The loss of "signal" around all six injectors
is clear, however, additionally, all four of
the structural highs measure higher soil iodine values after CO2
injections compared to the baseline survey.
Tar Pit
Sulukta Oil Spring
Geochemisty and Seepage
Geochemical Model
Burning Seep
Seepage Model
Oil Drop Seep
Near surface geochemical exploration for hydrocarbons is a natural extension of the first exploration method, seepage. The first
oil well drilled by Colonel Drake in 1858 was drilled on the banks of Oil creek and over the next 60 years most oil was
discovered from seeps.
Along with macro-seepage detection, a number of very successful
oil finders claimed that they could "smell" the oil they discovered.
Advancements in seismic data
collection and interpretation have
recognized the effects from
hydrocarbon gas in the
subsurface. "Acoustic signal
attenuation" has been used to
describe these effects on the
seismic response.

These pictures have validated the
empirical model used by
geochemical scientists for seventy
years. Not only do hydrocarbons
"leak" from the subsurface to the
surface they make this journey in
a near vertical path. Placing your
mouse over the picture will draw
vertical lines to demonstrate that
the columns of gas penetrate
both dipping and flat beds
without changing their vertical
path. It is also important to note
that the column is not expanding
as it rises and shows no
discernible expansion from bottom
to top
Massive seepage, like tar pits or oil springs represent a tiny fraction of hydrocarbon accumulations, a slightly larger percentage
have small but still visible seeps. However, almost all accumulations have detectable amounts of seepage when using modern
analytical chemistry.
Iodine Chemistry
Geochemistry - Theory and Techniques
Geochemisty and Seepage
Geochemistry was developed after
many of the large discoveries
using macro seepage were fading
from memory.  Surface
geochemistry found many
indications of hydrocarbons
directly above petroleum
accumulations but had not much
more than the cartoon to the left
to explain the phenomena. The
enormous empirical data base of
these geochemical anomalies still
met with resistance and
skepticism. Recently sophisticated
geophysical surveys have
confirmed the basic hypothesis
represented by the simple
cartoon. Mechanisms and
explanations of the gas plumes is
still debated but pictures are
worth a thousand words when it
comes to the "vertical migration of
Seismic, Gas Plumes
Once the vertical leakage of hydrocarbons has been established, what is the best way to detect this leakage and use the data
to find petroleum. Research has shown that the leakage of hydrocarbons at the surface is inconsistent and the flux rates vary
with temperature and pressure. Flux rates are so variable that direct detection of hydrocarbons has been difficult and often
unsuccessful. Various types of time integrated collection methods have been tried but none have proven reliable and all are
difficult and expensive. Natural integration of the leakage is a much better method and many elements and soil properties
respond to the addition of leaking hydrocarbons. For many of these elements or properties the initial conditions and natural
variations in concentrations are to great to make the changes produced by hydrocarbons detectable. Picking the proper tool is
the key to effective geochemical evaluations.
Geochemical Exploration Techniques
Iodine has a number of unique properties that make it an excellent choice for geochemical exploration surveys. As the cartoon
above demonstrates soil iodine originates from the atmosphere, eliminating varying initial conditions. Like all halogens, iodine is a
strong oxidizer and reacts readily with hydrocarbons. Volatile hydrocarbons combine with iodine changing hydrocarbon gases into
iodo hydrocarbon solids. These compounds can be used to track hydrocarbon seepage.
GrayStone Exploration Labs, Inc
GrayStone Exploration Labs, Inc