Project Title: Cleaning Technology of Drilling Barrel in Shale Oil Horizontal well

Participating Enterprise: CNPC Changqing Oilfield Shale Oil Development Branch

Award Received: Technological Improvement Award

Achievement Level: International Advanced Level

Project Number: ECF-2025-SET-1019

Main Participants: Zhang Yaohui, Ma Lijun, Huang Zhanwei, Ma Hongxing, Wang Xiaorui, Liu Weidong, Guo Chaoying, Gai Hong’en, Guo Sichen, Zhang Shuai

Expert Review Comments:
International advanced level. This project targets the challenges of complex, time-consuming, and costly wellbore cleaning operations in shale oil horizontal wells. It innovatively developed the “one-trip seven-in-one” wellbore cleaning technology, which integrates multiple functions—drift, sand washing, scraping, brushing, fishing, well washing, and magnetic debris removal—into a single operation.
The technology features a compact structure, simple operation, and reusability, enabling the completion of multiple downhole tasks with one trip of the tool string. This greatly improves operational efficiency while reducing cost and risk. The results have been successfully applied in 12 wells in Changqing Oilfield, demonstrating significant economic and social benefits. The technology provides a practical and efficient solution for low-cost, high-efficiency shale oil development and has strong potential for large-scale promotion.

Main Innovations:

The one-trip wellbore cleaning technology for shale oil horizontal wells breaks the traditional limitations of single-function operations and multiple trips. It integrates multiple wellbore maintenance tasks into one operation, realizing a “seven-in-one” horizontal well operation mode that combines drift, sand washing, scraping, brushing, fishing, well washing, and magnetic debris removal in a single trip.
This innovation enables one-trip wellbore cleaning with seven or more functions, offering a new technological engine for low-cost and high-efficiency shale oil development.

Main Uses and Technical Principles:

This technology is designed for the efficient cleaning of shale oil horizontal wellbores, addressing issues such as wax, scale, sand, and metal debris accumulation.
Based on the characteristics of downhole debris, the system operates using large-flow-rate forward and reverse circulation and integrates a “horizontal well debris catcher + casing scraper + casing brush” toolstring combination.
The system utilizes conventional downhole power combined with mechanical rotation to efficiently remove sand, wax, scale, rubber residues, cable heads, metallic debris, and wire fragments.
This integrated approach enables one-trip completion of seven or more cleaning functions, meeting the urgent need for efficient and low-cost wellbore cleaning in shale oil horizontal wells.

Technical Applications:

The one-trip wellbore cleaning technology for shale oil horizontal wells has shown excellent industrial application potential and clear advantages through successful field implementation.

From 2024 to the present, it has been applied in 12 wells in Changqing Oilfield, achieving a one-trip operation success rate exceeding 90%, demonstrating strong field reliability.

Economic and Operational Benefits:

• Operational Efficiency: The average well operation cycle was shortened by 5–6 days per well.

• Cost Reduction: Average operation cost was reduced by 50,200 RMB per well.

• Increased Production: The average incremental oil value per well reached 109,600 RMB.

• Total Economic Benefit: Each well generated an average combined benefit of 159,800 RMB.

• Tool Cost Efficiency: The composite tool manufacturing cost is only 28,500 RMB, and due to simple operation and reusability, the average tool cost per well is controlled below 100,000 RMB, providing a high cost-performance ratio.

Overall, this innovation serves as a highly efficient and economical tool for large-scale shale oil development, meeting the strategic needs of intelligent, low-carbon, and high-efficiency production. It possesses all the core conditions necessary for wide-scale industrial promotion across China’s shale oil development sector.