Exploration History of the Intrasalt Carbonate Stringers in the South Oman Salt Basin Free

Carbonate intrasalt stringer exploration in the South Oman Salt Basin (SOSB)started with the accidental discovery, in 1976, of moveable oil in Nasir-1.This started the first phase of exploration of the Cambrian stringers and focused on the Birba and Dhahaban areas. Despite significant volumes addition during this campaign, the stringer play proved to be complex. Limited knowledge of the stringers depositional systems and diagenetic history made predicting reservoir quality difficult and explaining production behaviours next to impossible. Difficulty in delivering expected reserves forced the play to become dormant in 1986. The second phase of stringer exploration started in1988 after a review of deep exploration opportunities that highlighted the play potential outside the proven Birba-Dhahaban area. All wells drilled during this phase failed to discover commercial hydrocarbon accumulations, forcing the play to become dormant for the second time. This short lived campaign, however, led to the Cambrian Al Noor Athel discovery, which kicked off an Athel exploration campaign that lasted until 1997. Interest in the Ara stringers was revived after the discovery of oil in Harweel Deep-1 in 1997. Continuous success in the Harweel area has maintained interest in stringer exploration to this day (UR Oil Expectation at 53 million m3) and led to fast track the development of some of the Harweel discoveries (currently producing more than 3000 b/d), thereby positioning the stringers to significantly contribute to PDOB's future oil production. Continued stringer exploration in the coming years will require expanding the play outside the current proven fairway, which will not be without challenges. Success in this upcoming phase of exploration will require significant advances in the following areas: seismic imaging, prediction of reservoir occurrence and hydrocarbon charge history.