In recent years Bahrain has experienced a rapid growth in gas demand for industrial use, electricity generation, gas injection, and artificial lift. The main source of gas for these needs is the Khuff reservoir only. This recognition of this fact has been the main driver for the exploration of the deep gas prospects in Bahrain field.

Jauf formation has been found to have hydrocarbon potential regionally. It has been found hydrocarbon bearing in the flanks of Ghawar anticline. Jauf sandstone has also been found to be highly prospective exploration target in the Bahrain field, since it has been proved gas bearing in the crestal well. The well flowed with moderate gas rates before sanding up.

In addition to the crestal well, five other wells penetrated Jauf zone. Three wells gave clear gas shows and two peripheral wells tested water. Long testing was done in one of the three wells to produce gas from Jauf. This well produced from Jauf for more than two years before Jauf was plugged and more prolific layers were opened in the well. Jauf produced at an average rate of 15 MMSCFD.

In order to estimate the gas reserves and the production potential in Jauf, uncertainties with gas reserves estimate and the reservoir continuity should be considered. Rock properties, drive mechanism, fluid properties, pressure, gas quality, and the production tests play vital role in estimating the reserves. Therefore, two approaches were used to estimate the Jauf gas reserves: around gas tested well-bores and as a continuous medium. The paper will describe each approach and further will present the results.

As there are good reasons for the Jauf reservoir to be continuous within the Bahrain field area, a simulation model was built considering the data from all the drilled wells using only the lower limits for all the reservoir parameters like porosity, net thickness, and saturation. Performance forecast was also carried out to evaluate the sustainability of the plateau gas rates, which will be discussed in this paper.

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