On June 1^st, the YK35-11H5 well, contracted by ZPEC Rig Team 2 of the Yan’an Project, was successfully completed 12.67 days ahead of the drilling cycle. The Yanbei Project Department of SCP Oilfield Services, Party A, promptly issued a letter of commendation and awarded a bonus of 120,000 RMB to the team.

Located in Yongping Town, Yanchuan County, Yan’an City, Shaanxi Province, the YK35-11H5 well is a four-spud horizontal well with a total depth of 4,340 meters and a horizontal section of 1,000 meters. It is a key developmental well deployed by Party A for 2026.

Prior to the construction, the Drilling Company and the Yan’an Project conducted thorough planning. In response to regional challenges, such as lost circulation, poor drill ability, difficulty in wellbore trajectory control, and high wellbore friction, the team fully reviewed the drilling experience and adjacent well data from the first three wells on the same platform, and organized drilling, mud engineering, directional drilling, and logging teams to conduct an in-depth analysis of the geological and engineering designs. They carried out risk identification in advance, refined construction procedures, optimized operational organization, and made notable innovations in the selection of drill bits, positive displacement motors (PDMs), and directional instruments besides using high-impact, abrasion-resistant high-performance PDC bits and high-power, high-torque PDMs.

During construction, the technical and operational teams worked in close coordination to implement dynamic monitoring of drilling parameters and make innovative adjustments when necessary, while enhancing trajectory detection at geological interfaces and sections prone to deviation. In addition, high-efficiency lost circulation materials and anti-sloughing agents were added to optimize the drilling fluid formulation and to improve wellbore cleaning and formation stability. These measures effectively addressed the challenges of lost circulation in the Liujiagou Formation, poor drill ability in the Shiqianfeng Formation, and the risk of coal seam collapse in the Shanxi Formation within the horizontal section. Thus, both operational safety and technical acceleration throughout the well were achieved.

Li Zhenhua, Project Manager of the ZPEC Drilling Company’s Yan’an Project, said, "This achievement contributed to the efficient collaboration between our integrated team and our partner. It is an action demonstrating the full implementation of ZPEC ’s Management Enhancement 2.0 Plan, the 'Major Transformation, Major Adjustment, Major Development' strategy, and the 'Iron Blood Journey' spirit.". The Yan’an Project will take this as a starting point to continue advancing technological innovation and quality-efficiency enhancement measures, and will achieve a substantial breakthrough in the second quarter."

(Yan’an Project/ Text by Ma Guofang, Photo by Liu Shangde)