On April 23, it was reported that PetroChina Changqing Oilfield has successfully completed drilling the country’s first ultra-long horizontal coalbed gas well with a 2,500-meter horizontal section. This achievement sets three new records for China’s onshore coalbed gas development: the longest horizontal section, the longest one-run drilling in the horizontal section, and the longest open hole section. It marks a major technological and managerial breakthrough for PetroChina in coalbed gas development under complex geological conditions.

Coalbed gas is a key strategic substitute resource for the sustained growth of China’s natural gas production. It plays a vital role in ensuring national energy security and achieving the “dual carbon” goals. As the leading unit in coalbed gas development in the Ordos Basin, Changqing Oilfield has advanced both reserves expansion and production by optimizing management and driving technological innovation.

In the eastern Ordos Basin, coal seams are characterized by weak tectonic structures and are prone to collapse. This makes horizontal drilling difficult due to the challenges in wellbore trajectory control and high risk of drill string sticking. How did they manage to drill such an ultra-long horizontal well? Wang Cheng, a drilling engineer from the Eastern Ordos Gas Evaluation Project Team, explained: “We adhered to an integrated approach of geology and engineering, optimizing the entire process from design, geological steering, equipment matching, to mud properties simultaneously, ensuring safe and efficient drilling operations.”

Changqing Oilfield has continued to innovate in coalbed gas exploration and development, establishing a proprietary core technology system. It has developed and applied fast and efficient drilling techniques suited for the eastern basin, promoted low-cost anti-collapse drilling fluids, implemented a “three-high” drilling model, and introduced borehole cleaning measures that reduce risk and improve efficiency.

In response to complex formations and harsh wellbore conditions, PetroChina's various units collaborated to optimize cementing quality and ensure safe post-drilling production. “We developed specialized pre-flush spacer fluids, unique cement slurry systems, and a series of cementing tools that significantly improved cementing quality,” said Wei Zhousheng, a technical expert at Changqing Cementing Company of Chuanqing Drilling.

As of now, the Eastern Ordos Gas Evaluation Project Team of Changqing Oilfield has completed drilling 50 coalbed gas horizontal wells, with a cumulative gas output exceeding 190 million cubic meters.