Upstroke: Traveling Valve Loading, Standing Valve Intake, and Dynamometer Card Diagnosis

The upstroke is the portion of a sucker rod pumping cycle during which the polished rod, rod string, and downhole pump plunger travel upward and the pump lifts fluid toward surface. In a conventional beam pumping unit the walking beam rocks the horsehead up, pulling the polished rod out of the stuffing box and raising the entire rod string and the plunger inside the downhole pump barrel. At the instant the plunger begins to rise, the traveling valve, a ball-and-seat check valve carried on the plunger, closes under the weight of the fluid column above it, so the plunger now carries the full hydrostatic load of the tubing fluid and lifts that column upward. Simultaneously, the standing valve, the intake check valve fixed to the bottom of the pump barrel, opens because the rising plunger reduces pressure in the barrel below it, drawing formation fluid up through the perforations and into the pump chamber to fill the volume the plunger is vacating. The upstroke is therefore the production stroke: it lifts the fluid already above the plunger while drawing a fresh charge in beneath it, and the downstroke that follows transfers that new charge past the open traveling valve for the next lift. Because the rods must support the fluid load only during the upstroke, the peak polished rod load occurs on the upstroke and the minimum on the downstroke, and the difference between them drives the counterbalance design, the gearbox torque rating, and the fatigue loading that governs rod string life. In the Western Canadian Sedimentary Basin, sucker rod pumping, often called beam pumping, is the dominant artificial lift method on mature Viking, Cardium, and Mannville oil wells and on many cold heavy oil Sparky and Clearwater completions, where relatively modest rates of 5 to 80 m3/day (31 to 503 bbl/day) suit a rod pump. Operators diagnose upstroke behaviour with a dynamometer, which records polished rod load against position through the full cycle; the shape of that card during the upstroke reveals whether the traveling valve is holding, whether gas is interfering with the fluid charge, whether the pump is fully filling, and whether the barrel is worn, so the upstroke is not just a mechanical phase but the primary diagnostic window into downhole pump health. Reading the upstroke correctly lets a field operator decide whether to adjust pumping speed, change stroke length, install a gas separator, or pull the pump, decisions that directly control lifting cost and uptime.

Fluid Pound and Incomplete Fillage on the Upstroke

When the reservoir cannot deliver enough fluid to fill the pump barrel during the upstroke, the plunger on the following downstroke slaps down onto a partially gas-filled or fluid-short chamber, producing fluid pound that hammers the rods, tubing, and pump. The dynamometer card shows the fluid load dropping off sharply late in the upstroke as fillage falls short. On a Clearwater cold heavy oil well near Bonnyville pumping 20 m3/day (126 bbl/day), fluid pound often signals the well is being pumped faster than the sand-laden reservoir can supply, and the fix is usually slowing the pumping speed with a pump-off controller or shortening run time, protecting the rod string from fatigue failures that each cost a rig trip.

Gas Interference and Compression on the Upstroke

Free gas entering the barrel with the fluid charge compresses and expands instead of transferring cleanly, so the traveling valve stays closed longer into the downstroke and the standing valve opens late in the upstroke, rounding the card corners. A gassy Cardium or Sparky well can lose a large fraction of pump displacement to gas that never leaves the barrel. Field remedies include setting the pump below the perforations, adding a downhole gas separator or gas anchor, and tuning pump intake pressure. On a Pembina Cardium rod pump, adding a gas anchor and lowering the pump 30 m improved fillage from roughly 55 percent to over 85 percent, a direct uplift in net oil for about CAD 12,000 in equipment and a single service trip.

Related Terms

The upstroke is one phase of a system best understood through its neighbours. Sucker rod strings transmit the surface unit motion downhole, and the traveling valve and standing valve are the two check valves whose timing defines the stroke. The dynamometer is the tool that renders the upstroke visible as a load-position card, and artificial lift is the broader category placing beam pumping alongside gas lift, ESPs, and hydraulic pumps used elsewhere in the WCSB.

Real-World WCSB Scenario: Viking Rod Pump Near Kindersley

An operator runs a 1,150 m Viking oil well near Kindersley on a conventional pumpjack producing about 14 m3/day (88 bbl/day). A routine dynamometer survey shows the upstroke load building normally but collapsing before the top of stroke, the classic incomplete-fillage signature, and gas-rounded valve corners. The pump-off controller had been set aggressively after a rate test, over-pumping the modest Viking deliverability and inducing fluid pound that had already cracked two rod couplings over four months.

The field team slowed the unit, retuned the pump-off controller to idle on low fillage, and added a small gas anchor at the next scheduled service. Fillage recovered above 80 percent, fluid pound disappeared from the card, and rod failures stopped, saving an estimated CAD 50,000 per year in avoided service rig trips and deferred production on that single well.