Artificial Lift Techbook 2019

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56 | April 2019 | ARTIFICIAL LIFT: CASE STUDIES A pair of magnetic couplings is used to transmit torque from the motor unit through the isolation can to the magnetic bearing rotor. Using a magnetic coupling to transmit torque eliminates the need for a solid shaft, and thus no need for shaft seals to isolate the motor from the environment. All seals are known to fail eventually. Seal failures will lead to the ingress of downhole fluids into the parts that cannot be exposed to the downhole flu- ids. This eventually causes multiple possible failure modes of the downhole rotating devices. To funda- mentally eliminate all these failure modes, the best approach is to eliminate the protector containing the shaft seal, which is why the architecture is described as "protector-less." The magnetic bearing unit is connected to the top of the motor unit. The bearing unit contains active magnetic thrust bearings and passive magnetic radial bearings to support the loads from the hydraulic unit. The most important advantage of using magnetic bearings compared to the traditional mechanical bear- ings is their reliability and efficiency for high-speed rotating devices. Since there is no physical contact between the rotors and stators of magnetic bearings, there will be no failure caused by introductions of foreign debris on the contact surfaces and efficiency loss due to frictions. The hydraulic unit houses the gas compressor, which is designed to increase the pressure ratio of the discharge pressure to the intake pressure of the subsurface compressor. The compressor rotor is fully levitated by the magnetic bearings and spins at high speed without any physical contacts to the stationary part of the compressor. Summary and status Upwing's SCS increases gas production by decreas- ing bottomhole flowing pressure and causing higher reservoir drawdown. Effective drawdown can only be achieved by downhole compression near the perforations, where the gas is denser due to the higher downhole pressure. The effective drawdown increases the production rate significantly, which increases cash flow and net present value. The SCS proof-of-concept field trials demon- strated an increase in gas production ranging from 30% to 58%. Gas well simulations with SCS instal- lations have shown gas production increases rang- ing from 20% to 150%. In addition to better gas production, analysis shows that the SCS increases condensate production rates and improves con- densate yield, particularly in horizontal liquid-rich formations, which positively impacts well perfor- mance and value. n Major system components of the Upwing SCS are depicted. (Image courtesy of Upwing Energy)

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