Doctoral Dissertations

Keywords and Phrases

Data analysis; Drilling; Drill stem vibration; Optimization

Abstract

"Drill stem vibration is a major cause of premature failure of drill stem components and drilling inefficiency. In severe cases, drill stem vibration may lead to wellbore instability that could lead to increased operational cost. Drill stem vibrations are affected by design decisions and the drilling environment. Examples are; bottom hole assembly configurations, selection of operational parameters, and frequent changes in lithology. Vibration modeling, analysis of vibration data, and specialized vibration reduction tools are methods in use to prevent and mitigate severe vibrations.

A drill stem vibration model was created using nonlinear strain formulation which couples the axial, lateral and torsional vibration of the entire drill stem. The model includes the effect of geometric stiffening arising from the applied axial load, two new developed vibration reduction tools used to reduce drill stem vibrations and fluid flow inside and outside the drill stem taking into account two different fluid rheological models. The obtained equation of motion was assembled using the finite element analysis which was solved numerically in Matlab®.

The sensitivity analysis using Euler-Bernoulli and Timoshenko models, showed that the Euler-Bernoulli assumption is satisfactory when modeling drill stem vibrations at typical drilling conditions. Analyzing three adjacent wells in the North Sea with different bottom hole assembly and recorded vibration data, revealed that including drill stem vibration reduction tools reduces drill stem vibration and decreases stick-slip tendency. Including drilling fluid circulation, by imposing dynamic pressures on the inside and outside of the drill stem, affect lateral natural frequencies. High flow rate and wrong selection of total flow area at the drill bit could lead to vibrations"--Abstract, page iii.

Advisor(s)

Nygaard, Runar

Committee Member(s)

Bai, Baojun
Dunn-Norman, Shari
Wei, Mingzhen
Stutts, Daniel S.

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

Ph. D. in Petroleum Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Fall 2015

Pagination

xvi, 146 pages

Note about bibliography

Includes bibliographic references (pages 140-145).

Geographic Coverage

North Sea

Rights

© 2015 Mohammed Fayez Al Dushaishi, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

Drill stem -- Vibration -- Mathematical modelsDrill stem testing -- North SeaBoring

Thesis Number

T 10812

Electronic OCLC #

936205197

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