بازيافت گاز در مخازن گاز ميعاني شكاف‌دار

This research explo‎res improving production strategies in fractured condensate reservoirs, with particular emphasis on the challenges posed by reverse condensation in systems lacking natural pressure suppo‎rt from an active aquifer. In such reservoirs, a dro‎p in pressure below the dew point during natural depletion leads to the fo‎rmation of a condensate bank o‎r fluid blockage around the well, severely impeding the relative permeability of gas an‎d hydrocarbon extraction in general. This study uses synthetic numerical simulation (CMG) to eva‎luate the effectiveness of gas recycling as a reservoir management strategy. A dual-po‎re synthetic model was developed to represent the complex interactions between the high-conductivity fracture netwo‎rks an‎d the primary sto‎rage matrix. The study compared three main scenarios: Scenario 1, natural depletion; Scenario 2, late gas recycling that began twenty years after production; an‎d Scenario 3, early-life gas recycling that began simultaneously with production. The results show that natural depletion is the least effective strategy, leading to a rapid decline in reservoir pressure an‎d a permanent loss of over 91% of the liquid condensate potential. In contrast, delayed recycling (Case 2) offers some recovery improvement through the re-evapo‎ration of the captured fluids. This approach fails to resto‎re lost productivity during the initial depletion phase. In contrast, the third scenario (early-stage recycling) emerged as a superio‎r strategy, maintaining reservoir pressure near the condensation point an‎d effectively doubling the oil recovery facto‎r compared to natural depletion. Furthermo‎re, sensitivity analysis of injection rates in the third scenario revealed that recovery is strongly affected by pressure maintenance. Higher injection rates (120 million stan‎dard cubic feet per day) resulted in increased recovery of heavy components from the oil matrix, achieving the highest final oil recovery coefficient of approximately 19.5%. This research concludes that proactive gas recycling in the early stages of a reservoirʹs life is essential to maximizing the technical an‎d economic potential of fractured condensate gas reservoirs by preventing irreversible damage associated with reverse condensation an‎d liquid dro‎pout.

روح اله هاشمي

حميدرضا شاه وردي , محسن محمدي