The idea of exploration

I think that it was Wallace Pratt, the legendary Esso Chief Geologist, who was approached by a young man with a question: “Sir, where should we look for oil?” The answer was direct: “Oil is found within the minds of men.” It was not the geographic answer that the young man expected, but it was perfectly correct (although in this day and age we would probably append the completing phrase “and women”). And, we would probably include, within the scope of the question, natural gas and less ‘conventional’ forms of hydrocarbons.

What the seer (Pratt or not) meant was that oil is found by application of intellect, and that this is more important than the actual geography of the search. As you think about this aphorism, deeper and deeper layers of meaning emerge. In the first place, it is clear that simple ideas are sufficient to find the ‘easy’ oil and gas, while more complex ideas are required to find the rest.

For millions of years, natural gas has leaked from the earth in certain places, and has been ignited by lightning. In Azerbaijan, there are many such locales; they were early recognized as special places, even holy places, and each is (or once was) the focus for a Zoarastarian temple. It seems relatively straightforward to predict that more gas might be found nearby to such ‘eternal flames’, and in fact the entire Apsheron peninsula surrounding Baku is one of the world’s great provinces for oil and gas.

In a similar way, there are tar pits and other seepages of liquid oil at various places around the world, all noted by early inhabitants. The Drake Well #1, the first oil well drilled in America, was drilled on the theory that where oil seeped out of the ground, there might be more to be found by drilling nearby. That simple idea provided the early foundation of the American oil industry.

New tricks

However, the list of such places is short, and the oil and gas to be found by such simple ideas is limited. Soon, explorers developed more complex ideas, such as ‘creekology’ – the idea that oil would be found by drilling where creeks converge. This was a simple extension of the observation that oil seeps were frequently found in watersheds, so why not drill upstream? After all, a variant of this idea works for finding placer gold. Painful experience soon showed that this idea had little merit.

After your chuckle subsides, however, think about just how different creekology really is from the still-current idea of ‘trendology’ – drilling along the extension of a trend of successful wells. When I was young, a popular board game named ‘Gusher’ employed the same principle: players would compete to find oil by ‘drilling’ on a map, where, in the absence of other meaningful information, the only viable strategy was to drill near successful wells. These days, when a well can be expensive to drill, the idea of trendology is best complemented by a good understanding of the subsurface geology – in other words, by the application of more complex ideas.

Subsequent evolution of the ideas of exploration included drilling near salt domes, which resulted in many successes including the famous Spindletop well, which almost doubled the world’s production of oil overnight. Images of gushers spewing oil hundreds of feet into the air form the basis for the public’s perception that the petroleum industry is a dirty, roustabout industry. While not denying the reality of some spillage (even today), a deeper understanding reveals that, at its core, the exploration for oil is exploration with ideas.

This is not the place for an exhaustive discussion of the historical sequence of ideas for finding oil and gas. But, I will mention some highlights, and bring us to consider their implications. This history of ideas will lead us to the current situation of enormous supply, and enormous demand, and great uneasiness about the future stability of this hydrocarbon-based economy. Will the flow of new ideas be sufficient to enable the finding of new oil to maintain this enormous economy?

The appliance of science

The next stage in the evolution of ideas was to bring real science to bear on the problem of exploration. Many geological and physical ideas have been tested; by far the most fruitful has been the idea of reflection seismics. Explorers have learned that sound waves generated near the surface (such as by dynamite) propagate down, reflect off the various formations and return to the surface, where they can be recorded and the data transformed into an image of the subsurface formations. Some of the subsurface structures thus revealed are amenable to the accumulation of hydrocarbons.

This idea has been developed for the past 80 years, with continuously increasing sophistication and success. Most of the world’s oil (i.e. most of the foundation for our modern economy) has been found via this idea. When I entered this business in 1981, one of the leading practitioners told me that it was too bad that such a bright lad as myself would choose to enter a mature field such as exploration geophysics, where all the important ideas had been had by his generation. Since then, of course, we have seen the invention of 3D seismics, 4D seismics, multi-component seismics, anisotropic seismics, wide-azimuth seismics, and seismic methods that go beyond mapping the subsurface formations to estimating their hydrocarbon content prior to drilling a well.

These days, the application of this idea requires enormous resources, undreamt of by the pioneers. An image like that shown on the right emerges from a seismic survey that costs several tens of millions of dollars to conduct, and acquires several terabytes of data. These raw data are passed through large computers, operating at rates of several teraflops, employing sophisticated computational algorithms to produce better-focused images than previously. Eventually, these images lead to a new idea, which can be expressed in only a few hundred bits: ‘Drill here!’

Our work

The Society of Exploration Geophysicists is the leading professional organization worldwide, for those who explore in this way. The mission of the society is to advance geophysics today, and inspire geoscientists for tomorrow; in part, we do this by facilitating the flow of ideas among professionals. If your firm is involved in the exploration for oil and gas it is imperative for your business that you have access to this flow of ideas, via individual and/or corporate membership in SEG.

This steady flow of new ideas, and elaboration upon old ideas (in all of the petroleum sciences), has led to a steady increase in hydrocarbon production, as shown on the left side (the historical side) of the figure below from the Uppsala Hydrocarbon Depletion Study Group, 2004. This graph is a surrogate for the history of the discovery of said hydrocarbons (and of its future, about which more shortly), in which discovery precedes production by a few years, sometimes by a few decades. It is a dramatic history, showing a twenty-fold increase in production over the span of the historical graph (i.e. over the living memory of some of us).

It is an even more dramatic prediction of the future (the smooth right side of the graph), predicting a marked contraction of the production of the main energy that drives our civilization. Much has been written about this phenomenon of ‘peak oil’; I do not propose to abstract this discussion here, except to note that much of the legitimate debate seems to be over details, such as the timing of the peak. However, most of the larger companies that I know expect to be in business 50 years from now, and this time span includes all of the serious estimates of the date of the peak. Likewise, most of the larger countries that I know expect to be in existence 50 years from now, and like the companies, they should be planning now on how to cope with the changed circumstances then. When massive economies face fundamental changes in where they derive their energy supplies, it takes time to make adjustments, so we should start now.

Looking ahead

Instead of quibbling over the details of timing, I want to speculate on how the ingenuity in the minds of men and women will rise to the challenge posed by the figure. In the first place, it is simply naïve to assume that great new ideas will appear to indefinitely prolong the increase in the finding and production of the past 80 years. Despite what some economists imagine, the supply of hydrocarbons is ultimately finite, and so we will eventually enter into decline. The challenge of today’s petroleum industry may be seen as the difficult task of making the transition to a sustainable energy economy as smooth as possible.

This will require the invention of new ideas to postpone the peak by finding (or enabling the production of) oil and gas that was inaccessible to the older, simpler ideas. One such idea, discussed briefly by Apache Corporation’s David Monk in the previous issue of O&G, may be that of controlled source electro-magnetic surveying. Interestingly, this may be viewed as a modern variant of an idea of Conrad Schlumberger, with which he discovered the very first oil field using geophysical methods in Romania in 1922, even before the invention of exploration seismics.

Many of the new ideas will apply to the data-rich production context, rather than the data-lean exploration context. The difference is that, in the production context, a lot of data is available, of many different types (e.g. geophysical, geological, petrophysical, engineering) and at many different scales (from thin-sections, cores, logs, seismics), so that some of the simplifying assumptions that are necessary before the first well goes down may be discarded. The integration of these various data into an understanding of the subsurface, sufficient for optimal production of the reservoir, is a task still to be properly accomplished. Of course, one of the difficulties in learning these new ideas is the ‘un-learning’ of ideas that were sufficient in their day, but are now seen as merely approximations to the better ideas of today and of tomorrow.

Ideas have always been central to the petroleum industry; they have driven our progress every year since the beginning, and will surely continue to drive the high-tech progress of the future. In fact, as we struggle to delay the peak and then to delay the decline, ideas will be even more important as the technology becomes more expensive, and it becomes even more important to know what we are doing. Young people entering the field now can count on full and engaging careers, but only if they embrace the challenge of creating and applying the ideas of 21st century petroleum.

• “When massive economies face fundamental changes in where they derive their energy supplies, it takes time to make adjustments, so we should start now”
• “Ideas have always been central to the petroleum industry; they have driven our progress every year since the beginning, and will surely continue to drive the high-tech progress of the future”