Project Title: Key Technologies of Drilling and Completion Fluids for Unconventional Natural Gas and Its Industrial Application

Participating Enterprises: Drilling & Production Engineering Technology Research Institute, CNPC Chuanqing Drilling Engineering Co., Ltd.
CCDC Drilling Fluids Service Company
CCDC Changqing General Drilling Company

Award Received: Scientific and Technological Progress Award

Project Number: ECF-2026-SYE-1026

Main Participants: Wang Lan, Ming Xiansen, Luo Yufeng, He Hai, Jing Minjia, Ai Jiawei, Yang Ye, Shu Xiaobo, Wu Gang, Li Wei, Jing Yujuan, Tang Wenyue, Wang Guoshuai, Hai Bo, Wang Zeyu

Expert Review Comments:

Unconventional gas drilling fluids must balance wellbore stability, long-lateral friction control and formation protection. This achievement develops coordinated sealing and lubrication, oil- and water-based anti-collapse systems, and low-damage formation-protection methods tailored to different reservoir conditions. Industrial application in 1,542 well operations during 2022–2025 demonstrates the translation of materials and fluid systems into field services. The technology is relevant to demanding shale gas operations in Sichuan–Chongqing and tight gas operations in the Ordos Basin. Its practical contribution is better matching fluid performance to operating needs, supporting fewer downhole complications, more efficient long-lateral operations and reduced formation damage.

Main Innovations:

Targeting wellbore instability, water lock damage and high friction in Sichuan-Chongqing shale gas and Ordos tight gas wells, three innovative technologies are developed: integrated plugging-lubrication fluid for 3210m-long horizontal shale wells with ≥95% oil-base plugging rate and 95% friction reduction; dual oil/water anti-collapse tight gas systems lifting rock recovery above 90%, cutting hole enlargement from 20% to 8% and shortening drilling cycles by 17–19 days; low-damage recyclable fluids with >95% recycling rate, <25% formation damage and 20% higher single-well gas output. The project owns 29 patents and generated 1.154 billion RMB extra profits from 2022 to 2025.

Main Uses and Technical Principles:

It applies to drilling and completion of Sichuan-Chongqing shale gas and Ordos tight gas wells, solving high friction, wellbore instability and water lock damage. It guarantees safe operation of deep high-temperature horizontal wells, cuts construction cycle and development cost with low reservoir damage, suitable for wide industrial promotion. Adopt nano self-assembly plugging and metal surface bonding adsorption lubrication to form integrated plugging-lubrication technology for long horizontal shale wells; adopt particle bridging film plugging and polyamine ion exchange inhibition to form dual oil/water anti-collapse fluids for tight gas; adopt ion temporary shielding and wettability adjustment to develop recyclable low-damage reservoir protection fluids.