Maugeri on peak oil

About half of Maugeri’s calculated 17.6 mb/d in net additional production capacity comes from two countries– the United States and Iraq (see his Table 2). I have earlier discussed the situation for the United States. To briefly recap, more than half of the increase in total U.S. oil production since 2005 has come from biofuels and natural gas liquids, neither of which should be added to conventional crude production for purposes of calculating the available supply. Another important contribution to recent U.S. production gains has come from shale/tight oil. I agree with Maugeri that this will be an important factor in the future, but it is not cheap, and there are some big uncertainties in extrapolating recent gains, about which I will have more to say below.

But first let’s take a look at Iraq, which by itself accounts for 5.1 mb/d, or 29% of the net combined global gains that Maugeri is anticipating. His starting point for these calculations (see his Table 1) is the “production target” associated with a dozen oil fields for which the Iraqi government has signed contracts with oil companies. These targets call for these fields to reach maximum levels of production which, when added together, come to 11.6 mb/d. To win a contract, oil companies had to specify two key parameters: a “target” level of production and a remuneration per barrel, with awards going to the companies that specified the highest target and lowest remuneration. Some have characterized the announced targets simply as propaganda. Once awarded, there seems to be a separate process in which the production targets get renegotiated. Maugeri acknowledges the logistic and security challenges in meeting the targets, and accordingly cuts the official estimates in half. Doing so would still be a stunning achievement, requiring an Iraq that would be substantially more stable and successful over the next decade than it has been over the last three.

A separate issue is that new production from places like the U.S. and Iraq are needed in part to replace declining production flows coming from mature fields. A key question in any study like this is the assumed magnitude of that decline. As Stephen Sorrell notes, Maugeri does not state his assumed rate, and confuses the issue by mixing discussions of the depletion of an existing reservoir (for which purposes Maugeri is correct to raise the offsetting factor of additions to reserves) with the declining production flow rate from a given field (the relevant number for purposes of calculating the net addition that new fields bring to annual production). Sorrell suggests we can infer the implicit assumed decline rate from Maugeri’s Table 2, which reports a difference between his adjusted gross additions and adjusted net additions of 11 mb/d. That seems to imply that Maugeri is assuming that the total decline in production from existing fields between now and 2020 will be 11 mb/d, which I calculate to correspond to a 1.4% annual decline rate (ln(82/93)/9 = -0.014). As Sorrell notes, this compares for example with the IEA’s (2008) substantially less optimistic numbers:

Based on data for 580 of the world’s largest fields that have passed their production peak, the observed decline rate– averaged across all fields and weighted by their production over their whole lives– is 5.1%. Decline rates are lowest for the biggest fields: they average 3.4% for super-giant fields, 6.5% for giant fields and 10.4% for large fields. The average rate of observed post-plateau decline, based on our data sub-set of 479 fields, is 5.8%.

Standard oilfield-production profiles by category of field. The thick lines are derived from observed data; the thin lines show the trajectory assuming full depletion of the field. Source: IEA.

To get another feel for this issue, the figure below plots annual production rates for the four most important U.S. oil-producing states. Note that this graph includes all of Gulf of Mexico’s production in the panel for Louisiana. Despite the tremendous technological gains and new fields developed offshore, the Louisiana + GoM production level in 2011 was 53% lower (as measured by difference in natural logs in order to allow calculation of average annual compound decline rate in the next step) compared to its peak in 1971, for an average annual decline rate of 1.3% per year. In other words, we would have had to find new fields to produce an additional 1 mb/d (over and above the new fields and new production that in fact were added in Louisiana + GoM since 1971) just to keep LA + GoM production from falling from its 1971 levels.

Annual crude oil production (in thousands of barrels per year) from 4 leading producing states, 1860-2011. California includes offshore and Louisiana includes all Gulf of Mexico U.S. production. Updates Figure 6 from Hamilton (2012).

One encounters the same basic facts in every U.S. state except North Dakota (see my recent survey article). The table below summarizes the net average annual decline rates– again, already inclusive of all new production– for each U.S. region from that region’s production peak.

RegionDecline rate

US total-1.3%

A particularly important question is the decline rate to assume for the new shale/tight oil production. Maugeri (page 50) states that he used the following assumption for this:

A combined average depletion rate for each producing well of 15 percent over the first five years, followed by a 7 percent depletion rate

Heading Out finds this assumption at odds with the conclusion of the North Dakota Department of Mineral Resources.

Source: North Dakota Department of Mineral Resources.

I agree with Maugeri that new production from places like the United States and Iraq is going to be very helpful. But I think he substantially overstates the case for optimism. If we are counting on sources such as shale/tight oil, oil sands, and deepwater to replace production lost from mature conventional oil fields, the days of cheap oil are never going to return.