Oil Mining

Oil sands, or technically called bitumen, is an unconsolidated sandstones that contained water and oil in a thick form. Extra-heavy oil and natural bitumen are formed gradually through the process, which is generated and degraded from remnants of immense volumes of conventional oils. Based on the texture, extra-heavy oil and natural bitumen are identical with the residue of light oil from refinery distillation. The resource of extra-heavy oil and natural bitumen is quite enormous and possible to encourage the reserve of the future oil supply. In Indonesia, one of the promising resources is located in Central Sumatra. Based on the data of USGS (2007), Central Sumatra held 40,6 BBO from 49,827 BBO in Indonesia. Furthermore, we can know that Central Sumatra is the biggest holder of extra-heavy oil and natural bitumen in Indonesia. The production method that technically feasible for oil recovery is open-pit mining. Open-pit mining would apply to deeper reservoir of heavy oil and obtain the overburden and heavy oil from its deepening pit until the base of the oil storage. And because of that, this open-pit mining method holds the potential of oil recovery greater than 80 percent of the Original Oil In Place (OOIP) than the most of conventional oil reservoirs that just have 30-40 percent of the recovery. Production continues to the bitumen extraction stage using hot water extraction.
From the geological aspects, Central Sumatra Basin is one of a series rift basins whose position is currently in the back-arc position which extends along the edge of Sundaland. This area led to Upper Telisa and Lower Telisa Formation that was buried from Early to Middle Miocene. The thickness of the bitumen layer is approximately about 144 meters (Ilyas, 2003). Bitumen flakes that have been developed are believed by experts as a potential source of hydrocarbons. With the increasing demand for oil supplies and the decrease in oil production in Indonesia, it is time for Indonesia to move to optimize the use of unconventional reservoirs. By seeing its potential and excellence, oil mining is a golden opportunity and hope for Indonesia to boost national sustainable energy.