Re: Natural radioactivity in oil

[Doug Aitken <daitken@sugar-land.oilfield.slb.com>]

At 07:36 PM 5/18/2004 +0300, Jose Julio Rozental wrote:

>

>Only to complement informing the IAEA published a recent text  related 

>with oil and gas industry possible to download:

>Radiation Protection and the Management of Radioactive Waste in the Oil 

>and Gas Industry, Safety Reports Series No.  34, February 2004

><http://www-pub.iaea.org/MTCD/publications/PDF/Pub1171_web.pdf>http://www-pub.iaea.org/MTCD/publications/PDF/Pub1171_web.pdf





This is an excellent "primer" to learn about radiation in the Oil and Gas 

E&P (Exploration and Production) business.

I will look at it more closely, but an initial cursory review caused one 

point to jump out:

In the (sealed source) waste minimization plan, they promote as one of 

their strategies the use of short-half-life isotopes. IMHO, while this is 

an evident strategy for unsealed sources (e.g. tracers), it is not 

reasonable in the sealed source end of the business, as it would actually 

exacerbate the problems faced by the operator!

The shorter the half-life of the source, the greater the problems for the 

service company operationally, as equipment would have to be calibrated 

much more often (entailing both down time and increased exposure of workers.

Shorter half-lives would also increase the problem of waste disposal, as 

the sources would quickly become useless and have to be replaced when 

significant radiation still existed.

As an example, Cs sources used in well logging and gauges typically have a 

useful life of 10-12 years. This is because obviously the desire of the 

tool designers is to use the minimum source strength commensurate with 

measurement accuracy (and statistical variation thereof). But there comes a 

time when the source strength drops below a point at which its measurement 

can be effectively calibrated and the source must be replaced. Most often 

the cesium cannot be recycled as its specific activity is too low and thus 

the total number of sources continues to rise, with large quantities of 

weak, but useless, sources being kept in long-term storage.



A longer half-life source (such as the Am-Be source typically used for 

neutron porosity measurements) obviously does not have this problem.





Doug Aitken             Schlumberger Drilling and Measurements QHSE 

Advisor

Phone (Sugarland):      281 285-8009

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