Production-stabilizing technologies for tight condensate gas reservoirs rich in water cut:An example from Xujiahe Formation,Anyue gasfield,Sichuan Basin
In Anyue gasfield,Sichuan Basin,gas reservoirs of the second member in the Upper Triassic Xujiahe Formation(Xujiahe 2 Member)are elastic gas driving sandstone ones in the context of lithological trap.With some water cut and medium content of conden-sate,Xujiahe 2 gas reservoirs feature low porosity and permeability as well as high pressure.Meanwhile,there exists abundant bottom water in the reservoirs.It is pretty difficult to stabilize the production due to water invasion and retrograde condensate pollution during well production.Thus,combined with both liquid-producing characteristics of reservoirs and wells,some stabilizing technologies were applied to condensate gas reservoirs with water,and their application experiences were summed up and analyzed.Five technologies with better performance were selected,including gas huff-n-puff,water drainage by electric submersible pump(ESP),gas lift with on-board compressor,plunger gas-lift drainage,and automatic well opening and shut-in.Results show that(i)to reduce reservoir damage caused by retrograde condensate,the principles on well selection are defined for the application of single-well gas huff-n-puff technol-ogy;(ii)because of the characteristics of waterbody occurrence and water-invasion mode,two technologies of water drainage by ESP and gas lift with on-board compressor are used to make countermeasures against water drainage and recovery;(iii)the technology of plunger gas-lift drainage is optimized under conditions of oil,gas,and water three-phase flow in order to deal with insufficient lifting owing to small formation pressure;(iv)the technology of automatic well opening and shut-in is adopted for intermittent production wells with low pressure,which may increase efficiency and reduce labor costs.After evaluating these five technologies,it is suggested that they are conducive to the stable production of Xujiahe 2 gas reservoir in Anyue gasfield.All results provide stabilizing reference for similar tight condensate gas reservoirs rich in water cut.
Sandstone gas reservoir with water cutRetrograde condensation pollutionPlunger gas-lift drainageGas huff-n-puffXu-jiahe gas reservoirProduction-stabilizing technology
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