Impressive is the versatility of a single grain of sand. Through irritation, it can create and destroy. That single grain can become, in time, a pearl on the strand of your grandmother’s favorite necklace. It also can be the grit in your grind when trying to enjoy an oyster dinner.

Its usefulness is demonstrated by propping open the pathways necessary for oil and gas to flow out of unconventional reservoirs. But it causes big problems in the nooks and crannies of the pumps used to create lift when reservoir pressures decrease.

From causing premature seal failures to the gradual scraping away of material, sand is an ever-present production nuisance. To help in the battle against premature wear and tear in rod pumps, Weatherford International released its new line of sand-tolerant pumps (STPs) in September.

Aimed to optimize the life of wells, the STP is an alternative to standard rod pumps in wells with high sand production in that it prevents abrasion caused by sand accumulation in the barrel/plunger. A wiper assembly and filter coupling reduce sand damage by moving sand upward through the pump and away from the barrel/plunger interface, according to a press release.

The outside of the wiper assembly creates a barrier, keeping sand out of the plunger/barrel interface by continuously pushing the sand upward while the internal components of the assembly prevent sand from falling back into the plunger. The filter coupling enables only clean produced fluid to pass through the equalization ports to the plunger/barrel interface, a product brochure said.

The ports provide the necessary lubrication for the pump as the plunger moves up and down. The internal screen of the filter coupling prevents sand from escaping through the ports with the fluid. According to the brochure, the filters move with the plunger, with the fluid’s sweeping action on the downstroke cleaning the filter and keeping sand suspended within the production fluid.

“The sand-tolerant pump is a demonstration of the improvements made in pump designs to increase runlife and mitigate sand damage. So far, the longest run time with the sand-tolerant pump is 781 days in very harsh sand-laden environments,” Bob McDonald, vice president of reciprocating rod lift at Weatherford, said in a press release.

Available in most American Petroleum Institute pump sizes, the STP can perform in temperatures up to 182 C (360 F). Based on the results from field trials conducted in California, the STP has demonstrated up to 5.5 times longer runlife than conventional rod pumps in sandy conditions.

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