Foamy oil properties and reservoir performance

In this study, the pseudo-bubble point pressure model is modified to more accurately model the foamy oil properties by modifying the properties of conventional oil and to study the performance of foamy oil reservoir. The calculated results give reasonable fit to the experimental results. The properties of foamy oil and reservoir performance are dominated by the entrained gas. Above the bubble point pressure, foamy oil has the same properties and performance as the conventional oil. Between the pseudo-bubble point pressure and bubble point pressure, the formation volume factor and recovery factor of foamy oil both increase sharply due to the increase of entrained gas fraction. In this period, the recovery factor is as high as 15%. Below the pseudo-bubble point pressure, the formation volume factor decreases significantly and the recovery factor increases slowly resulting from the decrease of entrained gas fraction. The recovery factor in this period is 6%. The overall recovery factor of foamy oil reservoir is 21%, much higher than the recovery factor of 9% of conventional oil reservoir. Most oil is produced in the pseudo-single phase period for foamy oil reservoir. Therefore, it is favorable to prolong this period.