Hydrocarbon liquid fraction mapping functions for gas-condensate well test evaluation

The simulated flash behaviour of equation of state characterised well stream fluids is characterised to develop scalable yet robust condensate mass fraction well test mapping functions. These were used to calibrate historical well test results as part of a field review project. Instead of test to production conditions correlations, which are demonstrated from the Goodwyn field case study to be dependent on the degree of reservoir pressure depletion and gas cycling, the intermediate separator independent C5+ mass fraction parameter is developed, from which train dependent liquid yield can be mapped. An advantage of this approach is that it is able to track changes in liquid yield between well composition sampling events. Evaluation of this technique vs the previous temperature only correction approach indicates that production separator liquid yield is being overestimated. The overestimation highlights the significant impact gas cycling and falling separator pressure has on liquid yield, and how the mapping functions accomodate for it by using the intermediate train independent C5+ parameter.