Bill Wilks, Managing Director / Principal Geophysicist, Merlin Energy Resources
The next phase of exploration in the Sultanate of Oman is underway, with the recent announcement by the Ministry of Energy and Minerals (MEM) of a licensing round for 2025. Three onshore blocks are on offer and, interestingly, they are all adjacent to the western border of the sultanate and its neighbours Saudi Arabia and the UAE.
Blocks 36 and 66 are on offer.
Blocks 36 and 66 border Saudi Arabia along a zone where the geology is transitioning between ‘typical’ South Oman Salt Basin (SOSB) and the Rub’ Al-Khali Basin. This is in the vicinity of the compressional ‘Western Deformation Front’ (WDF), which was recently tested in Tethys Oil’s Kunooz-1 well. Whilst we retain a deep interest into the Cambrian collisional tectonics within the WDF, these blocks will primarily focus on the younger Safiq Group Play (within the Haima Supergroup) and will revolve around the proven Silurian Sahmah Formation hot shale source rock (and seal). The underlying Hasirah Fm sands represent a proven reservoir target, and younger sands within the Gharif and Al Khlata Formations also have potential, at least in Block 66. The primary challenges will lie in defining subtle trap configurations, especially for pinch-outs, together with the mapping of effective top seals. In addition, the top-seal capacity of the Sahmah shales will need to be circumvented if the Permian is to come into play. Both Circle Oil (Block 49) and Maersk (Block 48) have historically pursued these plays on the same trend. Circle exited in 2015 after encountering drilling issues on its Shisr-1 well, so it is reasonable to assume that it didn’t disprove the play! As noted above, the deeper plays in the Huqf Supergroup (as targeted in Kunooz-1) are secondary and can be considered to have a higher risk profile. That said, work by Phillips Petroleum, when operating Blocks 36 and 38, cited gravity modelling to speculate the existence of a salt sequence to the west of the Ghudun-Khasfah High, which would be the time equivalent of the Ara Group in the SOSB. Although their published 2D seismic data were poor, this observation is consistent with our data-driven model for the evolution of the WDF, together with the more recent drilling results of PDO, PTTEP and Tethys Oil in the region. This story book has certainly not closed on these Huqf plays, and the provision of modern 2D seismic data, through acquisition or reprocessing, may reveal more!
Block 43A is on offer.
Block 43A lies along-trend from the active exploration in Ras Al Khaima in the UAE and similarly targets plays within the foreland and hinterland of the Oman Mountains. It is fair to say that plays are better constrained in this region, although not sufficiently explored. The challenge will be in unravelling the structural and stratigraphic configurations and relative timings, together with defining the charge and migration fairways. For that, good quality seismic data will be required, together will a deep dive into the source rock systems and migration pathways (as a recent proprietary project of ours showed). It sounds like my kind of fun!
If you are interested in pursuing these blocks but need a helping hand, reach out to the team at Merlin and leverage its experience on source rocks, petroleum systems and regional geology in Oman.
