3D Petroleum Systems Modeling of Eastern and Central Saudi Arabia

By

 Mahdi Abu Ali¹, Christof Keuser², Bjorn Wygrala², Dietrich Welte²

(1) Aramco, Dhahran, Saudi Arabia (2) IES, Julich, Germany

 3 Dimensional Petroleum Systems Modeling (3D PSM) is an integral process that describes and models petroleum migration, dynamically and through geologic time, from source to trap. It considers all petroleum system elements such as source, reservoir, seal, trap, migration and timing of all key processes. In contrast, conventional basin modeling is mainly concerned with hydrocarbon generation within the source rock.

A 3D model was constructed for Eastern and Central Arabia that described thermal and maturation histories of the Paleozoic geologic successions. This model emphasized hydrocarbon generation and migration histories from the Silurian Base Qusaiba source rock to the Devonian Jauf and Permo-Carboniferous Unayzah reservoirs. Migration of different hydrocarbon compound classes was modeled using a compositional generation scheme for the Silurian Qusaiba source rock.

Results show that Tertiary tilting of the basin has affected present-day drainage areas. Several sensitivity runs were performed to test the influence of certain petroleum systems elements such as reservoir, seal, source and migration properties on the distribution and composition of hydrocarbons within the study area. A 3D hybrid Darcy/Flowpath simulator was used to test different migration scenarios taking into account open and/or closed fault systems. Present-day accumulations were compared with the simulation results to validate their sensitivities.

The results demonstrate that 3D petroleum systems modeling technology, if well calibrated, provides an excellent exploration tool to predict distribution and type of petroleum occurrences. Once reservoir hydrocarbon compositions are reasonably predicted, the application of such a tool will witness a new era in petroleum exploration and development.