Chapter 9 - Gas and Water Coning

Abstract

This chapter discusses the gas and water coning. The objective of this chapter is to provide the theoretical analysis of coning and outline many of the practical solutions for calculating water and gas coning behavior. Coning is a term used to describe the mechanism underlying the upward movement of water and/or the down movement of gas into the perforations of a producing well. Coning can seriously impact the well productivity and influence the degree of depletion and the overall recovery efficiency of the oil reservoirs. The specific problems of water and gas coning are: costly added water and gas handling, gas production from the original or secondary gas cap reduces pressure without obtaining the displacement effects associated with gas drive, reduced efficiency of the depletion mechanism, the water is often corrosive and its disposal costly the afflicted well may be abandoned early, and loss of the total field overall recovery. Finally, coning is primarily the result of movement of reservoir fluids in the direction of least resistance, balanced by a tendency of the fluids to maintain gravity equilibrium.