Stratigraphy and Petroleum Geology of the Blue Monday Sandstone, Central West Virginia

Abstract

The Upper Mississippian Blue Monday sandstone is a primarily gas producing unit found in several central West Virginia gas fields. The purpose of this study was to characterize the stratigraphy and petroleum geology as well as establishing the depositional setting. Stratigraphically, with the underlying Lillydale Shale (Pencil Cave), it occupies a position between the Greenbrier Limestone (Big Lime) below and the Reynolds Limestone Member of the Bluefield Formation (Little Lime) above. In the study area it was deposited as a sheet sand from anastamosing fluvial channels flowing into the Bluefield Sea with a delta/barrier system to the south. This was deposited during the regressive sequence between the transgressive Pencil Cave and Little Lime. The Blue Monday sandstone has been a prolific producer in the past and remains a secondary target for exploration. Production data for wells completed only in the Blue Monday are sparse as Blue Monday sandstone production is typically commingled with production from other zones. Well log porosity in the Blue Monday sandstone ranges from one to twenty percent. Well logs exemplify the fact that the sand has lenses of more and less porous material, indicating flow unit differentiation. Production might be enhanced by hydraulic or chemical fracturing. The highest well log porosities were not always found in the channels which may be due to diagenetic factors such as cementation or the presence of shale interbeds.