An Nagyah Field, Upper Jurassic Lam Member Discovery—Marib/Shabwa Basin, Republic of Yemen

Bruce Allen Wright
Vintage Petroleum, Inc, Tulsa, OK

An Nagyah Field, Upper Jurassic Lam Member Discovery – Marib/Shabwa Basin, Republic of Yemen

Vintage Petroleum's recent sub-salt discovery in Yemen has opened up a new reservoir and exploration corridor in the southern flank of the Marib/Shabwa Basin, Republic of Yemen. Rift-filling Lam Member sandstones of the early Tithonian Stage have been found productive for light gravity oil in the An Nagyah Field. To date, the basin's main production has been from the mid to late Tithonian intra-salt Alif Member sandstones of the Sabatayn Group. Unlike the Alif, which is thought to be deposited as a braided stream system sourced from the northwest, the Lam sandstones at An Nagyah were deposited in a proximal setting to a southern tectonic mountain front in the form of alluvial fans and fan delta deposits. This depositional model is supported by whole cores taken in wells drilled by Vintage. The field is located over a tilted basement-related horst block, trapped by faulting and the overlying salts of the Sabatayn Group. Understanding the relationship between the Jurassic rifting, subsequent deposition of the Lam, and the migration / sealing events is an important ingredient for further exploration in this emerging play.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005