Environmental Forensics in the Context of the Oil and Gas Industry
It is inevitable that any industrial operation at some stage of development or production will have some sort of environmental problem. The oil and gas industry is no exception to this-some problems are clearly visible as manifested by the recent incident in the Gulf of Mexico or more subtle as in the case of issues involved with shale exploration and development. However with all of these issues there are two major questions - what is the source of the contaminant and is it undergoing natural attenuation or degrading? There are many analytical techniques that have been used to address these issues in the past but one tool that has seen an exponential increase in application in the area of environmental forensics in the past decade has been the utilization of stable isotopes. Whilst analytical techniques such as gas chromatography and gas chromatography mass spectrometry are powerful fingerprinting techniques they can easily provide ambiguous results in the case of groundwater contaminants. While these techniques can identify groundwater contaminants, they are of little use in distinguishing sources. However incorporation of stable isotopes, both C and H, introduce another element of characterization that may enable differentiation of one source from another. Furthermore it is also important to note that as a groundwater contaminant undergoes degradation it will become isotopically enriched providing an ideal tool for monitoring this process.
In the case of shale gas problems, one area where stable isotopes can play an immediate role is first distinguishing sources of microbial and thermogenic gas on the basis of the isotopic compositions. In addition gases from different sources and thermal maturity regimes can be differentiated through this approach.
So in brief this presentation will provide a number of examples where stable isotopes have been used in the manner described above, including oil spills, groundwater contamination with a variety of products and environmental issues associated with shale gas development.
It should be noted that it is not being suggested that stable isotopes will solve every single environmental problem. However it does provide an extremely powerful tool that may provide the difference between solving a problem and obtaining an ambiguous solution.
AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California