Spatial distribution of production in a Marcellus Shale well: Evidence for hydraulic fracture stress interaction

• Production log data presented for a Marcellus Shale gas well.
• Variability of production shows bias towards the heel-ward clusters and outer clusters for each stage.
• The performance of the stages is slightly better for stages with more uniformly-distributed production.
• We suggest approaches that reduce impact of reservoir variability and stress shadow.
• The impact of improving uniformity of production may be more pronounced as the well increases in age.

Detailed examination of the distribution of production along a horizontal, Marcellus Shale gas well shows non-uniformity of production that is not consistent with random variation within each set of 4 perforation clusters that were grouped together as stages during stimulation. Nor is the data indicative of variation that is purely dictated by large scale reservoir variations – i.e. variation with a wavelength on the order of the entire horizontal part of the well. Instead, production is biased toward clusters that were at the heel-ward side of their respective fracturing stage. Production is further biased toward clusters that were in the outer positions within a fracturing stage over those that were in the central positions. These observations are consistent with so-called stress shadow effects wherein growth from toe-ward clusters is suppressed due to the induced stresses from previously-placed hydraulic fractures in prior stages and, furthermore, growth from inner clusters is suppressed due to the elevated compressive stresses in the central part of an array of growing hydraulic fractures.