A Regional Jurassic Stratigraphic Framework and Basin Evolution Model Using 3-D Seismic Data
Lawrence, Paul *1; Tang, David Z.1; Tan, Wenbin 1; Bakhiet, AbdelFattah 1; Gregory, Greg 1; Wharton, Stanley R.1; Shokair, Khalid 1
(1) Saudi Aramco, Dhahran, Saudi Arabia.
A 3D seismic stratigraphy study has defined a new regional stratigraphic framework for the Jurassic using extensive seismic data covering a large part of the Eastern Province of Saudi Arabia. The 3D seismic has revealed new satellite-like high resolution images and details of the Jurassic carbonate depositional environments that were not clearly defined using well control alone. The integration of the seismic with well data provided critical constraints at each stratigraphic level, allowing for confident delineation of major regional depositional environments such as carbonate platforms, lagoons and basins and their associated margins. Smaller scale depositional environments, such as channels and debris flows, were also identified. These provided valuable conceptual geological models useful for future exploration.
The entire Jurassic interval, in this study area, was found to consist of four stratigraphic genetically related megasequences: the Marrat, the Dhruma, the Hanifa/Tuwaiq Mountain, and the Arab formations. They reveal the extremely dynamic nature of the deposition and basin evolution throughout the Jurassic period since each megasequence is found to be sequentially quite unrelated to the other. Most of the Jurassic depositional environments defined in the study area are low depositional relief carbonate ramps, except for the Dhruma and Hanifa/Tuwaiq Mountain where clear clinoforms exist, indicating relatively steeper depositional slopes. In addition to revealing depositional details at known stratigraphic levels, possible new reservoirs and source rocks have also been identified.
In summary, 3D seismic data was the key factor in this integrated regional study that has defined the basin evolution, a regional stratigraphic framework, and major and minor depositional environments at numerous levels within the Jurassic allowing for high confidence in targeting their stratigraphic exploration potential.
AAPG Search and Discovery Article #90141©2012, GEO-2012, 10th Middle East Geosciences Conference and Exhibition, 4-7 March 2012, Manama, Bahrain