Novel Technique to Eliminate Gas Condensation in Gas Condensate Reservoirs Using Thermochemical Fluids

摘要

In situ heat generation is one of the promising techniques to enhance hydrocarbon production, by removing the condensate damage from the near-wellbore region, and improve gas mobility. This technology is performed by injecting two thermochemical solutions that will react at reservoir conditions and generate heat and pressure. The use of thermochemical fluids will reduce the injection cost to within 60% compared to the solvent injection. During thermochemical treatment, a considerable alteration in the fluid phase behavior will take place. This paper presents a novel technique and the first application of using thermochemicals to eliminate gas condensation. Experimental measurements and computer modeling group (CMG) modeling were performed to investigate the effect of injecting thermochemical fluids on the gas condensate behavior. A new reactor was fabricated to study the reaction kinetics of thermochemical materials. Thereafter, the influence of thermochemical treatments on removing the condensate, reducing the capillary forces, and improving the gas production was studied. Also, the impact of energizing the condensate region with nitrogen that was generated by thermochemical reaction was emphasized. Finally, the propagation depth of the generated heat from thermochemical reaction was determined as a function of injection time. The obtained results showed that injecting thermochemical fluids will increase the reservoir temperature and pressure beyond the dew point curve. At reservoir conditions, a pressure of 1300 psi could be achieved from the thermochemical reaction. The generated pressure is higher than the dew point pressure; therefore, the condensate liquid will be converted into the gaseous phase. Calculations of capillary forces revealed that thermochemical treatment reduced capillary forces by 25-36%. An exponential relationship was observed between the injection time and the radius of heat propagation. Increasing the injection time will increase the radius of the heated area exponentially. The heat propagation model can be used to determine the injection time required to heat the condensate region inside the reservoir.