Oil/gas well cement sheath sealing integrity testing device and method for carrying out evaluation through device

Abstract

The invention relates to an oil / gas well cement sheath sealing integrity testing device. The testing device comprises a pressure kettle and a simulation wellbore located in the pressure kettle. The testing device further comprises a pressure control system, a temperature control system, a fluid channeling detection system, a strain measuring system and a mud cake simulation system. The simulation wellbore comprises a casing pipe and a core located on the periphery of the casing pipe. An annular gap is formed between the sleeve and the core, and a cement sheath is formed in the annular gap. The upper ends and the lower ends of the casing pipe and the core are provided with an upper end cover and a lower end cover respectively. The temperature borne by the cement sheath under different downhole working conditions and complex loads from the casing pipe and a stratum can be truly simulated, and the process range covers well cementation at the oil / gas well drilling and completion stage and pressure tests, producing tests, circulating injection production, fracturing and other improvement working conditions in the production process. The influence rule of the cement sheath sealing integrity can be evaluated by changing the thickness of the cement sheath, the character of mud cakes, the maintenance temperature and other factors.

Description

Technical field [0001] The invention belongs to the field of oil and gas resource development, and specifically relates to a device and an evaluation method that can simulate the casing and stratum complex loads borne by a cement ring under downhole working conditions, and test the sealing integrity of the cement ring. Background technique [0002] In all stages of the life cycle of an oil and gas well, the control of the fluid in the wellbore and formation is the primary task. If the fluid flows uncontrollably, the oil and gas wells will not have physical and functional integrity, which may lead to serious and even catastrophic consequences. As an important part of the wellbore of oil and gas wells, the main function of the cement ring is to prevent the flow of formation fluids in the process of drilling, production and reconstruction, and to effectively fix and support the casing. In recent years, with the in-depth development of the exploration and development process, most o...

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Problems solved by technology

[0004] Chinese patent CN 104153760 A oil and gas well cement sheath sealing characteristics simulation testing device and experimental method discloses a kind of oil and gas well cement sheath sealing characteristics simulation testing device, including kettle body, upper kettle cover, lower kettle cover, heating jacket, booster pump, Pressure relief pumps, liquid volume and gas volume recorders, and multiple pipelines are connected to control and test confining pressure, pressure relief, and casing pressure. However, from the actual operation of this research group, the sealing performance of this device is not enough Well, the main reason is that the connection structure between the pressure plate and the upper kettle cover used with different sizes of casing cannot bear too much pressure difference, so the predetermined goal can only be achieved to a certain extent

Furthermore, this device can only realize the measurement of the influence of cement sheath loading and cement sheath sealing characteristics, while the actual downhole cement sheath needs to bear multiple pressures, and only by loading the cement sheath to measure the characteristics of the cement sheath sealing cannot meet the needs of comprehensive measurement

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