Numerical simulation and parameter optimization method of volume fracturing in unconventional dual-media reservoirs

Abstract

The invention discloses an unconventional dual-media reservoir volume fracturing numerical simulation and parameter optimization method, the steps are as follows: based on the dual-media poroelasticity theory, considering the friction effect between fractures, developing hydraulic fracture viscoelasticity based on explicit time integration Plastic damage model; using the method of embedding zero-thickness fracture units in the internal boundary of the calculation model grid to simulate the random intersection and bifurcation of hydraulic fractures meeting natural fractures, and establishing a mathematical model for the expansion of hydraulic fractures in volume fracturing of unconventional dual-media reservoirs; The finite element program for volume fracturing of unconventional reservoirs is complex multi-fracture rupture and competitive expansion, and the hydraulic fracturing finite element model of casing containing natural fractures-cement sheath-perforation holes in clusters-reservoir matrix is ​​established; Research on the law of initiation and propagation of complex fractures in the well zone, carry out research on the law of synchronous propagation of multi-cluster hydraulic main fractures in stages, and optimize the construction technology of volume fracturing. The invention has comprehensive simulation factors and optimizes the oil and gas exploitation construction scheme.

Description

technical field [0001] The invention relates to the technical field of oil and natural gas development, in particular to a method for numerical simulation and parameter optimization of unconventional dual-media reservoir volume fracturing. Background technique [0002] For a long time, the contradiction between energy supply and demand in my country has been prominent, and the dependence on foreign oil and natural gas has been increasing year by year. In 2017, my country's dependence on foreign oil reached 67.4%, and natural gas reached 39.4%, which greatly exceeded the internationally recognized warning line and seriously threatened my country's energy security. According to a global survey conducted by the U.S. Energy Information Administration (EIA), my country's shale gas reserves are 36.1 trillion cubic meters, ranking first in the world. As a typical unconventional natural gas resource, my country's shale gas resources have great development potential. my country's sh...

AI Technical Summary

Problems solved by technology

However, these studies all assume that after multi-cluster perforation fracturing, a main fracture is formed at each perforation cluster, and the main fractures of each perforation cluster expand together. field and fracture morphology, few scholars have studied the expansion, propagation, intersection and bifurcation behavior of multiple fractures initiated from perforation holes in the perforation cluster in the near-wellbore zone

At the same time, unconventional dual-media reservoirs usually contain a large number of natural fractures, which are typical dual-media systems. However, in existing hydraulic fracture propagation models, unconventional dual-media reservoirs are generally treated as conventional single-media or even impermeable media. , which will affect the calculation accuracy of the fluid pressure distribution near the main fracture during the fracturing process, and then affect the fracture initiation and propagation behavior of the unconnected natural fractures after the hydraulic fracture meets the natural fracture and around the main fracture

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