Detailed Core Description of a Dolomite Sample From the Upper Madison Limestone Group

Abstract

Improvements in reservoir characterization can greatly enhance reservoir performance predictions. Heterogeneity within most reservoirs, such as the Madison Group, can be better understood from integration of results from detailed core analyses. A fractured dolomite core sample from the Upper Madison Group, near Carter Creek gas field in southwest Wyoming was studied in detail to supplement the current methodology for delineating heterogeneities in core samples. Directional permeability, fracture system orientation, and other heterogeneities related to the core sample fabric were determined and quantified by studies of: impregnated thin-sections and use of computed tomography x-ray intensity, x-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. Computed tomography (CT) is a fast, nondestructive, qualitative and quantitative tool for the evaluation of fracture systems and associated mineralogy. The scanning procedure employed involved assigning a density range that would highlight minerals having characteristic CT densities. This procedure helped to identify variations of fracture infilling materials. The core analyses data were integrated with the regional geology, downhole logs, and production data for final evaluation.

Computed tomography scan imaging of natural open fractures in a porous rock; geometry and fluid flow

“…The CT scan of the core for fractured reservoir description has previously been reported in a number of papers (see Withjack, Devier and Michael 2003 for overview). 3D analysis and visualization of fracture networks have been performed by Sellers, Vervoort and van Vleynenbreugel (2003) and Honarpour et al (1986). Furthermore, the CT scan of the core has been used to estimate fracture and matrix porosity (Moss, Pepin and Davis 1990).…”

Computed Tomography for Petrophysical Characterization of Highly Heterogeneous Reservoir Rock

“…Hunt, Engler, and Bajsarowicz (1988) examined the abilities of second, third, and fourth generation CT scanners in measuring mud invasion in Berea sandstone. Similar work was performed by Honarpour et al (1986) using CT scans to measure fluid invasion into pre-existing fractures. The development of more advanced CT machines and the emergence of 3D reconstruction allowed fracture analysis of unprecedented detail through mapping the internal features and fractures of a core segment (Honarpour et al 1986).…”

“…Similar work was performed by Honarpour et al (1986) using CT scans to measure fluid invasion into pre-existing fractures. The development of more advanced CT machines and the emergence of 3D reconstruction allowed fracture analysis of unprecedented detail through mapping the internal features and fractures of a core segment (Honarpour et al 1986). Several early efforts were made to directly measure the porosity of homogeneous core samples using single scan techniques; however Moss and Russo (1991) laid the foundation for using modern dual-scan CT machines for accurately measuring fracture and matrix porosity by scanning whole core samples from two wells, measuring their porosity, and correlating with pre-existing wireline density logs.…”

Studying low-salinity waterflooding recovery effects in sandstone reservoirs

“…The Brooks-Corey function (Honarpour et al 1986) is used with the following modifications: (1) decrease in relative permeability to water phase as salinity decreases, and (2) increase in relative permeability of oil phase as salinity decreases. The Brooks-Corey exponential index (Corey, 1954) is adopted, and two normalized fluid …”