UPSCALING GAS-WATER RELATIVE PERMEABILITY MEASUREMENTS FROM AMBIENT TO RESERVOIR CONDITIONS

摘要

A model that can accurately upscale ambient relative permeability curves to reservoir conditions is of great importance to the oil/gas industry. Whereas ambient data is easily accessible, the cost of generating gas-water relative permeability at reservoir conditions [high pressure, high temperature (HPHT)] is quite high and technically complicated. Under these extreme conditions gas exhibits a great change in its physical properties, thus affecting gas solubility in liquid phases and its interaction with solid phases (mineral grains). Therefore, utilizing ambient gas relative permeability data in reservoir simulation studies may result in unexpected production profiles. Consequently, reservoir engineers may need to spend many hours on simulations in order to obtain acceptable relative permeability curves through reservoir simulation, history matching processes. In this study, two sets of unsteady state relative permeability data will be obtained, compared, and analyzed. The first set was obtained under ambient conditions and the second set was obtained under reservoir conditions (HPHT). The main objective of this research work is to develop an analytical model to predict reservoir condition relative permeability data based upon ambient permeability data. A Corey model (power model) was used to match ambient relative permeability curves with reservoir condition curves. By modifying the power parameters in Corey correlation, both wetting and nonwetting phase relative permeability curves were able to be matched. The matching parameter can thus be used to generate reservoir relative permeability curves for reservoir sandstone from the experiments conducted under ambient conditions. Relative permeability curves were also investigated on full reservoir simulation models using a reveal simulator. The results indicated that recovery efficiency decreases by nearly 20% if ambient relative permeability data were used instead of reservoir condition relative permeability.