Controlling the Height of Multiple Hydraulic Fractures in Layered Media

Abstract

Fracture-height containment is desirable in hydraulic-fracturing treatments because it can result in better efficiency of oil or gas recovery and have less impact on the environment. Several mechanisms of the containment of a single hydraulic fracture were investigated in the past, and the outcomes of these studies are now well-documented in the open literature. However, the effectiveness of these mechanisms in the case of multiple closely spaced hydraulic fractures has not received much attention. The latter situation typically arises in the case of multiple transverse fractures emanating from a single horizontal wellbore.In this paper, we develop a mathematical model that one can use to assess the fracture-interaction phenomenon as well as the effect of the modulus contrast between adjacent rock layers. We consider the situation in which one must contain the hydraulic fractures entirely in the pay zone and investigate fracturing-fluidpressure control as a possible mechanism of height containment. It is demonstrated that when the fracture spacing becomes comparable with the fracture height, the interaction between the fractures produces a shielding effect. In this case, the fracturing-fluid pressure that ensures fracture containment is greater in comparison with the case of a single isolated fracture. However, the fracture opening is also smaller in the case of closely spaced fractures. The dependence of the fracturing-fluid pressure and fracture opening on the fracture spacing needs to be taken into consideration during the selection of fracture spacing for a particular treatment.

Experimental Study on Local Plastic Collapse in a Plate Weakened by Two Collinear Cracks

“…The resulting governing equations were based on the 3D fundamental solution for an edge dislocation in a plate of finite thickness obtained in [16]. The governing equations were solved using the GaussChebyshev quadrature and the numerical solution procedure is described in a number of articles by the authors [17][18][19][20][21][22][23].…”

Experimental and Numerical Simulation of Interlayer Propagation Path of Vertical Fractures in Shale

“…The vertical propagation of hydraulic fractures is one of the important factors to be considered in fracturing design. It determines the transformation range of volume fracture network in the vertical direction and is related to the effect of reservoir transformation (Jian et al, 2007;Zhu et al, 2015;Khanna and Kotousov, 2016;Guangqing et al, 2018). There are a lot of weak bedding cementation interfaces in shale reservoir.…”

The stress field due to an interfacial edge dislocation in a multi-layered medium

“…These structures are also prevalent in nature, ranging from the nano-scale structures, which provide unique properties to bio-materials such as nacre, tooth enamel and bone (Sellinger et al 1998;Gao et al 2003) to the large scale structures such as stratified rock formations in the earth's crust (Daneshy, 1978;Gudmundsson et al 2010;Khanna and Kotousov, 2015).…”