The Ranim Diapir - Active Salt Diapirism and the Relationship of Salt Structures to Sub-Salt Exploration Targets. Southern Gulf of suez, Egypt

By

 Mahmoud Abdelrahman Atta¹, Oscar E. Gilbert², Henry B. David²

(1) Ocean Energy Egypt Ltd, Cairo, Egypt (2) Ocean International Ltd, Houston, TX

 Non-piercement salt structures are widely recognized at many localities in the Gulf of Suez, but piercement diapers have only recently been documented at Ranim Island and SW Gebel el Zeit. Both types of structures may bear a genetic relationship to major petroleum-trapping structures in the sub-salt section; sub-salt traps are otherwise difficult to interpret due to the detrimental effect of the deformed salt on seismic data quality.

Recent drilling confirmed the existence of a diaper adjacent to Ranim Island. Recumbent folds and thrust faults were formed by flow of Belayim Formation salt into the overlying Hamman Faraun Member and the South Gharib Formation salt. This contradicts the previous interpretation, that salt structures were formed by subsidence (“downbuilding”) related to withdrawal or removal of the South Gharib salt.

The spatial relationship between salt structures and sub-salt faults at Ranim suggests a possible genetic relationship between salt structures and sub-salt faults. Such a relationship could be used to develop predictive models of sub-salt structure, and particularly the locations of the edges of tilted fault blocks that are the primary petroleum traps. Current improvements in seismic data processing make it possible to better image sub-salt structures, but the most powerful technology-pre-stack depth migration requires as input a high-quality structural model to constrain the lateral velocity field. Continued refinements in seismic data quality and the use of salt structures as indicators of sub-salt faults will help delineate additional exploration opportunities and reduce exploration risk in the established southern Gulf of Suez producing province.