Drill lateral well can effectively increase the footage of horizontal intervals in oil and gas layers, as well as the drainage area. It is significant for the economic and efficient development of varied hard-to-tap blocks. By applying lateral and fishbone well drilling and completion in recent years, CNPC has boosted its production per individual well significantly.

Four breakthroughs have been obtained in lateral well drilling, including geological and engineering design, selection of downhole tools and completion systems, hard formation windowing and drilling technologies for lateral bores, and reservoir protection in lateral wells. Five sets of process engineering were developed, including directional lateral wells, horizontal lateral wells, fishbone wells, multi-layer lateral wells, and underbalanced lateral wells. These technologies have been applied in the Liaohe, Jilin and Sichuan oilfields to drill and complete more than 80 lateral wells. Each of the 15 wells completed in 2009 delivered an output of 2-10 times that of neighboring wells in the same block.

By 2009, we had developed a complete series of four-level drilling and completion tools for lateral wells with independent intellectual property rights. We originated casing strings for the positioning and orientating of whipstocks, as well as circular arc whipstocks. We also developed a pre-holing branching suspension system with an optional reentry process and matching tools that address the technical challenge of optional reentry in main and lateral bores. This technology has been used to great effect in bi-lateral wells DC024 and LUHW301Z of the Xinjiang Oilfield. Compared with similar foreign technologies, it can deliver more comprehensive benefits with low engineering costs.