Experimental evaluation method suitable for coal-bed fracturing fluid flow filtration

Abstract

The invention relates to an experimental evaluation method suitable for coal-bed fracturing fluid flow filtration. The method comprises the following steps of: loading effective stress corresponding to burial depth to a core holder connected with a fracturing fluid cavity; stirring the fracturing fluid in the fluid cavity to allow the fracturing fluid to flow through the front end face of a core at a certain flow speed; pressurizing the fluid cavity by using a constant pressure pump to form a certain pressure difference between the front end and the back end of the core; and measuring the filtration loss and corresponding filtration time of filtrate at the outlet end of the core. A fracturing fluid filtration situation in a coal-bed yield-increasing and modifying process is simulated, and the scientific and effective measurement of the filtration property of the fracturing fluid which does not contain any propping agent under a formation condition is realized.

Description

technical field [0001] The invention belongs to the technical field of coal seam gas development and related experiments, in particular to an experimental evaluation method applicable to coal seam fracturing hydraulic fluid loss. technical background [0002] The leakage of fracturing fluid from fractures to formation is the basic phenomenon of coal seam fracturing. Coal rocks are different from conventional oil reservoir rocks. Coal rocks have a well-developed fracture system. When fracturing fluid is injected into the coal seam, because the pressure of the injected fluid is much higher than that of the formation fluid, it is easy to reopen or expand the original natural fractures, which greatly increases the permeability. increase, leading to serious leakage of coal seam fracturing fluid. According to the analysis results of previous fracturing operations, the fracturing fluid efficiency in coal seam construction is generally only 15% to 30%, and the filtration loss is ve...

AI Technical Summary

Problems solved by technology

[0003] The dynamic fluid loss evaluation method of fracturing fluid in conventional oil reservoir rocks is mainly to pump the fracturing fluid into the rock and adjust the back pressure so that the fracturing fluid flows through the core at a certain fluid loss pressure difference and a certain shear rate. The main defects of this method are: (1) The pressure difference between the two ends of the core is mainly adjusted by the pump, so that the pressure difference between the two ends of the core is maintained inside and outside the formation fractures Therefore, the requirements for the pump are relatively high. When the pressure at the inlet end of the core is too high, it may easily cause damage to the pump; Deviated