Gas lift optimisation increases production on mature asset

In Brief
Gas lift optimisation performed using simulation tools, nodal analysis and network modelling system techniques increases production
Production Optimisation
  • Mature multi-platform asset with 17 active wells (14 platform and three subsea)
  • Production network comprising three production pipelines, plus one gas lift and one gas export pipeline
  • Lift gas supply was perceived to be inadequate for current production conditions
  • A further threat was the future addition of four platform infill wells
  • Additional challenges included: determining how much gas lift was being directed to each well; uncertainty of individual well production due to infrequent well testing; no immediate scope to gather downhole data
Expro Excellence
  • Early focus given to a review of historical data (from the well intervention operations, reservoir engineering, projects and flow assurance studies) allowing robust well and system models to be produced - revealed a lift gas injection issue on one well which was resolved without intervention 
  • Smoothing out artificial lift inefficiencies allowed other issues, such as inflow performance, to be examined
  • Unsuitable well test information was screened out
  • A method proposed by the client to derive a lift gas metering calibration erroe was scrutinised and compared with two other developed methodologies; this resulte in an error correctins being implemented with confidence
  • A matched suite of nodal analysis well models and a surface network model were produced as part of an integrated production model (IPM)
  • Gas lift operations training was provided to offshore personnel in order to reinforce knowledge transfer
  • Collaborations with Expro's cased hole services team to provide a range of tools to help identify physical well integrity issues including corrosion, scale, deformation and leak detection
Value to client
  • Gas injection lift was optimised to yield an additional 900 STB/day
  • The IPM allowed key wells to be targeted for future intervention, and well testing schedules were optimised to allow asset production to be adequately monitored
  • The calibrated integrated production model allowed the onshore production team to provide reliable well rate potentials to the offshore production team: building trust

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