A strategy to manage and control gas coning problems in the Akal-Cantarell field, based on correlations developed by extensive single-well dual porosity numerical modeling of gas coning phenomena, is presented in this paper. Attention was given to the range of reservoir parameters and production conditions that were found relevant to and representative of the Akal field. The effect of high permeability channels, left behind in the casing by improper cementation, on the evolution of gas coning was also analyzed.

It was found that the main variables that govern gas coning and channeling phenomena in the naturally fractured Akal field are: the effective permeability of fractures, Kf, oil production rate, qo, and the distance between the gas-oil contact and the perforations at gas breakthrough, Dzcp. A range of qo and Kf values, characteristic of the Akal field, was considered. For each pair of qo and Kf values, the distance between the gas-oil contact and perforations, Dzcp, at which the gas cone breaks into the well, was determined. A log-log graph of Dzcp versus qo, for given Kf value, resulted in a straight line for both coning and channeling phenomena.

Correlations developed for Dzcp as a function of qo and Kf as well as those developed to determine the times required for gas cones to dissolve, when the well is shut-in or choked, were used to define a production strategy to maximize the life of wells and optimize production. A field application is presented.

Keywords:
upstream oil & gas, correlation, reservoir simulation, cone, complex reservoir, breakthrough, production rate, well model, oil production rate, full field model
Subjects:
Fluid Characterization, Reservoir Simulation, Unconventional and Complex Reservoirs, Phase behavior and PVT measurements, Naturally-fractured reservoirs
Copyright 2012, Society of Petroleum Engineers
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