Artificial Lift Techbook 2018

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Page 44 of 51 | July 2018 | 43 ARTIFICIAL LIFT: CASE STUDIES T he majority of the world's gas-lifted wells are routinely operating in a non-optimal state. Addressing this with existing technology is typically time-consuming, costly and risky, requir- ing frequent well interventions with associated production loss. Additionally, it is not currently possible to fully automate the day-to-day opera- tion of a gas-lifted well. A data-driven approach to on-demand in-well adjustment of lift gas depth and rate to assure maximum and stable production is not possible. Despite being extremely compliant, gas lift cur- rently presents some challenges. These include uncertainties around the effective monitoring and measurement of gas-lift efficiency, and intervention for valve deployment to optimize production. The combined effect of a lack of data and the need for costly intervention create production limitations. Eliminate uncertainties For production engineers operating gas-lifted wells the day-to-day challenges are how to produce more efficiency with less intervention and how to obtain more data to enable decisions with less uncertainty. These challenges typically revolve around answer- ing questions that are rarely easy to answer. These include if the well is completely unloaded or if it is multipoint injecting, the lift depth, whether the well is optimized on gas lift, if the well could be lifted at a greater depth and if the wellbore hydraulic model is a good match for the actual well performance. Other important questions center on the extent and timing of required intervention, allocating available lift gas and the details of the lifting life cycle. Because of the limited functionality and flexibility of legacy completion hardware, answering these ques- tions and making adjustments to optimize gas-lifted wells has until now involved a considerable amount of costly well intervention, nonproductive time and associated risk. This can include the need to gather surface data, planning and running a production log and analyzing that data, deciding which valves to change out, executing an intervention, changing out the appropriate valves if possible and bringing the well back on test. This whole process can take weeks or even months of work and is rarely accomplished to the degree necessary to assure continuously optimized gas-lift production. Technological limitations have meant that a lack of understanding and insight into the exact condi- tions downhole and the time it can take to remedy or adapt to them has tended to generate a high degree of uncertainty in the gas-lift process. It has also created a culture of costly over conservatism, particularly when it comes to such issues as deciding on the number and spacing of valves required for unloading and effective lift. However, the recent rise in the adoption of digita- lization in the oil field, with the creation of intelligent fields and wells, have enabled significant advances and created a paradigm shift in the way gas-lifted wells can now be operated to achieve optimum production. More production, less intervention The new Digital Intelligent Artificial Lift (DIAL) gas-lift production optimization system developed by Silverwell Energy is leading that cultural and process change in artificial lift. The DIAL system Digital intelligent artificial lift system creates a paradigm shift in gas-lift operations. Gas Lift in the Digital Oil Field By Graham Makin and Stephen Faux Silverwell Energy

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