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Dissertation/Thesis Abstract

A Closed Loop Control System for Pressure and Flow Detection Using a Vibrating String Transducer
by Ehigiator, Oziengbe Junior, M.S., University of Louisiana at Lafayette, 2015, 123; 1592980
Abstract (Summary)

The importance of safety in the oil and gas industry cannot be over-emphasized, hence the need for adequate and efficient measures to ensure the safety of personnel and equipment’s on a drilling rig. The ability to detect abnormal pressure buildup and early small size kicks is vital to the overall safety of the drilling process. A theoretical circuit is designed that detects abnormal pressure buildup by monitoring the return flow pressure and flow, using a vibrating string transducer and a stepper motor for automating a drilling choke manifold for the application of surface back pressure on the well. The measuring device is placed on the mud return flow line acts under variable stress, such that a change in the wire’s tension caused by an abnormal increase in pressure (which could result in a kick) or an abnormal decrease in pressure (which could result in a loss of circulation scenario) or flow causes a corresponding change in frequency of vibration of the wire from its natural resonant frequency, which is read of a vibration measuring instrument. Simulations are carried out by varying the force of the fluid flow in the return flow line, and monitoring the changes in vibrating frequency of the wire. Various scenarios are created by varying the length of the vibrating wire to observe its impact on the sensitivity of the instrument. The stepper motor receives signals based on the degree of vibrating frequency obtained from the output of the frequency meter and a digital computer. A drilling choke manifold is automated by receiving instructions from the stepper motor, which is controlled by a programmable logic controller (PLC). It rapidly changes the pressure situations in the well in the case of a kick or loss of circulation of mud by quickly applying backpressure on the kick zone.

Indexing (document details)
Advisor: Hayatdavoudi, Asadollah
Commitee: Boukadi, Fathi, Madani, Mohammad
School: University of Louisiana at Lafayette
Department: Petroleum Engineering
School Location: United States -- Louisiana
Source: MAI 54/06M(E), Masters Abstracts International
Subjects: Petroleum engineering
Keywords: Closed loop control system, Managed pressure drilling, Pressure detection, Rotating control device, Stepper motor, Vibrating string transducer
Publication Number: 1592980
ISBN: 978-1-321-88998-7
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