Hard and brittle shale microfracture manufacturing method and plugging capability testing system

Abstract

The invention relates to the technical field of petroleum exploration and development experimental facilities, in particular to a hard and brittle shale microfracture manufacturing method and a plugging capability testing system. The testing system comprises a stable gas source, a high-temperature and high-pressure dynamic displacement device, a shale sample clamp, an outlet liquid receiving device and a circulating press pump, wherein the stable gas source is connected with the high-temperature and high-pressure dynamic displacement device through a section of high-pressure pipeline, the shale sample clamp is used for clamping a shale sample to be tested and is connected with the high-temperature and high-pressure dynamic displacement device through screw threads, the outlet liquid receiving device is connected with the outlet end of the shale sample clamp through a valve, the circulating press pump is connected with the shale clamp through a high-pressure pipeline, and stable pressure is provided as the pressure of the circulating press pump through the stable gas source. The manufacturing method and the plugging capacity testing system can be used for plugging agent preference selection experiments and drilling liquid plugging capability test experiments, and a reliable testing means is provided for the researches of the well wall stability of a hard and brittle shale stratum.

Description

technical field [0001] The invention relates to the technical field of experimental equipment and methods for petroleum exploration and development, in particular to a method for making micro-cracks in hard and brittle mud shale and a testing system for plugging ability. Background technique [0002] At present, wellbore instability has caused at least about 600 million US dollars of losses to the world oil industry every year, and the time consumed is about 5% to 6% of the total drilling time. According to statistics, mud shale formations account for 70% of the total drilled formations, and more than 90% of the wellbore instability problems occur in the mud shale formations, of which about two-thirds of the wellbore instability problems occur in Hard and brittle shale formations. This is due to the development of micro-fractures in hard and brittle mud shale, which not only hydrates and expands when exposed to water, but also migrates with the fluid, especially after the...

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Problems solved by technology

However, there is a large gap between them and the real environment of hard and brittle mud shale under high temperature and high pressure conditions at the bottom of the well, and the material and fracture surface characteristics are quite different from those of real mud shale, so it is impossible to truly simulate the hard and brittle mud shale under high temperature and high pressure conditions. The changing process of drilling fluid and the sealing process of fractures

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