New Oil in an Old Reservoir Through an Integrated Approach on Recharacterization of a Matured Clastic Reservoir: Lower Burgan, Sabiriyah Field, North Kuwait

Khan, Ali Nasar Khan, Nouf Abdullah Al-Mayyas Al-Mayyas, Moudi Fahad Al-Ajmi Al-Ajmi, H. B. Chetri Chetri, Ealian H Al-Anzi Al-Anzi, Kuwait Oil Company, Ahmadi-Kuwait, Kuwait

Sabiriyah field, located on the crest of Kuwait arch in Northern Kuwait is an elongated faulted anticline. The Lower Burgan is a multilayered clastic reservoir. The production per­formance of the reservoir is excellent, with a pressure depletion of only 50-450 psi from an initial reservoir pressure of 3900psi and 20% average water cut for cumulative production of 65% of the estimated recoverable reserves. Based on sedimentalogical and pressure studies, the Lower Burgan reservoir has been subdivided into Massive (M) and Layered (L) sands. The M Member forming the lower unit of the reservoir is composed of high quality sand and has produced most of its reserves. The overlying L Member has relatively inferior quality of sand and contains the majority of remaining reserves to be produced from the reservoir.

Review of the wells logs, cores and the reservoir performance emphasized on the need to revise the infill drilling program of the reservoir. The well logs have been looked into for ascertaining the oil water contact. Image logs have been used for Paleocurrent studies for chasing the extension of the reservoir and for pinpointing the infill locales of drilling. New logging tool-3DEX has been used for interpretation of thin sand shale intercalations.

The results of infill and other wells drilled so far have revealed the extension of the pay sand within and outside the foot print of the reservoir, encountering top of the reservoir rel­atively at shallower depths and deepening of the OOWC. All these culminated in an upward revision of STOIIP and Reserves; thereby an improved development strategy for the opti­mization of production of the reservoir has been formulated