Injecting Carbon Dioxide Boosts Recovery

Many energy industry observers like to reference that the “easy” oil is becoming difficult to find. Yet, technology is unlocking more oil in each reservoir while extending the life of mature fields.
In Oklahoma, technology is the key to exploiting these marginal and mature fields, according to producers Charles Wickstrom and Ken Oglesby.
Oil and natural gas fields are labeled “mature” once their primary production begins to decline to a marginal economic basis. At that point, additional work has to be done as the field enters a phase where there is a pressure drop, increased water influx, sand production and lower flow rates.
“Enhanced 3-D seismic and the use of downhole electrical submersible pumps are two methods that have increased the life of mature fields, said Wickstrom, managing partner of Spyglass Energy Group, 15 E. 5th St. “The 3-D seismic has enhanced recovery from horizontal drilling.”
The downhole pumps, using 200 HP motors, can increase fluid production 10-fold, Wickstrom said.
“It increases fluids from 100 barrels to several thousand barrels a day,” he said. “It allows us to produce marginal oil wells at an economic rate.”
The method is expensive as the pumps run 24/7. Also, operators have to dispose of the large volumes of saltwater produced by the pumps.
Historically, as the price of oil fell to $10 a barrel or lower wells became too expensive to operate and were plugged. Operators needed oil to be at $65 a barrel to make it worth their while to extract the last few drops of oil from the rock.
Today, $65 remains the price floor for operators, Wickstrom said. But drilling costs and equipment has quadrupled.
Today’s prices are historical, said Oglesby, president of Tulsa-based Oak Resources Inc., 5350 E. 46th St., Ste. 131.
Another successful method to boost enhanced recovery that operators are using is carbon dioxide.
“We pull CO2 out of the air and inject it into reservoirs,” Oglesby said. “It is a big deal. It is a wonderful thing.”
The problem? It is expensive, he said. “Very expensive.”
The first thing operators have to decide is how long will these prices stay up, Oglesby said.
Operators have to spend millions of dollars up front and it might be three years before there is any income from the investment.
“Equipment, compressors, tanks—there is a large upfront investment,” he said. “To be able to justify the investment takes several years to do study it, buy the equipment, get it in place and then wait.”
Oak, an E&P company Oglesby established in 1987, has drilling and production operations in Oklahoma and Texas.
While the industry recognizes the success of CO2 recovery, the combustion by-product needs to be piped to the field.
“The best sources for CO2 are from power generation plants, coal plants, gas plant — any kind of fertilizer plant,” Oglesby said. “Anywhere they have residual CO2 coming off a stack.”
Another more “mature” enhanced recovery method is horizontal drilling.
”At these prices, more and more operators will apply that technology to marginal wells to improve production,” Oglesby said.
All oil and natural gas wells are drilled vertically. But with a horizontal well, the hole is drilled to a point and then the pipe is angled out and made to run horizontally. That “leg” or a “lateral” can run several thousand feet.
While the technology is expensive, too, costing up to $2 million on a horizontal well, it is becoming economical. Again, it is a guessing game for the operator who has to decide to justify the cost to attempt to produce from these low flowing wells.
“Because that technology has become cheaper, it has having greater impact on more wells and fields as time goes on,” he said.
A newer technology is referred to as “gel” technology, Oglesby said.
The injected substance shuts off the water in a formation, allowing operators to pump more oil and gas. ?



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