Multi-segment Well Modeling in a Sequential Implicit Coupling Framework

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Abstract/Contents

Abstract
Accurate well modeling becomes essential in the reservoir simulation because more and more complex well operations are employed in the petroleum industry. The prevailed standard well model is proved to be computationally efficient, while it lacks the ability to capture the multiphase flow details within the wellbore. MultiSegment well (MSWell) model was then proposed to approximate the actual physical shape of the well and perform accurate simulation within the wellbore. However, the increasing complexity of the MSwell model also introduced additional difficulties in solving the coupled MSWell and reservoir flow problem. Several nonlinear solver and linear solver techniques were proposed to accelerate the convergence of the MSWell problem, while there isn't a systematic discussion about the convergence and the accuracy of the various proposed techniques. In this work, we discuss the convergence and the accuracy for different coupling strategies for coupled MSWell and reservoir flow problem. First, we introduce the numerical implementation of the MultiSegment well (MSWell) in an in-house simulation Automatic-Differentiation General Purpose Research Simulator (AD-GPRS) under the General Implicit Coupling Framework (GENIC). A consistent normalization technique for MSWell equations is discussed and carefully clarified. In addition, the component-based CFL number and the phase-based CFL number for MSWell equations are introduced, which are coherent with the CFL number defined in the reservoir block. After the clear illustration of the model details, we investigate three different coupling strategies for couple MSWell and reservoir flow problem, which are fully implicit method, sequential fully implicit method and fully implicit method with local facility solver. Numerical examples are constructed to validate the convergence and the accuracy of these three coupling strategies. Then a general discussion about the convergence and accuracy based on CFL number is conducted regarding different time step and grid size (segment length). The numerical results and the theoretical analysis show that the relative nonlinearity between the MSWell equations and the reservoir flow equations is the primary factor affecting the global convergence rate, while the time step will significantly influence the simulation accuracy of the wellbore flow. Thus, we proposed a possible solution to achieve both high accuracy for wellbore flow and global computational efficiency.

Description

Type of resource text
Date created November 2018

Creators/Contributors

Author Li, Jiawei
Primary advisor Tchelepi, Hamdi
Degree granting institution Stanford University, Department of Energy Resources Engineering

Subjects

Subject School of Earth Energy & Environmental Sciences
Subject Energy Resources Engineering
Subject MultiSegment Well
Subject Sequential Implicit Coupling
Genre Thesis

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User agrees that, where applicable, content will not be used to identify or to otherwise infringe the privacy or confidentiality rights of individuals. Content distributed via the Stanford Digital Repository may be subject to additional license and use restrictions applied by the depositor.
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This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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Preferred Citation
Li, Jiawei. (2018). Multi-segment Well Modeling in a Sequential Implicit Coupling Framework. Stanford Digital Repository. Available at: https://purl.stanford.edu/ht722pc2219

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Master's Theses, Doerr School of Sustainability

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