Oil Formation

This is just a just post about oil formation itself. Thank god for my A-level Chemistry knowledge here. Petroleum is made up of naturally occurring hydrocarbons in rocks originating from the decay of organic materials. Over millions of years thus geological time scales the temperature and pressure rises and organic maturation begins. During this processes fossils are converted into insoluble mixture of extremely large organic hydrocarbons known as kerogen and as the process continues, hydrogen rich molecules break off forming a liquid (Miller, 2013). The generation of oil as we know it, as a liquid starts at around 70C and continues until 120-160C. This temperature interval during which oil formation occurs is know as the oil window. Higher temperatures cause further decay of hydrocarbons into C1-C5 hydrocarbons known as methane to pentane. The rate of oil formation is very slow at only a few million barrels per year- much slower than the rate of extraction of oil for human consumption hence it is not surprising that we are running out of oil which is at 30 billion barrels annually. (Miller, 2013). Figure 1 below shows a crude oil fractioning column which shows the size of different hydrocarbon molecules and what type of oil they are.

Figure 1.

Source: BBC, 2014. Crude oil fractioning column.

Conventional oil includes crude oil, condensate and NGLs. It is the oil that is currently extracted and used for everyday human consumption. However non-conventional oil also exists and this includes tight oil, extra-heavy oil, oil sands and kerogen oil. Tight oil is similar chemical composition to crude oil thus some literally classifies it as conventional rather than non-conventional oil. Non-conventional oil has the potential to be converted into crude oil and other conventional oils for human use and research is currently being done in this sphere. At the moment those, it is economically unprofitable and requires unsustainable processes thus conversions are not widely performed other than for research processes. However with oil running out, the price of oil will increase and perhaps conversion of non-conventional oil will be the global solution to oil thirst rather than the use of renewable energy. I will discuss non-conventional oil further on in this blog.