UBC Theses and Dissertations
The theoretical basis for the modelling of chemical reactions in rock-water systems with specific reference to the heat flow, fluid flow and solute transport laws Perkins, Ernest Henry
In order to understand the processes involved in water and steam floods during secondary and enhanced oil recover, waste disposal, in-situ mining and leaching, or many different types of geological phenomenona, the chemical interactions between the fluid and the surrounding minerals must be known as a function of pressure, temperature and composition. These systems are generally open systems, thus the changes in pressure, temperature and bulk composition are coupled to the chemical reactions occurring throughout the entire system and cannot be independently specified. Based on the equations of mass action and mass balance, further equations have been derived which allow chemical reactions between a fluid and solid phases to be evaluated. The equations are based on the derivatives of the mass action and mass balance equations with respect to time, and are used in a series expansion to predict the composition of the fluid and the solid phases at future times. The equations are coupled to those constraining pressure, temperature and mass flux-which have been modified to allow this coupling. Because of various limitations on many of the equations used, only a single fluid in porous media can be modelled. A computer program has been written to test the equations and concepts developed in this thesis. The results allow the following generalization for natural flow systems with decreasing pressure and temperature along the flow path to be made. Excluding systems with sufficient mechanical energy to create new flow paths and excluding all phases which exhibit decreasing solubility with increasing temperature or with decreasing pressure, every natural flow system which attempts to maintain equilibrium between the fluid and solid phases in contact with the fluid will ultimately seal itself.
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