Advances in drilling equipment, drill bit design, and PDC cutter technology have resulted in significant time savings through increases in penetration rate and the entire hole section being completed in a single bit run. However, the wellbore condition has become an important consideration as the time spent to improve the quality of the wellbore to facilitate tripping and running casing is increased. The paper discusses a case study in the Jatiasri and Akasia Bagus fields, West Java, Indonesia, where both the 17½-in. and 12¼-in. hole sections are considered challenging. Pipe stall, overpull, stuck pipe, and tight spots are typically experienced during drilling and tripping, resulting in difficult trip-out and subsequent trip-in with casing. Those two case studies describe poor borehole conditioning related to micro-doglegs or tight hole issues. A unique bi-directional eccentric reamer tool was introduced to help improve the wellbore quality. The tool removes or smooths out irregularities in the wellbore geometry during drilling and reaming operations. To work effectively, the correct placement within the BHA is critical. Using proprietary multifunctional advanced placement software, the reamer is ensured to be optimally placed while analyzing bending stresses and contact forces throughout the run for safe and trouble-free operation. The run results showed significant time savings in pulling out of hole by 38 to 91% in the 12¼-in. section and 20 to 57% faster in the 17½-in. section compared to the offset runs. In addition, wiper trips can be eliminated or greatly reduced, and casing speed is also improved. The casing shoe was also set or landed close to the designated depth, eliminating the need for dedicated cleanout runs. For more than 17 runs, the performance showed consistency in time savings while reducing the potential for stuck pipe, string stall, and tight spots. This unique bi-directional eccentric reamer has added a new capability for drilling improvement and optimization through borehole conditioning, reducing nonproductive time and interval costs which ultimately contributes to lower well construction cost.

There are several challenges for polycrystalline diamond compact (PDC) drill bits when drilling through volcanic and interbedded applications. Roller cone (RC) bits have historically been used in geothermal applications. However, low rate of penetration (ROP), bearing life, and repairability limitations have halted progress in performance and economic gains. This paper presents game-changing PDC technology that addresses the limitations of previous conventional drill bits in a challenging geothermal application. A reimagining of drill bit body geometries, the latest in shaped cutter technology, and durable backup elements were lab tested and customized on an unconventional drill bit chassis to maximize ROP, improve durability, and reduce downhole torque variation. The initial design phase focused on identifying and overcoming these key challenges. The second phase was to field test the new drill bit in the target application and compare it to offset runs, including roller cone, hybrid, and conventional fixed cutter bits. Key performance indices such as ROP, durability, steerability torque generation/variation, and cost per meter (CPM) were considered when evaluating the new design's performance. Initial testing in the 16-in. section showed promising results in the field. Higher-than-average ROP and excellent interval resulted in the lowest cost per meter run. In addition, the drill bit complemented the bottomhole assembly (BHA) design well, as minimal effort was needed to keep the trajectory as planned. The delta torque generation was lower than conventional PDC bits whilst displaying higher ROP than roller cone alternatives. The improved durability of the new design also allowed it to be run multiple times without repair, which was not possible with previous bits due to bearing hours or durability issues. This was always a challenge through the volcanic formations seen in this application. In remote locations that do not have facilities to repair drill bits, the ability to run multiple times without the need to repair is critical. The operator saved costs by not needing to transport the bit and repair any PDC cutters or secondary components after multiple runs. This outstanding run validated the benefits of the new design in terms of both technical and economic perspectives.