Effect of Formation Modulus Contrast on Hydraulic Fracture Height Containment

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractMuch study has been conducted on the effects of formation Young's modulus and in situ stress on hydraulic fracture height containment in layered formations. It has been well documented that in situ stress contrast is the dominant parameter controlling fracture height growth and that Young's modulus contrast is less important. However, a recent study pointed out that modulus contrast can have significant implications on fracture geometry and proppant placement. To expand on this topic further, we consider the combined effects of modulus contrast and in situ stress contrast on fracture geometry. A pseudo 3D (P3D) hydraulic fracture simulator with a rigorous layered modulus formulation is used in this study. The fracture height calculated based on uniform modulus versus layered modulus, under the same in situ stress contrast conditions, is compared. 1 The results are analyzed and explained, based on fracture mechanics fundamentals as well as the coupled fluid pressure effect in hydraulic fracturing. One important finding is that fracture height can also be contained by low modulus layers. The results from this study can be applied to hydraulic fracturing treatments in formations with moderate to significant modulus contrast. The mechanisms studied in this work could also partially explain some recent results from microseismic or tiltmeter mapping that show more fracture height containment than that predicted by commonly used P3D hydraulic fracturing simulators based on averaged modulus.

Three-dimensional finite element simulation and parametric study for horizontal well hydraulic fracture

“…If the net pressure is not available for penetrating through high stress barrier layers, then fracture height must be contained. Studies have pointed out that modulus contrast can also have significant effect on fracture height growth (Smith et al, 2001;Gu and Siebrits, 2006). Lower modulus layers do not enhance, but hinder fracture height growth (Gu and Siebrits, 2006), which is also verified in the present paper.…”

“…Studies have pointed out that modulus contrast can also have significant effect on fracture height growth (Smith et al, 2001;Gu and Siebrits, 2006). Lower modulus layers do not enhance, but hinder fracture height growth (Gu and Siebrits, 2006), which is also verified in the present paper. Fracture toughness can fairly affect both the height growth and the propagation of hydraulic fractures (Thiercelin et al, 1987).…”

“…Fracture height has been recognized as one of the critical factors which can determine the success or failure of a hydraulic fracturing treatment. Many studies have been conducted for the effects of in-situ stresses, formation Young's modulus, fracture toughness and layer interfacial slip on hydraulic fracture height containment in layered formations (van Eekelen, 1982;Teufel and Clark, 1984;Thiercelin et al, 1987;Wang and Clifton, 1990;Warpinski et al, 1982Warpinski et al, , 1998Smith et al, 2001;Gu and Siebrits, 2006;Gu et al, 2008;Daneshy, 2009;Iyer and Podladchikov, 2009;Lewis et al, 2009).…”

Coupled flow-stress-damage simulation of deviated-wellbore fracturing in hard-rock

“…Theoretically, if the stress intensity factor of the fracture tip is close to 0, the fracture can hardly propagate. When the fracture propagates from a high elastic modulus formation to a low elastic modulus formation, fracture propagation is restricted due to the decreased stress intensity factor (Gu and Siebrits, 2008;Leguillon et al, 2000). Before fracture propagates into a high elastic modulus formation from a low elastic modulus formation, the high elastic modulus formation may have produced a new fracture already (Fig.…”

“…10. Fractures propagate to the interface in layered formation (Gu and Siebrits, 2008). plotted in Figs.…”