Application Challenges – Unconventionals

The Borets Packet pump delivers reliable ESP production and longer run life in unconventional wells. Using the innovative “packet” construction, the Packet pump is better able to withstand the harsh conditions and abrasive production typically experienced by ESPs in unconventional wells.

Rapid decline rates, increasing gas volumes and unstable flow − typical in unconventional wells – can result in an ESP frequently operating in down thrust conditions. The Packet pump is better able to withstand prolonged down thrust using an adaptive thrust management technique with enhanced axial and radial support, including the industry’s most robust tungsten carbide bearing design. Our Packet pump design also incorporates a larger shaft diameter to withstand higher loads often experienced producing from deeper unconventional reservoirs.

The proven technology of permanent magnet motors (PMMs) has shown to reduce operating expenses attributable to ESP power consumption by up to 20%, and in some unconventional fields, even more. PMMs also experience lower heat rise than an induction motor (IM) equivalent, contributing to improved reliability and longer run life. The higher horsepower (HP) rotor density available means PMMs are also significantly shorter than an IM equivalent, which enables deeper pump setting depths as well as facilitating better access through severe doglegs or tortuous well paths often encountered in unconventional wells.

As the global leader in PMM technology development and experience, Borets has deployed more than 14,500 PMMs worldwide, including more than 300 in the Permian Basin.

Capable of operating at both standard (3600 rpm) and high speeds (6000 rpm), PMMs are also a key enabling technology for ESP operation across a wider operating range.

Borets’ 406 series ESP permanent magnet motors (PMM) and induction motors (IM) provide maximum horsepower availability to electric submersible pump systems in casing sizes with more restrictive internal diameters (ID).

Wells completed with 5.5 in. and either 20 lb/ft, or 23 lb/ft casings cannot easily accommodate ESP systems using 456 series motors. Without exceptional steps to reduce the motor outside diameter (OD), motors with an OD of 4.56 in. have very small or insufficient annular clearance to fit these casing sizes. Smaller ESPs using 375 series motors (with 3.75 in OD) fit in these casings sizes, however, even triple-tandem configurations will lack sufficient horsepower to provide the full range of production required. ESP systems powered by Borets 406 motor technology overcome such limitations in these applications.

With a nominal OD of just 4.06 in, Borets 406 series motors power ESP systems up to 402 hp. Benefiting from higher horsepower rotor density than IMs, 406 PMMs come as single-section motors up to 264 hp and are shorter in length than any IM hp equivalent. The 406 PMMs deliver the additional benefits of reduced electrical power costs and lower heat rise, which positively influence equipment reliability and system run life. Developed and first introduced by Borets in 2006, this motor technology has a long, proven track record of performance and can reduce electrical power cost up to 20%.

Reliable ESP operation in gas-prone unconventional wells is achievable. With a suite of gas handling and separation technology available, Borets ESP systems produce reliably in unconventional wells having up to 90% gas fraction, by first separating and venting gas, then homogenizing and producing the remaining gas.

Borets offers both rotary and vortex-type gas separators, but it is the Vapro multiphase gas handling pump, when combined with more conventional gas separation techniques, that provides for more reliable ESP performance in high GLR wells.

Like the packet pump, the Vapro multiphase gas handling pump employs the same “packet” construction, robust tungsten carbide bearings for increased wear tolerance, and a high-strength Inconel shaft to routinely handle higher horsepower loads that may be required in unconventional wells.

Reliable ESP operation in gassy wells is further enhanced through a gas-lock prevention and control algorithm enabled in the Borets Axiom II Universal Variable Speed Drive. The advanced algorithm utilizes multi-parameter programmatic control to detect potential gas lock conditions and then adjust ESP operating conditions to help reduce the potential for gas lock and avoid unnecessary alarms or shutdowns.

The highly reliable Borets Axiom II Universal Variable Speed Drive (VSD) operates and controls both induction and permanent magnet motors. Unlike IMs, PMMs require a specific control algorithm to perform with maximum efficiency and control stability with minimum heat rise.

The Axiom II VSD employs a proprietary vector control algorithm ensuring optimal PMM performance across the entire motor load range encountered. This is a significant advantage in unconventional well production where ESP motors often encounter variable loads associated with both gas and flow rate instability or rapid reduction in reservoir inflow (decline). In this environment, Borets PMMs operating under vector control still deliver maximum efficiency and performance while minimizing electrical power consumption.

The rapid decline rates, high GLR, and abundant solids production that often characterize unconventional production historically have meant shorter ESP run life, either through equipment failure or system inefficiency and the need to change out and resize the ESP design.

Enabled through Borets PMMs and a novel manufacturing technique, the new Borets WR2 ESP System offers a wider operating range and is more wear-resistant to abrasive solids than previous generation ESPs.

WR2 stages are manufactured using a special metal injection molding technique enabling stage designs, surface finish, and hydraulic performance unattainable with conventional cast stages. Resistance to unconventional production conditions such as frequent down thrust is further enhanced in the WR2 system using the same “packet” pump construction.

Utilizing high-speed PMMs up to 6000 rpm, the WR2 is capable of operating efficiently over a wider operating range than conventional ESP systems. Longer equipment run life and a wider operating range in unconventional production means fewer equipment changeouts over the duration of production decline, saving operators both intervention and resized equipment costs.

The Borets SandTrapper solids-exclusion device helps protect ESP equipment against the harmful effects of solids fallback in the production tubing string. Unconventional well production often includes significant volumes of sand and abrasives. Installed above the ESP discharge head in the tubing string, the SandTrapper prevents sand and debris from falling back on and potentially plugging ESP equipment in the event of unexpected or planned system shut down.

The SandTrapper also helps prevent backspin, potentially eliminating the need for a drain or check valve.

The simple design of the Borets SandTrapper makes it easily serviceable upon ESP changeout and a cost-effective measure to help achieve longer ESP run life in unconventional wells.