The reservoir is now 90 per cent depleted. The reservoir pressure has decreased from an original value of 5,070 to 700 psia. The volatile-oil reservoir covers 1,600 acres and is developed with 11 wells. The history concerns a field in North Louisiana discovered in late 1953, producing from the Smackover lime at approximately 10,000 ft. The predicted performance was published by Jacoby and Berry in 1957. This information is of particular importance for crude stabilization calculations and for design of gasoline plant facilities to recovery LAG and natural gasoline.Ī case history of the depletion performance of a reservoir producing volatile crude oil is presented and compared with prior predictions of performance. Wellstream compositions have also been used to determine variation in stock tank oil composition and liquid content of the separator gas. Calculated maximum produced gas-oil ratio is less than one-fourth of the conventional prediction. Calculations are presented for a reservoircontaining a volatile crude oil, and predicted tank oil recovery by primary depletion is more than twice that predicted by conventional methods which are known to be adequate for ordinary black crude oils. This method uses relative permeability data and multi-component flash calculations to predict oil and gas production as a function of reservoir pressure. In order to improve predictions for reservoirs which produce volatile oils, a stepwise method of calculation has been developed. Surface recovery is not simply related to the total quantity of liquid flowing into the well under reservoir conditions. In such cases recovery of stock tank oil per unit of pressure decline can be predicted only from a detailed knowledge of the separator conditions and the over-all composition of the fluid entering the wellbore at each stage of depletion. This is because laboratory differential vaporization test procedures do not adequately represent the reservoir depletion process and the performance of surface separation facilities. when the reservoir fluid is very volatile, however, certain assumptions implicit in the use of the conventional methods are no longer valid. 14–17, 1956.įuture depletion performance and ultimate oil recovery from reservoirs producing under volumetric control are often predicted with the aid of a material balance equation. Paper presented at Petroleum Branch Fall Meeting in Los Angeles, Oct. Published in Petroleum Transactions, AIME, Vol.

Mccain gas oil ratio