A method for judging the failure cause of plugging zone of fractured reservoir leakage plugging material

Abstract

The invention discloses a method for judging failure reasons of a blocking belt of a crack type reservoir blocking material. The method comprises the following steps: dividing a crack type reservoir blocking material into two parts, and carrying out primary friction coefficient testing by using one part; stirring the other part of the crack type reservoir blocking material with a drilling fluid ata high temperature, carrying out crack blocking testing, collecting a blocking material inside a crack rock sample before instability of a blocking belt, confirming a variation curve of friction coefficients of the blocking material along with time, and judging the instability reasons of the blocking belt of the blocking material according to static friction sectional times and sliding friction coefficients. High-temperature aging of the blocking material is taken into account, and circulation corrosion of the blocking material in a well cylinder is relatively really simulated; on the basis of the structure and the stability of the blocking belt of the blocking material, pressure bearing instability of the blocking belt in actual blocking process is simulated, instability reasons of the blocking belt of the blocking material are accurately judged, important bases are provided for rapidly and effectively solving blocking belt instability problems, and the method also has great significance for reasonable preference of crack type reservoir blocking materials.

Description

technical field [0001] The invention relates to the field of working fluid loss control in the drilling and completion process of the oil and natural gas industry, in particular to a method for judging the instability cause of the plugging zone of a plugging material in a fractured reservoir. Background technique [0002] Fractured oil and gas reservoirs are widely distributed in the world and have huge resources. The developed fractures are the main seepage channels for oil and gas, but the existence of fractures will lead to the loss of drilling fluid. Drilling fluid loss not only loses a large amount of drilling fluid, prolongs the drilling cycle, induces accidents such as well collapse and blowout, but also causes serious reservoir damage, which greatly restricts the efficient development of oil and gas reservoirs. Therefore, the leakage control of fractured reservoirs is particularly important. [0003] The commonly used physical plugging materials for fractured reserv...

AI Technical Summary

Problems solved by technology

The instability of the sealing zone is an important reason for leakage failure and repeated leakage

[0004] However, there is still a lack of effective analysis methods for the instability of the plugging zone at home and abroad, and it is difficult to accurately determine the cause of the instability.

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