An Effective Method to Improve Borehole Tortuosity and Tripping Out Speed in Interbedded Lithology Using Dual Cutting Eccentric Reamer in Swamp Drilling Operation

Abstract

Handil field in Mahakam block has crowded wells and scattered reservoirs in which typical 3D trajectory such as S-type trajectory need to be done to respect anti-collision with surrounding wells and optimize reservoir coverage in a single line trajectory. However, a typical S-type trajectory causes a high stick-slip issue to arise and induces bad hole quality. In some wells, this potentially leads to additional time for dedicated wiper trips, a longer time during pull-out Bottom Hole Assembly (BHA), more usage of lubricant mud additives, and ROP reduction. As a result, a longer rig time would have occurred leading to a tight margin for a well to be produced economically. A technology called Dual Cutting Eccentric Reamer (DCER) could help to tackle the problem mentioned. It is a typical stabilizer BHA which has eccentric dual cutting structures that allows the tools to enlarge the hole then it passes through in two directions both when up-reaming and down-reaming. As a result, the tool helps improve hole quality as the tool also helps trim the ledges produced when drilling the hole. This paper is introduced to analyze the benefits of the reamer and its opportunity for future development in swamp drilling operations. The tool was applied during drilling on an 8-1/2” section. One of the challenges during drilling this S-Type trajectory was to minimize the difficulty during pull-out BHA that may lead to additional pull-out duration as well as the rig time or even dedicated wiper trip. The result of reamer utilization shows that pull-out BHA speed could be improved to 196 m/hr from 82 m/hr or 139% improvement compared with typical offset well. Furthermore, combined with good proper bit design and BHA configuration, the stick-slip issue could be minimized while ROP could be increased up to 9% compared to conventional well with S-type trajectory on the first trial. This utilization has been successfully implemented without any safety incidents and related Non-Productive Time (NPT). This positive result leads us to open the opportunity for future drilling campaigns in swamp asset such as DCER as the standard BHA configuration especially for S-type trajectory.