Hydrocarbon Belts

Abstract Hydrocarbon belt is as a tectonic zone along which most hydrocarbons accumulate. Five major hydrocarbon belts are identified on the Arabian scale that are consistent; possess similar trends and geologic history. These are the NE-SW trend of the onshore Abu Dhabi fields, the N-S trend of Saudi Arabia, Kuwait and southern Iraq, the NW-SE trend is represented by Southern-Central Iraq, and the E-W trend in northern Iraq, Syria and Turkey. The fifth category includes fields related to salt doming events, which are not characterized by a systematic trend but can be restricted to specific areas where salt movements played a major role. Understanding these belts and their geologic concepts can predict new exploration potentials between or within the existing fields. The extent to which the stress state has influenced hydrocarbon distribution through geologic time can be directly seen on the fields maps. An important element on the existence of the hydrocarbon accumulation belts are that almost all fields in the Arabian plate and the foreland basin have not been obliterated by subduction. The continental collision of the Arabian plate with Eurasian plate produced high-pressure/low-temperature structural belts forming hydrocarbon traps resulting from deformation. This lead the hydrocarbon to move from high-pressure to low-pressure zones, leading the hydrocarbon migration and entrapment process towards low-pressure regions. Many wells drilled with direct measurements of in situ stress allows the estimation of the direction of the stress vectors. Using the local stress orientations in Abu Dhabi while linking this to tectonic events and combining with the Arabian stress trajectories fed the methodology and workflow presented in this paper. The results show that the stresses affecting Abu Dhabi can be categoriesed into: (1) The differential stress generating detectable azimuthal variations due depth; (2) The pre-inherited stress trajectories; and (3) the stresses related to the wrench fault segments. The pressure associated with these stress trajectories is the main driver for the hydrocarbon migration and filling of the traps. Applying these stress trajectories with the variances in the state of stress of different stratigraphic layers, enables understanding of where the hydrocarbon is trapped. Prediction of the migration trajectories is a very useful tool for exploration, specifically for the identification of new leads and plays, as well as for constructing new theories on the equilibration of the fluid levels and observations of residual oil below the current established free water levels.