oil production, but the current research on brittle earthquake prediction still needs to be further developed. [0003] Scholars at ...

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Problems solved by technology

Therefore, accurate prediction of reservoir brittleness is of great significance for tight oil production, but the current research on brittle earthquake prediction still needs further development.

[0003] Scholars at home and abroad have done a lot of research on brittleness and made some progress, but there are still disputes about the accurate definition and prediction of brittleness.

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