Abstract
In October 1992, production sharing contract for Block 15-2, offshore Vietnam wasconcluded between Mitsubishi Oil Co., Ltd. and Vietnam Oil and Gas Corporation (Petrovietnam), and the license was assigned to Japan Vietnam Petroleum Co., Ltd. (JVPC) for the implementationof exploration and development. Block 15-2 locates in Mekong Basin, which has a granitebasement overlaid mainly with thick Tertiary clastics and includes Back Ho field, the largest oilfield in Vietnam producing since 1986.
Based on the geological and geophysical studies, first exploration well was drilled in RangDong prospect and confirmed the significant oil flow over 14, 000 bbl/day from the granitebasement and Lower Miocene sandstone reservoirs in June and July 1994. After appraisal wellsdrilling, “Commercial Discovery Declaration” was made in June 1996.
Target reservoir is the granitic basement fractured reservoir, with very unique features mainlydeveloped by tectonic. Detection of the fracture distribution in the basement and evaluation of itsstatic and dynamic properties were not so easy, but could be accomplished to a considerableextent. Meanwhile there still exist lots of uncertainty in quantitative evaluation of the fracture.Due to such uncertainty, the northern part of the field was decided to develop as first phasedevelopment, prior to entering into fullfield development.
Being high pour point about 30°C, produced oil is separated to liquid and associated gas onWellhead Platform, and the separated fluid is then transported to a tanker converted FPSO(floating, process, storage and offloading system) for exporting oil to shuttle tanker, instead of toonshore via pipeline.
18 months after commencement of the fabrication of production facilities, first oil productionwas achieved on August 30, 1998, with six predrilled production wells. As of December 1999, totalnine production wells are on stream. JVPC is planning to conduct further appraisal works in theremaining southern part of the Rang Dong field for future development.
