Implementing MPD Technology as a Trial to Reduce Rig Days and Mitigate Major Drilling Hazards in New Unconventional Drilling Campaign Field Hence Improving Overall Drilling Process Efficiency, Case Study of 53 Wells

Abstract The paper explains how MPD (Managed Pressure Drilling) technology was tested in drilling through extended horizontal wells in unconventional reservoirs presenting challenges in several aspects of the drilling process. Among the obstacles observed in the case study field were slow rates of penetration, excessive numbers of bit trips and high background gas readings leading to several days of well control events. The successful trial resulted to continue using MPD technology in over 53 wells and still counting. The amount of overbalance plays an important role in the bit performance, along with other variables, such as bit selection and drive mechanism. Managed pressure drilling (MPD) optimizes the bottomhole pressure by first performing pore pressure tests to drill with minimum required overbalance while maintaining background gas readings within acceptable levels. The target bottomhole pressure is adjusted almost instantly by adjusting the surface pressure at the MPD choke, normalizing well conditions in case higher background gas readings are observed. Conventionally during well control while raising the mud weight, losses were encountered due to high frictions in the extended horizontal sections. Initially the major challenges posed in the campaign field were: 1- well control due to high background gases, 2- loss circulation due to high annular frictions in the extended laterals and 3- extremely low rate of penetrations due to the unconventional tight gas reservoir. The challenges of extended periods of well control situation, more duration required for increasing mud weight in case of background gas increase, mitigating loss circulation and improving the relatively low rate of penetration due extra overbalance gave a chance for MPD to prove its worth and reduce the overall rig days for each well. Due to the flexibility of drilling in a near balanced condition, the pump rate can be designed for optimum hole cleaning conditions without concern for exceeding the fracture gradient. The extra overbalance removed by MPD mitigated stuck-pipe hazard. Furthermore, the utilization of lighter MPD mud reduced mud costs. The background gas readings were kept within established limits throughout the operation by instant bottomhole pressure adjustment as dictated by the well throughout the drilling process. Moreover, bit performance was observed to improve by drilling in a near balance state. The rate of penetration is higher and footage per bit is longer—thus reducing bit trips, reducing rig time and cost associated to other services. Managed pressure drilling optimizes the overall drilling process and mitigates major drilling hazards like well-control, loss circulation and differential stuck pipe. Its early kick detection system, ability to almost instantly adjust the bottomhole pressure and added safety factor by diverting returns away from the rig-floor proved great value to the client's operations. This publication summarizes the details of how the MPD CBHP technique, early kick detection system & advanced gas detection & control system made it possible to efficiently and successfully execute the drilling process safely. MPD enabled to drill the un-drillable wells without any NPT for well control situations with the value added benefit of better ROP at the same time.