Comparison of Well Productivity Between Vertical, Horizontal and HydraulicallyFractured Wells in Gas-Condensate Reservoirs

摘要

Gas condensate reservoirs usually exhibit complex flowrnbehaviors due to the build-up of condensate banks around thernwells when the bottomhole pressure drops below the dewrnpoint. The liquid phase accumulation in the near-wellborernregion forms a ring that reduces the gas relative permeability.rnAs a result, gas production decreases and the liquid phasernwhich is a significant part of the value of the field remains inrnthe reservoir.rnVarious solutions have been implemented in order tornremediate such a productivity loss. They include drillingrnhorizontal wells instead of vertical wells 1-3 , hydraulicallyrnfracturing vertical wells before or after the development of therncondensate bank, and acidizing after the condensate bank hasrnformed 4-14 .rnIn this work, we used reservoir simulation to quantify thernincrease in well productivity from different remediationrnsolutions and assess their effectiveness. The empiricalrncorrelations needed to model non-Darcy flow and capillaryrnnumber effects, which are among the main parameters thatrncontrol gas condensate well performance, were calibrated withrnactual well test data.rnAs should be expected, we found that horizontal wells andrnhydraulically fractured vertical wells improve wellrnproductivity. The degree of productivity enhancement,rnhowever, depends on well and reservoir parameters such asrnhorizontal well lengths, permeability anisotropy, fracturernlength and fracture conductivity. Different simulation modelsrnwere run above and below the dew point pressure at the samernreservoir and flow conditions. The results of our simulationsrnshow that horizontal wells enhance productivity significantlyrnbelow the dew point. Performance improvement withrnhydraulic fractures, on the other hand, depends on facturernlength and fracture conductivity.