Project Full Name：The Key Technologies and Applications of Well Cementing in Ultra-Deep Wells for Oil Exploration and Development

Company：

Tarim Oilfield Branch of CNPC,Tazhong Operating Area

Yangtze University

Awarded：Exploration & Production Technology

Standard:  International  Advanced Level

Project Number：ECF-2024-SEP-1014

Principal Accomplishers：  Chen Jun, Li Zehan, Zhu Guangyou,Duan Yongxian, Han Jianfa, Hong Yinglin, Li Liang 

Key Innovation Points：

Ultra-deep oil and gas exploration faces challenges due to complex formations and high well cementing requirements, This achievement, based on geological research, integrates innovations incement slurry systems, cementing processes, and tools. Two cement slurry systems were developed:one is a high-temperature, high-salt-resistant, self-healing anti-gas migration slurry for bottom holetemperatures of 130-250°C,with densities from 1.88-2.50 g/em'(up to 2.65 g/em', depths of9,888m);the otherisan ultra-low-density system(1.20-1.30 g/em')for long open-hole,high-temperature differential cementing(upto 7,000m open hole,100°C difference). Twocementing methods were created: modular cementing based on “*cement return height" and a cementplug method controlling the artificial bottom hole, along with matching ultra-deep well tools fromthe wellhead to the bottom.

Main Application and Technical Principal： 

Ultra-deep well cementing technology refers to the process of using cement slurry to seal the casingand borchole during deep well completion, blocking casing, oil, gas, and water layers in preparationfor subsequent drilling, testing, and production. This technology developed a system to reduceannular friction and fluid column pressure, along with a high-temperature, salt-resistant, self-healinganti-gas migration cement surry and supporting tools,it addresses global challenges such ascomplex formations, high temperatures, leakage-prone layers, and long open holes with largetemperature difierences, achieving effcctive cementing, preventing leaks, and enhancing welllongevity, thus significantly improving exploration and development eficiency in ultra-deep wells.

Technology Application： 

This achievement has been fully popularized and applied in Tarim Oilfield since 2016, and the cumulative application reached more than 1000 wells in 2022-2024, creating a number of well records such as the highest cementing temperature of 188℃, the maximum well depth of 9888m, the highest cement slurry density of 2.65g/cm', the maximum oil-water interlayer pressure difference of 22.5MPa, and the longest bare borehole length of 7133m and many other well records.

The high-temperature and long-term strength stabilization technology of cement stone and the long-term sealing control technology of cement ring formed by this technology have been widely applied in Xinjiang oilfield, Qinghai oilfield, Southwest oil and gas field, etc.; the high-efficiency jacking technology of complex oil-water relationship formed in Dagang oilfield and Daqing oilfield has been well utilized; the high-temperature cement slurry admixture system and the technology of self-healing cement slurry when encountered with gas have been recognized for their effects of application in Bohai Bay and South China Sea, with broad prospects for their application. The prospect of application is broad.