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Abstract Formations with a narrow mud window between the pore pressure and fracture gradient have always imposed a significant risk on well integrity during drilling and post-drilling operations. One of the main risks associated with such formation behavior is complete or partial loss of returns while drilling or cementing leading to many counterproductive consequences. For example, complete or partial loss of drilling fluid while drilling a hole section could reduce the hydrostatic pressure to below the bottom hole pressure resulting in the intrusion of formation fluid into the well bore. Another major risk is differential sticking of drilling and casing strings while performing well control securement procedures or by being stationary for any other reason. As a result, Managed Pressure Drilling (MPD) system was introduced to drill an 8-3/8" hole section in an unconventional well with a 3,500 ft interval that has a narrow mud window. The well was drilled with 106 pcf while maintaining an EMW of 120 pcf where the required overbalance is met. Other wells on the same area have suffered tremendously while drilling the same interval conventionally yielding high non-productive time which proved the concept of utilizing MPD system as a pro-active solution instead of reactive once needed. The next major challenge was to run and cement 7" liner to achieve the required cement barrier for isolating the problematic interval. Losses or well control while cementing 7" liner would compromise the integrity of cement barrier. Therefore, to mitigate losses and keep the required overbalance simultaneously during running and cementing 7" liner, Managed Pressure Cementing (MPC) was the effective solution. This paper illustrates the entire procedure and results of successfully utilizing MPD system for running and cementing 7" liner string twice in a challenging environment where various stuck pipe and well control incidents occurred. Despite the fact of the extra budget and time for utilizing such systems, the increased safety risks, such as influx or well flow, and the extra cost that are associated for fixing what a stuck pipe can create is much higher.
Alzahrani et al. (Mon,) studied this question.