Advanced technique for screening enhanced oil recovery and improved oil recovery methodologies for a petroleum reservoir

A method for recovering oil from hydrocarbon reservoirs comprising:

• inputting into a computer system data related to properties of a hydrocarbon reservoir and depletion of the hydrocarbon reservoir;
• calculating, with the computer system, a current oil saturation (So) and a current gas saturation (Sg) of the hydrocarbon reservoir based on the data, and utilizing the current oil saturation and the current gas saturation to determine if waterflooding could provide enhanced oil recovery, wherein the current gas saturation is calculated by:
• (a) calculating the current oil saturation (So) from a material balance equation as:
• So=(1−Sw)(1−Np/N)(BO/BOi), where Sw is the water saturation at start of a waterflood;
• NP is the cumulative oil production at start of waterflood;
• N is the initial oil in place in stock tank barrels (STB);
• B0 is the initial oil formation volume factor (“FVF”), in reservoir barrels (RB) per STB);
• B0i is the oil FVF at a start of the waterflood in RB/STB, and calculating Sg as Sg=1−Sw−So;
• and
• (b) calculating free gas saturation (Sg) from a free gas-oil ratio (“GOR”);
• and
• (c) comparing the two calculated Sg values as a quality check of pressure, volume, temperature (PVT) data;
• if the current oil saturation (So) is less than 0.4 and the current gas saturation (Sg) as calculated by (a) and (b) is less than 0.3, determining and comparing, with the computer system, a current reservoir pressure to a bubble point pressure and an initial pressure and, if the current reservoir pressure is less than the bubble point pressure and the initial pressure based on the data, calculating, with the computer system, a time to repressure the hydrocarbon reservoir by waterflooding based on the data;
• if the current reservoir pressure is not less than the bubble point pressure and the initial pressure or if the time is less than 5 years, comparing, with the computer system, the data related to properties of the hydrocarbon reservoir to enhanced oil recovery screening criteria for the data related to properties of the hydrocarbon reservoir;
• selecting a flooding technique from a plurality of flooding techniques, with the computer system, based on finding that the data related to properties of the hydrocarbon reservoir satisfy the oil recovery screening criteria of the flooding technique;
• and
• flooding the hydrocarbon reservoir with the flooding technique.