THE
AMERICAN OIL & GAS
REPORTER
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VOL.40 NO.6 |
JUNE1997 |
Special Report: Artificial Lift Technology
DARTT® Valve Although some pumping wells experience problems with pumping units or leaking tubing, most production problems are associated with downhole pumps, ac- cording to Joe Nelson of DARTT™ Valve Co. The most common pump problems include gas lock, partial fluid fill and associated fluid pound, ball dance and fluid cut seat damage, sand plugging, and plunger and barrel wear. DARTT™ Valve Co. is using new technology in their hydraulic amplifier valve to ensure the traveling valve opens on every downstroke, and closes on each upstroke, Nelson confirms.
"Our valve acts like a full-sized relief valve," he states. "It will handle the maxi- mum flow. With the DARTT® Valve in- stalled within the pump, the operator is able to operate with 100 percent pump efficiency, and to maintain this until lowering the liquid level in the well to the seating nipple. The reason is because DARTT® Valve makes certain the traveling valve is closed in the upstroke, and the forces the traveling valve to open in the downstroke before transient forces can take effect."
Nelson says the valve prevents gas lock by ejecting even gas into the production tubing, and thus permits the standard plunger pump to pump gas as well as li- quid. He claims the key is to pump the gas long enough to prime the pump and to finally pump liquid, and to pump gas- fluid emulsions as they occur. The physics of the DARTT® Valve simply make the pump work as it should, regardless of the gas content in the well, he says.
Without the DARTT® Valve, partial filling of the pump with gas can cause fluid pound with its associated catastrophic damage, continues Nelson. Being lighter than liquid, the gas rests on the liquid within the pump barrel. In the downstroke, as the plunger and rod string encounters the gas, it falls freely through it toward the liquid without opening the traveling valve. Then, as the plunger and rod string hits the liquid, the ball is instantaneously sealed into the seat while the liquid, which is not compressible, stops the fall, caus- ing fluid pound.
By forcing the traveling valve to open soon after the beginning of the downstroke, and by keeping it open throughout the entire downstroke, the DARTT® Valve al- lows the fluid to move through the pump consistently, sidestepping the fluid pound problem entirely, he asserts.
Nelson says in two years the company has been in business, use of the valves has spread to China, Venezuela, Canada, and Trinidad, as well as throughout Texas, Oklahoma, New Mexico, and Michigan. One company installed the product in 50 wells in southeast Texas, and has not been forced to pull a valve for maintenance. "Before our valves, they had workover rigs in their field all the time," he says.
Another company has been using the valves on 60 wells near Levelland, Tx., for a year-and-a-half without any valve or rod failures, Nelson notes.
A third success story comes from Michigan, where in the first five test wells, a company reported that a well was producing an average of 220 barrels of oil a day prior to installing a DARTT® valve. After installing the valve, production has aver- aged 320 barrels a day, Nelson avers. "Me reason is they no longer have gas interference, and can now get all of the fluid out of their well."
Another textbook case comes from South Texas, where a company is success- fully reclaiming abandoned gas wells which were not economically viable with old technology. "Now, they are proving to be very profitable with the installation of DARTT® Valves," Nelson says. He adds that observable benefits of valve installation include increasing production, and decreasing pump maintenance and electricity costs.
Nelson adds that full information can be obtained on DARTT® Valve's Web site at www.darttsystems.com, including an animated look at the valve in operation.
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The DARTT™ Valve makes certain the traveling valve is closed in the upstroke, and forces the traveling valve to open in the downstroke before transient forces can take effect achieving 100 percent pump efficiency. |
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