A coal reservoir fracturing fluid stagnation self-absorption detection device and method

Abstract

The invention relates to a coal reservoir fracturing fluid retention self-priming detection device and method and belongs to the field of coalbed methane development and geology. The device includes aframe rack, a true triaxial loading system, a fluid injection system, a neutron imaging system and a data acquisition and processing system. A fracturing test piece is prepared; the elastic forces ofdifferent series of strong springs are measured; it is ensured that the magnitudes of the elastic forces of the strong springs in the left-right direction, up-down direction and front-rear directionare consistent; the prepared standard fracturing test piece is arranged in an assembled cube II, a fracturing fluid is made to enter the standard fracturing test piece in the assembled cube II from asteel injection tube through a fluid conduit from a fracturing fluid storage device; after the standard fracturing test piece is injected with the fracturing fluid, the retention self-priming behaviorof the fracturing fluid in the coal sample is monitored in real time, the fracturing capacity of the fracturing fluid and the damage degree of the standard fracturing test piece are detected, fracturing fluids of different formulas are replaced, so that the response characteristics and sensitivity of a coal reservoir to different fracturing fluids can be identified, and therefore, the formula ofthe fracturing fluid can be optimized. The device and method of the invention have the advantages of simple structure and good detection effect.

Description

technical field [0001] The invention relates to a coal reservoir fracturing fluid retention self-absorption detection device and method, in particular to a coal reservoir fracturing fluid retention self-absorption detection device and method used in the geological field of coal bed methane development. Background technique [0002] my country is rich in coalbed methane resources, among which the geological resources with a buried depth of <2000m are 36.81 trillion cubic meters. Coal bed methane mainly occurs in the coal seam in an adsorbed state. The coal seam is not only the gas source rock of coal bed methane, but also its main reservoir, and the coal rock pore and fracture system is its main storage space. There is a critical desorption pressure in the coalbed methane mining process. When the coalbed pressure is higher than the desorption pressure, the coalbed methane is in an adsorbed state. Therefore, the production of coalbed methane needs to go through the process ...

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Problems solved by technology

[0007] The above-mentioned invention patents have many limitations: First, they are all experiments or methods under non-true triaxial loading conditions, which are significantly different from the real formation state under the actual current in-situ stress field, and cannot accurately approximate the actual fracturing conditions ; Two, after fracturing, the fracture system in the rock develops, and the retention and self-absorption behavior of the fracturing fluid in the rock must be different from that of the intact rock before fracturing, so it cannot accurately approximate the actual rock property state after fracturing

Therefore, the reliability of the above findings is low

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