Development of Optimum Well Spacing Proxy Equations on Waterflooding Project

Abstract

Secondary recovery has been implemented widely since decades ago as pressure maintenance especially waterflooding both in green and brown fields. Advanced experiences are gained already by operators throughout development stages of waterflood project both in technical and economic aspects. However, challenges to predict waterflood performance with less time consuming and costly yet accurate still exist. Full field waterflood performance is very dependence with well pattern spacing. This paper will introduce a novel technique to predict and optimize well spacing with proxy equations.
Series of synthetic data is generated to create proxy equations of profitability index and recovery factor. This generated data incorporates reservoir properties, fluid properties, and wells operating conditions. The proxy equations are validated or tested with existing field data. Through numerical technique, the validated proxy equations are used to optimize well spacing. The optimized spacing is then represented as a map on top of reservoir boundaries. The map is utilized to reshaping, realigning the existing pattern geometries and wells placement. The model with proposed well spacing is tested using numerical reservoir simulation to see its impact on recovery of a pattern and structure/field.
As a case study, series or ranges of input data of Rantau Structure are used. The optimized well spacing map of this field is incorporated into a reservoir model and simulated. The proposed well spacing is able to improve the recovery factor and profitability index, although the improvement is achieved by having less number of wells.
Finally, this general technique is proven to be an effective and efficient for waterflood application. Moreover, there is no restriction that similar technique to optimize well spacing should be able to be developed and implemented to many other applications, e.g., Enhanced Oil Recoveries (EOR).