Project Title: Key Technologies and Large-Scale Application of Stuck Pipe Prevention in Multi-Stage Fractured Shale  Horizontal Wells

Participating Enterprises: 

Engineering Technology Research Institute of PetroChina Southwest Oil and Gas Field Company；

Southwest Petroleum University；

Sinopec Southwest Oil and Gas Branch Unconventnional oil and Gas Exploration and Development Management Department；

Sichuan Changning Natural Gas Development Co., Ltd；

Sichuan Shale Gas Exploration and Development Co., Ltd；

Yangtze University

Award Received: Scientific and Technological Progress Award - Gold Award

Achievement Level: International Advanced Level

Project Number: ECF-2025-SET-1018

Main Participants: Wang Xudong, Chen Ye, Hu Xihui, Dai Feng, Liu Wei, Zhang Peiyu, Fan Xiangyu, Zhang Qiangu i, Xia Chengyu, Liu Lu, He Haikang, Liu Houbin, Huang Danchao, Wang Zhiqiang, Wang Qiren

Expert Review Comments:
International advanced level. This project addresses the global technical challenge of collapse and stuck-pipe incidents in horizontal wells targeting fractured-brittle shale formations. It systematically proposes a coordinated anti-sticking theory integrating “inhibiting solid rock sealing, mechanical support for collapse prevention, and efficient purification for sand control.” The project developed multi-level particle stacking and nano-flake sealing technologies, established a high-performance oil-based drilling fluid system for collapse prevention coupled with a wellbore stability evaluation model, and created wellbore cleaning tools, rapid purification techniques, and intelligent early-warning systems. This forms a multidimensional, coordinated safety wellbore technology system for collapse and sticking prevention. These achievements have propelled shale horizontal wells from “impossible to drill” to ‘drillable’ and then to “high-quality drilling.” They have been applied at scale in demonstration zones like Changning-Weiyuan, supporting the establishment of China's largest shale gas production base. This has significantly enhanced drilling success rates and safety, yielding outstanding economic and social benefits. These advancements hold significant demonstrative value for the efficient and safe development of shale gas in China.

Main Innovations:

To address the key technical challenges in the safe well completion of fractured-brittle shale horizontal  wells, this study proposes a collaborative anti-sticking and anti-collapse drilling theory centered on  "inhibition, plugging and rock consolidation, mechanical support for anti-collapse, and efficient  purification for sand control", as well as a multi-level particle stacking and nano-sheet plugging technology  for micro-nano scale fractures. It has also developed a high-performance anti-collapse oil-based drilling  fluid system suitable for fractured-brittle shale formations, a coupled wellbore stability evaluation  technology considering the structure, temperature, mechanics and chemistry of fractured-brittle shale, camtype and spiral-push wellbore cleaning tools, a high-speed "conveyor belt" -type wellbore purification  technology for long horizontal wells, and an intelligent early warning system for stuck pipe. These efforts  have achieved major breakthroughs in the key technologies for anti-collapse and anti-sticking in drilling  operations.

Main Uses and Technical Principles:

Key technical challenges in fractured-brittle shale horizontal wells, such as unclear mechanisms of wellbore  collapse and pipe sticking, poor anti-collapse performance of drilling fluids, inaccurate collapse pressure  prediction, insufficient wellbore cleaning capacity, and high difficulty in early warning of pipe sticking risks,have been resolved. Critical technical bottlenecks in "mechanism, material, process, tool, and system" have  also been overcome. A key technical system for multi-dimensional collaborative anti-collapse and antisticking safe well completion of fractured-brittle shale horizontal wells has been established, enabling the  transformation of such wells from "unable to drill" to "able to drill" and further to "well-drilled". Records  have been set, including a horizontal section length of 3,150 meters and a drilling cycle of 18.83 days, while  downhole complex accidents have been minimized. This has supported the construction of the ChangningWeiyuan Shale Gas National Demonstration Zone with an annual output of 15.95 billion cubic meters—the  largest shale gas production base in China—and contributed to the realization of the national energy strategy  and the "dual carbon" goals.

Technical Applications:

This project has overcome key technical barriers in core theoretical methods, tools, and processes for preventing wellbore collapse and stuck pipe in fractured-brittle shale horizontal wells. It has established proprietary intellectual property rights for high-performance oil-based drilling fluids with strong sealing properties for collapse prevention, stability evaluation technology for fractured-brittle shale horizontal wells, high-speed “conveyor belt”-style wellbore cleaning technology for horizontal wells, and stuck pipe early warning systems. As of October 2024, these technologies have been successfully applied at scale in drilling operations across 800 wells within CNPC's Changning, Zigong, and Luzhou blocks, as well as Sinopec's Yongchuan and Weirong blocks. They effectively address the challenges of rock block detachment and collapse, and stuck pipe in fractured-brittle shale horizontal wells. This has significantly reduced stuck pipe and buried drill pipe rates, ensuring safe and efficient drilling for shale gas horizontal wells. It has strongly supported the production capacity development of the Changning-Weiyuan National Shale Gas Demonstration Zone, achieving a major breakthrough with an annual output reaching 15.95 billion cubic meters. The zone has been developed into China's largest shale gas production base, laying a solid technological foundation for the construction of the “Chongqing-Sichuan 100-billion-cubic-meter natural gas production base.”