Print this pageA New Quantative Method for Analysis of Drill Cuttings and Core
The advent of advanced technology from the mining industry has broad applications for quantitative rock analysis in oil and gas industry. The automated, high resolution petrophysical data provided from QEMSCAN® analysis of drill cuttings and core provides a more accurate and precise data analysis than conventional optical analysis is able to provide.
Drill cuttings are the first piece of data available from the subsurface during drilling. These samples of the subsurface formations are collected at surface and used by wellsite geologists to prepare a striplog and then typically disappear from the data stream once wireline logs are run. These samples can provide valuable information and in the absence of core, provide the only actual contact with the rock. Recently with increased interest in unconventional reservoirs such as shale gas where coring of the total interval may not be possible there is increased interest in the acquiring data from drill cuttings with the application of advanced techniques (Scanning Electron Microscopy, X-ray Dispersive Energy Spectroscopy, Back Scattered Electron Imaging and Digital Imaging and Processing).
QEMSCAN® is an automated mineralogy system that has a long history in the mining sector. It is a combination of a Scanning Electron Microscope (SEM) and Electron Dispersive Spectroscopy (EDS) with automated analysis software that uses BSE (Backscattered Electron Intensity) and EDX (Energy Dispersive X-ray) spectra to identify the mineral or phase present at the analysis point. QEMSCAN® can measure and identify up to 600 points per second with a beam resolution of approximately 3µm. This speed allows for detailed mineral mapping of samples, with the production of digital images, and superb statistical data on the modal mineralogy; typically millions of data points are measured during each analysis. QEMSCAN® is able to analyze cuttings, conventional and rotary cores.
SGS and Breaker Energy have completed a pilot study to evaluate the applications of this new technique on a recently drilled well. The horizontal well in NE British Columbia targeted the Monteny Formation, a tight shaly gas sand with localized phosphatic zones. The QEMSCAN® data provided mineralogy and textural information on the distribution of coarse grains and shale, visual confirmation of cementation mineralogy and fabric as well as quantative porosity numbers. This paper will present the methodology, data and conclusions of this study.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009