Hydrocarbons Injection To Improve Recovery From Gas Condensate Reservoirs: A Simulation Approach

摘要

Hydrocarbons injection has been reported, in theopen literature, to improve both gas and condensaterecovery from gas condensate reservoirs. Theinjection process is considered once a liquid ringbuilds up around the well bore thereby reducingdrastically gas delivery. Actual reservoir and fluidsdata from a deep gas condensate well, completed infive distinct layers, were used as input to acompositional reservoir simulator to assessthe following:1) Evaluation of various (four) injection fluids; 2)impact of shut in and injection as well as shut inalone; 3) Impact of minimum flowing bottom holepressure constraints; 4) evaluation of a single layermodel equivalent to the original multi layer well; 5)impact of shut in and injection on the equivalentsingle layer model; 6) impact of shut in alone on theequivalent single layer model and 7) evaluation of abinary system (77% C1 and 23% nC4) at a relativelylow pressure and temperature.From the four tested injection fluids the C4-C5mixture gave the best results for productivityrestoration. The injected C4-C5 mixture, at the highdew point considered in this work, creates, throughmiscibility, a single liquid phase around thewell bore.At the trailing edge of the liquid-phase aroundthe well bore the capillary number increases sharplyindicating a sharp drop in IFT. Hence the gascoming in towards the well bore is just like the liquidsfully miscible with the liquid phase around thewell bore.Simulation runs done on a binary system, at alow dew point pressure indicate the miscible processwill also work but the single phase around the wellbore will be a vapor phase.