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Closed-loop reservoir stimulation system offers operators an environmentally friendly alternative to traditional methods with promising production increases.
Until other techniques become available, hydraulic fracturing (fracing) will remain the preferred method of reservoir stimulation for extracting hydrocarbons from shale plays. With the increased environmental issues that have arisen recently with traditional fracing, however, operators are looking for more environmentally friendly alternatives.
Liquid petroleum gas (LPG) fracing has emerged as a viable and production-enhancing alternative to hydraulic fracturing. According to Zeke Zeringue, president and CEO of Calgary-based GasFrac Energy Services, LPG fracing can accomplish the same task as oil-based fracs but at a lower cost and with better results due to the lower viscosity of LPG and its lower surface tension.The company has deployed this technology at its Canada and US operations.
“GasFrac uses waterless gel technology to stimulate reservoirs with the primary ingredient being propane,” Zeringue explained. “This enables us to gel the propane with a nominal number of additives and proppant in a closed blending system.”
Effectively the technology uses hydrocarbons to stimulate new hydrocarbons with no biocides or carcinogens in the gel. This creates a cleaner and more environmentally friendly reservoir stimulant.
GasFrac’s gel reacts with the newly stimulated hydrocarbons, transforming into a gaseous state and flowing back into the pipeline. This eliminates the need for post- job cleanup and offers the ability to recapture and reuse or sell the propane. There also is virtually no damage to the formation.
Using LPG instead of water for fracing is said to have multiple benefits, including increasing the production yield and income from oil and gas wells and increasing recoverable reserves up to 30%. The fact that it does not require any water and produces no wastewater also are major pluses, especially in today’s highly sensitive times when public scrutiny of fracing and its side effects is acute.
“We’re creating much larger effective frac lengths than water fracs can,” Zeringue said. “Our proppant is delivering a larger pay zone height, both initially and long term. Ninety-day IP is off the charts when compared to other methods because the fluid recovery is immediate, recapturable, reusable, and nearly 100%. We’re able to create a fluid-free reservoir within days of stimulation, whereas water can stay in the reservoir for years and create flow-back blockage.”
With more than 1,000 propane fracs carried out so far, recent contract awards indicate growing industry acceptance. Husky Energy last year awarded GasFrac a three-year contract with a two-year renewal option on its liquids-rich formation at Ansell in west-central Alberta, Canada, after carrying out a series of significant tests and analysis on reservoir deliverability. The Ansell development is a large project with the potential for up to 2,600 Cardium and deeper Mannville wells, and the contract is a vote of confidence by Husky – an early adopter of GasFrac’s LPG process – in the technology.
Every job that GasFrac performs is in a closed-looped system, meaning no part of the process is exposed to open air. The company is working with others toward having a fully recycled system, where it would use its LPG gel to stimulate the fractures, recapture the propane in its gaseous state when it returns to surface with the hydrocarbons with no flaring, and reuse it for the next stage or treatment. This would greatly reduce costs in multistage horizontal wells, according to Zeringue.
“What is needed to do this are the facilities to recapture, separate, and reuse the propane,” he said. “There are operators in certain areas that have these facilities, and over time, as our process becomes more of an accepted industry practice, those facilities will grow.
“We also are looking at the next generation of LPG fluids and how we can enhance our current process. R&D will play a big part in our growth.”
Zeringue added that the company’s biggest challenge is finding the right people and partnerships for success. He expects to double the fleet size in 2012, which will require more employees. “We’ve invested heavily in infrastructure and should have ample proprietary turnkey spreads by the end of 1Q 2012. We are also looking at forming partnerships with companies that can facilitate and complement our process.”
There has been some understandable industry and regulatory concern about the safety of the LPG fracturing process because of its flammability, Zeringue conceded.
“Our number one goal as a company is to be safety-focused at all times,” he said. “We have put advanced safety features and protocols in place that other traditional fracing processes don’t necessarily need to have.”
Zeringue noted that some of the major operators have spent up to two years vetting the company’s process and performing numerous safety audits. “We were finally able to perform our first jobs for them in 4Q 2011,” he said.