# Zipper fracturing has also been

Sequential propagation of hydraulic fractures in two parallel wells with offset in perforations

Fig. 15. Induced shear stresses in the field due to the creation of fractures with offset.Figure optionsDownload full-size imageDownload as PowerPoint slide

Fig. 16. (a) Zipper-Frac network obtained after four fractures reach their target lengths and the (b) maximum principal stress distribution around them. The fractures are created sequentially with an offset of 5 m between the fractures from two parallel horizontal wells.Figure optionsDownload full-size imageDownload as PowerPoint slide

Fig. 17. (a) Induced shear stresses near the sequential zipper fractures with offset. (b) The change in fracture tip pressures as they Phenformin grow in length.Figure optionsDownload full-size imageDownload as PowerPoint slide

Comparison of stimulated rock volume (SRV) between the conventional zipper fracturing and modified zipper fracturing

In the context of this paper, the stimulated rock volume (SRV) is defined as the volume of a rock where critical disturbance in the initial stress state occurred due to the creation of fractures. The new stress state might increase the failure potential of the rock near the fractures (Ghassemi et al., 2013). The induced shear stresses might cause the activation of faults and natural fractures. The induced compressive stresses might cause shear failure in the rock. To estimate the SRV we assumed Mohr–Coulomb failure criterion for the rock in compression (with a tension cutoff):equation(13) τ =S0+σtan?where ? is the friction angle, So is the cohesion, τ and σ are the shear the normal stresses acting on the failure plane respectively. The equivalent form of the above Eq. (13) in terms of principal stresses σ1 and σ3 can be written as follows:equation(14)σ1=2S0tanβ+σ3tan2βwhere 2β=900+?2β=900+?equation(15)f(σ)=σ1−2S0tanβ−σ3tan2β=0