Issue 58

Q.-C. Li et alii, Frattura ed Integrità Strutturale, 58 (2021) 1-20; DOI: 10.3221/IGF-ESIS.58.01

(A): Low fluid viscosity

(B): High fluid viscosity Figure 13: Fluid invasion from perforation to reservoir during fracturing operation with oriented perforations in shale reservoirs.

Figure 14: Effect of fluid viscosity on reorientation radius during fracturing operation with oriented perforations in shale reservoirs.

Fig.14 displays the influence of fluid viscosity on reorientation radius of hydraulically induced fracture during fracturing operation with oriented perforations in shale reservoirs. We can see from Fig.14 that the reorientation radius of hydraulically induced fracture will nonlinearly become longer with the increase of fluid viscosity. When the fluid viscosity is 30 mPa · s, the reorientation radius is only 10.32m. However, the reorientation radius has increased to 14.34m when the fluid viscosity is 180 mPa · s, which is 4.02m longer than that when the fluid viscosity is 30mPa · s. This can also be explained by Fig.13. As shown in Fig.13, when the fluid viscosity is high, fluid within the perforation is difficult to invade into the reservoir, and the pressure in perforation is high. Therefore, when the fluid viscosity is high, the fracture has propagated a long distance before reorientation.

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