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����ɫ�� geoscientists have helped to pioneer a new method to monitor hydraulic fracturing in unconventional oil and natural gas development. The technique could significantly reduce the cost of hydraulic-fracture monitoring while enhancing well-completion design.

In a collaboration with an oil and gas producer and OptaSense, a Luna company, which specializes in fibre-optic based acoustic sensing, a research team in the Department of Geoscience in the Faculty of Science implemented a field test of a temporary, retrievable optical fibre that was deployed four kilometres into a recently drilled unconventional gas well.

Through the optical fibre and distributed acoustic sensing technology, the team was able to “listen” to nearby hydraulic fracturing operations as they were occurring, and watch the fracture growth and other information being collected in real-time.

Hydraulic fracturing involves injecting a high-pressure slurry of mainly water and sand into underground formations, creating a network of small cracks or fractures through which oil and gas can flow into wells.

Collaboration between academic research and industry

“This project truly exemplifies synergistic collaboration between academic research and industry,” says Dr. David Eaton, PhD, professor of geophysics in the Department of Geoscience.

“It has opened the door to acquiring a wealth of new data, at a fraction of the cost of permanent fibre installations.”

The use of fibre optic methods to measure tiny changes in strain and temperature of a geological formation promises to improve environmental and economic performance in unconventional oil and gas development. But to acquire this type of data, companies typically permanently cement the optic fibre and sensing equipment into the well.

“This is one of the first projects of its kind in Canada to deploy a temporary optical fibre to monitor hydraulic fracturing operations,” notes project manager Kelly MacDougall, project co-ordinator for the Microseismic Industry Consortium in the Department of Geoscience.

“It was a very cost-effective operation and ran very smoothly,” she said, crediting the success to the expertise of the oil and gas producer and three oilfield service firms involved onsite.

Postdocs, graduate students have full access to dataset

MacDougall guided the complex experimental project through nearly two years of planning, design and implementation.

The dataset was acquired in January 2021, from a long lateral well drilled into the Montney Formation in northeastern British Columbia, during large-scale fracturing operations in a multi-well pad.

OptaSense provided the specialized monitoring equipment. Oilfield service firm ESG Solutions installed the wireline (cable) that carried the fibre, while Altus Intervention provided the “well tractor” technology that conveyed the wireline four kilometres into the well.

“We’re proud of the work done with the ����ɫ��, which validates the performance of our diagnostic intervention solutions. It’s important that operators have flexible and cost-effective alternatives for acquiring valuable reservoir data,” said Tony Meszaros, managing director of OptaSense Oilfield Services.

Same results for a fraction of the cost

Initial results from the project show the temporary optic fibre system provides strain monitoring results comparable to a permanently installed optic fibre, but at approximately two to three times less cost. In addition, the fibre can be retrieved and used in other wells, giving the operator a more comprehensive picture in order to optimize hydraulic fracturing and production.

“The project is significant for the university because we now have access to this unique dataset for research by highly qualified personnel, to advance the technology,” Eaton says.

Dr. Chaoyi Wang, PhD, a postdoctoral researcher and expert in geomechanics modelling who joined Eaton’s group in January, has started analyzing the dataset. Because having access to industry data is so rare, Wang’s past work has involved either computer simulation or laboratory work.

“This is an invaluable opportunity for me to access real-world field data,” he says.

Wang will use the dataset to visualize, map and better understand the behaviour of natural and hydraulic fracture networks in sedimentary rock formations. Along with lowering the cost of monitoring hydraulic fracturing, another goal is to reduce the risk of “induced seismicity” – small-to-moderate earthquakes sometimes triggered by industrial hydraulic fracturing operations.

Collaboration key to project

The project was embedded in and supported by Eaton’s NSERC/Chevron Industrial Chair in Microseismic Dynamics. This allowed UCalgary to acquire and own the dataset, after the oil and gas producer participating in the project agreed to share it.

Such collaboration is made possible through the Microseismic Industry Consortium (MIC), co-founded by Eaton. “It would be impossible for a university to collect this important data without collaborating with industry,” he notes.

Last November, MIC received a prestigious Natural Sciences and Engineering Research Council Synergy Award for Innovation, which recognizes outstanding examples collaboration that stand as models of effective partnerships between industry and universities or colleges.

Some of the cash prize from the Synergy Award, along with separate funding from NSERC, has been earmarked for a second project using a temporary optic fibre, with another oil and gas producer, MacDougall says.

This kind of collaboration is a priority in the ����ɫ��’s “Unstoppable: Growth through focus” plan, which includes “deeper community integration” through pursuing and securing industry and community partnerships.