Publications

Well test, production performance, and drilling observation in Ujung Pangkah Field indicate that there are fracture systems involved. Total and partial lost circulation in drilling operations are correlated to conductive zones as shown in the borehole image. It is very important to all future operations to identify the fracture zones in Ujung Pangkah Field. Ujung Pangkah is one of the oil and gas producing fields in the East Java Basin. The field is located in the southwestern part of the JS-1 Ridge. The field is bounded to the east by the Central Deep and onshore East Java to the south. The northern margin is formed by left lateral strike-slip faulting. A period of compression in Neogene triggered a major WNW-ESE sinistral strike-slip fault that delimits Ujung Pangkah to the north. This strike-slip system has formed two recognized fracture systems. The first is parallel to the regional maximum horizontal stress and the second is formed at ±600 to the regional maximum horizontal stress (predominantly NE-SW). The geometry attributes, variance and coherency are clearly shown the fracture pattern. Further study combining seismic attributes validated by image logs have yielded three fracture zones in the field identified by the dominant fracture azimuths: NE-SW, NW-SE, and E-W direction. The NE-SW fracture zone is the most dominant azimuth in Ujung Pangkah whereas the NW-SE and the E-W fracture azimuths are located in the southeastern part of Ujung Pangkah Field away from the sinistral strike-slip. The Ujung Pangkah Field is located mostly in the area of predominantly NE-SW fractures.