EPI Presents on Cluster Spacing Effects at 52nd ARMA Conference in Seattle

June 1, 2018

”Early Time Fracture Growth and Cluster Spacing Effects” by S. Green, G. Xu, B. Forbes, J. McLennan, G. Green, D. Work is accepted for the ARMA Annual Symposium in Seattle.  Sidney Green will present the paper during the podium presentation, Tuesday June 19th, in the Technical Session track - Hydraulic Fracturing Geomechanics II.

ABSTRACT: The injection of large quantities of treating fluid and proppants during fracture stimulation of low permeability formations causes local insitu stress changes, sometimes referred to as stress shadowing or stress interference. Recent procedures for improving production have led to closer spacing of clusters, from approximately 80 feet spacing a few years ago to about 20 feet spacing now, or less in some cases. That is, there are now about four times the number of potential fracture initiation locations (clusters) per foot of lateral well, while the sand pumped per foot of lateral continues at about 1700-1800 pounds per foot. With four times the number of clusters and the same mass of sand pumped, the stress disturbance of one cluster to another cluster has changed. This paper addresses the near wellbore stress interference effects for close cluster spacing. Numerical simulations are presented using a robust linear-elastic 3-D hydraulic fracturing computer code that calculates fracture ‘bending’ and fracture width change due to stress interference. The stress interference that changes the fracture width is the most significant because the resistance to fracture fluid flow at high velocities in these narrow channels is the primary driver of stress shadowing fracture geometry changes. Continue..