Research and Application of Ultra-High Pressure Intelligent Well Control Technology for Ultra-Deep Carbonate Rocks

Abstract The exploration and development of the Tarim Oilfield is vigorously advancing into ultra-deep layers. Since 2021, more than 200 deep wells of the 8000m class have been completed. Ultra-deep drilling has brought about risk challenges such as ultra-high pressure, ultra-high temperature, and high hydrogen sulfide content. At present, the maximum formation pressure tested in the Tarim Oilfield is 182 MPa, and the maximum hydrogen sulfide content in the formation reaches 41×104 ppm. Therefore, the ultra-high pressure intelligent well control disposal technology for ultra-deep carbonate rocks and supporting equipment have been developed. Tarim Oilfield has taken various technical measures to solve the risk of ultra-high pressure well control. Firstly, in terms of engineering design, Tarim Oilfield has formed an integrated risk intelligent identification technology for "five specials" (special surface, special lithology, special geological phenomenon, special fluid, special temperature and pressure field), and adopted a comprehensive prediction technology for "five pressures" (pore pressure, collapse pressure, loss pressure, closure pressure and fracture pressure) to predict formation pressure intelligently. Secondly, in terms of well control technology, the application of controlled pressure drilling, DROC and other technologies has successfully ensured the safe drilling of ultra-high pressure Wells in this block. Finally, supporting equipment for ultra-high pressure intelligent well control has been developed, and a remote management and control support center for oilfield drilling and completion has been established, enabling capabilities such as real-time monitoring, abnormal alarm, emergency response, and remote command, thus achieving intrinsic safety in well control. Well control disposal technology and ultra-high pressure intelligent well control supporting equipment technology have been successfully applied in 51 ultra-deep Wells in the Tarim Oilfield. A series of equipment has been developed, including 175MPa ultra-high pressure blowout preventer stacks, 175MPa casing heads, 175MPa electric choke/kill manifolds and control systems, and 175MPa Christmas tree. In addition, a risk assessment technology for an ultra-high pressure well control equipment, a full life cycle management system for well control equipment, a one-click automatic alarm for overflow, a one-click shear well shutdown, and a one-click well shutdown pressure relief and blowout ignition system have been established. It has successfully handled complex accidents of high casing pressure and overflow in 17 wells, with the maximum shut-in pressure reaching 47.57MPa and the maximum overflow disposal pressure reaching 64.4MPa. These efforts have ensured well control safety in the block and achieved high oil production. The promotion and application of the ultra-deep and ultra-high pressure intelligent well control risk disposal technology and supporting equipment in the Tarim Oilfield have provided excellent engineering cases and experiences for the development of ultra-high pressure intelligent well control. This paper also discusses the development trend of intelligent well control treatment technology under extreme working conditions.