Liquid CO2 logging spacer fluid presetting process

Abstract

The invention relates to a liquid CO2 logging spacer fluid presetting process. The problem that in existing liquid CO2 logging, ice blockage is formed in a wellhead and a blowout prevention pipe, so that a logging instrument cannot descend into a well, and logging fails is mainly solved. The presetting process is characterized by comprising the following steps that S1, pressure data in a well aredetermined before a liquid CO2 gas well is tested, and construction preparation work is made; S2, after a logging instrument is placed in a blowout prevention pipe, the blowout prevention pipe is slowly filled with spacer fluid, after the spacer fluid flows out of an emptying pipeline of high-pressure equipment, an emptying valve is closed, slow pressurization continues to be conducted through a high-pressure grease injection pump, and after it is observed that it is determined that the pressure balance between preset fluid and liquid CO2 fluid in the well is achieved, spacer fluid presettingsucceeds preliminarily; and S3, a test valve is slowly opened, the pressure change condition is observed while the test valve is opened, after the test valve is completely opened, the logging instrument slowly descends into the well to successfully preset the spacer fluid. According to the preset process, the labor intensity is reduced, the logging efficiency and safety are improved, and the logging instrument can smoothly descend into the well.

Description

technical field [0001] The invention relates to the technical field of unconventional oil and gas exploration in oil fields, in particular to a liquid CO 2 Well logging spacer fluid preset process. Background technique [0002] CO 2 It is a gas with high solubility in both oil and water. When it dissolves in a large amount in crude oil, it can expand the volume of crude oil, decrease its viscosity, and reduce the interfacial tension between oil and water; CO 2 The carbonic acid formed after dissolving in water can also play an acidifying role. It is not affected by conditions such as well depth, temperature, pressure, formation water salinity, etc. Due to the above effects and wide application conditions, CO injection 2 The range of applications for enhanced oil recovery is vast. Through a large number of indoor experiments and field experiments, it has been proved that CO 2 Is an effective oil repellant. [0003] CO 2 The special physical properties of carbon dioxide...

AI Technical Summary

Problems solved by technology

[0005] The present invention is to overcome the existing existing use of liquid CO in the background technology 2 The problem of well logging failure due to the formation of ice blockage in the wellhead and the blowout preventer that the logging instrument cannot go down the well, and a perfect liquid CO 2 Well Logging Spacer Fluid Preset Technology

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