Onset time of lift-assisted foam drainage gas recovery in adjacent wells
An innovation of lift-assisted foam drainage gas recovery in adjacent wells has been put forward to make conventional foam recovery more useful,that is,injecting gas from the next wells into annular in one gas well with liquid accumulation while foam agent into this annular.For the innovation,the agent's onset time is important for well production because it may control both shut-in time and gas production rate.Nevertheless,there is no such study in the industry.Thus,based on available discussion on the shut-in time after intermittent injection of foam agent in tight gas wells,both traveling and dispersion time of this agent was judged in line with changes in wellhead pressure,gas flow and temperature after foam injection,and then the onset time could be determined.Moreover,compared with conventional foam-agent injection,the advantages and principles were analyzed for this new process.Results show that(i)for two kinds of foam agent individually used in conventional and new processes,the flow pattern is different.The agent in the con-ventional process represents a linear downward travel along oil casing wall with"static"annulus.While that of the innovation trav-els like liquid droplet downward rapidly along with gas from the adjacent wells after entering the"dynamic"annulus in the gas well with liquid accumulation;and(ii)this innovation may significantly shorten the onset time to 1.1 h from 8.2 h,implying an increase of efficiency by 86.6%.Better drainage can be gained through lift in the liquid accumulation well assisted by injecting gas from the next wells.It not only enables some with low production and pressure to resume normal production but provides fresh ideas for water drainage recovery in them,which is worth to popularize.
Liquid accumulationFoam drainage gas recoveryLift-assisted in adjacent wellTravelling timeDispersing time
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维普
