Survey Design
Exploration Reconnaissance
Large tracts of lands can be evaluated quickly and inexpensively
using near surface geochemical exploration, this is especially true
when using soil based tools like iodine or the CASE. In many
areas samples taken along roads can provide sufficient data to
determine on which parts of the larger area you might want to
concentrate . All of this can be done, in many cases, prior to lease
investments.
using near surface geochemical exploration, this is especially true
when using soil based tools like iodine or the CASE. In many
areas samples taken along roads can provide sufficient data to
determine on which parts of the larger area you might want to
concentrate . All of this can be done, in many cases, prior to lease
investments.
Using a detailed map (i.e. USGS 7.5 quad) of your area of interest mark collection points on all the
available roads. Base the sample spacing on the anticipated size of the prospect typical for your area.
As an example, if your looking for something a number of miles across in it's smallest dimension,
samples taken every half mile could be used. If your trying to find a small reef or a channel you might want
to take samples every 1/10 (500 ft.) or 1/20 (250 ft.) of a mile. Use numbered bags and list the bag
number on the map as you collect each sample. Try to collect samples, if possible, between 40 to 50 feet
off the road.
available roads. Base the sample spacing on the anticipated size of the prospect typical for your area.
As an example, if your looking for something a number of miles across in it's smallest dimension,
samples taken every half mile could be used. If your trying to find a small reef or a channel you might want
to take samples every 1/10 (500 ft.) or 1/20 (250 ft.) of a mile. Use numbered bags and list the bag
number on the map as you collect each sample. Try to collect samples, if possible, between 40 to 50 feet
off the road.
Exploration Detail
Many times the exploration reconnaissance survey will yield one or more areas of interest. At this point
you might want to add a detailed geochemical survey to these prospects. Detailed surveys will most often
require collecting samples "off road." Although collection of off road samples can be done using a vehicle
odometer and a compass, the best way is to use a GPS. The relatively small investment in a GPS with a
computer interface (~$200) is more than made up on the certainty of sample location and the
simplification of the whole process.
you might want to add a detailed geochemical survey to these prospects. Detailed surveys will most often
require collecting samples "off road." Although collection of off road samples can be done using a vehicle
odometer and a compass, the best way is to use a GPS. The relatively small investment in a GPS with a
computer interface (~$200) is more than made up on the certainty of sample location and the
simplification of the whole process.
Many times the simplest method of collecting "off road" samples is to walk. A man in reasonably good
condition should be able to walk eight to ten miles per day collecting 100 or more samples. Of course
this option becomes less practical as sample density expands but a dirt bike or an ATV can make
almost any survey simple even fun.
condition should be able to walk eight to ten miles per day collecting 100 or more samples. Of course
this option becomes less practical as sample density expands but a dirt bike or an ATV can make
almost any survey simple even fun.
As mentioned above, the sample density of the detailed survey will be determined by the size of the
expected prospect. A good rule of thumb is to use a sample density sufficient to place 3 to 4 samples
across the smallest dimension of the prospect. If you are walking, organizing the walks to minimize
distance and the number of samples you are carrying is important.
expected prospect. A good rule of thumb is to use a sample density sufficient to place 3 to 4 samples
across the smallest dimension of the prospect. If you are walking, organizing the walks to minimize
distance and the number of samples you are carrying is important.
Prospect Evaluation
Geochemistry can be used to "check" prospects. Depending on the size, as few as four high density
lines using 40 to 60 samples can confidently evaluate a prospect. Failure to find a geochemical
signature does not mean the prospect will not be successful it just means the odds have gotten very
long. If on the other hand the limited evaluation shows promise the survey can be expanded to help
guide drill site selection and future development.
lines using 40 to 60 samples can confidently evaluate a prospect. Failure to find a geochemical
signature does not mean the prospect will not be successful it just means the odds have gotten very
long. If on the other hand the limited evaluation shows promise the survey can be expanded to help
guide drill site selection and future development.
Prospect Detail
Detailed geochemical surveys of prospects generated by other means can be very useful. Often the
integration of the geochemical data will improve the interpretation of the data used to generate the
prospect. An ultra high density geochemical survey is often warranted based on the relatively minor
additional costs verses the enhanced data. See the above "Exploration Detail" section for more
information.
integration of the geochemical data will improve the interpretation of the data used to generate the
prospect. An ultra high density geochemical survey is often warranted based on the relatively minor
additional costs verses the enhanced data. See the above "Exploration Detail" section for more
information.
Development Evaluations
Development evaluations begin with high density "baseline" surveys. Additional surveys over time can
be preformed to find bypassed compartments and track the depletion of the deposit. If secondary and
tertiary recovery programs are implemented continuing surveys can determine the efficiency of the
recovery program.
be preformed to find bypassed compartments and track the depletion of the deposit. If secondary and
tertiary recovery programs are implemented continuing surveys can determine the efficiency of the
recovery program.
Geochemical surveys over existing fields, both old and new, have been used primarily as case
studies. Little consideration has been given to using geochemistry for development but this application
may prove to be geochemistry's best. Geochemical surveys can detect untapped compartments, avoid
edge wells and dry holes and track hydrocarbon movements related to tertiary recovery injections.
Check out the project I participated in with the Colorado School of Mines over the Vacuum Field in
New Mexico in 1998. I conducted multiple surveys that seemed to indicate that surface geochemical
data was tracking the movement of hydrocarbons between the CO2 injectors and the collectors. Also,
Dr. Ron Klusman has recently published (AAPG Bulletin, v. 87, no. 9, Sept. 2003) a study of the CO2
injection project at Rangely Field that also finds hydrocarbons and CO2 at the surface related to the
injections 6500 ft. below.
studies. Little consideration has been given to using geochemistry for development but this application
may prove to be geochemistry's best. Geochemical surveys can detect untapped compartments, avoid
edge wells and dry holes and track hydrocarbon movements related to tertiary recovery injections.
Check out the project I participated in with the Colorado School of Mines over the Vacuum Field in
New Mexico in 1998. I conducted multiple surveys that seemed to indicate that surface geochemical
data was tracking the movement of hydrocarbons between the CO2 injectors and the collectors. Also,
Dr. Ron Klusman has recently published (AAPG Bulletin, v. 87, no. 9, Sept. 2003) a study of the CO2
injection project at Rangely Field that also finds hydrocarbons and CO2 at the surface related to the
injections 6500 ft. below.
As an example, a standard
square mile section using a
1/10 mile grid would have
81 off road samples. I have
designed three walks each
starting from a different
point on the surrounding
roads. The longest walk is
3.7 miles collecting 36
samples. As always the
assignment of a number to
a point should be at the
time of collection, taking
that number from the pre
numbered bag. This entire
survey, including the 40
samples along the roads
(not marked), and 8 1/2
miles of walking can be
collected by one man in one
or two days.
square mile section using a
1/10 mile grid would have
81 off road samples. I have
designed three walks each
starting from a different
point on the surrounding
roads. The longest walk is
3.7 miles collecting 36
samples. As always the
assignment of a number to
a point should be at the
time of collection, taking
that number from the pre
numbered bag. This entire
survey, including the 40
samples along the roads
(not marked), and 8 1/2
miles of walking can be
collected by one man in one
or two days.
GrayStone Exploration Labs, Inc
Survey Design
Survey Design
Survey Design
Survey Design
