Upper Devonian Burket/Geneseo Shale – Appalachia’s Little Brother to the Marcellus
11/12/2016
The Upper Devonian Burket/Geneseo Shale is the organic-rich mudstone that lies immediately above the Tully Limestone and 20’ to more than 800’ above the Marcellus. The thickness of the shale expands from only a few feet in western West Virginia to more than 150’ in its depo-center in central Pennsylvania. Drilling depths increase from less than 4,500’ in NW PA to more than 7,500’ in the center of the Basin. Net thickness of the organic-rich portion of the Burket has been mapped and identifies two “sweet spots” of better quality reservoir. Most of the current productive wells are located within these southwest and northern pods of increased reservoir quality.
The key geologic controls on production are projected to be similar to those that control the Marcellus Shale, with rock quality (porosity/permeability) directly related to Total Organic Carbon % (TOC). There is no reliable hard data available publicly on pressure gradients at this time, but early indications and personal communication indicate that the unit is significantly over-pressured, enhancing production capabilities. As with the Marcellus, structural complexity is a key negative to production performance and complicates geo-steering.
Long term production data is available for a relatively small database via state reporting agencies, but provide enough information that some early projections can be advanced. Analysis of the available production combined with geologic mapping allow us to identify the Northern and Southwestern Core Areas within which the highest performing Burket/Geneseo wells are located. The Southwest Core Area appears to be the better of the two areas based on limited data. Five wells have at least one year of production data and average 1.5 BCFe in their first twelve months on line. The Northern Core Area covers an area of about 800,000 acres, but is less proven and may not reach the production potential of the Southwest Area. Six (6) wells on production had average first year production of ~700 MMCF.
Technically recoverable reserves in the Core of the Core are projected to be in excess of 150 TCFe within the two core areas.
