Robin Watts, Linde’s Oil and Gas Technology manager, will be discussing the use of energised solutions in hydraulic fracturing to improve economics and productivity at the American Institute of Professional Geologists (AIPG) conference.

In her paper, Watts will show how energized solutions incorporating nitrogen or carbon dioxide can increase the overall productivity of wells while also reducing the water needed for the fracturing process. She discusses how the use of energised fluids in the production of hydrocarbons from unconventional reservoirs, such as tight gas formations and shale, may be advantageous in a variety of situations. These include depleted, or water sensitive formations, when producers encounter poor water flowback or blocking (high fluid retention), and for enhanced mobility of more viscous hydrocarbons around the wellbore.

“The addition of highly soluble carbon dioxide gas is ideal to provide energy to aqueous solutions to facilitate flowback,” Watts says. “However, when nitrogen gas is more readily available, additional measures are available for engineers to use to ensure that the energised solutions adequately penetrate the invaded zone where extraction occurs.”

Watts emphasises that the variability inherent in unconventional reservoirs requires tailoring stimulation solutions to the unique circumstances of the site in order to optimise well productivity. Key factors include maximising Expected Ultimate Recovery (EUR) and the lifetime potential recovery of the well; ensuring effective production occurs sooner rather than later; and minimising reservoir damage, needed material and labour inputs, and total fracturing costs. She also recommends the use of mini-test fracturings, when possible, to allow calibration and optimisation of the operational design.

Energised solutions can add value at every stage of treatment, but are essential for refracturing operations, where they can overcome low pressure and capillary forces and enhance the mobility of more viscous hydrocarbons. Energised refracturing has been successful in a wide variety of fields and basins.

“The huge increase in shale gas activity has brought many new operators into the field, and my goal in this presentation is to introduce our new colleagues to the expertise developed over the years on how and when use of energised solutions can provide excellent economic and environmental returns,” adds Watts. “Energised solutions currently are estimated to comprise about one-third of all fracturing operations in North America, and we believe that the data clearly demonstrate the benefits of using energised fracturing in a variety of situations. Reported results indicate that well-managed energised fluid fracturing has the potential to achieve significantly more gas recovery than non-energised approaches, at the same time that it makes production in water-restricted locations more feasible.”

Watts’s paper will be presented at the conference, which will be held from October 23 to 26 at the Omni Interlocken Resort in Broomfield, Colorado. The American Institute of Professional Geologists (AIPG), founded in 1963, is the largest association dedicated to promoting geology as a profession.