Horizontal multi-stage fracturing can be 44% of the cost of conventional oil drilling approaches for certain oil formations. Horizontal multi-stage fracturing should draw billions of barrels of oil from older oil formations
What we're doing in the Pembina field will be transferable to a large percentage of conventional reservoirs in the Western Canadian Sedimentary Basin." Many older oilfields have unswept and high-pressure areas that appear to be strong candidates for horizontal injection.
Jeff Saponja, president and CEO of TriAxon Resources Ltd., points out that an agile junior producer can also participate in this technology-driven game. "When multi-stage fracs clearly became viable in the Bakken [tight oil] and Montney [tight gas] formations, we jumped early into evaluating the potential of this technology for more conventional reservoirs," the professional engineer says.
Saponja cites two primary operating risks in horizontal multi-stage hydraulic fracs. First, the frac equipment must be placed in position at the end of the wellbore without developing leaks, getting stuck, or settling short of the bottom. Once placed, 8 to 11 frac stages must be performed sequentially (typically at 200 m apart) without sanding off or screening out at any stage.
"The goal is to place 10 to 20 tonnes in a nice, uniform pack, enough proppant to sustain a good [oil] flow through the reservoir," Saponja says. In wells that typically cost $2 million to $3 million apiece, halting pumping operations so a coiled tubing unit can clean out problems can quickly render the operation uneconomic. Strengthened by success in the Bakken, TriAxon had the confidence to evaluate more than 100 conventional reservoirs across Alberta and Saskatchewan as candidates for the new frac technology.
"We looked for prospects with large oil in place, low primary recovery rates, and multiple stratified layers within the reservoir," the TriAxon founder says. Historically, many conventional stratified reservoirs have responded poorly to horizontal drilling because their natural porosity and permeability tend to be horizontal plane rather than vertical.
Reservoirs with underlying water drives should be avoided; water will flow upward into a horizontal wellbore if frac stimulation opens vertical paths in the rock.
Horizontal multi-stage fracturing has been essential for the recent boom in the development of the Bakken Oil Formation. Now companies like Penn West are applying it to older oil fields to enhance the oil recovery there at a lower cost than prior oil drilling methods.
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