Log-Based Gas Content and Resource Estimates for the Antrim Shale, Michigan Basin

Abstract

Antrim Shale multicomponent gas storage mechanisms of adsorption, porosity and solution in bitumen preclude the use of conventional gas-in-place volumetric calculations. Total in-situ gas content has been measured using canister degassing techniques adapted from coalbed methane technologies. Gas measurements ranged from approximately 5 scflt to 166 scflt. Gas contents exceed apparent gas-filled porosity by 6 to 8 times where organic content is high. Cross plots of gas content to companion TOC and density measurement resulted in a direct correlation between increasing gas content corresponding to progressive increases in organic matter and an inverse relationship between increasing gas content and decreasing density. The linear function relating density and gas content can be used in conjunction with open-hole log bulk density measurements to calculate gas-in-place.A side-by-side comparison of gas content measurements from rotary sidewall core and whole core demonstrated that the measurements from both core sampling types are of equal accuracy. From the standpoint of cost, sample homogeniety and sampling selection, rotary sidewall cores are preferred over whole core. The total gas contained in the shale can be completely released as a single measurement by crushing the core upon retrieval. Utilizing the on-site gas content measurements, density/gas content relationship and density log it is possible for the first time to locate and quantify gas bearing Antrim shale intervals from well logs.References and illustrations at end of paper. LOG-BASED GAS CONTENT AND RESOURCE ESTIMATES FOR THE ANTRIM SHALE, MICHIGAN BASIN SPE 25910Using digital log-derived bulk density data and simple spread sheet calculations, interval gas-in-place calculations can be performed. A plot of gas-in-place by Antrim shale interval for the Mercury Exploration Dey AI-15 well is shown in Figure 13. This analysis shows that the currently producing Norwood and Lachine members are the most important gas reservoirs, with combined resources of 7.3 Bcf/mf. The Upper Black member is an attractive secondary target, estimated to contain 8.6 Bcf/mf of gas-in-place. CONCLUSIONS services.John-Mark Coates and Tracy Lombardi were responsible for data collection and compilation. Word processing was by Iris Drayton and Kathy Horst with editing by Scott Stevens.

Modification of ΔlogR method and Nonlinear Regression Application for Total Organic Carbon Content Estimation from Well Logs

“…It is also proved that the density log can be properly correlated with TOC [10]. Furthermore, in their study Decker et al stated that rig site gas content measurements are proven to be more effective through density log measurements to quantify the gas content of the shale intervals [12].…”

Efectos de la estimulación hidráulica (fracking) en el recurso hí- drico: Implicaciones en el contexto colombiano

“…Es la etapa donde se determina el almacenamiento de gas en una formación [31] y la viabilidad técnico-económica que tendrá [32]. Se utilizan actualmente varias técnicas, pero las más comunes son los métodos sísmicos de tecnología geofísica [16], los cuales producen imágenes 3D del subsuelo y permiten guiar las perforaciones a los puntos adecuados de las formaciones [8], [16].…”

“…Esa energía se devuelve a la superficie y luego es medida por instrumentos llamados geófonos, que trasmiten la información a equipos de interpretación. Algunos autores recomiendan estudios fisicoquímicos adicionales de la formación [31]- [34].…”

The Use of Net Pay Concepts in the Exploitation of Shale-Gas Deposits

“…As an example, Fig. 4 shows a crossplot for the Antrim Shale of the Michigan Basin (Decker et al 1993). Here bulk density is plotted against TOC with the bulk density that corresponds to a TOC of 2.0 weight % (cf Table 3) being determined as a proxy density cut-off for TOC.…”