Assessment of Undiscovered, Conventionally Recoverable Petroleum Resources of Arabian-Iranian Basin

Charles D. Masters, H. Douglas Klemme, Anny B. Coury, James A. Peterson

Undiscovered, conventionally recoverable petroleum resources in the Arabian-Iranian basin are estimated at probability levels of 95%, 5%, and statistical mean. Estimates for oil are 72, 337, and 174 billion bbl; for gas, they are 299, 1,792, and 849 tcf.

Petroleum occurrences can be accounted for in five definitive geologic settings or plays. Undiscovered resource potential is assessed, assuming that new discoveries will expand the occurrence of petroleum in these basic plays. The five plays listed in sequence are: (1) Upper Cretaceous and Tertiary, (2) Lower and middle Cretaceous sandstone, (3) Lower and middle Cretaceous limestone, (4) Jurassic, and (5) Permian. The Permian play is located in the south-central Arabian Gulf region and extends northeast-southwest from southern Iran to the Ar Rub' al Khali in Saudi Arabia. It accounts for more than four-fifths of the mean estimate of undiscovered gas. The Jurassic play, located on the south side of the Arabian Gulf, accounts for slightly less than one-third of the estimated undiscovere oil, which is split equally between Saudi Arabia and Iraq. The Lower and middle Cretaceous limestone play is located in the southern gulf region and accounts for about one-fifth of the undiscovered oil. The Lower and middle Cretaceous sandstone play is centralized in Kuwait at the head of the Arabian Gulf, with significant potential extending northwest into Iraq. This play accounts for about one-third of the undiscovered oil. The Upper Cretaceous-Tertiary play is located in the Zagros foldbelt of Iran and Iraq, and accounts for about one-fifth of the undiscovered oil.

Data are unavailable for certain broad regions, abandoned wells, and several significant dry holes, which may affect our estimates. However, the regional geology is reported well enough that geologic projections can be made and inferences can be drawn from selected wells to allow workers to estimate the resource potential.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.