Duvernay shale gas reservoir, an essential high-pressure unconventional resource for PetroChina abroad, lies at a depth of 3200 to 3800 m. Since 2012, advancements in drilling and completion techniques have been deployed to reduce the time and expenses associated with drilling long horizontal wells in the Duvernay shale gas field, yielding favorable economic outcomes. This article delves into the intricate drilling and completion strategies employed in the Duvernay project in Canada, specifically focusing on ultra-long horizontal wells (horizontal section > 3000 m). Duvernay’s remarkable enhancements in drilling efficiency stem from five key areas of refinement: ①continuous upgrading of drilling rigs and equipment; ②optimization of drilling and completion designs; ③implementation of an intelligent drilling dynamic tracking system, enhancing downhole tool reliability; ④optimization of drilling parameters, and carry out “one-bit-run” for each drilling operation; ⑤High efficiency casing run tool and coiled tubing bridge plug drilling and milling tool for well completion to improve the reservoir stimulation effect and single well production. These optimizations have extended horizontal section lengths from 1702 m to 4425 m, reduced drilling time from 71 to 17 days, and lowered drilling costs from 1777 C$ per m to 722 C$ per m. The application of ultra-long horizontal well drilling and completion technologies in the Duvernay project has significantly boosted production and doubled the single well’s estimated ultimate recovery (EUR). It serves as a technical guide for cost reduction and efficiency improvement in horizontal well drilling of China’s unconventional reservoir.