BP discovers oil field in Gulf of Mexico

This article is reproduced from my blog. Image © BP p.l.c.

‘BP said the discovery, amounting to more than three billion barrels, would “support the continuing growth of our deepwater Gulf of Mexico business into the second half of the next decade”.’  (BBC News)

I think we can agree that three billion barrels of oil appears to be a fairly large amount.  On one hand we are told that oil is in decline, but then we discover more oil fields and the world continues to turn.

But by how much do finds like these really delay the ultimate depletion of oil?  How long will the three billion barrels last?

There are a couple of ways of doing this calculation.  First is the gross simplification: divide the amount of oil discovered by the amount of oil consumed globally.

According to BP figures, the world used about 85 million barrels per day in 2008.  If we assume BP can recover all 3 billion barrels from Tiber (the new oil field discovered), then it would last the world about 35 days.

The BBC article quotes a BP spokesperson, saying that “… only as much as 30% is extracted from the ground in practice“.  Given that, the number of days’ supply falls to about 11.

That is a fairly poor estimate, though, as it does not take into account the fact that oil production from a new well follows a normal distribution (a bell curve).  Production increases as infrastructure and access to the well improves, then peaks, and as the well is a finite resource, starts to decline again.  This is also known as a Hubbert Peak.

A better way to consider the impact of this new well is to add its bell curve to the bell curves of all the other oil fields globally.  The largest oil field is called Ghawar in Saudi Arabia, producing about 5 million barrels per day and estimated total reserves of 75-83 billion barrels.

Ghawar is but one of the giant fields, others include Burgan, Safaniya and Samotlor, all significantly larger than young Tiber.  There are also thousands of smaller ones.

Imagine all these bell curves overlapping one another, adding up to make one very large one (with a definite peak).  What is the effect of adding a new discovery like Tiber to it? 

The problem is that adding one bell curve to many does not change the average of them by very much at all.  In fact, given the relative size of this new field compared with the total, I cannot imagine the peak of the total bell curve shifting by more than a couple of days, if that.

Unfortunately an actual number is beyond my resources to find – I’m sure there are hundreds of highly paid analysts working for BP and others trying to find exactly the same thing.

The point is that, though new oil discoveries do happen, they are simply not of the scale or number needed to push the “end of oil” back very far at all.  The chances of finding another super-giant like Ghawar are slim now, and searching in harder to reach places (Tiber is the deepest known field, at about 10km deep) increases cost.

I fear that hoping that new discoveries will continue to allow our current oil consumption is folly of the highest order.  Most oil fields are now in decline and, though this is contested, it would appear that oil has most definitely “peaked”.

Time for something new.  Gas, nuclear, or renewables?  Or, in fact, all three, as well as recovering oil from less conventional sources like oil sands/shale.

Sources Used

BBC news story
BP oil usage statistics (BP)
Hubbert Peak Theory (Wikipedia)
Ghawar reserves statistics (foreignpolicy.com)
List of oil fields over 1 billion barrels (Wikipedia)