【论文题目】Well control procedures for extended reach wells
【论文作者】BJORN GJORV
【院校】 Texas A&M University
【时间】 August 2003
【内容简介】 The limits of directional drilling continue to be pushed back as horizontal or near-horizontal reservoir sections are being drilled, cased, cemented and completed to tap reserves at extreme distances. Continuous development of new technology and adopting a technical-limit approach to performance delivery are key elements for the success and further development of extended-reach drilling projects. For this study a two-phase well control simulator was used to evaluate different kick scenarios that are likely to occur in extended-reach wells. An extensive simulation study covering a vide range of variables has been performed. Based on this investigation together with a literature review, well-control procedures have been developed for extended-reach wells. The most important procedures are as follows: Perform a "hard" shut-in when a kick is detected and confirmed. Record the pressures and pit gain, and start to circulate immediately using the Driller's Method. Start circulating with a high kill rate to remove the gas from the horizontal section. Slow down the kill circulation rate to 1/2 to 1/3 of normal drilling rate when the choke pressure starts to increase rapidly. The simulator has been used to validate the procedures.
【目录】
ABSTRACT ..................................................................................................................... iii
DEDICATION.................................................................................................................. iv
ACKNOWLEDGMENTS................................................................................................. v
TABLE OF CONTENTS ................................................................................................. vi
LIST OF TABLES............................................................................................................ ix
LIST OF FIGURES........................................................................................................... x
INTRODUCTION............................................................................................................. 1
Introduction to Extended Reach Drilling (ERD)............................................................ 1
BP's Wytch Farm oilfield ............................................................................................... 2
Well-control challenges in ERD wells ........................................................................... 3
Simulating wellbore pressures during a kill procedure .................................................. 5
WELL CONTROL METHODS........................................................................................ 6
Introduction .................................................................................................................... 6
Kick causes ..................................................................................................................... 7
Kick detection and verification....................................................................................... 9
Shut-in procedures ........................................................................................................ 10
Circulation kill techniques and procedures .................................................................. 11
OBJECTIVES AND PROCEDURES............................................................................. 13
Research objectives ...................................................................................................... 13
Procedures .................................................................................................................... 13
TWO-PHASE WELL CONTROL SIMULATOR.......................................................... 14
Description of the simulator ......................................................................................... 14
Simulator input ............................................................................................................. 14
Simulator output ........................................................................................................... 16
Simulation procedures .................................................................................................. 18
SIMULATION RESULTS FOR THE EXTENDED REACH WELLS ......................... 19
Effect of varying kick sizes and true vertical depth ..................................................... 19
Introduction ................................................................................................................ 19
Discussion of the results............................................................................................. 19
Effect of varying water depth and kick size ................................................................. 21
Introduction ................................................................................................................ 21
Discussion of the results............................................................................................. 22
Effect of varying kick sizes and circulation rates for different hole sizes.................... 24
Introduction ................................................................................................................ 24
Discussion of the results............................................................................................. 25
Effect of varying kick intensity for different water depths .......................................... 30
Introduction ................................................................................................................ 30
Discussion of the results............................................................................................. 31
GAS REMOVAL IN HIGHLY INCLINED AND HORIZONTAL WELLBORES...... 32
Introduction .................................................................................................................. 32
Recommendations for gas removal in ERD wells........................................................ 32
SUMMARY, CONCLUSIONS AND RECOMMENDATIONS ................................... 34
Introduction .................................................................................................................. 34
Effect of kick size......................................................................................................... 34
Effect of water depth .................................................................................................... 34
Effect of circulation kill rate......................................................................................... 35
Effect of hole size......................................................................................................... 35
Effect of kick intensity ................................................................................................. 35
Recommendations for well control procedures in ERD wells ..................................... 35
Recommendations for future work ............................................................................... 36
NOMENCLATURE........................................................................................................ 37
REFERENCES................................................................................................................ 38
APPENDIX A: PLANNING A KILL............................................................................. 42
APPENDIX B: WELL CONTROL COMPLICATIONS ............................................... 46
APPENDIX C: CONVERSION OF ANNULAR VELOCITY TO FLOW RATE ....... 50
VITA............................................................................................................................... 51
