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Ask the Expert Webinar series

NORM Issues in Oil and Gas Exploration

About this webinar:

With radiation in space and beneath the surface of the earth, we live our lives in peace and harmony with our environment while surrounded by radiation.  However, what risks do we take when we drill into the earth's surface for precious natural resources such as shale oil and gas?

Naturally Occurring Radioactive Material (NORM) as well as a variety of radioactive elements are present within the earth's crust at a relatively shallow depth.  When drilling and mining exploration activities take place, these radioactive elements enter our waste streams and present challenges for the operators and regulators alike.

Topics the presentation will cover:

  • What is NORM
  • What radioactive elements are typically present
  • Are these waste streams hazardous?  Dangerous?
  • How do you test for these contaminants?
  • What regulations and disposal criteria should be followed?

Who should attend?

  • Consulting and Engineering firms
  • Commercial entities engaged in drilling or mining activities
  • Regulatory personnel who oversee drilling and mining activities

NORM Issues in Oil and Gas Exploration Webinar Questions and Answers

(click on a question to view the answer/response from TestAmerica's expert Terry Romanko)

1. What about reuse of drill cuttings for pipe bedding? Summary of Wastes/Risk slide

I am not aware if there are specific regulations regarding the reuse of drill cuttings for pipe bedding.  A potential hazard could be if the cuttings come from a layer/strata containing a higher concentration of radionuclides than the area it is packed within and a) people could be exposed to the packing area (if at/close to the surface) or b) surface/ground water could preferentially percolate through the bedding and mobilize added radionuclides to an unwanted area.

2. What is a planchet?

A planchet is stainless steel dish (similar to a metal Petri dish without a top - ) used in Gas Flow Proportional Counting analysis.  The sample aliquot or sample precipitate from chemistry separation is dried down on/in the planchet and then put into the detector for counting.

3. What is the practical method for calculating the concentration of Radium ions trapped within the crystal lattice of the scaling material which have co-precipitated from produced water or Frac flowback effluent with scale forming cat ions during scale formation?

The most practical means of analyzing Ra-226/Ra-228 on scale/sludge is to collect sufficient sample to be analyzed by gamma spectroscopy.  Analysis of approximately 350 grams of dried material sealed in a tuna can (to trap the Rn-222 daughter of Ra-226 and allow for equilibrium to be reached) will result in minimum detectable concentration (MDC) of 1 pCi/g or less to be reached for both Ra-226 and Ra-228.  The laboratory could report a standard NORM library in the same process.  An in-situ (in place) measurement would be more challenging, but may be possible using remote probes/instrumentation depending upon the circumstances and how much information about the system is available (or can be gathered).

4. How do you get a negative result in analytical results? for example, - 1 pCi/g Pb-210

Radioactive decay by nature is a random process.  During the count interval, a population of decay events is recorded - this population can be handled using population statistics.  For a sample that is truly the same as the shielded instrument background (zero activity), multiple measurements of this sample will yield results statistically populated about the mean background (some higher, some lower).  When corrected for background (sample result minus background), approximately 50% of the results will be positive and approximately 50% will be negative.  As the actual sample activity increases to naturally occurring levels and beyond, fewer and fewer negative results should be seen. Read a more thorough description of negative results here.

5. I work with interstate natural gas transmission systems. Is the natural gas within the pipe "typically filtered"? How does this not become a downstream issue to industry and home owners.

I am not certain as to the extent natural gas is filtered beyond particulate and/or liquid contaminants.  I'm guessing this is dependent upon the particular gas company as well as the intended use.  I would expect that Rn-222 would be transported down the line.  As the Rn-222 decays, it will tend to "fall out", with daughters such as Pb-210/Po-210 plating out on surfaces.  Concentrations will be dependent upon the formations from which the gas originates.  Note that the half-life of Rn-222 is about 92 hours, meaning that ½ of the activity present decays away approximately every three (3) days.  Thus, I would expect higher concentrations to be found closer to the source (whether in tanks or pipeline).  By the time the gas reaches the end-user, much of the activity has probably decayed out.  By 30 days (approximately 10 half-lives), the activity will be reduced by a factor of 2 to the tenth power (~1/1000).

6. How does micro rehms per hour compare to pico curies per gram?

REM stands for Roentgen Equivalent Man, which is a unit of dose equivalent to man which attempts to measure the health impact to man/tissue.  The microrem (uR) would be 1E-6 of a REM.  A curie is a unit reflecting the amount of activity present, related to the number of decays per second.  A picocurie (pCi) is 1E-12 curies.   Unfortunately, there is not a simple "one-size-fits-all" factor to convert from dose to activity.  This is a fairly complex subject and is best suited to specially trained Certified Health Physicists.  The dose is dependent upon factors such as the type of radiation (e.g. alpha/beta/gamma), the means of exposure (e.g. external/internal), and even the energy distribution of the radiation.

7. We didn't hear much about risk. What are the risks associated with NORMs to O&G workers or the environment?

Rather than try to regenerate what already exists, I would refer you to a fairly comprehensive treatment of this subject "Radiation Protection and the Management of Radioactive Waste in the Oil and Gas Industry" put out by the International Atomic Energy Agency (IAEA).  One location on the internet (at the time of this writing) is "http://www-pub.iaea.org/MTCD/publications/PDF/Pub1171_web.pdf ".  One thing to note - the risks will be related to the actual concentrations of the radioisotopes present in the formations as well as the type of operation being performed.

8. What are the radionuclides in Propane?

I would expect radionuclides that might be present in propane would consist of Rn-222 and daughters (see #5 above)

9. What are the health and safety isues for field technicians when sampling for these constitutents?

See #7 above.

10. When using a lab such as test America's, to what degree is the data received "confidential" between the lab and the client? Is it ever disclosed to governmental sources?

Data produced at the laboratory for a client belong to that client and are treated as confidential.  TestAmerica's laboratories do not typically release data to anyone other than the client unless requested to do so by the client.  I suppose it would be possible for the laboratory to receive a court-ordered subpoena, but that would be an unusual circumstance.

11. What method is low energy photon spectroscopy?

In this context, gamma-ray and photon are used interchangeably.  Thus low energy photon spectroscopy (LEPS) is simply looking at the low energy region (below approximately 50 keV) of the spectra using gamma spectroscopy detectors that are manufactured/configured for this region.  As low energy emissions are relatively easily shielded, the detector must be such that it allows as many of the low energy to reach the active area of the detector as possible.

12. What NORM criteria are disposal facilities using for the "General Hazards" of waste rejection option?

I'm not sure that I can provide a satisfying answer for this question.  Having not worked with disposal facilities or the disposal process in general I am not familiar with this "option".  I do know that many disposal facilities have portal monitors set up at the entrance and will "reject" shipments that set off the detectors.  I do not know what sensitivity they have these set to, or what activity level this would relate to.  One would need to contact each facility directly to find out their requirements/allowance (and you still may not get a direct answer).  In speaking with our lab's waste coordinator in the past, I know we have differing pricing depending upon whether our waste can go to a typical landfill, a "NORM" landfill, or must go to a Rad facility.

13. How does the "minus" or "plus" in reported lab results enter into the evaluation of the concentration when comparing to a regulatroy action level?

Negative results are addressed in "theory" in a question above.  The sign in front of the value should not change the evaluation - if the result is less than a regulatory action level, it simply is less than the action level.  Note that the advantage to having the actual result reported (not just a "ND" or "<") will allow for complete statistical evaluation of a site, whether in coming up with an average concentration over a large area/number of samples or in coming up with an average concentration for a particular well over a long period of time.  It is difficult to include a "ND" result into an average - do you call this a zero (0) (thus possibly biasing the average low), or do you call it the number of the detection limit (thus possibly biasing the average high)?

14. Do you test Radionuclides in Pittsburgh office?

No - only TestAmerica's St. Louis, MO and Richland, WA facilities test for radionuclides.

15. How would you keep in place safety procedure while testing Marcellus shale samples if you do not whether radionuclides are present or not in the frac water sample?

I'm not sure if this question is directed toward work at the laboratory or work in the field.  At our laboratory, we utilize process knowledge from the client along with laboratory procedures (general ALARA principles, several EH&S SOPs, as well as routine screening of samples) to help protect workers.  In the field, similar procedures should be followed, all though they may be tailored specifically for the operation.  If samples are suspected to possibly contain radionclides at elevated levels, they should be screened/evaluated in the field to ensure they can be shipped and labeled properly/legally according to DOT requirements.  Many companies are not equipped to handle this, and should seek help from a qualified engineering firm with proper expertise.

16. As a EH&S manager, would you comment on health issues if any related to sampling ground water wells that may contain NORM

Given proper training and EH&S procedures are in place, I don't suspect sampling of ground water wells to be any more of a safety issue than other procedures.  While some wells might contain fairly elevated concentrations (that can possibly be seen using fairly simple monitoring equipment to determine magnitude), I don't expect ordinary water wells to contain elevated levels that would pose a direct external hazard.  Even sampling of oil/gas wells during the production process is unlikely to lead to immediate concerns.  As with many other EH&S concepts, we need to look at reducing long-term exposure and help prevent exposure that might be most risky.  I would suggest internal dose caused by ingestion/injection would be much more hazardous than external exposure ("don't drink the water").  At our laboratory, with very few exceptions, the chemical hazards associated with our operations far outweigh radiological concerns.

17. What type of environmental chemistyr testing is typically being done by energy exploration companies in support of the shale gas extraction process? Are they required to do anything under regulations.

While I have quite a bit of experience in analytical radiochemistry, I am not an expert in the regulatory side of Oil & Gas operations.  However, I believe part of the controversy in the Shale Gas operations stems from a lack of regulatory guidance.  There are some groups (including the State of PA, other coalitions, as well as the EPA) currently trying to work on this.  Generally what we have seen in terms of analyses for Shale Gas operation are Gross Alpha/Beta, gamma spectroscopy, Ra-226, Ra-228, and some uranium and thorium analyses.

 

 

 

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The Presenter:

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Terry Romanko

Radiochemistry

Technical Director, TestAmerica

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