Topicos

10.5.2 Electrical Submersible Pumping. As an example area in which ESPs are applied extensively,
THUMS Long Beach Co. was formed in April 1965 to drill, develop, and produce the
6,479-acre Long Beach unit in Wilmington field, Long Beach, California. It was necessary to
choose the best method to lift fluids from the approximately 1,100 deviated wells over a 35-
year contract period from fourman-made offshore islands and one onshore site. ESPs have
been the primary system in this environment for the contract period.
Fig. 10.4 shows a schematic of a typical ESP system. The chapter on ESP in this section
of the handbook contains more complete details of this mechanical-electrical-hydraulic system.
Major ESP Advantages. ESPs provide a number of advantages.
• Adaptable to highlydeviated wells; up to horizontal, but must be set in straight section.
• Adaptable to required subsurface wellheads 6 ft apart for maximum surface-location density.
• Permit use of minimum space for subsurface controls and associated production facilities.



Quiet, safe, and sanitary for acceptable operations in an offshore and environmentally conscious
area.
• Generally considered ahigh-volume pump.
• Provides for increased volumes and water cuts brought on by pressure maintenance and
secondary recovery operations.
• Permits placing wells on production even while drilling and working over wells in immediate
vicinity.
Major ESP Disadvantages. ESPs have some disadvantages that must be considered.
• Will tolerate only minimal percentages of solids (sand) production, althoughspecial
pumps with hardened surfaces and bearings exist to minimize wear and increase run life.
• Costly pulling operations and lost production occur when correcting downhole failures,
especially in an offshore environment.
• Below approximately 400 B/D, power efficiency drops sharply; ESPs are not particularly
adaptable to rates below 150 B/D.
• Need relatively large (greater than 4½-in.outside diameter) casing size for the moderateto
high-production-rate equipment.
Long life of ESP equipment is required to keep production economical. Improvements and
recommendations based on experience are in the chapter on ESP in this section of the Handbook
and in Ref. 4.

Introduced in 1936, the PCP is of simple design and rugged construction. Its low (300 to
600 rev/min) operatingspeeds enable the pump to maintain long periods of downhole operation
if not subjected to chemical attack or excessive wear or it is not installed at depths greater than
approximately 4,000 to 6,000 ft. The pump has only one moving part downhole with no valves
to stick, clog, or wear out. The pump will not gas lock, can easily handle sandy and abrasive
formation fluids, and is not normally pluggedby paraffin, gypsum, or scale.
With this system, the rotating rods wear and also wear the tubulars. The rotating rods
“wind” up on start and “unwind” on the shutdown. Rotating rods must be sealed at the surface,
and many installations have oil leaks at the surface. These problems must be addressed during
system design.
Major PCP Advantages. PCPs have the following major advantages.
• Thepumping system can be run into deviated and horizontal wells.
• The pump handles solids well, but the coating of the rotor will erode over time.
• The pump handles highly viscous fluids in a production well with a looser rotor/stator fit.
• Several of the components are off-the-shelf ESP components for the ESPCP.
• The production rates can be varied with the use of a variable-speed controllerwith an
inexpensive downhole-pressure sensor.
• For appropriate conditions, the PCP can operate with a power efficiency exceeding other
artificial lift methods.
• The PCP can be set in a straight section of a deviated well.
• Use of an ESPCP eliminates the rotating rods and eliminates problems with rods rotating
in a deviated well.
Major PCP Disadvantages. PCPs have the following...