True triaxial fracturing simulation device of simulating proppant placement and working method thereof

Abstract

The invention relates to a true triaxial fracturing simulation device for simulating proppant placemen and a working method thereof, and belongs to the technical field of oil and gas field development. The device comprises a fracturing fluid stirring tank, a fracturing pump, a proppant stirring tank, a crack extension simulation component, and an integrated control system which are sequentially connected by a main line. The proppant stirring tank has parallel branch lines. A steering switch is arranged between the fracturing pump and the proppant stirring tank to control the connection and disconnection between the main line and the branch lines of the proppant stirring tank; and a metal-threaded shaft with a certain deformation is installed inside a fracturing simulation rock sample. Theindependent proppant adding device and the steering switch are arranged to improve the shape of the shaft and add a fiber material, the sealing strength between the shaft and the rock sample contact surface is improved, sand adding simulation is achieved during a crack initiation / expansion process, the success rate of true triaxial fracturing laboratory experiments is improved, and the true triaxial fracturing simulation device has important guiding significance for studying the proppant migration law and the optimal design of a fracturing construction scheme.

Description

technical field [0001] The invention relates to a true triaxial fracturing simulation device for simulating proppant laying and a working method thereof, belonging to the technical field of oil and gas field development. Background technique [0002] my country's unconventional oil and gas reservoirs are widely distributed. Due to their characteristics of low porosity and low permeability, the seepage resistance of oil and gas in the reservoir matrix is ​​extremely high. Usually, fracturing stimulation technology is used to achieve economical and effective exploitation of low permeability oil and gas reservoirs. . Hydraulic fracturing is a very complicated stimulation process for oil and gas wells. The ground high-pressure pump group is used to pump fracturing fluid into the well with a displacement exceeding the absorption capacity of the formation, and the high pressure is generated at the bottom of the well. When the pumping pressure overcomes the well wall When the nearb...

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Problems solved by technology

In order to avoid the above problems, laboratories usually reduce the wellbore diameter to 3-10mm (inner diameter 1-8mm) to reduce the cemented interface to improve the sealing between the wellbore and the rock sample, resulting in the wellbore being too thin to simulate pump injection support agent fracturing process

In addition, the pressure range required for rock sample fracturing is 20-80MPa, and the supporting fracturing pump is required to be a high-precision equipment that can provide higher pressure. Because the proppant particles are easy to wear the working blades or pistons of the pump, the service life of the fracturing pump will be reduced. Therefore, it is not suitable for pumping proppant materials (the proppant materials for fracturing are quartz sand or ceramsite particles with a particle size of 0.1-1.5mm)

[0005] At present, due to the problem of the sealing technology between the wellbore and the rock sample and the high-pressure pump is easy to wear, the success rate of the true triaxial fracturing laboratory experiment is low, and it is impossible to realize the fracture initiation / expansion and fracturing sand-carrying process inside the rock sample. Simultaneous simulation of

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