Oil prices have climbed rapidly, but along with them, the cost of power to run sucker rod pumps has climbed, unless an operator can use field fuel. A new pumping system offers a way for some operators to take a bite out of those high costs.
The Deluge Inc. Natural Energy Engine grew out of a project in Saudi Arabia dealing with the expansion and contraction of liquid gases. Brian Hageman, founder of the company, describes himself as an inventor. He found that CO2, stored under enough pressure to keep it liquid, can expand up to 50% with increased temperature, compared with 1% to 2% for water or oil.
He built that principle into an engine with liquid CO2 behind a piston inside a cylinder. As warm water - currently around 185°F (84.9°C) - flows over the cylinder, the CO2 expands to move the piston. A timer switches the flow to cooler water - around 85°F (29.4°C) - which allows the CO2 to contract.
The piston, with a 24-in. stroke on current models, provides the engine power for a conventional polished rod and downhole pump system.
Using conventional industry language, Hageman calls the system the Deluge Artificial Lift (DAL) 12-24, meaning the 24-in. stroke can handle a 1,200-lb capacity.
Although tests have been run only on shallow wells to date, Hageman said he has designed systems that will work at 3,000 ft (915 m) and he can design the system with up to a 120-in. stroke. The only physical limit is how big the company can build the cylinder, and it can build cylinders up to refinery size. So far, the biggest system built was rated at about 10 hp.
Any water source will do. At the Rocky Mountain Oilfield Testing Center (RMOTC) at Teapot Dome field in Wyoming, the company used warm water from a geothermal well - 180°F (82°C) at 30 psi - to power the Natural Energy Engine in tests reviewed by the Petroleum Technology Transfer Council. That volume would allow the company to run 100 pumps off one geothermal water well.
That field has 600 wells that produce about 95% water and 5% oil under full-time traditional pumping. Pumps on a timer get a larger percentage of oil. Hageman timed the stroke of the pump with the flow of oil into the casing and managed to produce 100% oil. "We got up to 6 b/d. The others (pumpjacks) got more barrels but less oil," he said.
The National Energy Laboratory of Hawaii uses deeper sea water at 40° and shallower sea water at 85°. Deluge has successfully tested the Natural Energy Engine in their workshop using these temperature differentials.
The Federal Laboratories Consortium awarded its 2005 Outstanding Technology Development Award to Deluge and RMOTC for the Teapot Dome project. In California, it used warm water from steam floods to drive pumps to produce oil. Since the engine can be used for any purpose, Hageman said the volume of hot water in that area could produce 1 Mw of power from heat normally wasted in cooling ponds.
Deluge is studying possibilities of CO2 injection for enhanced oil recovery (EOR) for companies that are already doing EOR using electricity throughout the United States.
The company has its own nine-well prototype field near Parsons in southern Kansas, and it has racked up 30,000 hours on the nine wellhead systems. It is pumping oil at stripper rates, but it will sell the oil. Although the system requires one unit per well, the warm and cool water can come from a central source.
The systems pump fluids at the same rate, or a little better, than nearby wells with traditional pumpjacks, but company systems use a lot less power, he said. In this area, a pumpjack normally requires a 10 hp to 12 hp engine. The CO2 engine does the same job while producing about 3 hp. That means it uses less electricity. The new engines, he said, are about 40% efficient, compared with around 28% for steam or gas-powered engines.
Since the systems still are in the prototype stage to gain enough background statistics to overcome oilpatch resistance to new ideas, they aren't for sale. Eventually, the company would like to license the technology.
From his own experience, Hageman said, the systems get a real competitive advantage over traditional engines as the size grows from 20 to 100 to 1,000 hp, but the real advantage comes from the lower operating cost of an engine with only one moving part and no expensive energy requirement to keep it running. "Electricity runs 75% less than with an electric motor system. I expect the total production cost to be well below US $5/bbl," he said.
The Parsons area field is the company's first commercial endeavor, and Deluge has acquired more leases. Deluge has created an oil services division to sell crude oil, but after a couple of years, it may move to a new business model that includes licensing.
As a side benefit, Hageman said, the new engine can desalinate water at a lower cost than reverse osmosis, which could be a boon for oilpatch applications on a small scale or for nations on a larger scale.

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