Abstract

Producing oil from a bottom-water drive reservoir through the use of conventional vertical wells is subject to severe water coning, leading to a low oil recovery. Indonesia has many reservoirs associated with bottom water acting as the dominant driving fluid. These reservoirs could be the target for horizontal well application in an effort to imporve the oil recovery. A production predictive tool, however, is needed to support the economic evaluation prior to implementation.

The purpose of this paper is to present a new method for horizontal-well coning prediction. This attempt is made by considering that the available published correlations are based on a uniform flux model, which is not the case for most field conditions as the reservoir flow geometry is affected by wellbore hydraulics. In the present study, a one-dimensional displacement governing equation is used to develop the correlation. To account for both non-uniform flux and flow geometry, a factor derived from production history matching of a field case is introduced. This factor accounts for drainage area, well length, and well position with respect to water/oil contact.

Two example applications by using other field data are given to demonstrate the applicability of the method developed. The calculation procedure is simple. The method proposed can forecast oil production and water cut versus time. These are vital for an economic evaluation and designing the capacity of water handling equipment. Results also suggest that permeability characteristics data and well placement design are of importance in the process of evaluation.