Hassanzadeh, HassanChen, ZhangxinMohagheghian, Erfan2020-08-282020-08-282020-08-26Mohagheghian, E. (2020). Numerical Modeling of Multi-mechanistic Gas Production from Shale Reservoirs (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.http://hdl.handle.net/1880/112444Shale and ultratight gas reservoirs have recently been contributing to the energy industry and gas market to a large extent. The dynamics of shale gas transport in porous media is of practical importance in several scientific and engineering applications. The characteristics of the transport inside the pore space are governed by the mechanisms that occur at the pore level. Recent advances in computational power provide the opportunity to investigate these phenomena further. In this study, a methodology is developed to create a model in which all the major transport mechanisms involved in shale gas flow are taken into account. The mechanisms include viscous flow, gas slippage, Knudsen diffusion, competitive adsorption of different gaseous components, pore size variation and real gas effect. The model is then utilized on one hand to derive parameters such as apparent gas permeability and matrix-fracture fluid exchange term (a.k.a. shape factor) which can reduce the computational load while preserving the accuracy and on the other hand to study the response of shale gas reservoirs to the feasibility and potentials of carbon storage and enhanced gas recovery as well as phenomena such as nano-confinement and chromatographic separation. The compositional effects of shale gas can be lumped into a single component using the apparent permeability which deems to capture the relevant physics and can replace the Darcy permeability. The shape factor required for Darcy scale simulation of shale gas reservoirs obtained from the detailed numerical simulations of multi-mechanistic multi-component shale gas flow can be modeled versus dimensionless pressure to capture the transient behavior of the matrix-fracture fluid transfer in a time-independent fashion. The stronger adsorption of CO2 over CH4 to shale surface makes the partially depleted shale gas reservoirs a promising target for CO2 storage as well as enhanced natural gas recovery. Up to 55% of the injected CO2 can be trapped as adsorbed phase and up to 16% incremental methane recovery can be achieved. The phase behavior of the confined shale gas is significantly different than the behavior of the bulk fluid. Nano-confinement could shift critical properties significantly. The effect of confinement on phase diagrams and compositional variations of the gas in place was also investigated via numerical simulations. The computed apparent permeability and shape factor can be directly used in the macroscale reservoir simulators to accurately predict the performance of a shale gas reservoir and the outcomes of this study will find applications in the design and implementation of an efficient CO2 injection and investigating compositional effects in shale gas simulations.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Shale gas reservoirsMultimechanistic shale gas flowApparent gas permeabilityMulticomponent adsorptionKnudsen diffusionSlip flowCO2 sequestrationCO2-EGRShape factorConfinementPhase envelopeCritical properties shiftEngineering--Petroleumdoctoral thesishttp://dx.doi.org/10.11575/PRISM/38126