From a geological standpoint the Gaspé Peninsula is part of the Appalachians, a mountain range stretching from Labrador in north-eastern Canada to Alabama in the south-eastern United States. The Appalachian range was formed 450 million years ago, over a period of 150 million years. The range has a rich history of fossil fuel exploration, discovery, and production.
When the Appalachians were formed sandstone and reef limestone deposits were created, forming potential oil reservoirs. The rocks in the Gaspé area have been “folded over” by movements of the earth’s crust to create anticlinal folds, dome-like shapes with the potential to “trap” sizeable oil pools.
The rock in the Gaspé Peninsula also meets another requirement for forming oil and gas deposits: because temperatures increase the deeper you descend below ground, buried rock reached the correct temperature for hydrocarbon formation. Had the source rock been buried too deep, it would have been too “cooked,” destroying the hydrocarbons.
The York River sandstone has all the properties necessary for reservoir formation. The formation is made of sedimentary rock that formed in a shallow marine environment during the Lower Devonian period, making them around 400 million years old. The map below shows, in brown, how this formation extends to the outskirts of Gaspé. Most of the wells where shows of oil or small-scale production have been recorded were located along the York River Formation.
In 2005 Pétrolia’s exploration work confirmed this oil potential when the Haldimand deposit was discovered.
The Haldimand deposit is lodged in the sandstone of the York River Formation. Thanks to data from the 3D seismic survey and two test wells, experts were able to estimate the volume of oil in place and the volume of recoverable oil using existing production methods. Pétrolia’s estimates, confirmed by Sproule Associates, a leading petroleum consulting firm, put the total oil in place at 21.9 to 198.1 million barrels (see our July 6, 2010 press release). This means there is a 50% chance of recovering 7.7 million barrels, using technologies that currently exist or are under development.
Our research in recent years suggests that parts of the Haldimand deposit are home to a naturally fractured reservoir, and has pinpointed the areas within the larger deposit where these natural fractures can most likely be found.
Based on data gathered since 1986, Pétrolia and Québénergie believe traditional production is feasible on the Haldimand deposit. This means hydraulic fracturing will not be necessary. What is more, Pétrolia and Québénergie’s field work and analyses have yielded invaluable data about the reservoir, which has been crucial in determining the location and path of Haldimand 4.
Core sample extraction at Haldimand
Seismics, Haldimand
Main parts of an oil system
Source Rock
Over time, layers of sediment rich in organic matter such as algae and micro-organisms built up on the bottom of the ocean. As these layers of sediment were buried deep beneath the ocean floor, this organic matter was “cooked” by the heat emanating from the earth’s core, transforming it into petroleum and, at even greater depths, natural gas.
The Gaspé Peninsula oil reserves were created when a vast section of ocean floor at the equator gradually drifted north to its current location, then emerged to form the land mass. This process, which took place over hundreds of millions of years, is known as “continental drift.”
Cap Rock
Cap rock is nonpermeable rock that “traps” the petroleum released from the source rock. Hydrocarbons are lighter than water, so their natural tendency is to rise to the surface; cap rock prevents this from happening.
Reservoir Rock
Reservoir rock can be sand or porous rocks such as carbonates. Its high porosity makes hydrocarbon accumulation possible.
Traps
When the reservoir rock is covered by a layer of impermeable rock, this layer acts as a cap blocking hydrocarbon migration to the surface. This is known as a “trap”: a structure (such as a dome) where hydrocarbons accumulate and cannot escape. When traps are large enough, they are considered potential deposits.
In the Gaspé Peninsula we are looking for several different types of traps:
1) Traps at the top of anticlinal folds—a structure where alternating layers of permeable rock (sandstone) and impermeable rock (clay) have formed an arch.
2) Traps created by a fault line where fluids circulating within a permeable layer are trapped under impermeable layers in a “pinch” or wedge shaped by the movement of layers along the fault.
3) Porous reef limestone (former reefs) covered with impermeable layers.
4) Porous rock cut by an angular unconformity (erosion surface), then covered by impermeable layers.