Mangala Area - Reservoir Properties

Reservoir Properties

Despite containing a massive 3.6 billion barrels (570,000,000 m3) of in-situ oil, the recovery factor for the field is roughly around 30%, giving it reserves of approximately 1 billion barrels (160,000,000 m3). This level of recovery is a result of the properties of the oil rather than to do with the geological settings of the reservoir which can often hamper recovery factors. The oil has an API gravity of between 25 and 30, which makes it slightly heavier than Brent Crude at 38 API. However, more importantly, the oil is very waxy. This waxiness causes it to be a solid at room temperature (20°C, which is much lower than typical daytime temperatures of Mangala). Brent crude typically has a pour point at 3°C while Mangala oil has a pour point of 42°C.

To assist with increasing the recovery factor, two types of Enhanced Oil Recovery (EOR) are being evaluated which could increase the recovery by up to 25%. The less riskier and costly of them would be to undertake a Polymer flood instead of a traditional water flood. This is strategy is not very dependent on the oil price, well location or extensive testing. The other option is to undertake Alkaline-Surfactant-Polymer flooding (ASP). ASP flooding would be riskier in terms of costs, well spacing, development time (five years), and would be more sensitive to the oil price. However, the rewards for it are significantly higher, potentially increasing the incremental reserves by 25% when compared to polymer or water flooding.