An experimental analysis method for the study of compressibility of shale samples

Abstract

An experimental analysis method for studying the compressibility of a shale sample, comprising the following steps: processing the shale sample into a cylindrical plunger, and drilling a hole axially along the axis of the plunger; The plunger sample is placed in the sleeve; the outer edge of the sleeve with the built-in shale plunger sample is coated with silicone grease and put into the autoclave; the fluid is pumped into the autoclave, and the autoclave is heated at the same time and detected by the pressure sensor Pumping pressure; after the shale sample is broken, adjust the temperature of the autoclave until the fluid solidifies, and keep it for a time t1; cut and grind the formed fractured specimen into thin slices, and analyze and observe the fracture morphology characteristics. The present invention simulates the fracturing of shale fluid and maintains the original state after fracturing. With the help of technical means such as microscope, scanning electron microscope and energy spectrum analysis, the shape, direction, quantity and mechanism of fracturing of fluid fracturing are analyzed. Conduct observation and statistical analysis to provide theoretical guidance for shale sample frackability evaluation and fracturing practice.

Description

technical field [0001] The invention is an experimental device and method for evaluating the compressibility of shale applied in the field of geology, in particular an experimental device and method for evaluating the compressibility of mud shale. Background technique [0002] Fracturing is a necessary technical means to obtain high-yield gas flow in shale formations, and the fracability evaluation of shale is an important part of shale gas evaluation research. The frackability of shale refers to the property that shale reservoirs can be effectively fractured to increase production. Shale with different frackability forms different fracture networks during hydraulic fracturing. In order to evaluate the compressibility of shale, many scholars have carried out a lot of research work from different angles. [0003] Some analyze and study the avalanche fragments of shale samples through uniaxial strength experiments, and take the arithmetic average of the brittleness index, str...

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Problems solved by technology

However, from another perspective, there are few reports on the mineral composition of shale and fracture formation after fracturing. The formation and distribution of shale fractures after fracturing, especially the The relationship between brittle minerals (quartz, etc.) has not been clarified. Are cracks formed inside brittle minerals? Or is it easy to form between brittle mineral particles? Or does it develop at the edges of brittle mineral grains? These studies on the mechanism of shale fracture formation need to be deepened in order to better guide the evaluation of shale compressibility and the practice of shale gas development

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