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Real Time Torque and Drag Analysis During Directional Drilling

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Real Time Torque and Drag Analysis During Directional Drilling University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2013-03-06 Real Time Torque and Drag Analysis during Directional Drilling Fazaelizadeh, Mohammad Fazaelizadeh, M. (2013). Real Time Torque and Drag Analysis during Directional Drilling (Unpublished doctoral thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/27551 http://hdl.handle.net/11023/564 doctoral thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Real Time Torque and Drag Analysis during Directional Drilling by Mohammad Fazaelizadeh A THESIS SUBMITTED TO FACUALTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF CHEMICAL AND PETROLEUM ENGINEERING CALGARY, ALBERTA March, 2013 © Mohammad Fazaelizadeh 2013 Abstract The oil industry is generally producing oil and gas using the most cost-effective solutions. Directional drilling technology plays an important role especially because the horizontal wells have increased oil production more than twofold during recent years. The wellbore friction, torque and drag, between drill string and the wellbore wall is the most critical issue which limits the drilling industry to go beyond a certain measured depth. Surface torque is defined as the moment required rotating the entire drill string and the bit on the bottom of the hole. This moment is used to overcome the rotational friction against the wellbore, viscous force between pipe string and drilling fluid as well as bit torque. Also, the drag is the parasitic force acting against drill string movement to pull or lower the drill string through the hole. The drill string friction modeling is considered an important assessment to aid real time drilling analysis for mitigating drilling troubles such as tight holes, poor hole conditions, onset of pipe sticking, etc. In directional drilling operations, the surface measurement of weight on bit and torque differs from downhole bit measurement due to friction between the drill string and wellbore. This difference between surface and downhole measurements can be used to compute rotating and sliding friction coefficients from torque and hook load values respectively. These friction coefficients are used as indicators for real time drilling analysis. To do this analysis, analytical and finite element approaches were used to develop practical models for torque and drag calculations for any well geometry. The reason why two different approaches were used to develop torque and drag models is that the drill string was assumed to be soft string in the analytical approach which has full contact with the wellbore. In the finite element approach, the effect of drill string stiffness was included in the model and the drill string does not have full contact with the wellbore. Also, a new method for effective weight on the bit estimation was developed using wellbore friction model. The new method only utilizes the available surface measurements such as hook load, stand pipe pressure and surface rotation. Using the new method will eliminate the cost of downhole measurements tools and increase drilling rate of penetration by applying sufficient weight on the bit. In this research, different effects which have great contributions on torque and drag values were investigated precisely. These effects include buoyancy, contact surface due to curve surface area, ii hydrodynamic viscous force, buckling, hydraulic vibrations, adjusted unit weight and sheave efficiency. Finally, some field examples from offshore and onshore wells were selected for model validation and verification. The field data include hook load and surface torque for different operations such as drilling, tripping in/out and reaming/back reaming. iii Acknowledgments I would like to express my appreciation to Dr. Geir Hareland for his supervision, advice, and guidance from the beginning of my study as well as giving me valuable experiences all the way through my research work, with his endurance and knowledge, while allowing me the opportunity to work independently. I wish to thank Dr. Bernt Aadnoy, University of Stavanger, and Dr. Zebing (Andrew) Wu, University of Calgary, for their help and contributions during the development of analytical and finite element method modeling. My gratitude also extends to Dr. Raj Mehta, Dr. Gordon Moore, Dr. Larry Lines and Dr. Mesfin Belayeneh for serving on my examination committee. I would thank Dr. Mazeda Tahmeen and Mohammad Moshirpour for programming and software development as well as Benyamin Yadali and Patricia Teicheob for editing and proofreading of my thesis. I am really thankful of Department of Chemical and Petroleum Engineering, University of Calgary for the giving me the chance to pursue my studies in the Doctor of Philosophy program. Finally, I would like to thank my family, particularly my wife, Mahdieh Salmasi, for their constant support and inspiration throughout my entire studies. iv Table of Contents Abstract ...................................................................................................................................................................... ii Acknowledgments ................................................................................................................................................. iv Table of Contents .................................................................................................................................................... v List of Tables ........................................................................................................................................................ viii List of Figures ......................................................................................................................................................... ix Nomenclature ......................................................................................................................................................... xii CHAPTER ONE: INTRODUCTION ............................................................................................................... 1 CHAPTER TWO: LITERATURE REVIEW ................................................................................................. 5 2.1 Analytical Modeling ............................................................................................................. 5 2.2 Finite Element Modeling .................................................................................................... 13 CHAPTER THREE: TECHNICAL APPROACH – ANALYTICAL ................................................. 18 3.1 Buoyancy Factor ................................................................................................................. 18 3.2 Straight Sections Modeling ................................................................................................. 19 3.3 Curved Sections Modeling .................................................................................................. 23 3.5 Combined Axial Motion and Rotation ................................................................................ 33 3.5 Application of the New Model ........................................................................................... 38 3.5.1 Case A: Analysis of a Two Dimensional S-shaped Well ............................................. 38 3.5.2 Case B: Analysis of a 3-dimensional Well .................................................................. 45 3.5.3 Case C: Combined Motion in 3-dimensional Well ..................................................... 46 CHAPTER FOUR: TECHNICAL APPROACH- FINITE ELEMENT .............................................. 49 4.1 Hamilton’s Principle ........................................................................................................... 50 4.2 Shape Function.................................................................................................................... 50 4.3 The Dynamic Equations ...................................................................................................... 51 4.4 The Mass Matrix ................................................................................................................. 52 4.5 The Stiffness Matrix ........................................................................................................... 54 4.6 The Damping Matrix........................................................................................................... 57 4.7 Force Vector........................................................................................................................ 58 4.8 Transform Matrix ................................................................................................................ 60 4.9 Global Matrix ...................................................................................................................... 62 4.10 Boundary Conditions ........................................................................................................ 63 4.11 Solution Method...............................................................................................................
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