Sectional combined type water pressure cracking stress measuring filter

Abstract

The invention relates to the technical field of measuring of ground stress, in particular to a sectional combined type water pressure cracking stress measuring filter. The sectional combined type water pressure cracking stress measuring filter comprises a hollow pipe column, a first filter and a second filter, wherein the first filter and the second filter are respectively of a hollow column body structure; the second filter is sheathed at the outer side of the first filter; one end of the first filter is connected with one end of the hollow pipe column. The sectional combined type water pressure cracking stress measuring filter has the advantages that after simple assembly, the graded filtering can be performed, so that the iron rust is prevented from entering a push-pull switch, and the testing can be smoothly performed; the blockage of filter holes by chemical grease is avoided, the liquid is guaranteed to normally enter the push-pull switch, and the testing can be smoothly performed.

Description

technical field [0001] The invention relates to the technical field of geostress measurement, in particular to a segmented combined hydraulic fracturing stress measurement filter. Background technique [0002] In-situ stress is the initial stress existing in the crustal rock mass, and it is also one of the important physical property parameters of the solid earth. In-situ stress is the root force that causes deformation, instability and failure of rock mass. Therefore, the measurement of in-situ stress has important scientific significance in the study of earthquake mechanism, mine tunnel design, and large-scale dam foundation construction. [0003] The most important method for measuring ground stress is hydraulic fracturing. Hydraulic fracturing is a method of determining the magnitude and direction of in-situ stress by isolating a section of open rock hole in the drill hole, injecting high-pressure liquid into the isolated section, and causing the rock mass in the fractu...

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Problems solved by technology

[0007]1) Due to the corrosiveness of the drilling fluid, a large amount of rust peels off the inner wall of the drill pipe. Breaking or splitting the fluorinated high-pressure resistant sealing ring, resulting in test failure;

[0008]2) Some water sources contain chemical substances such as butter, saponification (oil) liquid, etc. These oils will absorb various impurities in the water, gather into groups, and then block and adhere On the outside of the filter tube, the small hole is completely blocked, so that the liquid cannot enter the push-pull switch, resulting in measurement failure;

[0009] 3) During the measurement process, the backwater of the fracturing section has a certain pressure. When this high-pressure water flow passes through the filter tube and returns to the drill pipe, it will raise the mud accumulated at the bottom of the annular space between the filter tube and the drill pipe. Sand and other impurities, suspended impurities may re-enter and block the push-pull switch, causing secondary damage

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