Method for detecting channeling condition by static gelatinization strength of cement

Abstract

The invention provides a method for detecting a channeling condition by the static gelatinization strength of cement, which comprises the following steps of: (1) acquiring a channeling detecting point and channeling detecting pressure delta P according to a channeling detecting well and cement slurry parameters; (2) preparing cement slurry according to the American Petroleum Institute (API) standards; (3) putting the cement slurry into a sealing container and stirring; (4) measuring the static gelatinization strength of the cement slurry continuously; (5) stopping stirring the cement slurry; (6) releasing the pressure at one end of the cement slurry in the sealing container, and inputting pressure gas or water or oil to the other end of the cement slurry; (7) judging the channeling condition of the cement slurry under the condition of the channeling detecting well according to the gassing condition of the other end of the cement slurry; and (8) increasing differential pressure slowly until the cement slurry is channeled, and recording the maximum channeling preventing capacity. In the method, downhole environment is simulated by adopting the sealing container, so it is convenient to ventilate, pressurize and measure the pressure of the cement slurry filled in the sealing container, the downhole temperature, pressure and flow conditions can be simulated completely, and it is convenient to determine the channeling condition of the cement slurry by observing the gassing condition.

Description

technical field [0001] The invention relates to a method for measuring the static gel strength of cement. Background technique [0002] Cementing has two main purposes: the annular cement has sufficient strength to support the casing and isolate the formation. At present, API (American Petroleum Institute) standard cement slurry "thickening test, water loss test, compressive strength test and rheological test" and other evaluation methods can be designed to safely pump the surface cement slurry to the predetermined location underground, and can Ensure that there is sufficient strength to support the casing after the specified waiting time, but there is no industry test standard to judge whether the cement slurry used has sufficient ability to prevent interlayer passage. [0003] At present, the gas / liquid channeling performance is mostly measured by the "gas channeling sensitivity analyzer" and other cement slurry gas channeling ability evaluation instruments. Although the...

AI Technical Summary

Problems solved by technology

Although these instruments can simulate the downhole temperature, the simulated downhole pressure is low, and cannot simulate the change process of the flow state, and cannot truly reflect the hydration degree of the downhole cement slurry at the corresponding time, resulting in the measured anti-channeling ability results differing from the real data. There is a large gap, and the repeatability is poor, so it can only be used for relative comparison, and cannot be used to judge whether the cement slurry is channeled under a given downhole condition

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