Compression pump construction technology has been used in electric submersible pump (ESP) systems for several decades to transfer pump downthrust to the protector thrust bearing, thereby preventing pump downthrust wear in abrasive and gassy applications and to extend their service life in applications where the flow rate was expected to decrease below the catalog-recommended operation range of the pump.
The development of unconventional shale plays raised the requirements for artificial lift systems and particularly ESPs. These applications often combine some of the most challenging conditions for ESP operation, including production of solids, high gas-to-liquid ratio, steep decline rates, and unsteady flow.
An enhanced pump technology was developed and qualified to address the challenges and meet the demand of ESP systems with much broader flexibility in terms of flow rate and multiphase flow handling and toughness required to continue to operate and achieve the target run time. This new pump design, combined with customized operating procedures, has been applied across a wide range of operations, not only geographically across the different basins in the USA, but also covering conventional and unconventional applications with different fluid properties, operating philosophies, and large variations of flow rates, which sometimes start at or above the maximum recommended operating range (ROR) for the pump stage and eventually decrease to flow rates that fall substantially below the catalog ROR, within the flat section of the Head-Rate (H-Q) curve. The evaluation of the systems concluded they are statically and dynamically stable even when operating in the flat or dip section of the head–flow rate curve.
In the Bakken, this technology has been a key element in managing a steep production decline, in which the initial production of above 4,000 bbl/d declined to only 1,000 bbl/d after 90 days of operation in unconventional wells producing from 9,000-ft deep reservoirs. In the Powder River basin, the technology has been applied in conventional applications that are characterized by more stable production of approximately 4,000 bbl/d from shallower reservoirs at 7,000 ft and with lower gas content. The technology has also been successful in CO2 flood applications in the Permian basin that produce in excess of 7,000 bbl/d total liquid.