Publications

X-11 is an infill well which will be drilled horizontally where the horizontal section will be positioned inside the reservoir. The targeted resevoir of X-11 is limestones in the Baturaja formation. This formation is located at 2712 ft to 2732 ft TVD with reservoir thickness of about 20.41 ft. The drilling process of X-11 was divided into 3 sections (surface, intermediate, horizontal). The drilling procedure of surface and intermediate section was done successfully and the well managed to enter the targeted reservoir successfully. Subsequently, not long after the horizontal section drilling started, X-11 stopped penetrating limestone and kept penetrating shale. The drilling procedure was then stopped because it was predicted that the well path of X-11 had exceeded the reservoir section. X-11 was finally plugged and abandoned. In order to produce the targeted reservoir, another well must be drilled. Therefore, a sidetrack well, X-11ST was decided to be drilled with a geosteering tool. Once the sidetrack drilling procedure was done, the targeted reservoir was well reached and able to be produced profitably. Through the drilling process of a sidetrack well, X-11 ST, it was discovered that the main cause of the X-11 well path got out of the reservoir was that the actual reservoir differs from the planned reservoir model. Before the drilling was done, the reservoir model was predicted to be fully horizontal, whereas the actual reservoir has a dipping structure. The false geological modelling occurred because of the misinterpreted geophysical interpretation that happened from the uncorrected noise caused by shale gas from the upper layer, Cisubuh.