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What is a conventional hydrocarbon deposit?

When we talk about oil and gas in Quebec or elsewhere and especially the possibility of reservoirs, it is not everyone who can easily tell the difference between the types of natural reservoirs rocks. Moreover, in the media, confusion remains and therefore leaves people with a certain apprehension in the face of this unknown. In this blog, we will talk about the so-called conventional hydrocarbons reservoirs rocks.

“For a hydrocarbon deposit to qualify as a conventional oil and gas system, the presence of a source rock, a reservoir rock and a cover rock is necessary. In this system, hydrocarbons migrate from the source rock where they formed to the reservoir rock where they will be stored. The degree of porosity and high permeability of a rock characterizes its ability to be a reservoir rock. Hydrocarbons remain trapped in the reservoir rock through a cover rock (seal) that is characterized by a lower degree of porosity and permeability. (Source: MERN)

The first thing to remember about these conventional reservoirs is that for these, the methods of extraction of their hydrocarbons have been well known for more than 160 years (1859: Titusville, Pennsylvania) and above all they do not require the use of hydraulic fracturing. And as the above definition of MERN says, to be conventional, the reservoir must be porous, permeable and naturally insulated by a impermeable layer preventing a migration of hydrocarbons to the surface (blog # 2: seeps). This implies that, for the production of a conventional reservoir, a simple well will be necessary to extract hydrocarbons at the surface. This method is ultimately very similar to that used to produce drinking water, but at greater depths.

So why talk about conventional reservoirs? 

It is that a reframing of the terms used in the public space is necessary. Indeed, for several years, there has been talk in the public discourse on hydrocarbons thatshale gas.

 However, these are non-conventional resources. In this case, hydrocarbons are trapped in the source rock (Blog # 1) and that to recover them, hydraulic fracturing is the only cost-effective way to create the porosity and permeability that are necessary to enable production.

You have to know that in Quebec there are possibilities of conventional reservoirs (which can be exploited without fracturing). The latter are located mainly in the Gaspé / Lower St. Lawrence in the Devonian and Silurian rocks, but also in the St. Lawrence Lowlands in the limestone formations of Trenton and Black River. (Ordovician).

Do you have any questions about this scientific note? You can contact the Squatex team at any time to answer your questions!

For questions of a scientific nature:

Alexandre Aubiès-T., PhD., Geo.


For media Inquiries:

Jean-François Thibault, ing. jr


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