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Hyperspectral Imaging of the Leonardian Third Bone Spring Shale, Collier 1201 Core, Delaware Basin: Application and Results

Abstract

The Leonardian Third Bone Spring Shale in the Delaware Basin is an active unconventional exploration target. In this thick calcareous siliceous mudstone, mineralogy and TOC are important parameters needed to define brittleness and high TOC for selecting sweet spots. These parameters can be obtained from hyperspectral imaging (HI) of core. Originally developed for the mining industry, HI uses a combination of short-wave infrared light (SWIR) and long-wave infrared light (LWIR) to create a continuous visual ‘map’ of the minerals in a core that respond to reflectance principles. HI, which requires no special preparation other than that the core is slabbed, clean, and dry, can be applied rapidly and provides mineralogical results related to various energy emitted in wavelength spectrum by either halogen bulb reflectance (short-wave quantification) or heat reflectance spectra (long-wavelength quantification).

We collected hyperspectral core imaging data from 300 feet of Leonardian Third Bone Spring Shale core located on the western slope of the Central Basin Platform in the Delaware Basin. We obtained detailed, continuous high-resolution mineralogical and textural information of the cored interval. Digital HI-derived single mineral and TOC curves, calibrated to discrete X-Ray Diffraction (XRD) and TOC measurements respectively, were imported as curves to display mineralogical variations with depth alongside X-Ray Fluorescence (XRF) data and mechanical data. We integrated the hyperspectral data with core description, thin-section, XRF, XRD, and TOC data to determine the mineralogy of different facies and to facilitate property ‘up-scaling’ from SEM and thin-section scales to understand the controls on reservoir quality. Mineralogy at the sub-cm scale was observed. Results were of much higher resolution than was obtained by core description or limited thin-section analysis. The calculated TOC compared favorably to measured RockEval data points, but the HI analysis has the advantage of being continuous. Hyperspectral imaging of cores is a valuable method for obtaining continuous rock-property data that can be integrated with other data to characterize a production interval.