Implementing Water Flood in the Greater Burgan Field, Kuwait: Improved Development Planning Through Pilot Testing and Field Appraisal Activities

摘要

The Greater Burgan Field is the largest clastic oilfield and the second largest oilfield in the world. First discovered in 1938, and developed from 1946, production to date has relied on primary recovery methods. More recently secondary and enhanced recovery techniques have been investigated and water flood is now at an advanced state of implementation. The first such water flood project is being implemented in the Upper Cretaceous (Cenomanian) Wara Formation, which is one of the main producing reservoirs within the Greater Burgan complex. Here, production has been accompanied by steadily declining reservoir pressure. The Wara Formation comprises multiple sandstone units deposited in a fluvial-tidal coastal system with a total thickness of approximately 140 – 180 feet. The reservoir exhibits a considerable degree of permeability heterogeneity. Lateral and vertical extent, and the pressure communication between sand bodies is highly complex. Understanding of hydraulic connection and volumetric sweep are therefore one of the key development challenges to address in this complex reservoir. To avoid costly water disposal and to make best use of available resources the full field waterflood will re-inject produced water. Therefore project planning required an assessment of water injectivity using several water sources and an investigation of the required water quality requirements for the full field water flood. A peripheral waterflood configuration has been selected for Wara reservoir taking advantage of some 1200 feet of vertical relief between the flanks and crest of the anticlinal structure. Prediction and optimization of this waterflood project required appraisal of structure, pressure, reservoir quality and fluid type in largely undrilled lower flanks areas. This paper summarizes the pilot waterflood projects, flank appraisal activities and related study work to understand hydraulic connection, reservoir properties, injectivity and reservoir performance. It describes the approach taken and the learning points from each of the activities together with their implications for the full field water flood project.