Systems Approach to ESP Design and Optimization of Heavy-Walled Wellbores Utilizing Ultra Slimline Equipment

Abstract The increased use of smaller ID, heavy-walled casing in the industry is pushing standard slimline electric submersible pumps (ESPs) to their operational limits in conventional and unconventional applications. Challenges with more highly deviated wellbores, paired with increased gas volumes, have led to undesirable drawdown and runtimes. High-speed 3.19-in. OD ultra slimline ESPs, coupled with permanent magnet motors (PMMs), provide more stable and longer operations in a broad range of wellbore conditions, while increasing production and decreasing downtime for 5.5-in. and 4.5-in. casing applications. Thoroughly evaluating design criteria is crucial for any artificial lift application. Dogleg severity (DLS) surveys help determine the deflection of the ESP equipment while tripping in the hole and at the desired landing point for the system's intake. The 3.19-in. high- speed ESP PMM has exceptional power density. This efficiency reduces the number of pump stages required to achieve proper lift, thereby shortening the overall length of the system, which allows it to better handle increased dogleg severity. With added stage count, standard 3.75-in. induction motors (IMs) increase the length and diameter of the system, decreasing the chance of successful landing. Three-phase fluids add another challenge, as with any ESP system. The need for additional equipment to manage increased gas handling is evaluated for each application. Higher gas void fractions (GVF) cause turbulent operations. Using gas separators, multiphase gas handling pumps, and increased frequency to better compress free gas at the production pump inlet can stabilize operations and reduce nuisance shutdowns with 3.19-in. ESP systems. Radial balancing within the 3.19-in. pumps enables the system to operate at higher speeds, increasing the acceptable GVF limit from that of 3.75-in. standard ESPs. Annular natural gas separation is greatly increased with 3.19-in. equipment, reducing the free gas present within the production stream. In field applications where wellbore configurations and inflow performance present challenges for traditional slimline ESPs and other methods of production, the 3.19-in. OD PMM ESP system improved reliability and uptime across several high-value assets. Several case studies are highlighted in this paper, including conversion from a beam unit to an ESP, modification of previous designs and set depths, and optimization strategies to stabilize performance. Run life on these assets improved up to 170% by following a systematic approach to better ESP efficiency and operation. This paper presents successful alternative methods of production and optimization to produce challenging wells that have extensive historical failure data. By implementing the 3.19-in. OD PMM ESP system, continuous operations and lower Opex were achieved in frequently failing wells.