Drill cuttings represent a huge source of valuable data bearing on reservoir quality issues. Cuttings are produced during the drilling of every oil and gas well. However, technological innovations are lacking that would allow these materials to be utilized for assessing storage and transport properties such as effective porosity, permeability, electrical properties, capillary pressure characteristics, and geologic properties like fracture distribution, permeable pathways, and diagenetic alteration. Conventional coring and core analysis can be used to supplement well logging, but the cost of these operations and the risks that are sometimes entailed in coring deep and highly deviated wells often preclude collection of valuable reservoir quality data. The Phase I program couples an ultra-high resolution imaging technology called confocal scanning laser microscopy with state-of-the-art image analysis capabilities to form an analysis capability for direct estimation of important transport and reservoir quality parameters. The objective is to apply this new integrated technology to drill cuttings. The method can also be applied to sidewall cores, which often cannot be characterized by conventional core analysis techniques owing to size constraints and the condition of specific samples which may be damaged during recovery. It has been found that intrinsic 3-D properties of porous networks, such as tortuosity, can be directly mapped by confocal microscopy permitting application of Kozeny-Carmen relationships for calculation of transport properties without overreliance on geometric approximations. Demonstrated capillary pressure curve correlations can also be usefully applied to estimate permeability by using image analysis methods to measure the pore size distribution of samples. Biases introduced by sample surface roughness, vertical heterogeneity, and artifacts of image processing for pore separation can be eliminated by use of the optical sectioning of confocal microscopes. Anticipated Results /Potential Commercial Applications as described by the awardee:The Phase I program will generate cuttings and sidewall core analytical protocols that will support accurate, rapid, and highly cost-effective assessment of reservoir quality factors including permeability, total porosity, effective porosity, formation factor, pore size distribution, capillary pressure response, as well as details of the permeable pathways, fracture distributions, and the impact of diagenesis on fluid storage and migration. Successful demonstration of the application of this technology will lead to a commercialization effort where the developed technology will be packaged for routine use by industry.
