Modelling Multi-Fractured, Multi-Well, Tight-Gas Reservoirs

Date
2013-10-02
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Abstract
Exploration and development of Canadian natural gas resources is shifting to ultra-low permeability resource plays. Unlike conventional high-permeability gas reservoirs, the flow regime shows a subtle and prolonged transition between early and late time behaviour. Moreover, early time behaviour is strongly impacted by completion techniques. It is inappropriate, or at least very inefficient, to use traditional solutions on the gas resource plays currently under development. To address these issues, this thesis proposes a series of novel analytical and semi-analytical solutions based on Chebyshev polynomial basis functions. The solutions are found using simple and compact computer codes which are included in the text. The solutions cover a variety of flow geometries (1D, 2D, radial and elliptical flow) as well as Dirichlet and Neumann boundary conditions. The simplicity of incorporating Dirichlet boundary conditions makes the method particularly amiable to constant flowing pressure problems. The thesis provides a full description of the theory and mathematical development of the proposed solutions. The thesis also discusses the stability requirements for the proposed solution algorithms, in particular the grid-point requirements for early-time solutions, limitations on time-step lengths and limitations imposed by finite precision mathematical operators. Most significantly, the algorithms developed in this thesis demonstrate significant improvements in numerical efficiency over existing full-life solution techniques, especially for near-wellbore and early-time behaviour. The methods can be used with explicit time stepping algorithms as well as Laplace transform algorithms. This makes the solution methods very flexible and extensible. This opens up new avenues with which to explore and generate fundamental solutions to the diffusivity equation.
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Petroleum
Citation
Morgan, M. D. (2013). Modelling Multi-Fractured, Multi-Well, Tight-Gas Reservoirs (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/26957