The drilling technology for fishbone Jing 52-H1Z horizontal well

In order to develop the difficult-to-produce reserves in paleo-buried-hill formation, increase single well output and oil recovery of oil reservoir, reduce the cost for comprehensive development of horizontal wells, and improve economic benefits, 20 branch wells are designed and constructed in the horizontal section of Jing 52-H1Z well. In order to tackle the difficulties including the sidetracking, the reentrance of the main hole, the well bore trajectory control, and the poor drillability of the formation, some technologies are put forward, such as the sidetracking technology of compound holes, the pipe string reentrance technology of main holes, the well bore trajectory control technology, and the drilling speed increasing technology. All the technologies have been applied to the field successfully, greatly shortening the drilling cycle and guaranteeing the safe and fast completion of the well. The successful drilling of the 20 fishbone branch wells provide rich experience and powerful technical support for the fishbone horizontal wells in domestic oilfields to develop into more branch wells. Meanwhile, it marks that the horizontal well drilling technology of China National Petroleum Corporation （CNPC） is more approaching the world’s advanced level.