Naturally fractured reservoirs represent significant portion of the world's oil and gas reserves. In most of the reservoirs, fractures are important contributors to fluid flow. Thus, modeling and simulation of discrete fracture network is essential to assess responses of the reservoirs under stimulation pressure, develop the best hydraulic fracture treatments, carry out feasibility studies, design optimum production methods and improve reservoir potentials. It is also a very complicated process. Natural fractures are by nature highly heterogeneous with different size, orientation and spatial distribution. The complexity is further raised, taking into account the role of matrix, the flow interaction between matrix and fractures, the effect of production-induced stress on fluid flow. Previous works fail to balance sufficient geological complexity and excessive needs of high computational resources. This thesis presents an innovative procedure to simulate stress-dependent fluid flow through discrete fracture network. Three numerical models (tensor, flow and deformation) are developed and coupled iteratively for this purpose. - A tensor model calculates grid based permeability tensor from discrete fracture network model, which includes individual fracture properties such as spatial distribution, length, location and orientation. The tensor model accounts for fluid flow from the matrix to matrix and matrix to fracture. It also includes flow through connected and disconnected fractures. - An unsteady state simulation model investigates fluid flow through the fracture system and gives pressure profile, velocity profile as output. - A dual continuum deformation model studies the reservoir rock deformation and its effects on fluid flow. The geo-mechanic solution is decomposed into matrix and fracture parts that allow calculation of dynamic porosity and permeability separately. The proposed work procedure has been validated to match nicely with analytical results. Furthermore, several case study scenarios are carried out to illustrate how it could help evaluate different aspects of reservoir performance including fracture connectivity, rock deformation, well injectivity and productivity, recovery and even distribution of fluid inside reservoir as a result of rock deformation. The case studies have proven the method to be very efficient in terms computational resources. It also eliminates most of the limitations in the previous models such as handling fracture connectivity, permeability anisotropy and change in effective stress.
| Identifer | oai:union.ndltd.org:ADTP/258602 |
| Date | January 2008 |
| Creators | Shaik, Abdul Ravoof, Petroleum Engineering, Faculty of Engineering, UNSW |
| Publisher | Publisher:University of New South Wales. Petroleum Engineering |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | http://unsworks.unsw.edu.au/copyright, http://unsworks.unsw.edu.au/copyright |
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