CAUSES OF DECREASED CONDENSATE RECOVERY FROM LOW- PERMEABLE FORMATIONS AND WAYS TO INCREASE IT

摘要

The paper investigates the processes of condensate recovery from low-permeable formations during depletion-driven development of gas-condensate deposits. The studies were based on simulating multi-component flow of various gas- condensate mixtures in reservoirs with a large range of permeabilities. As a result, the key causes of decreased condensate recovery from low-permeable formations compared to “regular” reservoirs have been established. It was shown that for low- permeable formations, due to large pressure drawdown cones, the additional condensation of С5+ components because of an “non equilibrium” effect is possible, where the flowing gas phase is out of equilibrium to the retrograde condensate. The main technological factors influencing the condensate recovery from low-permeable formations were identified, as well as possible ways to increase condensate recovery.