Oil in Place (OOIP)
Compute a reservoir's original oil in place (OOIP) by the volumetric method, OOIP = 7758·A·h·φ·(1−Sw)/Boi, in stock-tank barrels (STB). It combines the reservoir area (acres), the porous thickness (ft), the porosity (φ), the water saturation (Sw) and the oil formation volume factor (Boi). The constant 7758 converts acre-feet into barrels. It is the basis of any oil-field evaluation. Enter the area, thickness, porosity, water saturation and Boi.
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Óleo in place (OOIP)
Quanto petróleo há numa jazida? A primeira estimativa vem do método volumétrico: OOIP = 7758·A·h·φ·(1−Sw)/Boi. A lógica é geométrica — multiplica-se a área (acres) pela espessura porosa (ft) para obter o volume de rocha, depois pela porosidade (φ, a fração de espaços vazios) e por (1−Sw) para descontar a água que ocupa parte dos poros, restando o volume de óleo nas condições do reservatório. O fator Boi (formation volume factor) converte esse volume de subsolo em barris de superfície (o óleo encolhe ao subir e perder gás). A constante 7758 é o número de barris num acre-pé. O resultado, em STB (stock-tank barrels), é o ponto de partida de toda avaliação econômica — mas é só o óleo presente; quanto será recuperado depende do fator de recuperação. Informe a área, a espessura, a porosidade, a Sw e o Boi.
Related Tools
Reservoir Recovery Factor
Compute a reservoir's recovery factor, RF = (Np/N)·100%, the fraction of the original oil (N, or OOIP) that will actually be produced (Np). It is one of the most important — and uncertain — numbers in the industry: primary recovery (natural energy) is usually 5–15%; with secondary recovery (water/gas injection) it rises to 30–50%; and advanced methods (EOR) can go further. It defines the field's economic value. Enter the cumulative production and the original oil in place.
Recoverable Oil Reserves
Compute the recoverable oil reserves by multiplying the original oil in place (OOIP) by the recovery factor (%). While the OOIP is the total volume present in the rock, only a fraction is technically and economically extractable — those are the reserves that actually have value and enter oil companies' books. It is the number behind asset valuations and investment decisions. Enter the OOIP and the recovery factor.
Gas-Oil Ratio (GOR)
Compute the gas-oil ratio (GOR) by dividing the produced gas volume by the oil volume, in scf/STB (standard cubic feet per barrel). It is a central petroleum-production parameter: it indicates how much gas accompanies the oil, characterizes the reservoir fluid type (black oil, volatile, gas-condensate) and sizes the surface separation equipment. A rising GOR can signal gas-cap breakthrough at the well. Enter the gas and oil volumes.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.