It is anticipated that the average price at the gas pump in the US may climb as high as $5 per gallon by summer’s peak driving season. Understandably, many are worried that continuing turbulence in the Middle East could propel prices even higher.
However, a process known as pulsed injection offers potential new life for US oil fields that were previously believed to be past their productive lifetimes, permitting additional barrels to be extracted domestically. In total, the US Department of Energy estimates that there might be as much as 430 billion barrels of oil that is technically recoverable in the United States.
Before the development of pulsed injection, an oil company tasked with extracting additional oil from an older field would inject various fluids, mainly water, underground to help recover it-an operation known as secondary recovery. But there exists an overall drawback to this approach: Injected fluids have a tendency to seek the path of least resistance through porous media, tracing a different trajectory followed by the inaccessible oil and resulting in lower overall oil recovery rates.
In opposition to this conventional approach lies a process known as pulsed injection, which is comparable to what occurs when a kink is released from a garden hose. Specialized equipment oscillates the flow of water on and off, building up kinetic energy that will impel more water to come into contact with oil. Each surge of water and energy puts additional oil in contact with water when it might otherwise have stayed out of reach.
This process can enhance oil recovery using two main mechanisms: First, the pulsed injection of water overcomes the path of least resistance and enhances the so-called “finger density” of oil through the field. Second, the momentum of the pulsed fluid breaks up residual oil globules that exist underground. Both of these mechanisms make it far simpler for oil to be recovered from the field.
The potential prize of improving ultimate oil recovery with pulsed injection is considerable. A 1% increase in recovery equals 2 billion barrels of additional reserves globally; a 5% increase in recovery-a conservative increase thought to be achievable-would produce an extra 300 to 600 billion barrels. Ultimately, the use of pulsed injection can result in enhanced oil recovery from a field of between 5 and 10 percent depending on reservoir conditions.
A related application of pulsed injection is designed to aide in-ground environmental groundwater remediation cleanup strategies. This variant process has been shown to be a highly fruitful approach for introducing remedial fluids into aquifers. Verified as an effective environmental remedial strategy by Environment Canada’s Environmental Technology Verification Program, this process is capable of obtaining results that are unattainable by conventional injection methods. It helps treat environmental sites quickly and at minimal cost by broadly distributing remedial fluids throughout the aquifer.
The pulsating action forces remedial fluids into contaminated underground sites to effectively reach contaminates. The technology works within a wide range of soil and rock conditions and can access hard-to-reach locations, even under buildings. It offers several advantages in an environmental cleanup. First, it eliminates or greatly reduces problematic remedial fluid surfacing (daylighting) during injection. Second, the pulsating action produces a momentary expansion of the effective porosity, allowing injected fluid to enter pore networks not accessible to conventional pumping technologies. Third, the low-maintenance design of pulsed injection tools allows for on-the-fly adjustments to match site-specific characteristics. Finally, operators can use standard piping/fitting to connect pulsed injection tools between the injection pump and a standard injection well or direct push injection point.
Wavefront Technology Solutions, based in Edmonton, Alberta, is one company that has been involved in the development of both applications of pulsed injection as described above. Since their first application in 1998, Wavefront’s pulsed injection processes-which create a pulsating injection stream with typically 20 to 40 pulses per minute, at speeds of up to 100 meters per second-are administered via tools that it leases to oil companies for use on their wells. The company reports that it has consistently delivered successful results for optimized oil well stimulation and secondary oil recovery. In some cases, its technology has reportedly increased the production of individual wells by greater than 300%. To date, its pulsed injection system for oil recovery-which the company markets under the name Powerwave-has been used in more than two dozen fields in Canada and the U.S. The company has also recently implemented its process in major oil production operations around the world, including Argentina and the Middle East.
In a recent quarter, Wavefront secured four key contracts for Powerwave totaling 24 tools: A six-tool contract with the largest oil production company in the Sultanate of Oman; contracts with Pluspetrol in Argentina and Clayton Williams in Texas; and an 11-tool, three-field contract with a major Calgary-based oil producer. To describe just one example of how the process has aided recovery, consider an ongoing CO2 flood project undertaken by Core Energy of Michigan.
For Core Energy, the Powerwave system was implemented in a carbonate pinnacle reef field; the reservoir is naturally fractured and reservoir quality is highly variable. The project was designed to broaden CO2 distribution through existing oil well infrastructure, thus allowing for enhanced oil recovery. After 11 months, the average oil cut increased to 94% compared to the previously established trend of 82%. In January 2011, Core Energy had increased its production rate from this field by 46 barrels of oil per day to 84 bopd.
In conclusion, pulsed injection processes can assist in maximizing ultimate oil recovery from existing and new oil fields and facilitating groundwater remediation efforts.
Sebastian Thaler is a freelance science and technology writer based in New York City. His work has appeared in USA TODAY Magazine and various trade journals as well as a range of online publications. He holds a bachelor’s degree in astronomy from Columbia University and a master’s degree in journalism from Indiana University.
Sebastian’s comment appears here via IRG, which represents Wavefront Technology Solutions.