A Study of Water Coning Control in Oil Wells by Injected or Natural Flow Barriers Using Scaled Physical Model and Numerical Simulator

Document Type

Conference Proceeding

Publication Date

1-1-2002

Abstract

A scaled physical model (radial sand pack) and a numerical simulator were used in this study to investigate the time-dependent development and dynamic shape of the water-oil interface around the well producing from a bottom-water-drive reservoir. The water cone development was then related to the monitored changes in oil production water-cut. Also observed was the effect of well completions (single or dual-with the bottom water drainage) on water coning in three different reservoir settings. The first was a homogeneous reservoir and was studied as a base case. The second scenario was an impermeable barrier injected around the well bore at the oil water contact (OWC). In the third setting natural heterogeneity was created comprising a low- permeability layer at OWC across the whole drainage area. The study revealed that in the homogenous reservoir, using dual completion, it was possible to decrease water-cut in the oil production by draining water from the bottom completion and producing oil from the top completion. It was also established that the radial sand pack could be used to demonstrate visually the dynamic change in OWC with time. The study showed that placing a man-made impermeable barrier around the well bore would not stop the water cone from forming. Water would simply flow around the barrier. Moreover if such natural barriers exist around the well, using dual completions for water control would not be effective. It was also found out that the presence of a continuous low permeability layer across the reservoir would merely delay the development of water problem without eliminating it. Water breakthrough will be postponed and the water-cut will be reduced. It was also observed that the low permeability layer affects the shape of the cone in such a way as to increase the size of the base and make the tip of the cone narrow. With increasing use of "smart completions" and injected barriers to control water coning, this study visually illustrates the limitations of these technologies. The results could help in selecting methods for specific reservoir conditions.

Publication Source (Journal or Book title)

Proceedings - SPE Annual Technical Conference and Exhibition

First Page

741

Last Page

755

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