Conditions in the second well were considerably more challenging, resulting in more downtime for sand flushing as well as an average runlife of just 78 days with conventional PCPs. In fact, the well had been shut in for nearly a year because Casabe Consortium could not justify its economics. As with the initial well, the improved sand handling eliminated flushing interventions and deferred production, enabling incremental production valued at $331,000. Drawdown also was increased by 13%, and the Left Helix pump more than tripled the conventional PCP runlife to 275 days, further reducing deferred production.
The improvements in runlife increased well production and reduced intervention frequency and associated costs. The success prompted Casabe Consortium to install the technology in 12 additional wells.
Protecting the rod pump
In the Permian Basin, rod pumps are carefully selected and engineered to maximize the lifetime for particular well conditions. Each downhole rod pump is designed with a specific clearance in relation to fluid viscosity and stroke speed, among other factors, to maximize production and pump efficiency. When the barrel and plunger are severely abraded by sand and solids production, clearance increases beyond the optimal range. The increased clearance results in increased fluid slippage, reduced pump efficiency and, in the worst case, a stuck plunger.
A leading operator in the Permian Basin asked for a solution to severe abrasion cutting in several wells with pump runlife ranging from 84 to 364 days. Schlumberger recommended adding a Don-Nan sand diverter, which is a modified plunger adapter that directs sand and solids away from the pump barrel. Compared with the conventional design for plunger adapters, the sand diverter has an increased outside diameter, providing a much closer fit, and a beveled leading edge with upwardly angled discharge ports. This combination of design features prevents sand and solid material from collecting between the barrel and plunger during operation or while the system is idle.
The operator installed Don-Nan sand diverters in 15 sand-challenged wells. Runlife for the pumps increased on average by 171 days (108%). The most improved well more than tripled its runlife (335%).
Sand production solutions
When recompletion and conventional sand control and remediation measures are uneconomical, as in the case of a mature well or field, operators must find alternative solutions that allow continued production to maximize the value of their substantial investments.
Improvements in material properties and hardware performance help ensure the longevity of downhole equipment even in harsh environments, and continuous improvement efforts have extended lifting equipment capabilities and lifetimes far beyond the expectation of even a decade ago.
Finally, by combining these physical improvements with increased digitalization and the Industrial Internet of Things, artificial lift systems can begin to respond automatically to the presence of sand and other damaging conditions. From a foundation comprising decades of artificial lift expertise, these next-generation systems automatically optimize performance for downhole conditions or predict impending failures early enough to preschedule an intervention or a change in artificial lift technology. The result is better economics and more efficient reservoir drainage, even in severely sand-challenged wells.