The Greater Burgan Field, operated by Kuwait Oil Company (KOC), is the largest clastic and overall the second largest oilfield in the world. First discovered in 1938, with production from 1946, production to date has relied on primary recovery methods. In recent years secondary and enhanced recovery techniques have been investigated with water flood now at an advanced state of implementation. The first such water flood project is in the Upper Cretaceous (Cenomanian) Wara Formation, one of the main producing reservoirs within the Greater Burgan complex where production has been accompanied by falling reservoir pressure.
The Wara Formation comprises multiple sandstone units deposited in a fluvial-tidal coastal system. The reservoir exhibits a considerable degree of permeability heterogeneity, which poses significant challenges to the implementation of waterflood. The highly complex nature of the reservoir necessitate for implementation of suitable strategies from an early stage of waterflood to ensure better volumetric sweep and ultimate recovery. Several initiatives/studies, including sector model simulation, were undertaken to formulate strategies and evaluate the waterflood performance in this multilayered reservoir.
This paper summarizes results of the studies and strategies:
Issues related to vertical sweep and lessons from pilot study.
Strategies for improving vertical sweep.
Evaluation of strategies by using sector model simulation to improve recovery.
Well completionstrategies and candidate selection criteria.