Integrated Technology of Bare Tubing Oil Testing and Fracturing in High-Temperature and High-Pressure Reservoirs

The Qingshuihe Formation in the western section of the southern margin of the Junggar Basin has reservoirs with deep burial depth, high temperature and pressure, and poor matrix physical properties. Factors such as ultra-high formation pressure, ultra-high formation fracture pressure, casing program, strings, and tool structures limit oil testing and fracturing stimulation. Therefore, according to the reservoir characteristics of deep high-pressure oil wells in the western section of the southern margin, a series of technical measures were adopted, such as reducing casing pressure by the displacement of heavy fluid into the annulus, preventing overpressure by the displacement of heavy pad fluid, and controlling pressure by oil-casing double-flow program, so as to form the integrated technology of bare tubing oil testing and fracturing. The technology has the advantages of avoiding the risk of tool failure, effectively detecting casing pressure, and allowing higher safety factors. The integrated technology of bare tubing oil testing and fracturing was applied 5 times in ultra-deep and ultra-high pressure wells in the western section of the southern margin. The success rate for implementing the technology was 100%, and the testing success rate was 100%. Specifically, Well Gaoquan 6 had a daily oil production of 126.81 m³ after fracturing, and the daily gas production was 8300 m³. This technology effectively supports the safe and efficient oil testing and fracturing of deep and ultra-deep wells in the southern margin of the Junggar Basin and provides reference and guidance for the application in similar types of wells.