THE SIGNIFICANCE OF MARCELLUS SHALE HETEROGENEITY ON HYDRAULIC FRACTURE STIMULATION

The Marcellus Shale Energy and Environment Laboratory (MSEEL) consists of a multidisciplinary and multi-institutional team undertaking integrated geoscience and engineering in cooperation with the operator, numerous industrial partners, and Department of Energy. MSEEL consists of two legacy horizontal production wells, two new logged and instrumented horizontal wells, a cored and logged vertical pilot bore-hole, and a microseismic observation well. Production from the new horizontal wells began in December 2015. MSEEL has been integrating geophysical observations (microseismic and surface), fiber-optic monitoring for distributed acoustic sensing (DAS) and temperature sensing (DTS), advanced well logs, core data and production monitoring, to better characterize subsurface rock properties, and propagation pattern of induced fractures in the stimulated reservoir volume.

Analysis of core and logs undertaken in the vertical and horizontal wells was used to develop a comprehensive lithologic and mechanical description of the Marcellus Shale vertically in the pilot hole and horizontally along the lateral. Significant geologic heterogeneity was observed along the lateral that affected fracture stimulation efficiency - both completion efficiency (percentage of clusters that receive effective stimulation), and production efficiency (percentage of clusters effectively contributing to production). Numerous studies illustrate that on average in horizontal unconventional resource wells, only 50% to 60% of the wells’ perforation clusters contribute significantly to production.

The DAS and DTS along with production monitoring from the MSEEL wells coupled with petrophysical analysis provide significant insight into the geologic parameters influencing fracture stimulation efficiency. A significant improvement in rate and estimated ultimate recovery (EUR) is possible, if we improve our understanding of the rock actually being stimulated per individual fracture stage and cluster, and use geologic data to strategically locate stages and clusters.

The MSEEL is developing new knowledge of the subsurface geology of the Marcellus Shale to identify best practices that can optimize hydraulic fracture stimulation that can increase flow rates, EUR and ultimately reduce the number of wells.