In Auto gas-lifted wells, gas from either a gas zone or gas cap is used to lift oil in a commingled way. Balancing gas zone energy depletion to the benefit of oil production requires an accurate understanding of zonal contribution and an ability to adjust and control inflow from both zones.

A project was undertaken for accurate zonal allocation and optimization of lift gas rates by designing an appropriate zonal contribution measurement procedure for five Auto gas-lifted wells on two fields. This approach utilized both production logging and production testing to obtain both zonal down hole and commingled surface flow measurements. As a result of the exercise, lift gas flow into the tubing was optimized, thus maximizing the oil production rate while conserving reservoir energy through efficient gas usage.

Measurement of zonal contributions in multi-zone intelligent well completions are often challenging due to the complex nature of fluid flow under varying dynamic conditions of multiple reservoirs. This paper will explain the zonal contribution measurement program design, implementation, interpretation of data and lessons learnt from the project.

Keywords:
reservoir surveillance, drillstem/well testing, production monitoring, upstream oil & gas, icv slot, flow metering, modeling, auto gas lift well, completion, production control
Subjects:
Well & Reservoir Surveillance and Monitoring, Formation Evaluation & Management, Downhole and wellsite flow metering, Drillstem/well testing
Copyright 2012, Society of Petroleum Engineers
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