Sequence Stratigraphy and Environments of Deposition of the Cenozoic of Central and Northern Arabia

D. Mark Steinhauff, Chengjie Liu, Keith C. King, and George J. Grabowski
ExxonMobil Exploration Company, Houston, TX

Detailed biostratigraphy and high-resolution well-log and seismic correlation provide the basis for understanding the stratigraphy and environments of deposition in Central and Northern Arabia.

Late Paleocene through Eocene deposition was dominated by passive-margin, carbonate-ramp sedimentation in Central Arabia (northern Saudi Arabia, Kuwait, and southern Iraq) during a global greenhouse time. Early Paleocene rocks are thin or absent in Central Arabia. Depositional patterns were influenced by eustatic and tectonic events. For example, subsidence typically out-paced sea-level fall resulting in deposition of a nearly continuous shallow-water carbonate succession.

In contrast, Paleocene through Eocene foredeep evolution provided accommodation in the Mesopotamian Trough. Deposition started earlier than in Central Arabia; Paleocene through Early Eocene shallow- and deep-water carbonate strata were deposited; and Late Eocene through Oligocene, progradational shallow-water carbonate facies completed the fill.

In both areas, Oligocene through Miocene evaporites, carbonates, and siliciclastic rocks were deposited episodically, largely in response to regional plate convergence (Zagros Orogeny) during a global icehouse period. This was most pronounced in northern Arabia. Our results suggest that the Ghar Sand was deposited in two major pulses: (1) during the late Rupelian lowstand and (2) during the early Aquitainian lowstand. Locally, channels within the Dibbidda fan probably incise the Ghar, possibly compromising Ghar reservoir potential (Bahrah field, Kuwait). We interpret the Ghar and Dibbidda sandstones to be lowstand systems tracts geographically limited to southern Iraq. Both were probably derived from the same point source, up-dip along Wadi Al Batin.