Existing pump designs rely on the ability of the pump to produce high
pressure in the compression chamber during the downstroke. This high
pressure is needed to open the traveling valve and allow fluid and gas to
flow through the plunger for lifting to the surface on the upstroke. Failure
of the traveling valve to open on the downstroke in gassy wells causes a gas
locked condition and no production.

    The new VSP® pump has a gradual taper in the upper barrel. As the plunger enters this taper near the top of the upstroke, slippage increases past the plunger, and pressure is equalized above and below the plunger and traveling valve. Therefore, when the plunger starts downward the traveling valve opens easily since high pressure in the compression chamber has already been achieved.

    Field dynamometer tests have shown an increase in minimum polished rod load (extends rod lifespan), a reduction of sucker rod harmonics and a decrease in sucker rod compression loading above the pump. When operated properly in the right application, this new pump will eliminate gas locking, lower the sucker rod stress range, do away with fluid or gas pound and reduce sucker rod and tubing wear above the pump.

    The initial VSP® sucker rod pumps will be in the RH configuration in 1-1/4" and 1-1/2" sizes. The VSP® taper barrel will connect to the top of a
standard 426* barrel, between the barrel and upper extension. The diagram
shows the RH pump barrel line up. The plunger assembly is standard.

    Initial installations must be coordinated with the Engineering Department
through myself or Mark Mahoney to insure that appropriate barrel and
extension lengths are chosen and that the appropriate downhole application
is being considered.

The Harbison-Fischer VSP® sucker rod pump will be available in mid 2001.

Please call Engineering if you have any questions.

Benny J. Williams, P.E.
Vice President of Engineering