Sharif Digital Repository

Enhancing oil extraction from oil sands with a hydraulic fracturing technique has been widely used in practice. Due to the complexity of the actual process, modelling of hydraulic fracturing is far behind its application. Reproducing the effects of high pore pressure and high temperature, combined with, complex stress changes in the oil sand reservoir, requires a comprehensive numerical model which is capable of simulating the fracturing phenomenon. To capture all of these aspects in the problem, three partial differential equations, i.e., equilibrium, flow, and heat transfer, should be solved simultaneously in a fully implicit (coupled) manner. A fully coupled thermo-hydro-mechanical... 

Streaming potential measurement is one of the electrokinetic techniques used to determine the average zeta potential of porous rock which can provide reliable information on reservoir flow behavior and wettability state of the rock surface. Streaming potential measurement using electrodes has recently been introduced in the oil reservoirs applications and there are still significant uncertainties during the measurements and interpretation of streaming potential results. The primary purpose of this work is to establish a setup to measure the streaming potential of porous media with low scattering and evaluate voltage measurements based on the paired stabilization and pressure ramping methods.... 

Reservoir flow simulation involves subdivision of the physical domain into a number of gridblocks. This is best accomplished with optimized gridpoint density and a minimized number of gridblocks, especially for coarse-grid generation from a fine-grid geological model. In any coarse-grid generation, proper distribution of gridpoints, which form the basis of numerical gridblocks, is a challenging task. We show that this can be achieved effectively by a novel grid-generation approach based on a background grid that stores gridpoint spacing parameters. Spacing parameter (L) can be described by Poisson's equation (▽2L = G), where the local density of gridpoints is controlled by a variable source... 

Most of the Iranian oil reservoirs are naturally fractured. Reinfiltration is a key proceess which controls oil flow from the upper to the lower matrix block. However, theoretical modeling of fracture aperture as well as fracture dip angle effects on flow rate of drained oil during reinfilteration process remains a topic of debate in the literature. Moreover, there is no reported experience in the literature that compared the oil velocity predicted by traveling oil bridges and continuum film flow approaches. In this work reinfiltration process is modeled through two different approaches: discrete traveling liquid elements and continuum film flow along inclined fractures. For a case study... 

Reservoir flow simulation involves subdivision of the physical domain into a number of gridblocks. This is best accomplished with optimized grid point density and minimized number of gridblocks especially for coarse grid generation from a fine grid geological model. In any coarse grid generation, proper distribution of grid points, which form basis of numerical gridblocks, is a challenging task. We show that this can be effectively achieved by generating a background grid that stores grid point spacing parameter. Spacing (X) can be described by Poisson's equation (∇2 L = G) where the local density of grid points is controlled by a variable source term (G). This source term can be based on... 

Fractures identification is essential during exploration, drilling and well completion of naturally fractured reservoirs since they have a significant impact on flow contribution. There are different methods to characterize these systems based on formation properties and fluid flow behaviour such as logging and testing. Pressure-transient testing has long been recognized as a reservoir characterization tool. Although welltest analysis is a recommended technique for fracture evaluation, but its use is still not well understood. Analysis of pressure transient data provides dynamic reservoir properties such as average permeability, fracture storativity and fracture conductivity.An infusion of...