Publications

Mobil Cepu Ltd and partners in the Cepu KKS, East Java basin plan to start development drilling of the Banyu Urip field in 2012 with a targeted startup in 2014. This is a very important development for Indonesia to maintain the Indonesian national production target as this field will produce 165k BOPD initially. The Banyu Urip field was discovered in 2001 and has been certified by ITB with more than 1 Billion BBL in place making it the largest onshore oil discovery in Indonesia in the last several decades. Banyu Urip is a high relief Oligo-Miocene carbonate isolated platform onshore at approximately 4000 feet TVDSS. 30 producers will be required to meet the initial target (5500 BOPD ave per well). 13 water injectors will be required to meet aquifer pressure maintenance target. This paper will describe the field and development concept. The Banyu Urip Field is an isolated platform that rises almost 3000 feet from the surrounding carbonate platform. The platform is made up of repeated 150 foot thick cycles of shallow water carbonate that has been exposed to fresh water repeatedly and leached to form high quality reservoir rock with average 26% porosity and 100 mD permeability in the interior. The edges of the platform are heavily cemented and prevented from being fresh water leached due to proximity to deep ocean energy. Because of the large ratio of column height to aerial footprint of the field ( 1000’ tall by 1500 acres), the wells will be drilled with relatively close spacing of approximately 50 acres per well. The wells will be targeted at only the high quality interior facies that should provide the necessary productivity. Managing perforations through the life of the field to mitigatewater and gas coning will be essential. * Mobil Cepu, Ltd. Perforations will start with 300’ of perfs approximately 300’ above the OWC. As water encroaches, perforations will be shutoff and new perforations added up hole with a ceiling of 115’ from the GOC to avoid gas coning. Obtaining good cement isolation will be critical but is very challenging in these carbonates. Production data from 4 wells that have been producing since 2008 confirm that the average well target of 5500 BOPD per well is realisticproviding a very high chance of success. These wells show average porosity of 26% and average permeability of 100 mD. The PI of most of the existing wells remain nearly constant over the 3 years of production indicating that the plateau can be confidently met. Two new build rigs will be procured to drill the 42 new wells from 3 pads. Drilling and completing these wells will be very challenging even though they are at such a shallow depth. The combination of carbonate fracturing with common total mud losses and the 600 feet of sand reservoir gas column overlying the carbonate dictates a conservative casing program. The 7” liner must be used to case off the gas column before the oil leg is drilled with 6” hole to avoid having gas open when encounter total losses. The result is drilling with no contingency string, small core and difficult cementing for zonal isolation. The other challenge is the logistics of drilling 14 wells with each rig and completing them for startup in 2 years. 52 days per well does not leave any room for delays. Planning will include batch drilling and rigless completion adjacent to the active drilling rig.