AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
The Role of Evaporites in a High Frequency Sequence Stratigraphic Framework for the Late Jurassic of Northeastern Saudi Arabia
(1) Eastern Area Exploration Division, Saudi Aramco, Dhahran, Saudi Arabia.
(2) Carbonate Research Consulting, Conifer Inc., Denver, CO.
Some of the most prolific carbonate reservoirs in the Middle East are located either within or adjacent to major evaporite units. Though the genetic relationships between these carbonate reservoirs and their evaporitic seals are obvious due to their proximity, their inter-relationships remain poorly understood. In order to address these issues and so assist in exploration and production decision making, a comprehensive sedimentological and stratigraphic study of the Jurassic succession of the northern part of Saudi Arabia was undertaken.
The study area focuses on northern Saudi Arabia and includes three major depositional terrains: the northern part of the Central Arabian Basin; the Rimthan Arch (a prominent structural high at Jurassic times); and the southern margin of the Gotnia Basin. In-depth studies of the sedimentology, diagenesis and sequence stratigraphy of the carbonates and anhydrites of the Upper Jurassic Arab Formations and the overlying Hith Formation have resulted in a number of unexpected and original insights. The new findings challenge some of the established evaporite paradigms (salina vs. sabkha anhydrites), and detailed sedimentological and stratigraphic analyses have resolved the seemingly contradictory facies relationships between the Gotnia Basin in the north and the Central Arabian Basin in the south. This has led to the establishment of a new sequence stratigraphic framework which highlights the fundamental role of evaporites in this part of the stratigraphic column.