Abstract:

Generally speaking, the fracturing can improve the reservoir single well production, however, whether it can reduce the retrograde condensation damage in gas condensate wells or not is urgent to be discussed further. By adopting the indoor core laboratory and single well numerical simulation method, we analyze the impacts of retrograde condensation on the gas phase permeability, the retrograde gas condensate saturation near the wellbore zone, the single well production and the recovery ratio before and after fracturing. The research shows that, after fracturing, the retrograde condensation damage is more serious and the damage time is earlier. However, the fractures reduce the condensate oil critical flow saturation. In the process of the depletion exploitation, the effective permeability value of the fractured gas phase is always larger than the value before fracturing. In addition, the gas phase flow ability increases substantially. After fracturing, the gas recovery speed of the single well is fast, the formation pressure reduces rapidly and the retrograde condensation damage is more serious. Furthermore, the recovery ratio of the condensate oil reduces by 3.48 % and the recovery ratio of the natural gas improves by 6.6 %. Accordingly, it concludes that, fracturing can’t effectively reduce the degree of the retrograde condensation damage, but it can improve the flow ability of the gas phase and the gas production of the gas condensate wells.

Key words: condensate gas reservoir, retrograde condensation, fracturing, full diameter core, numerical simulation