Prediction of gas coning in hydrocarbon reservoir using tNavigator

Abstract

Several approaches for avoiding gas breakthrough due to coning phenomena have been proposed. These methods include maintaining oil production rates below critical rates, inserting crosslinking gels near the well to create a gas-blocking area, and making perforation as far away from the initial gas-oil contact (GOC) as possible, often considered uneconomically solutions and not sufficient way to deal with the problem. Furthermore, this is a major source of concern in terms of the additional costs of separation procedures and equipment availability. Coning couldn’t possibly be totally eliminated, but it can be minimized by defining the breakthrough time and understanding the characteristics that have a significant impact on breakthrough time and how effectively may be manipulated to delay it. A mathematical and numerical approach was used in this research for the purpose of gas breakthrough time investigation and monitoring the gas-oil ratio (GOR). tNavigator embedded flow equation was used as a novel 3D compositional simulation principle in the software to predict the time of gas flow from grid cell to another reaching the perforation interval, for the purpose of utilizing the sensitivity analysis of certain parameters which had sufficient impact on GOR value and breakthrough time (tBt). Results show that the Oil column is the most effective parameter in the sensitivity analysis and the one factor to focus on while producing from gas cap reservoirs.