A numerical simulation method for quantitative prediction of proppant embedding and fracture conductivity

Abstract

The invention discloses a proppant embedment and fracture conductivity quantitative forecast-based numerical simulation method. The method comprises the following steps of: S1, establishing a physical model for reducing the real sizes of proppants; S2, applying closing pressure on the surfaces of an upper rock stratum and a lower rock stratum of the model, wherein the difference between average heights of granules on fracture surfaces of the upper rock stratum and the lower rock stratum is a fracture closing width w; S3, carrying out flow field grid dispersion on a filling layer to ensure that a flow field is wrapped by the proppants, setting viscosity and density of a fluid and pressure of the fluid at two ends of the flow field; S4, calculating a total flow q of the flow field; S5, calculating a permeability and a flow conductivity; and S6, changing physical parameters of the rock stratums or the fluid, and drawing a change curve graph indicating that the conductivity of the proppants with different sanding concentrations changes along with closing stress. The method has the beneficial effects of simulating the real processes of fracture closing, proppant embedment and interaction between granules and fluids, so as to effectively forecast the dynamic change of the flow conductivity.

Description

technical field [0001] The invention relates to the field of oil and natural gas development, in particular to a numerical simulation method for proppant embedding and fracture conductivity quantitative prediction. Background technique [0002] During hydraulic fracturing, hydraulic fractures initiate and extend, and proppant enters the reservoir with the fracturing fluid, migrates in large quantities in the main fractures and settles to form a multi-layer proppant paving form. After the hydraulic fracturing is completed, the fracturing fluid flows back to the ground, and the proppant particles are squeezed by the fracture wall and stay in the fracture. The proppant supports the hydraulic fracture, forming a highly permeable channel connecting the reservoir to the wellbore. The conductivity of a propped fracture is the permeability of the proppant pack multiplied by the width of the fracture. [0003] Since the porosity and permeability of the proppant in the fracture are ...

AI Technical Summary

Problems solved by technology

Due to the small size of proppant particles (0.15mm-0.83mm), there is a serious scale mismatch problem compared to formation rocks; the plasticity of rocks, the contact between proppant particles and proppant particles, the proppant and rock It is difficult to use a simple analytical model to describe the complex mechanical problems of highly nonlinear contact between proppant particles and shale.

At the same time, these analytical models usually can only roughly predict the fracture opening and proppant embedding degree, and the calculation of the conductivity still needs the help of Darcy's formula, and cannot consider the dynamic influence of the fluid-solid interaction on the actual conductivity

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