THE SUDANESE RED SEA: 1. NEW DEVELOPMENTS IN STRATIGRAPHY AND PETROLEUM‐GEOLOGICAL EVOLUTION.

Abstract

The development of the Red Sea‐Gulf of Suez Rift follows two tectonic phases: pre‐rift and syn‐rift: rifting of the Afro‐Arabian craton was initiated in Eo‐Oligocene times. Generally good reservoir‐quality fluvio‐deltaic and marginal‐to fully‐marine Palaeozoic, Mesozoic and lowermost Cenozoic (Palaeogene) rocks had been deposited and are partly preserved.Marine Upper Cretaceous shales, carbonates and sandstones in the Gulf of Suez change facies to more continental sandstones of the Sudanese Red Sea; similarly, Post‐Cretaceous pre‐rift limestones and shales change facies to shallow‐marine sandstones. Syn‐rift sedimentation on either side of the Red Sea axial trough is essentially identical to that of the Gulf of Suez. As a consequence of this, the Gulf of Suez ingredients of mature oil‐prone source rocks, reservoirs and seals are present in the Sudanese Red Sea. Heat flows are higher in the Red Sea than in the Gulf.During the early pliocene there was a further episode of doming, further Red Sea extension took place, and the Red Sea attained its current shape.Remapping of 5,000 kms of 1970's‐vintage seismic data in the Sudanese Red Sea has resulted in recognition of many new prospects, which include: post‐salt prospects, similar in structural style to the structures tested by the successful Sudanese Red Sea Suakin‐1 and Bashayer‐1A gascondensate and dry gas discoveries; base‐evaporite prospects of a structural style virtually untested in the Sudanese Red Sea, but known to be prospective in the Gulf of Suez; and preevaporite prospects with structural styles indentical to those most prospective in the Gulf of Suez.