American Oil and Gas Reporter - February 2016 - 46

SpecialReport: Unconventional Resource Science
by sand.
Not surprisingly, sand fallback has
been identified as the number one cause
of ESP failures in unconventional wells.
In propped horizontal shale wells, the
fluid column in the tubing string will almost always have significant volumes
of suspended sand. Therefore, some sustained level of solids production must
be accepted in order for a well to be produced, but establishing a proactive sand
management strategy is vital to protecting
the ESP, achieving an acceptable run
life, and keeping production flowing
smoothly.
One solution to controlling an ESP's
exposure to proppant flowback is using
curable resin-coated sand designed to
form a "pack" under temperature and
closure pressure conditions to mitigate
sand production while maintaining fracture
conductivity. The downside to this approach, especially given today's tighter
economic margins on well completion
and production operations, is the additional
cost of premium proppant materials compared with uncoated frac sand.

WHEN THE

Many ESP manufacturers have technologies engineered to cope with sand
passing through the pump. But when the
ESP shuts down from a power failure,
pump-off conditions, production shutdowns, etc., previously pumped sand falls
back onto the top stages where it wreaks
havoc on attempted restart.
Sand Control Tool
An alternative approach available to
operators is a low-cost mechanical tool
that is located in the tubing string just
above the ESP pump discharge to guard
against sand-related problems. The relatively simple device captures fallback
sand and segregates it away from the
pump. It diverts falling-back, solids-laden
fluid to an inner chamber, which in turn,
allows the fluid to drain off back through
the pump, while capturing sand and solids
within the chamber.
When the pump is restarted, the captured sands and solids are expelled from
the chamber by the flow action of the
pumped fluid, and are carried to the surface. The system can be cycled endlessly,

eliminating potential damage to the pump
at every shutdown while lowering lease
operating expenses by protecting downhole
equipment and increasing ESP run times.
Because it has no moving parts, it is
fail-safe and invisible to the ESP. An important technical feature of the technology
is an automatic self-flushing capability
that empties the pump after every restart.
Since there are no ports to the annulus
(the tool does not communicate with the
annulus), pumped recirculation is impossible.
SandRidge Energy is deploying the
technology in more than 30 ESP well installations in the Mississippian Lime play,
and the company is realizing substantial
increases in ESP run times in hydraulically
fractured wells that historically have suffered from problems caused by significant
sand production.
Figure 1 shows performance data on
ESP systems installed in 23 SandRidgeoperated wells equipped with the tool to
safeguard the downhole pumps. All of
the wells produce sand, and two of them
yield such heavy sand concentrations that

ON
DP 2000 DOUBLE FLUID PUMPER
Made to provide the high-volumes
and high-pressures for well
treatments.

500K TOP HEAD DRIVE DRILLING RIG
Designed for a 2-3 man crew with the most efficient,
safe and easy-to-operate features in the industry.

GEFCO an Astec Industries Company
2215 S. VAN BUREN - ENID, OK 73703 USA - 800.759.7441 - 580.234.4141 - gefco.com

46 THE AMERICAN OIL & GAS REPORTER
http://www.gefco.com
American Oil and Gas Reporter - February 2016

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