The fluid dynamical interaction of oil (and gas) reservoir with a wellbore which occurs usually in the near wellbore zone has been studied in this thesis. Such interactions dictate whether narrow tunnels between a wellbore and a reservoir would be constructed through a “shooting method” or a “drilling method”, and how to mitigate the impact of forma- tion damage. A relatively small improvement in fracturing or drilling technology may introduce an order of magnitude economic benefit in the petroleum industry. The thesis contributed toward the development of a modeling approach in which a coupled system of “wellbore and reservoir” can be simulated through either a scaled model of physical exper- iment or a numerical model through Computational Fluid Dynamics (CFD). Through this PhD project, laboratory experiments, field measurements, and numerical simulations have been combined to develop a CFD methodology to illustrate some aspects of fluid dynamics,
which are among primary concerns in the oil and gas industries. The newly developed ex- perimental setup has the capability to perform the investigation of the flow characteristics with a higher scale of parameters such as dimensions of the core sample compared to others setup, for example, Rahman et al. (2007c). A core sample is innovated in the laboratory for this study which has a higher permeability with high strength. The radially convergent and divergent flow facility of the device leads to perform more research in this research area. 3D NSE is applied to understand the fluid dynamics of at the near wellbore and reser- voir. An efficient CFD methodology is developed to solve the system of linear equations in a coupled manner for the flow through porous media. An Algebraic Multigrid solver is applied to accelerate the solution. Furthermore, an integrated wellbore-reservoir coupling approach with skin zone is applied to study nonlinear flow behavior of flow from the reser- voir to the wellbore. Finally, Allen-Cahn phase-field methodology is used to model surface force for the flow through porous media. Best of the author knowledge, the implementa- tion of the phase-field method for the flow through porous media is new. In this study, an optimal wavelet method is used for the solution technique.
1.8
Organization of the thesis
The research focused on this dissertation is organized as follows. Chapter 1 describes the motivation, background, challenges, and research opportunity of the present project in this field. The contributions of the different authors in published and submitted papers of this research project are given in chapter 1 with the details. The experimental prototype development to study near-wellbore phenomena and formation damages are described step- by-step in chapter 2 with the validation tests. The experimental facilities help to get the idea of a real situation of a problem although it has some limitations such as the parameters of interest cannot be changed as frequently as desired. The CFD investigation can help more
in this regard. In chapter 3, near-wellbore phenomena of a reservoir are described with 3D Navier-Stokes equations. A CFD algorithm based on a coupled solver is implemented with an algebraic multigrid technique for the simulations. The modeling of wellbore-reservoir coupling is described in chapter 4. The CFD algorithm developed in the previous chapter is used here and interface modeling for reservoir and wellbore boundary is also implemented. The different reservoir formations and skin zones are considered, and flow performance is analyzed in this chapter. Next, in chapter 5, we study fluid flows through a perforation tunnel to investigate formation damages. Perforation by drilling is introduced here as a new technique and its benefit is studied for the different conditions. In chapter 6, the two- phase flow through porous media is studied using the Navier-Stokes equations combining with a phase-field method. A wavelet-based phase-field method is used for the numerical simulations. This method will continue to provide insight understanding of multiphase flow in porous media. Finally, conclusions are drawn and perspectives on future work are discussed in chapter 7.
Design of an experimental setup to
characterise the flow phenomena at the
near-wellbore region
Title of the article: An experimental development to charac-
terise the flow phenomena at the near-wellbore region
Authors: M J alal Ahammad1, M ohammad Azizur Rahman2, Stephen D Butt3, J ahrul M Alam4.
Corresponding author:Mohammad Azizur Rahman; email: [email protected] T he 38th International Conf erence on Ocean, Of f shore and Arctic Engineering,
Glasgow, Scotland, U K, 9 − 14 J une 2019, ASM E. (Accepted f or presentation and publication).
Abstract:
The understanding of rock characteristic and fluid flow behavior at the near- wellbore region is an important topic. Triaxial experiment setup can help to investigate these properties. In this research, a new triaxial experimental setup has been developed where the higher scale of the parameters such as higher reservoir pressure, and compara- tively larger core sample can be used. High permeable synthetic porous samples are pre- pared to validate the device. The new triaxial experimental setup is validated with water as a base fluid. In the validation test, real samples and synthetic samples are used. First, flow in convergent direction is studied which represents as production at the in-situ condition. Then, the flow in divergent direction is examined that may represent the injection of fluid to enhance the hydrocarbon production. The near-wellbore flow phenomena are studied with real and synthetic samples. The results indicate that using this triaxial setup pressure drop and pressure buildup test can be explained. The new experimental setup is able to reduce the scale-up gap between laboratory data and field data to get actual reservoir flow phenomena.1Mathematics and Statistics, Memorial University, Canada, A1C 5S7 2Petroleum Engineering, Texas A& M University, Qatar
3Process Engineering, Memorial University, Canada, A1C 5S7 4Mathematics and Statistics, Memorial University, Canada, A1C 5S7
Keywords: Radial flow cell, permeability, high permeable synthetic sample, near-wellbore region, formation damage.