Near well bore streamline simulation

Hashem, Marjan (2011) Near well bore streamline simulation. Masters thesis, Memorial University of Newfoundland.

[English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (31MB)

Abstract

This thesis presents a methodology for generating and analyzing streamlines in reservoirs near wellbores using a finite difference method and the Pollock method. The proposed methodology has been applied in 2D using Cartesian and Polar coordinate systems. -- This proposed method demonstrates how all potential geological and mechanical factors affect streamline behaviour and analyze their effect on route of stream path lines movement. By using this method, stream path lines can be visualized for any given boundary conditions. Subject to the basic assumptions of incompressible fluid and avoidance of gravity effects, there is an opportunity to simplify numerical equations for streamline simulation and retrieve more effective results. Fluids are moved along the natural streamline grids. -- Permeability, well conditions and other process factors such as pressure, velocity and time of travel dictate the route and direction of streamlines. The advantages of this method include flow visualization, more efficiency and computational speed, and the ability to add of additional boundary conditions in various numbers of grid blocks. In particular, this method offers streamline visualization in inter-well connectivity. -- Streamline simulation is increasingly employed by geoscientists and engineers in the oil and gas industry to model the flow of fluids in reservoirs. Flow simulation can run on fine-grid, high-resolution models in reasonable times on off the shelf hardware. In addition, streamline simulation identifies fluid flow paths between sinks and sources. This visual and quantifiable information allows geoscientists to examine model connectivity, as well as drainage and irrigation zones associated with producers and injectors. Also, it helps reservoir engineers analyze streamline migrations and predict targets for efficient drilling. -- The Pollock's method generally is used for an orthogonal grid cell, however in reality most of the reservoirs near wellbore do not adjust in Cartesian modeling shape. Thus, the next advancement in this research explored ways to find stream path lines according to the Pollock method but with assuming Polar coordinates instead of Cartesian coordinates, when wells' location is in the center of the rings and all streamlines come from different directions and collect in the center of the circle. -- My contribution in this study includes the MATLAB implementation of the following steps: -- ● Developing specific finite difference grid blocks according to given reservoir parameters -- ● Implementing numerical pressure solvers in both Cartesian and Polar coordinates -- ● Finding time of flight for streamline movement in grid blocks according to published methods -- ● Visualizing streamlines in 2D by finding streamline entrance and exit points in each grid cell and connecting all points by line segments. -- Most of the mathematical formulations are taken from available literature and other documents. This methodology is demonstrated through the use of three case studies for both Cartesian and polar coordinates. The research includes two main topics: Streamline simulation in Cartesian and Polar coordinates. Each topic has two main parts: -- ● Theoretical part; in this part, all numerical and mathematical modeling is described, using finite difference methods for pressure solving. -- ● MATLAB code programming; in this part, a MATLAB program is written according to theoretical equations. -- The MATLAB code is included in an appendix. This MATLAB code can visualize all streamlines with different boundary conditions, various process and geological factors in different reservoir areas. The graphs which are resulted from this numerical method can provide valuable information for engineers to have better understanding of fluid flow in the reservoir. -- Regarding research novelty, streamline simulation in near well bore regions using radial geometry has not been done before. Numerical methods are effective tools to optimize time and costs in oil and gas projects and reduce uncertainties. -- Finally this research has significant potential applications in the future to improve fluid flow modeling near well bores. The numerical method discussed in this study can be extended to three dimensional coordinates. In this study fluid has been assumed to be incompressible. The method can be used with compressible fluids in future, which is closer to reality.

Actions (login required)

View Item