Maritimes Basin, Oil and Gas

In New Brunswick the sedimentary rocks of the Devonian and Carboniferous Periods are part of the Maritimes Basin, an area of mountains and valleys created as continents were rearranged to form the supercontinent of Pangea. In the Lower Carboniferous about 353 million years ago, the continents were pulling apart, creating faults that caused blocks of the Earth’s crust to subside. Organic-rich sediment accumulated in lakes formed within the basins. The fault-bounded valleys of the Albert Formation were filled with lakes, rivers and swamps. Algae grew in the lakes and formed thick layers of organic matter at the bottom. Over time, the organic matter was buried. The lakes eventually filled with sediment that slowly turned to sedimentary rock. As the rocks were buried deeper, higher temperatures and pressures converted the organic matter in the shales into hydrocarbons.

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The shales of the Albert Formation are the source rocks for the natural gas now held in sedimentary reservoirs, such as the Stoney Creek and McCully fields. The thick organic-bearing shales have potential for holding large volumes of natural gas. The shales have been familiar to palaeontologists since the mid-1800s when the first fossils of palaenoniscid fish were found there. The Albert Formation is also well known as the rock unit that contains the bitumen albertite, once used as a source for the production of kerosene.

Two deep subbasins within the Maritimes Basin have known petroleum potential. More than 250 exploration and production wells have been drilled over the last 100 years. New wells in the McCully Field and near Elgin have shown there are gas-prone organic shales in those areas. A number of companies such as Corridor Resources are actively exploring in our province.

In March 2010, the New Brunswick Department of Natural Resources awarded licenses to SWN Resources Canada to search an area of more than 1 million hectares for oil and gas in sandstone reservoirs and unconventional shale reservoirs of the Horton Group that includes the Albert Formation.

Unconventional shale reservoirs such as those in the Albert Formation consist of dense, fine-grained rock. A process called hydraulic fracture stimulation is required to produce economic quantities of natural gas. The shale is ‘tight’ and the gas cannot migrate through the rock. To extract the gas, fluid is injected into the rock to fracture the shale and release the trapped gas.

Unconventional shale reservoirs such as those in the Albert Formation consist of dense, fine-grained rock. A process called hydraulic fracture stimulation is required to produce economic quantities of natural gas. To extract the gas, fluid is injected into the rock to fracture the shale and release the trapped gas.