CASE STUDY

Increased Recovery by Tuning the Gas Lift

DFO sensing acquires data to optimize recovery

increased-recovery-by-tuning
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Results

  • Visualized well behaviour changes instantly in response to choke and gas injection rate settings
  • Visualized flow movements and flow energy
  • Pinpointed the exact location of gas flowing through a small orifice
  • Accurately determined the depth of gas bubbling at low rates

Objectives

  • Observe both the Gas Lift Valve behavior and the entire reservoir simultaneously
  • Monitor the flow regime while adjusting the gas injection
  • Observe real-time responses to GL adjustments in order to optimise production
  • Identify whether an unstable valve is causing production zones to turn on and off due to pressure fluctuations

Method

The Ziebel modular electric surface unit safely lowered the sensing rod into the well and pushed it far into the horizontal section. The sensing rod was parked in the wellbore for acquisition. The distributed fiber optic (DFO) sensing acquired both temperature and acoustic data. The temperature sensing uses the Joule Thomson effect which relates the rate of change of temperature to pressure. The acoustic sensing relates noise and frequency to gas rate. By adjusting the gas injection rate and the surface choke, and then observing the response of both the temperature and acoustic data, the optimal setting for the well could be determined.
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