Gas condensate field performance theory vs practice

Abstract

This report presents a study on how to represent wells in numerical simulation of a coarse-gridded, full-field study of a lean gas condensate reservoir. A "black oil" (formation volume factor representation of fluid properties) model had been historymatched by comparing tubing head pressures as well as adjusting the well deliverability by multipliers on the well productivity indexes, the "WPI Mult" approach. The objective of this work is to investigate how the historymatching of well deliverability approaches has an impact on the well flowing oil-gas ratio in original lean, fictitious medium and rich gas-condensates reservoirs. Alternative well deliverability approaches investigated are called "Perm Mult" and "Fault Mult" with adjustment of permeability or transmissibility of numerical blocks surrounding the well blocks. The condensate impairment to the gas flow is well-known issue in gas-condensate fileds, but it is not accounted in a coarse-gridded model. The behavior of the important Region 1 and the change in the size of Region 1 are observed in well grid-cell and neighbouring grid cells. The steady-state liquid saturation is seen in Rich gas-condensate behavior after 5 years of production. Instead of tuning fluid properties to obtain a reasonable match between the measured oil-gas ratio and the simulated one, it is proposed to consider alternative well deliverability approaches.