There's something about human nature that wants it both ways. We like it when some simple technology, something supposedly overlooked, succeeds wildly. It's a bit cultural too: The less educated especially like it. It's like poking a stick in the eye of megabucks PhD research and development.

Conversely, we are suspicious of anything that's too cheap, too easy. Surely, we think, the "big boys" with all their money and know-how, didn't overlook this simple idea. They probably looked into it, and deemed it unworthy.

All too often, the inventor or practitioner of the technology is unwilling to allow the technique to be critiqued, examined or make any attempt to prove its utility. "Why should I? I'll find all the oil and make all the money!" they would say. (But that doesn't stop them from asking me to publish them!) In such cases, it is fitting that their technology should remain largely unused.

Finally, there's the disruptive effect that such technology, especially when it's cheap, could potentially have on the status quo. Sometimes, the disruptive effect is real, such as when railroads and automobiles replaced wagons and horses. Sometimes, it's just logic with a touch of paranoia, such as when people believe that technology breakthroughs are being bought and squelched to prevent them from encroaching upon billions of dollars of current investment. Such conspiracy theories are almost always wrong. What follows are technologies that the author neither endorses nor ridicules, but out of the large number of unconventional, even maverick, technologies, these, in the author's opinion, have the potential to reduce exploration risk.

SURFACE EXPRESSION

In many ways, the expression of an oil or gas reservoir can trigger anomalous readings across many technologies. Structurally tilted strata that form deep traps can become shallow or outcrop, possibly resulting in anomalous readings that relate to the formation, such as mineralogy, radioactivity or electrical conductivity, and only coincidentally relate to hydrocarbon pore fluids.

Surface expression of seepage along transmissive faults, bedding planes or directly upward (microseepage) is often related to a deeper reservoir. This expression, in turn, can be revealed in alteration of microbial communities and the presence of soil gases, such as methane, ethane, butane, etc.

Sometimes, you can see the surface expression with your eyes, either as an early or late seasonal color change caused by stress in vegetation, plant species distribution (Fig. 1), crown density or vigor (dwarfs or giants). More subtle changes due to seepage are shown in spectral reflectivity, sometimes called hyperspectral analysis. Even early versions of Landsat, with a relatively small number of channels, showed field outlines.

[FIGURE 1 OMITTED]

Landsat continues to be used in exploration work today (Fig. 2), as do several other newer satellite systems, although more sophisticated airborne platforms yield much better spectral information on seeps, vegetation, mineralogy, and so on. An extensive library of spectral signatures is held by government agencies such as NASA (ASTER) and USGS. In all cases, ground truthing is needed for fine calibration.

[FIGURE 2 OMITTED]

Furthermore, seepage effects can result in mineralogical changes from oxidation/reduction reactions that might be revealed in changes in some attribute of the overburden, including electrical properties, such as capacitance and conductivity, magnetic properties and radiological properties. These can take the form of anomalous concentrations, deficits or halos. For example, consider the following case of radiometric anomalies.

An interesting study was done over Helez and Kochav oil fields in Israel. These fields have halo-type radioactivity anomalies associated with depletion of eU, eTh and K-40 in sediments overlying these fields, Fig. 3. Since their aqueous chemistries are quite different, it is difficult to account for such a uniform depletion--with concomitant flanking highs--by a process of vertical aqueous transfer of daughter nuclides; especially from a reservoir in which redox changes have led, primarily, to uranium accumulation. Nor can continuous gaseous-transfer processes, requiring Rn daughters of Th and U, be responsible for the surface elemental distribution (K has no gaseous precursor). (2)

[FIGURE 3 OMITTED]

"However, these elements do tend to behave similarly when entering the crystal structure of rock-forming minerals, and when adsorbed onto clay surfaces, mainly due to similarity in the ionic radius of these large cations. It thus appears that an upward flux of radionuclides leaking from the reservoir does not explain the observed features. Rather, it may be the hydrocarbon flux itself that can be corrosive, which leads to mineral alteration in the overlying sedimentary rock and the release of associated cations. These would tend to migrate laterally, away from the altered area, and become immobile at the periphery by adsorption on clays." (2)