Advanced Formation Fluid Evaluation While Drilling with a New Heavy Gas Detector
In this paper, a chromatograph which exploits the benefits of FID
technology, optimized for the high resolution detection of heavier hydrocarbon
gas components is described. The components analyzed span from n-hexane to
Flame Ionization Detector (FID) technology is not new to gas detection on the field; however it had never been applied to the detection of gases heavier than n-pentane.
The instrumentation has been installed and run on a number of wells in different fields and countries, and it has operated as a complement of an advanced surface logging system, for a period of two years. Unlike other technologies presently utilized for this scope, this system reduces dedicated equipment and personnel to a minimum.
The results presented show the clear identification of formation
fluid contacts with higher accuracy than standard light gas detectors, the
recognition of contaminants within the drilling fluid, and the practicality of
operating an advanced gas detection system with minimal operational and
Some of the indications obtained challenge common beliefs about gas detection: consistent extraction of heavy hydrocarbon gases from the drilling fluid is possible at relatively low temperatures, provided that the entire gas extraction system is rigorously controlled in terms of gas sample pressure, flow, and temperature. Furthermore, gas data analysis can yield indications on the fluid composition even when the gases analyzed are in extremely low quantity.
The system utilizes known technologies, developed and optimized to
obtain new results.
The system supports formation evaluation when LWD or wireline can be inconclusive, in the presence of a low porosity pay or fresh water. It can also guide and optimize the MDT testing program. Furthermore, the system takes into account the constraints of drilling operations, and strikes a balance between data accuracy and practicality of the application.
AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.