Experimental device and experimental method for simulating the corrosion process of cement sheath in formation

Abstract

The invention relates to an experimental apparatus and an experimental method for simulating the corrosion process of a cement sheath in strata. The experimental apparatus comprises a sealing cover, areaction vessel, a first constant flow constant pressure pump, a second constant flow constant pressure pump and an experimental specimen, wherein the experimental specimen is formed by sleeving thecement sheath outside a casing pipe; a spiral sieve tube coils in an annular space between the cement sheath and the reaction vessel; a cylindrical positioning bump is arranged at the center of the inner end face of the sealing cover; a water inlet hole, a water overflowing hole and a valve hole are formed in the sealing cover; the water inlet hole is connected with the first constant flow constant pressure pump by a high-pressure flow guiding wire; a pressure controlling valve is arranged at the valve hole; a liquid inlet hole is formed in the bottom of the reaction vessel; a one-way valve isarranged inside the liquid inlet hole; the liquid inlet hole is connected with the second constant flow constant pressure pump through the high-pressure flow guiding wire; the upper end of the spiralsieve tube is closed; the lower end of the spiral sieve tube is opened and is connected with the liquid inlet hole; a plurality of liquid dispensing holes are uniformly distributed in the spiral sieve tube. The experimental apparatus and the experimental method disclosed by the invention can ensure that all ion concentrations of water in strata cannot attenuate along with the operation of an experiment in the corrosion experiment process.

Description

technical field [0001] The invention relates to a cementing sheath corrosion experiment technology in the fields of chemical corrosion, petroleum engineering, etc., and in particular relates to an experimental device and an experimental method for simulating the corrosion process of the cementing sheath in formations. Background technique [0002] The cement sheath plays a vital role in the production of oil and gas wells, and its main purpose is to protect the production casing string and seal adjacent oil, gas and water layers. After the cement is set, it will form a hydraulic isolation system in the longitudinal direction of the entire well. This system must be able to achieve effective interlayer isolation during the entire life of the oil and gas well and after it is scrapped. In recent years, with the development of oil and gas well engineering, the direction of exploration and development tends to be deeper and more complex, which is more likely to cause cement sheath...

AI Technical Summary

Problems solved by technology

[0005] At present, some cement sheath corrosion test devices have the following shortcomings: first, it is impossible to determine the corrosion of the cement sheath cemented surface of the casing, and second, due to the closure of the corrosion experiment space, the concentration of various ions in the formation water decays with time, making the experiment The results obtained are not convincing

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