Research on open-hole surface pre-kickoff technology for cluster wells in offshore oilfields

This paper indicates the necessity of surface pre-kickoff technology in drilling cluster wells through the characteristics of dense placement of wellbores in development wells and easy collision in Bohai region. In view of the drawback of time-consuming dismantling of wellhead in traditional surface pre-kickoff technology, this paper presents the pre-kickoff technology with open-hole circulation without installing the wellhead but drilling directly with seawater and whipstocking by motor with large bend angle, and determines the optimizing scheme for BHA and drilling parameters. At present, this technology has been successfully applied in 54 wells in Bohai region, which has not only saved drilling costs but also greatly improved the drilling efficiency. This research is of some popularization significance to the offshore oilfields other than Bohai region.