Numerical Modeling of Hydraulic Fracturing in Oil Sands

Hydraulic fracturing is a widely used and efficient technique for enhancing oil extraction fromheavy oil sands deposits. application of this technique has been extended from cemented rocksto uncemented materials, such as oil sands. models, which have originally been developedfor analyzing hydraulic fracturing in rocks, are in general not satisfactory for oil sands. thisis due to a high leak-off in oil sands, which causes the mechanism of hydraulic fracturing tobe different from that for rocks. a thermal hydro-mechanical fracture finite element model isdeveloped, which is able to simulate hydraulic fracturing under isothermal and non-isothermalconditions. plane strain or axisymmetric hydraulic fracture problems can be simulated by thismodel and various boundary conditions, such as specified pore pressure/fluid flux, specifiedtemperature/heat flux. and specified loads/traction, can be modeled. the developed model hasbeen verified by comparing its results to existing analytical and numerical solutions for thermoelasticconsolidation problems. the model has been used to simulate a laboratory experimentof hydraulic fracture propagation in oil sands. the results from the numerical model are inagreement with experimental observations. the numerical model and laboratory experimentsboth indicate that, for uncemented porous materials, such as sands (as opposed to rocks), asingle planar fracture is unlikely to occur and a system of multiple fractures or a fracture zoneconsisting of interconnected tiny cracks should be expected