High Speed Chromatography Utilizing Semi-Permeable Membrane Technology for Direct Analysis of Hydrocarbon Gasses in the Drilling Fluid—Applications for Geo-Steering and Reservoir Characterization
Law, Douglas J.1,
David
Hawker2, Aurel Brumboi2,
Darrell Norquay2 (1) Datalog Technology
Ltd, Plymouth, United Kingdom (2) Datalog Technology
Inc,
The role of gas chromatography in providing data for real-time
formation evaluation and reservoir characterisation
has long been hampered by its reliance upon the mechanical agitator as a
method of gas extraction. Along with the inherently poor temporal and spectral
resolution of most Chromatographs, the potential for using real-time gas
analysis to geosteer wells has been limited.
The technique of gas extraction via a semi-permeable membrane
has been allied to the latest in TCD gas chromatograph technology to provide
direct gas in mud analysis at the point of extraction. This technique avoids
the problems associated with mechanical agitation, such as the retention of
heavy hydrocarbons, and gas trap loading. Significant improvements in spectral
resolution coupled with faster cycle times will provide benefits in terms of
geological & geochemical evaluation. This is demonstrated in the real-time
determination of fluid contacts and extended heavy gas component characterisation.
It has been
shown that the system provides an accurate and high-speed chromatographic
breakdown of mud gases from Methane (C1) to Octane (C8), along with aromatics
(Benzene & Toluene), sour gases (H2S & CO2) and
Nitrogen. Data is presented from a series of tests incorporating a mudflow loop
to simulate the interaction of the mud system and gas components. Field data
presented also demonstrates that the system provides excellent separation of
all component peaks and elution times. With analysis, incorporating C1-C8, aromatics
and non-hydrocarbon gases, within 50seconds, this represents a significant
advance in the characterisation of hydrocarbon
bearing zones.