Artificial Lift Techbook 2018

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44 | July 2018 | ARTIFICIAL LIFT: CASE STUDIES encompasses a fully qualified, tubing conveyed surface-controlled multi-rate gas-lift unit, rated to 10,000 psi burst, 6,000 psi collapse and 257 F. Each unit includes up to six independently actu- ated orifice valves and onboard pressure and tem- perature transducers. The system allows more production from enhanced lift efficiency to accelerate return on investment, less intervention with a reduction in opex and risk, more data through the increased insight afforded by mul- tiple in-well sensors, and less uncertainty with the potential for improved production management deci - sions due to the deployment of an integrated gas-lift optimization system. DIAL integrates downhole and surface monitor- ing/controls in real time. The different sized orifice valves housed in the in-well DIAL units accommodate a wide range of unloading and gas-lift production operating conditions. As reservoir conditions change, the injection rate and depth can be remotely adjusted from the surface and confirmed in real-time data. The system's design does not incorporate gas bel- lows, meaning there is no requirement for a gas charge with no dependence on pressure or temperature. It, therefore, overcomes the well design and operational limitations of existing side pocket mandrels and gas- lift valves, which are installed with pre-configured orifice sizes and require potentially risky well intervention to make adjustments as conditions change throughout field life. The DIAL gas-lift valves are not pressure dependent, making them less sensitive to uncertainties in well design variables. There is no requirement to design, at each unloading valve, a pressure differ- ential to avoid multipointing and valve chatter, enabling the deep- est possible injection point to be determined. The system is less prone to flow instability. Further- more, the injection orifice size can be adjusted without intervention and onboard pressure, tempera- ture and condition monitoring are achieved at all injection points in the completion string. A surface control unit pow- ers and transmits data to and from the DIAL units via industry standard ΒΌ-in. clamped tubing encapsulated cable and can be configured to support multiple units in a single well. The downhole control system is hermetically sealed with electron beam welds to assure life-of-well system reliability, while the gas-lift orifice valve assemblies are contained in a 10,000 psi burst rated housing. The operation of the DIAL unit is enabled by Silverwell's Binary Actuation Technology (BAT), which consumes no power until a low energy control signal is applied. This attribute of the BAT technology plat- form is instrumental in assuring the 10-year to 20-year design life of the in-well components of the system. Overall, through its benefits over legacy gas-lift technologies that have a relatively narrow operat- ing window, often excessive safety design margins that can limit achievable injection depths, multiple potential leak paths and challenges in assessing lift effectiveness, the DIAL system represents a significant reduction in the total cost of gas-lift operations. More data, less uncertainty DIAL has been deployed successfully in the Middle East and Southeast Asia beginning in 2017. In all cases, within days and weeks of installation, the sys- tem was being used to optimize lift efficiency without the cost and deferred production of intervention. In one case, without the need for intervention and by using downhole gauge measurements provided The DIAL Control Room Software monitors and controls system status including downhole valve positions, annulus and tubing pressure and temperature parameters, and system condition monitoring. (Image courtesy of Silverwell)

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