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Abstract:
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Many gas wells suffer a loss in productivity due to liquid accumulation in the near wellbore region . This problem starts as the flowing bottom hole pressure drops below the dew point in wells producing from gas condensate reservoirs . Chemical stimulation may be used as a remedy , by altering the wettability to non -liquid wetting . Successful treatments decrease liquid trapping , increase fluids mobility , and improve the well’s deliverability . The main focus in this research was to develop an effective chemical treatment to mitigate liquid blocking in gas wells producing from carbonate reservoirs . In the initial stages , screening tests were developed to quickly and effectively identify suitable chemicals from a large pool of compounds . X -ray Photoelectron Spectroscopy (XPS ) measurements , drop imbibition tests , and contact angle measurements with water and n -decane were found to be necessary but not sufficient indicators of the effectiveness of the chemicals and were used as screening tools .
An integral part of the development of the treatment solution was the selection of a solvent mixture capable of delivering the fluorinated chemical to the rock surface . The treatment solution , mixture of chemical dissolved in solvent , must be stable in the presence of both brine and condensate so that it will not precipitate and will not reduce permeability of the rock . Through phase behavior studies the compatibility of the treatment solution and in -situ brines were investigated to reduce the risk of failure in the coreflood experiments . The measured relative permeability values in Texas Cream Limestone and Silurian Dolomite cores are demonstrate from high -pressure , high -temperature coreflood experiments before and after treatment . Measurements were made using a pseudo -steady -state method with synthetic gas -condensate mixtures . To enhance the durability of the treatment a special amine primer is introduced . |