Condensate dropout and accumulation along with high water satur ation near the wellbore region result in a decrease in the gas relative permeability. This permeability is a functi on of fluid saturations, interfacial tension (IFT) and rock wettability between the condensate and gas. The need to mitigat e the reduction in well productivity caused by condensate build up below the dew point is the motivation behin d the research.
The primary objective of the work is to evaluate the feasibilit y of increasing the relative permeability to gas in cores via use of surfactants to either eliminate or minimize the impact of condensate accu mulation. Identification of suitable chemical agents with th e capability to restore well pr oductivity and reduce condensate banking effects at the wellbore has been undertaken.
Experimental investigation of ph ase behaviour, interfacial tens ion and relative permeability and a screening study on surfactants for ultra low interfacial tension is prese nted. We have completed a series of steady state corefloods to measure the relativ e permeabilities of gas and co ndensate in sandstones and limestone rocks over a range of initial water saturatio n and flow rates. These coreflo ods were conducted to study the effect of chemical treatments on the gas relative p ermeability after condensate bu ildup.
Simulation studies will be used as an aid in understanding th e required amounts of chemical needed and the length of time over which these treatments will be effective in heterogeneous formations in Trinidad and Tobago. Such simulations will also be useful i n estimating the appropriate r ange of capillary numbers for the corefloods. Based on the simulations, recommendations w ill be made regarding suitabi lity for horizontal or fract ures well use in Trinidad and Tobago.