Fractures identification and their contribution to production in khuff-3 Reservoir - a tight deep gas dolomite - in the Bahrain field

Janahi, Layla A. (Bapco - [email protected]) and Adel A. Al-Madani (Bapco)

The Khuff Formation (Permian age) is a major gas reservoir, which has been producing since 1970 under depletion drive mechanism. The Khuff Formation is considered to be the principle gas producer in the Bahrain field since 90% of the gas reserves are contained in it.  The remainder of the reserves is believed to be in the pre-Khuff sequence. Khuff Reservoirs produce around one BSCFD of non-associated gas.  The Khuff Formation is divided stratigraphically into four reservoir units: K0, K1, K2 & K3.  Matrix porosity and permeability are restricted to K0 to K2 units, with the best reservoir quality in K2 whereas reservoir development in the K3 is associated with fracturing.  Recently acquired 3-D seismic survey over Bahrain field, calibrated with wells information, has allowed à to far extent à the recognition of the structural style at Khuff levels.  The evaluation of fractures at K3 level was carried out by integrating well logs, borehole imagery and drilling information. This multidisciplinary approach has improved the understanding of the fractures distribution nature and occurrence in the Bahrain field at the Khuff level.  It is believed that this approach would reduce the drilling risk to developing the K3 reservoir and ensure that gas resources from this tight reservoir are well defined and optimally exploited and targeted.

Janahi, Layla A., and Al-Madani, Adel A., 2004, Fractures identification and their contribution to production in khuff-3 Reservoir - a tight deep gas dolomite - in the Bahrain field: Geo 2004, Bahrain, Gulf Petrolink.