HYPERSPECTRAL ANALYSIS OF RESERVOIR ROCK USING FOURIER TRANSFORM INFRARED SPECTROSCOPY

Compositional analysis of reservoir rock is vital to most oil exploration and production activities. In a broad sense, knowing the general mineral composition of a reservoir can help with characterization and interpretation of depositional environments. On a smaller scale, identifying mineralogy aids to calibrate logs, pick formations, design drilling programs and hydraulic fracturing strategies, and screen for intervals with potential problem minerals, such as swelling clays. The petroleum industry utilizes two main methods to find compositional mineralogy, x-ray diffraction (XRD) and thin section analysis. Both methods are time consuming, expensive, and destructive. An alternative method for compositional analysis of samples that includes quantitative mineralogy and total organic content (TOC) is a valuable prospect.

The remote sensing community has been using infrared spectroscopy to analyze mineralogy for years. Within the last ten years, the advancement of infrared spectrometers and processing programs have allowed infrared spectra to be taken and analyzed faster and easier than before. The objective of this study is to apply the remote sensing techniques used for quantitatively determining mineralogy, to the petroleum industry and develop a new methodology to compositionally analyze reservoir rock (including core and drill cuttings) for mineralogy and TOC. An infrared spectral library of minerals has been created. The minerals were chosen by minerals found using XRD of a core. As the library continues to grow, more accurate readings will be possible. This database will be used to unmix spectra using a constrained linear least squared algorithm. A core has been scanned using a hand held infrared spectrometer. Preliminary findings, compared to XRD data, show mineralogy to be within five percent.