Sourcing Our Energy

Hydrocarbon Basics

Vermilion focuses on conventional exploration and development in Europe and Australia, and on conventional, semi-conventional and unconventional exploration and development in North America.

Rocks and Reservoirs Explained

All hydrocarbons (including oil and natural gas) are created from microscopic plants and organisms that lived predominantly in the ocean millions of years ago. When these plants and organisms died, they sank to the ocean floor,  became preserved as kerogen and were covered by layer upon layer of sediment over millions of years. As the layers became more deeply buried and compacted, the heat and pressure within them began to rise, ultimately transforming kerogen into the hydrocarbons we know today.

Source rocks are the organic-rich layers of rock in which hydrocarbons are formed.


The pressure surrounding them generally forces the hydrocarbons to migrate upward from the compact or “tight” source rock into more porous and permeable layers of rock, known as reservoir rock


The classification of a reservoir as conventional, semi-conventional or unconventional depends on the specific geology of the rock and the reservoir conditions encountered at depth.

Conventional Deposits

Generally, conventional reservoir rocks such as sandstones, siltstones and carbonates have sufficient porosity (the vacant space within the rock) and permeability (the connectivity between pore spaces) to allow fluids such as crude oil, natural gas and water to flow within and through the rock. Left unimpeded, the hydrocarbons continue their migration up towards the surface and escape as natural gas vents or oil seeps. 

This upward migration, however, is often blocked by a layer of impermeable rock or other geologic formation. This traps the hydrocarbons, which then accumulate to form a hydrocarbon deposit


If the reservoir rock has sufficient permeability to allow the hydrocarbons to naturally migrate within and through the rock, they are often referred to as conventional pools or deposits


Recovering these hydrocarbons is generally referred to as "conventional” oil and natural gas exploration and development. Once the deposit is accessed, the hydrocarbons either flow to the surface under the reservoir’s natural pressure, or can be pumped to the surface.


Decades of oil and gas production around the world have resulted in a decline of conventional resources, with the majority of them already subject to development.

Semi-Conventional Reservoirs

Vermilion uses “semi-conventional reservoirs” to describe reservoirs that – while requiring technology beyond pumping to bring hydrocarbons to the surface – can be accessed with significantly less intensive techniques than are required for full-scale unconventional production such as that of shale oil or gas production. These stimulations use a lower amount of pressure, water and other assorted products than those needed for unconventional reservoirs. Approximately one third of Vermilion’s production comes from this reservoir type. 


An example of this is the Cardium formation in western Canada, which is considered one of the largest stratigraphically trapped reservoirs in the world. It has been developed conventionally with vertical wells and limited stimulation for decades. However, new techniques in the last decade such as hydraulic fracturing, horizontal drilling and new stimulation alternatives have made it technologically and economically feasible to access the reservoirs within the formation that historically have been too “tight” to produce.

Unconventional Deposits

Unconventional or “tight” deposits are usually classified as shale, siltstone or carbonates that are rich in mature organic matter, complex mineral compositions, laminated structures and tight storage space. They generally have ultra-low permeability and low porosity that prevent the hydrocarbons from flowing naturally through the rock. This means that the hydrocarbons don’t form easily accessible pools that can be produced at the surface.


This is where hydraulic fracturing plays a role: Multi-stage hydraulic fracturing using horizontal wellbores makes it both possible and economical to produce from these previously inaccessible unconventional reservoirs.


Regardless of how they are produced, or the type of reservoir they come from, unconventional hydrocarbons are essentially the same as conventional hydrocarbons. The term “unconventional” simply refers to the methods that are used to extract them as well as the type of reservoir rock from which they are produced. 


Shale gas or shale oil is a particular type of unconventional resource that has not migrated and is produced directly from the organic-rich source rock in which it was formed.

Hydraulic Fracturing

Hydraulic fracturing is a government-regulated technology that has been successfully used in North America for more than 60 years. Government regulations, in combination with industry operating practices and Vermilion’s own priorities of public and employee safety, environmental stewardship and operational excellence, help ensure safeguards are in place to protect the environment, including freshwater aquifers, and to ensure safe and responsible operations.


Hydraulic fracturing is a well stimulation technique in which rock is fractured by a pressurized liquid. The process involves the high-pressure injection of 'fracking fluid' (primarily water, containing sand or other proppants suspended with the aid of thickening agents) into a wellbore to create cracks in the deep-rock formations through which natural gas, petroleum and brine will then flow more freely. When the hydraulic pressure is removed from the well, small grains of hydraulic fracturing proppants such as sand hold the fractures open.


We publicly disclose 100% of the additives we use to FracFocus in both Canada and the United States, as well as via our regulatory submissions. We continue to work to decrease the required concentration of our additives and we work with our fracturing suppliers to source even better alternatives for future consideration.

For more information about our approach to water stewardship during fracking, click here.

We value your privacy

We use cookies to enhance your browsing experience, serve personalized ads or content, and analyze our traffic. By clicking “Accept & Close”, you consent to our use of cookies policy