Keywords: gas condensate, volatile oil reservoirs, compositional reservoir simulation, phase behaviour, pressure-volume-temperature, PVT, compositional gradient, condensate banking, liquefied petroleum gas, LPG, modelling, well deliverability, primary depletion, gas injection
PVT characterisation and compositional modelling of gas condensate and volatile oil reservoirs
In recent years, many gas condensate and volatile oil reservoirs have been discovered offshore. Many of these reservoirs are under high temperature and high pressure conditions. It is important to properly model and optimise gas condensate recovery during asset development in many oil and gas companies. A systematic approach to modelling gas condensate and volatile oil reservoirs by the use reservoir simulation is presented in this paper. The following topics are focused in particular: 1) simulation model selection; 2) generating a pressure-volume-temperature (PVT) model for modified black-oil models and tuning equation-of-state (EOS) parameters for compositional models; 3) initialising simulation model with a compositional gradient; 4) the concern of well deliverability caused by condensate banking effect; 5) development strategy - primary depletion or gas cycling; 6) PVT characterisation of liquefied petroleum gas (LPG) and quantification of LPG production under primary depletion and gas injection.