Belayim Marine 1 drilled in 1961 encountered oil in a Miocene sand-shale section. The well logged a clear oil-water contact in the lowest sand bed which at the time was believed to be the common oil-water contact for all the interbedded sequence. Based on the results of this well and other subsequent wells drilled inside the oil-water contour, the oil reserves were volumetrically calculated and a development program was effected. In 1978, when the field came back under the Egyptian control, a number of reservoir studies indicated that the oil in place is at least double the amount calculated. The additional reserves could not be accommodated in the rock volume sitting above the logged oil-water line. It was suggested then that the logged oil-water line is valid only for t e lowest sand bed and higher sand beds can have their own oil-water lines. The concept when checked by drilling proved to be valid. The additional reserves are now under development.

If the actual size of the field has been known at an earlier stage, a different and more rational development program could have been adopted. It is therefore highly recommended that in similar reservoirs in interbedded successions possible oil-water lines be thoroughly defined for the different sands at an early stage of development.

End_of_Article - Last_Page 486------------