Assessment of hydrocarbon potential in the Lower Eagle Ford Shale, Madison County, Texas

Assessment of the Lower Eagle Ford Shale in Madison County suggests greatest hydrocarbon potential is located in the southwest portion of the county where the combination of thickness, TOC content, lithology, porosity, and thermal maturity are best quality. The Lower Eagle Ford Shale is sufficiently thick in southwest Madison County (90-115m). Thermal maturity and average Rt generally increase from north to south across the county. Average resistivity of the Lower Eagle Ford ranges from 2.5-4.5 ohmm. TOC content of the Lower Eagle Ford calculated using Passey's DeltalogR method increases towards the west where TOC averages are highest (~2 wt%). These data suggest the Lower Eagle Ford Shale in southwest Madison County shows potential for volatile oil or gas condensate production. It does not appear that production trends from neighboring counties to the southwest, such as Brazos County, continue through the remainder of Madison County.