Evaluation of water production in tight gas sands in the Cotton Valley formation in the Caspiana, Elm Grove and Frierson fields

摘要

Normally in tight gas sands, water production is not a problem but in such lowpermeability reservoirs it is difficult to produce gas at commercial flow rates. Sincewater is more viscous than gas, very little water is normally produced in lowpermeability reservoirs. The production of large volumes of water from tight gas sands,say 50-100 bbls of water per MMcf of gas constitutes a cause for concern. High waterproduction (>200 bbls of water per MMcf of gas) has been observed in the lowpermeability Cotton Valley sands in the Caspiana, Elm Grove and Frierson fields ofNorth Louisiana.This research evaluates water production in the above tight gas sands using fielddata provided by Matador Resource, a member of the Crisman Institute in Texas A&Muniversity. The research is aimed at providing realistic reservoir scenarios of excesswater production in tight gas sands. Log analysis, property trends and well productionprofiles have been used in establishing the different scenarios. The reservoir simulationresults and the production trends show a possible water source from faults and fracturesconnecting the Travis Peak/Smackover sands to the Cotton Valley sands. An improvedunderstanding of the reservoir would help in further field development.