Using the resistivity and GR Log for Guide Control +- 415 m Slimhole Horwell section in the 3-5 m Baturaja Limestone Oil-rim Thickness, Between Gas Cap and water Zone at Musi-28 Well. Prabumulih, South Sumatera A Field Case Study Team Approach

摘要

Musi structure is located approximately 120 kilometers West of Prabumulih (Fig 1). It is divided into western and eastern block, based on the structural phenomena defined on the seismic profile. West Musi structure is mainly a gas reservoir. According to the nine wells drilled in this block, it's indicated the reservoar thickness between 80 to 100 meters with a 24 to 36 meters gas cap of Baturaja limestone. East Musi accumulation comprises gas cap and oil rim in the reservoir. Based on the log correlation, the gas cap was found between 70 to 80 meters thick, while the oil water rim was only from three to five meters thick above the water zone. A precise horizontal drilling is an alternative solution to optimally penetrate in to this thin oil rim, between the strong gascap & water drive mechanism. Based on the three dead wells (Musi-04, 05 and 06) two wells are no longer producing gas, while the other well gas plugged due to mechanical problem. It is assumed that the oil water contact (OWC) is flat, especially surround in the local area. This assumption was used to propose a horizontal well to drain the oil rim within the Baturaja limestone and. the drilling proposal comes in associated with many major dicipline as teamwork (Fig. 1). Resistivity and Gamma Ray log sensor that're set on the logging while drilling (LWD) and measured while drilling (MWD) tools, were used to control the horizontal drilling operation. As a result, a total of 415 meters horizontal section was perfectly openhole penetrated with a production test result of 780 barrels oil per day (BOPD) and 8 % to 10 % water cut. This success case will be applied similarly to the up-coming horizontal wells in the local field.