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Is it always right to say that a reservoir having initial gas cap is having reservoir pressure equal to bubble point pressure at GOC. If there is separate migration of Gas and then Oil, then I think both will be not equal. Please help!!

I would also like to know about this. Have you found the answer yet?

thanks

yet to find d answer!!

I am also interested in this. No answer yet, after so many months?

If a reservoir is explored with Gas Cap already in top of an oil column, it means that the initial reservoir pressure was below the reservoir oil bubble point pressure and the gas had moved upwards to form the gas cap. This type of reservoirs are called saturated oil reservoirs. But if the reservoir is found only with oil, it means that the reservoir pressure is at or above the oil bubble point pressure, once you start producing the oil, the pressure decreases and the gas comes out of the oil, some of the gas moves towards the producing oil ( produced gas) and some of he gas moves upward to form a gas cap. This type of reservoir is Under-saturated reservoir, because the time it was found, its pressure was above the P bubble. A diagram of Rs ( Solution gas ) vs pressure would be the best answer to your question.

Regards
Iman