Correlation between Specific Horizontal Lateral Placement and Gas Production in the Devonian Age Lower Huron Shale Formation in the Big Sandy Field, Kentucky
EQT Production Company, Pittsburgh, PA, [email protected]
An analysis of measured while drilling (MWD) gamma ray logs from 50 horizontal wells drilled to the Lower Huron Shale in the Big Sandy Gas Field of Eastern Kentucky has shown that horizontal lateral placement within a transgressive or regressive lithologic unit will contribute to variability in the production of a horizontal well. This variability in production is due to the differences in hydrocarbon storage and stimulation deliverability between the transgressive and regressive lithologic units. The Lower Huron shale becomes more organic and quartz-rich through a transgressive lithologic unit and progressively more inorganic and clay-rich though a regressive lithologic unit. Additionally, changes in the Lower Huron Formation thickness, total organic carbon (TOC), thermal maturity, and structural setting from west (distal) to east (proximal) leads to changes in the reservoir characteristics of each transgressive and regressive unit. In the distal basin, the Lower Huron is less mature, thinner, and the transgressive lithologic units consist of more concentrated, non-disseminated packages of low bulk density, organic shale. While in the proximal basin, the Lower Huron is more mature, thicker, and the transgressive lithologic units contain packages of low bulk density, organic shale that are more disseminated with higher density shale. Core data from the Lower Huron shows positive correlations between low bulk density and high TOC, as well as high TOC and high oil and gas saturations. These correlations, in conjunction with the MWD gamma ray and production data, suggest that drilling a horizontal lateral within a transgressive lithologic unit comprised primarily of non-disseminated, low bulk density, organic shale will have a positive impact on the overall production of a horizontal well.
AAPG Search and Discovery Article #90154©2012 AAPG Eastern Section Meeting, Cleveland, Ohio, 22-26 September 2012