CT Identification and Fractal Characterization of 3‐D Propagation and Distribution of Hydrofracturing Cracks in Low‐Permeability Heterogeneous Rocks

Understanding and characterization of the three-dimensional (3-D) propagation and distribution of hydrofracturing cracks in heterogeneous rock are key for enhancing the stimulation of low-permeability petroleum reservoirs. In this study, we investigated the propagation and distribution characteristics of hydrofracturing cracks, by conducting true triaxial hydrofracturing tests and computed tomography on artificial heterogeneous rock specimens. Silica sand, Portland cement, and aedelforsite were mixed to create artificial heterogeneous rock specimens using the data of mineral compositions, coarse gravel distribution, and mechanical properties that were measured from the natural heterogeneous glutenite cores. To probe the effects of material heterogeneity on hydrofracturing cracks, the artificial homogenous specimens were created using the identical matrix compositions of the heterogeneous rock specimens and then fractured for comparison. The effects of horizontal geostress ratio on the 3-D growth and distribution of cracks during hydrofracturing were examined. A fractal-based method was proposed to characterize the complexity of fractures and the efficiency of hydrofracturing stimulation of heterogeneous media. The material heterogeneity and horizontal geostress ratio were found to significantly influence the 3-D morphology, growth, and distribution of hydrofracturing cracks. A horizontal geostress ratio of 1.7 appears to be the upper limit for the occurrence of multiple cracks, and higher ratios cause a single crack perpendicular to the minimum horizontal geostress component. The fracturing efficiency is associated with not only the fractured volume but also the complexity of the crack network.

[1]  Shanyong Wang,et al.  A numerical investigation of the hydraulic fracturing behaviour of conglomerate in Glutenite formation , 2013 .

[2]  Davide Elmo,et al.  Volumetric Fracture Intensity Measurement for Improved Rock Mass Characterisation and Fragmentation Assessment in Block Caving Operations , 2015, Rock Mechanics and Rock Engineering.

[3]  D. Tiab,et al.  Influence of Stress and Lithology on Hydraulic Fracturing in Hassi Messaoud Reservoir, Algeria , 2000 .

[4]  Tao Xu,et al.  Do joint geometrical properties influence the fracturing behaviour of jointed rock? An investigation through joint orientation , 2015 .

[5]  S. Maxwell,et al.  Anisotropic velocity modeling for microseismic processing: Part 1—Impact of velocity model uncertainty , 2010 .

[6]  Tsuyoshi Ishida,et al.  Observations of Fractures Induced by Hydraulic Fracturing in Anisotropic Granite , 2015, Rock Mechanics and Rock Engineering.

[7]  Zaixing Jiang,et al.  Sedimentary Characteristics and Hydrocarbon Accumulation of Glutenite in the Fourth Member of Eogene Shahejie Formation in Shengtuo Area of Bohai Bay Basin, East China , 2010 .

[8]  Les Bennett,et al.  Key Criteria for a Successful Microseismic Project , 2010 .

[9]  R. P. Young,et al.  Distinct element modeling of hydraulically fractured Lac du Bonnet granite , 2005 .

[10]  Yang Ju,et al.  Experimental investigation of the effects of heterogeneity and geostress difference on the 3D growth and distribution of hydrofracturing cracks in unconventional reservoir rocks , 2016 .

[11]  Xiaowei Weng,et al.  Hydraulic Fracture Monitoring to Reservoir Simulation: Maximizing Value , 2012 .

[12]  Xiaowei Weng,et al.  Numerical Modeling of Hydraulic Fracturing In Naturally Fractured Formations , 2011 .

[13]  Shicheng Zhang,et al.  Experimental study of hydraulic fracturing for shale by stimulated reservoir volume , 2014 .

[14]  Bruno Chareyre,et al.  Intensity and volumetric characterizations of hydraulically driven fractures by hydro-mechanical simulations , 2017 .

[15]  Jian Ma,et al.  Experimental Investigation on the Basic Law of Hydraulic Fracturing After Water Pressure Control Blasting , 2014, Rock Mechanics and Rock Engineering.

[16]  Emmanuel M Detournay,et al.  Comparison between laboratory experiments and coupled simulations of saucer-shaped hydraulic fractures in homogeneous brittle-elastic solids , 2013 .

[17]  F. Gao,et al.  Experimental study on CH4 permeability and its dependence on interior fracture networks of fractured coal under different excavation stress paths , 2017 .

[18]  Y. Ju,et al.  Experimental study of dynamic mechanical properties of reactive powder concrete under high-strain-rate impacts , 2010 .

[19]  M. Zoback,et al.  Determination of stress orientation and magnitude in deep wells , 2003 .

[20]  L. Ning,et al.  Experimental study on the mechanism of hydraulic fracture growth in a glutenite reservoir , 2017 .

[21]  Yicai Wang.  Numerical modelling of heterogeneous rock breakage behaviour based on texture images , 2015 .

[22]  Mark D. Zoback,et al.  Poroelastic effects in the determination of the maximum horizontal principal stress in hydraulic fracturing tests—A proposed breakdown equation employing a modified effective stress relation for tensile failure , 1989 .

[23]  P. Rüegsegger,et al.  A new method for the model‐independent assessment of thickness in three‐dimensional images , 1997 .

[24]  Bing-xiang Huang,et al.  Experimental Investigation on the Basic Law of the Fracture Spatial Morphology for Water Pressure Blasting in a Drillhole Under True Triaxial Stress , 2015, Rock Mechanics and Rock Engineering.

[25]  Yang Ju,et al.  Multi-thread parallel algorithm for reconstructing 3D large-scale porous structures , 2017, Comput. Geosci..

[26]  Jinliang Zhang,et al.  Deposition and Diagenesis of Steep-Slope Glutenite Reservoirs: Shengtuo Field, Eastern China , 2014 .

[27]  Michael J. Mayerhofer,et al.  Hydraulic Fracture Complexity: Diagnosis, Remediation, And Explotation , 2008 .

[28]  Emmanuel M Detournay,et al.  Experimental validation of the tip asymptotics for a fluid-driven crack , 2008 .

[29]  Xiaowei Weng,et al.  Numerical Modeling of Hydraulic Fractures Interaction in Complex Naturally Fractured Formations , 2013, Rock Mechanics and Rock Engineering.

[30]  Guang-qing Zhang,et al.  A high-stress tri-axial cell with pore pressure for measuring rock properties and simulating hydraulic fracturing , 2014 .

[31]  Yao-Chung Chen,et al.  Investigation of Hydraulic Fracture Propagation Using a Post-Peak Control System Coupled with Acoustic Emission , 2015, Rock Mechanics and Rock Engineering.

[32]  Roberto Suarez-Rivera,et al.  Onset of Hydraulic Fracture Initiation Monitored by Acoustic Emission and Volumetric Deformation Measurements , 2014, Rock Mechanics and Rock Engineering.

[33]  T. Urbancic,et al.  Microseismic Imaging of Fracture Behavior in Naturally Fractured Reservoirs , 2002 .

[34]  Xiaowei Weng,et al.  Integrating Microseismic Mapping and Complex Fracture Modeling to Characterize Hydraulic Fracture Complexity , 2011 .

[35]  Michael J. Mayerhofer,et al.  What is Stimulated Rock Volume , 2008 .

[36]  L. Tham,et al.  Influence of Heterogeneity of Mechanical Properties on Hydraulic Fracturing in Permeable Rocks , 2004 .

[37]  N. Otsu.  A threshold selection method from gray level histograms , 1979 .

[38]  G. G. Murillo,et al.  Microseismic Hydraulic Fracture Monitoring To Determine The Fracture Geometry In Coyotes Field, Chicontepec , 2010 .

[39]  Anders Kaestner,et al.  Imaging and image processing in porous media research , 2008 .

[40]  Anisha Chaudhary.  Shale Oil Production Performance from a Stimulated Reservoir Volume , 2011 .

[41]  Xiaowei Weng,et al.  Integrating Microseismic Mapping and Complex Fracture Modeling to Characterize Fracture Complexity , 2012 .

[42]  T. Ishida,et al.  The distinct element analysis for hydraulic fracturing in hard rock considering fluid viscosity and particle size distribution , 2011 .

[43]  Y. Ju,et al.  Investigation on thermophysical properties of reactive powder concrete , 2011 .

[44]  M. Tuller,et al.  Segmentation of X‐ray computed tomography images of porous materials: A crucial step for characterization and quantitative analysis of pore structures , 2009 .

[45]  P. Richard,et al.  Composition of reactive powder concretes , 1995 .

[46]  Non-Darcy interfacial dynamics of air-water two-phase flow in rough fractures under drainage conditions , 2017, Scientific Reports.

[47]  J. Yang,et al.  Mesomechanism of steel fiber reinforcement and toughening of reactive powder concrete , 2007 .

[48]  Exploring the physicochemical processes that govern hydraulic fracture through laboratory experiments , 2012 .

[49]  Yang Ju,et al.  3D numerical reconstruction of well-connected porous structure of rock using fractal algorithms , 2014 .

[50]  Andrew P. Bunger,et al.  A comparison of numerical and experimental results of hydraulic fracture growth into a zone of lower confining stress , 2008 .

[51]  Yang Ju,et al.  A quantification method for shale fracability based on analytic hierarchy process , 2016 .

[52]  The Experimental Investigation of Hydraulic Fracture Propagation Characteristics in Glutenite Formation , 2015 .

[53]  Bo Huang,et al.  The Behaviour of Fracture Growth in Sedimentary Rocks: A Numerical Study Based on Hydraulic Fracturing Processes , 2016 .

[54]  Y. Ju,et al.  Fractal model and Lattice Boltzmann Method for Characterization of Non-Darcy Flow in Rough Fractures , 2017, Scientific Reports.

[55]  Zhou Xiang,et al.  Experimental Investigation into Hydraulic Fracture Network Propagation in Gas Shales Using CT Scanning Technology , 2015, Rock Mechanics and Rock Engineering.