This field is one of the the largest producer in Oman. It is mid-way through recovery and is expected to see additional development in the coming years. The field has been under water flood for over 20 years. Historically only the voidage management was sought and a voidage replacement ratio (VRR) policy was established and a lot of effort was put in place to meet it. This may have been sufficient during the initial phase of the water flood at the time when water production was still very low. As the water production has increased and more wells are starting to see water break through, a more comprehensive approach is needed to manage the field. There is a need to go beyond the simple material balance analysis in order to improve both vertical and aerial sweep efficiency of the water flood.
This paper presents the new strategy with several real examples being applied to improve volumetric sweep. It covers 3 main areas:
Integrated simulation model which sets the long term vision after matching the history and the overall reservoir behavior. It sets the field optimum reservoir pressure and offtake. However, the simulation model is too coarse to allow detail analysis at a well or pattern level.
Streamline simulation allows proper modeling of the no flow boundaries between producers and injectors and pattern definition and off-take optimization.
Analytical analysis which involves field performance monitoring and integration of new surveillance data to generate ‘snap-shot’ 3D pictures of the water flood front development. Many wells have been logged and the results are revealing a new 3D picture about the sweep performance.
The combination of the above three techniques may be used to set the well and reservoir management strategy in order to improve oil recovery from water flooded fields.