Near Wellbore Hydraulic Fracture Propagation from Perforations in Tight Rocks: The Roles of Fracturing Fluid Viscosity and Injection Rate

Hydraulic fracture initiation and near wellbore propagation is governed by complex failure mechanisms, especially in cased perforated wellbores. Various parameters affect such mechanisms, including fracturing fluid viscosity and injection rate. In this study, three different fracturing fluids with viscosities ranging from 20 to 600 Pa.s were used to investigate the effects of varying fracturing fluid viscosities and fluid injection rates on the fracturing mechanisms. Hydraulic fracturing tests were conducted in cased perforated boreholes made in tight 150 mm synthetic cubic samples. A true tri-axial stress cell was used to simulate real far field stress conditions. In addition, dimensional analyses were performed to correspond the results of lab experiments to field-scale operations. The results indicated that by increasing the fracturing fluid viscosity and injection rate, the fracturing energy increased, and consequently, higher fracturing pressures were observed. However, when the fracturing energy was transferred to a borehole at a faster rate, the fracture initiation angle also increased. This resulted in more curved fracture planes. Accordingly, a new parameter, called fracturing power, was introduced to relate fracture geometry to fluid viscosity and injection rate. Furthermore, it was observed that the presence of casing in the wellbore impacted the stress distribution around the casing in such a way that the fracture propagation deviated from the wellbore vicinity.

[1]  P. Pourafshary,et al.  Dealing with the challenges of hydraulic fracture initiation in deviated-cased perforated boreholes , 2010 .

[2]  L. A. Behrmann,et al.  Effect of perforations on fracture initiation , 1991 .

[3]  R. G. van de Ketterij.  Optimisation of the Near-Wellbore Geometry of Hydraulic Fractures Propagating from Cased Perforated Completions , 2001 .

[4]  Hazim H. Abass,et al.  Oriented Perforations - A Rock Mechanics View , 1994 .

[5]  S. Rahman,et al.  Hydraulic fracture initiation and propagation: roles of wellbore trajectory, perforation and stress regimes , 2000 .

[6]  C. Atkinson,et al.  Numerical and analytical solutions for the problem of hydraulic fracturing from a cased and cemented wellbore , 2002 .

[7]  Abbas Ali Daneshy,et al.  Experimental Investigation of Hydraulic Fracturing Through Perforations , 1973 .

[8]  S. Sastry,et al.  Compressibility and density of select liquid and solid foods under pressures up to 700 MPa , 2010 .

[9]  Jean Romero,et al.  Theoretical Model and Numerical Investigation of Near-Wellbore Effects in Hydraulic Fracturing , 1995 .

[10]  V. Rasouli.  A true triaxial stress cell (TTSC) used for simulations of real field operations in the lab , 2012 .

[11]  V. Rasouli,et al.  An Investigation of Hydraulic Fracturing Initiation and Near-Wellbore Propagation from Perforated Boreholes in Tight Formations , 2015, Rock Mechanics and Rock Engineering.

[12]  R. G. van de Ketterij,et al.  Impact of Perforations on Hydraulic Fracture Tortuosity , 1999 .

[13]  George V. Chilingarian,et al.  Petroleum Related Rock Mechanics , 1993, Developments in Petroleum Science.

[14]  T. K. Perkins,et al.  Stability and Failure of Spherical Cavities in Unconsolidated Sand and Weakly Consolidated Rock , 1988 .

[15]  Sunil N. Gulrajani,et al.  Evaluation and Modification of Fracture Treatments Showing Near-Wellbore Effects , 1996 .

[16]  Emmanuel M Detournay,et al.  Propagation Regimes of Fluid-Driven Fractures in Impermeable Rocks , 2004 .

[17]  Leen Weijers,et al.  Experimental Verification of Dimensional Analysis for Hydraulic Fracturing , 1994 .

[18]  M. P. Cleary,et al.  Field Implementation of Proppant Slugs To Avoid Premature Screen-Out of Hydraulic Fractures With Adequate Proppant Concentration , 1993 .

[19]  L. Weijers,et al.  The near-wellbore geometry of hydraulic fractures initiated from horizontal and deviated wells , 1995 .

[20]  Andrew P. Bunger.  Near-Surface Hydraulic Fracture , 2009 .

[21]  W. W. Aud,et al.  The Effect of Viscosity on Near-Wellbore Tortuosity and Premature Screenouts , 1994 .

[22]  Karin Ackermann,et al.  Mechanics Of Hydraulic Fracturing , 2016 .

[23]  T.P.Y. Lhomme,et al.  Initiation of Hydraulic Fractures in Natural Sandstones , 2005 .

[24]  B. M. Robinson,et al.  Analysis of Abnormally High Fracture Treating Pressures Caused by Complex Fracture Growth , 1993 .

[25]  L. V. Lehman,et al.  Etiology of Multiple Fractures , 1997 .

[26]  K. G. Nolte,et al.  Perforating Requirements for Fracture Stimulations , 1999 .

[27]  Keith K. Millheim,et al.  Applied Drilling Engineering , 1986 .