Exploration from the Flank of the Ghaba Salt Basin, Oman: New Play Concepts in from Old Basin Margin
Vincent Hamilton1 and Martyn S. James2
1Tethys Oil, Geneva, Switzerland
2Martyn James Consulting, Silverthorne, CO
The Ghaba Salt Basin is a prolific producing basin which contains 10 billion BOE discovered oil and gas. Within the Ghaba Salt Basin, hydrocarbons were generated from deeply buried source rocks within the Infracambrian Huqf Supergroup. These hydrocarbons are trapped in reservoirs aging from Precambrian to Cretaceous. Deep gas is produced mainly from Middle Cambrian to Lower Ordovician clastic reservoirs of the Haima Supergroup. Traps in nearly all hydrocarbon accumulations of the basin are structural.
Spanning an area of approximately 40,000 km2, Tethys Oil’s Blocks 3 & 4 are located in the eastern part of Oman along the flank of the Ghaba Salt Basin. Many Petroleum Development Oman-operated fields are located immediately to the west of the boundary of Blocks 3 & 4. Previous exploration efforts on the Blocks have been unsuccessful in finding commercial accumulations of oil, although numerous shows in the wells have demonstrated that some migration eastwards from the Ghaba source kitchens has occurred in multiple pulses.
Basin and play analysis on an extensive grid of 2-D seismic, abundant well control, together with basin modelling, has identified new potential traps for hydrocarbons. Many of the future new field targets will likely be paleohighs, combination stratigraphic/structural traps or low relief, subtle structures. Most of the obvious, conventional structures have already been drilled. Paleostructures would have been a focal point for migration throughout time, but demonstrating that a trap has remained intact through time will be a major challenge.
Natural gas has become a viable exploration target in Oman in recent years because of LNG exports and expanding domestic demand. Renewed exploration efforts in this area should also focus on gas, particularly deep gas, which historically have been disregarded due to lack of a market.
AAPG International Conference and Exhibition, Cape Town, South Africa 2008 © AAPG Search and Discovery