Experiment method for evaluating shale fracturing crack mesh forming capability

Abstract

The invention provides an experiment method for evaluating the shale fracturing crack mesh forming capability. The method comprises the following steps that: (a) a section of sleeve ring is intercepted from an oil field standard sleeve, and a shale core is selected and is processed into a cylinder test piece; (b) the shale core is placed into the sleeve ring, and an annular space formed by the shale core and the sleeve ring is filled with cement slurry; a hole is drilled in the center part of the shale core after the cement is hardened; and soundless breaking agent slurry is added into the drill hole; (c) the fractal dimension of the crack structure surface trace length distribution, the surface density and the crack number are used for carrying out quantitative characterization on the crack form of the pressed shale core surface, and the size and the number of breaking fragments are evaluated; and (d) a cement ring is dismounted, the crack number inside the pressed shale core, the bulk density and the size and the number of the fragments are obtained. The experiment method integrally reflects the brittleness of the shale and the natural crack system (and deposition stratification) characteristics, and is used for judging the crack mesh forming capability of the pressed shale; visualized effects and reliability are realized; in addition, the operation is simple; and the experiment method is suitable to be applied in an oil field site.

Description

technical field [0001] The invention relates to a shale gas reservoir volume fracturing stimulation technology, in particular to an experimental method for evaluating the ability of shale fracturing to form a fracture network. The invention can provide technical support for the compressibility evaluation of shale reservoirs. Background technique [0002] Through the survey and detection of the geochemical characteristics of shale reservoirs, after the block is determined to be a high-quality shale reservoir, it is necessary to evaluate its development effect, that is, "compressibility evaluation". Unlike conventional sandstone and carbonate reservoirs, the "fracability evaluation" of shale reservoirs does not refer to whether they are suitable for fracturing, but to evaluate the difficulty of hydraulic fracture network formation under the premise that fracturing must be implemented To demonstrate whether "volume fracturing" can be effectively carried out, there is no unifie...

AI Technical Summary

Problems solved by technology

Although the indoor physical simulation using a large-scale true triaxial experimental system is true and reliable, it requires a large-scale standard outcrop core, and the experimental process is complicated, so simple and convenient on-site detection and evaluation are not used

Images