What’s new in exploration

A variety of factors, depending on the timing, can make a significant difference in the eventual outcome of various concepts and projects.

Market: In 1981–1983, I owned part of a drilling company called Stellar Energy, operating out of Casper, Wyo. We built the first modular, winterized high-tower land rig at Cameron in Houston. Oil in 1981 was averaging $35/bbl [R, real; inflation adj. $99].

Judgment: Built a couple more units, Rigs # 4280 and # 4281, in 1982. Then there was the great “pause” of 1983, Oil, R $29. Today’s U.S. land rig count is about 988.

Fortune, like a Chinese proverb: Good. Amoco bought Stellar to finish a winter drilling program in the Williston basin. I took a job in Ponca City, Okla. Bad. DuPont bought us. Good. I was rescued by Marathon. Bad. USX showed up and spent the exploration budget.

Government overreach: League of Conservation Voters (LCV) v. Trump, 17-cv-000101, U.S. District Court, District of Alaska (Fairbanks). LCV [a 501(c)(4)] is an environmental derivative of the Sierra Club and Friends of the Earth. It operates a PAC and a super Pac. In a one-stop court action, U.S. District Judge Sharon Gleason prevented the U.S. Executive Branch and 328 million citizens from merely looking at a large portion of Arctic and Atlantic offshore for O&G exploration. Can’t have production, if you are not allowed to look! Process matters.

Governmental energy policy: Contrast Haiti vs. the Dominican Republic.

Fig. 1. The amplitudes (limited-az., limited angle), for a CIG bin of known fracture az (N20E), known wide apertures, and known high fracture density. The solid lines show the straight line fit (Shuey, 1985) for the floating-intercept-AVO gradient calculation. Note the very good fits to lines. Published with GSH permission.

Public opinion misconceptions: #1, Water to gasoline exists. #2, Global warming is a reason to not have children. #3, Green is not political. #4, Energy is not political. #5, Recent CO₂ measured at the top of a volcano in Hawaii is evidence of melting Arctic ice.

Money/capital: Self-explanatory.

Unknown technology advances. Last month, I stated, “we care now” about what happens on each existing seismic offset trace more than we did. Processing seismic offset traces into sub-angle groups by offset, angle or azimuth combinations is not new. Offset combinations can be very useful in interpretation and as a processing QC tool. Some seismic “anomalies” are not mistakes, but rather are attributed to rock parameters, fluid parameters and/or directionality. The more we use vectors, the more conjecture is resolved. Each data set we look at is a mere snapshot of conditions in time, combined with the theory used in data assembly and reduction. Seismic over time [4D] still has difficulty discerning permeability from hydraulic conductivity.

Dr. Heloise Lynn and I disagree on horses, and how to display shear wave data. We do agree on music, and that acoustic effects in the seismic method are many, variant, and warrant much more study. A recent GSH presentation by Lynn and Goodway¹ builds on the knowledge base of Hilterman, and hopefully challenges more investigation into creating sub-macro tools for improved rock physics, Fig. 1.

Here’s an excerpt from the paper’s abstract and conclusion: “The effect of porosity upon P-P Intercept-Gradient (I, G) plots is well-known, when lithology and pore fluid are held fixed (Hilterman, 2018). Expansion of this knowledge into the azimuthal world enables the comprehension of the effects of effective porosity sensed, as source-receiver (S-R) azimuth varies. The azimuthal variations of near-angle amplitudes are the result of the effective porosity sensed changing by azimuth. Alternatively, or additionally, there may be an azimuthal Q effect, due to fluid movement between macroscopic fractures and matrix porosity; or an azimuthal scattering effect. In azimuthal amplitude analysis, the VP, VS, and density can change by azimuth, and this needs to be allowed in the analysis codes”

Note that there are several amplitudes for any one x value, therefore amplitude, alone, cannot be distinguishing enough. While encouraged by this significant advance in interpretation, one can deduce that unique solutions still do not exist in seismic remote sensing methodology. That’s why we call it “interpretation.”

REFERENCE

1. Lynn, H., and Bill G., “Effective Porosity Sensed Changing by Azimuth: A Linear Crossplot of Azimuthal P-P,” GSH Journal, Geophysical Society of Houston, May 2019, Vol. 9, No.9, pp 17–24.

About the Authors

William (Bill) Head

Contributing Editor

William (Bill) Head is a technologist with over 40 years of experience in U.S. and international exploration.