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3225053 
Book/Book Chapter 
Examining hydraulic fracture: Natural fracture interaction in hydrostone block experiments 
Olson, JE; Bahorich, B; Holder, J 
2012 
Society of Petroleum Engineers 
Richardson, TX 
2012 SPE hydraulic fracturing technology conference 
SPE-152618-MS 
English 
is a chapter of 3229865 2012 SPE hydraulic fracturing technology conferenc
Field experience in shale gas and some tight gas sandstones suggests significant interaction between hydraulic fractures and natural fractures. Experimental analysis of this problem has mostly focused on frictional interfaces with regard to the natural fractures. We have performed tests to examine the effect of cemented natural fractures on hydraulic fracture propagation. The motivation for this type of work is that core observations from the Barnett and some other shale gas plays suggest that natural fractures are largely cemented (or healed) and trend obliquely or orthogonally to the present day hydraulic fracture direction. We embedded planar glass discontinuities into a cast hydrostone block as proxies for cemented natural fractures. Consistent with theoretical predictions, our results show that oblique embedded fractures are more likely to divert a fluid-driven hydraulic fracture than those occurring orthogonal to the induced fracture path. Hydraulic fracture - natural fracture interaction took three forms - 1) the hydraulic fracture bypassing the natural fracture by propagating around it (via height growth, not curving), 2) the hydraulic fracture arresting into the natural fracture and then diverting along it and sometimes kinking off the end of it, and 3) a combination of bypass and diversion. We also saw some leakage of fracture fluid along the interfaces of multi-layer blocks, even though such interfaces were perpendicular to the maximum compressive stress, suggesting an analogue for laminated and shaly sedimentary sequences. 
9781613991787 
SPE Hydraulic Fracturing Technology Conference 
The Woodlands, TX 
February 6-8, 2012