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Title: Annular flow of Herschel-Bulkley non-Newtonian fluids and mathematical modelling of efficient hole cleaning at various hole angles
Author: Gao, Erhu
ISNI:       0000 0004 2741 0026
Awarding Body: Heriot-Watt University
Current Institution: Heriot-Watt University
Date of Award: 1994
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The work detailed in this thesis has formed a major part of an industry sponsored project entitled "Drilled Cuttings Transport in Deviated Wells" in the Department of Petroleum Engineering, Heriot-Watt University. The contributions by the author to the project form the basis of this thesis, which includes both the theoretical and experimental investigations into drilled cuttings transport at various hole angles. It is composed of the following major areas: [1] Annular flow of Herschel-Bulkley t1uids: The various flow equations including the fluid velocity profile, viscosity profile, shear stress/shear rate profile for fluid flow of Herschel-Bulkley fluids through concentric annuli without pipe rotation were derived and numerically solved by the author. [2] Theoretical modelling of the minimum transport velocity (MTV) required for adequate cuttings transport in deviated wells: Two classic concepts - fluid drag force and fluid lift force were successfully used to model the complicated cuttings transport process. Two MTV models were developed by the author for cuttings removal in concentric annuli without pipe rotation. One is the MTV model for cuttings rolling and the other is the MTV model for cuttings suspension. [3] Development of a new model for cuttings settling velocity in dynamic non- Newtonian drilling fluids: A new technique was proposed by the author to derive the cuttings settling velocity in dynamic non-Newtonian fluids based on the measured MTV for vertical hole cleaning. The cuttings settling velocity data were then used for the development of a new model for cuttings settling velocity at dynamic flow conditions. As well as the predictions of cuttings settling velocity profile and cuttings transport velocity profile across the annulus, this model was also used for the predictions of the MTV for vertical hole cleaning in concentric annuli without pipe rotation.[4] Cuttings transport/Annular now experiments: The author contributed to the design and the implementation of an extensive experimental programme to investigate cuttings transport at various hole angles. The experiments were designed to provide the data base required for the development and validation of the MTV models by the author. Annular flow experiments were also designed and conducted to validate the various annular flow equations derived by the author. [5] Extension of the MTV models: A new method was devised by the author so that the MTV models were able to be extended from concentric annuli without pipe rotation into concentric annuli with pipe rotation and eccentric annuli with/without pipe rotation using the annular flow modelling by Larrucia'f?'. The effect of drill pipe orbital motion on the MTV, which was from the team work(88), was also incorporated into the MTV models. [6] The development of the MTV package: The author has developed all the source codes for the development of a new MTV package for hole cleaning design and analysis and has also supervised the detailed development of the package. [7] Field guidelines: Field guidelines on how to improve drilled cuttings transport in actual drilling operations were developed by the author based on both the theoretical modelling and the experimental results.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available