Wellbore pressure prediction after pipe connection operation in underbalanced drilling

In underbalanced drilling (UBD), bottom hole pressure (BHP) must be maintained in the defined limit. Maintaining underbalanced drilling conditions after pipe connection operation is required for the success of underbalanced drilling operations. Modeling and simulation of gas-liquid two phase flow in...

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Main Author:	Kootiani, Reza Cheraghi
Format:	Thesis
Language:	English
Published:	2015
Subjects:	TP Chemical technology
Online Access:	http://eprints.utm.my/id/eprint/54684/1/RezaCheraghiKootianiPFChE2015.pdf
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spelling	my-utm-ep.546842020-11-03T08:09:37Z Wellbore pressure prediction after pipe connection operation in underbalanced drilling 2015-11 Kootiani, Reza Cheraghi TP Chemical technology In underbalanced drilling (UBD), bottom hole pressure (BHP) must be maintained in the defined limit. Maintaining underbalanced drilling conditions after pipe connection operation is required for the success of underbalanced drilling operations. Modeling and simulation of gas-liquid two phase flow in an UBD operation is very significant in order to accurately predict the wellbore pressure and other parameters of two phase flow. After pipe connection operation in UBD, upon restarting mud circulation system, frictional pressure influenced the BHP and the fluid slugs in the drill string are transferred into the annulus. Therefore, the hydrostatic pressure will increase and UBD pipe connection operations create a BHP vibration, which is a critical point. This particular time can reduce the benefits obtained to drill the well in an underbalanced environment. In this study, a mechanistic steady state gas-liquid two phase flow model was used to simulate the two phase flow after pipe connection operation in UBD. Simulation was carried out to predict the parameters; such as wellbore pressure, liquid holdup, and velocities of the two phases at different flow patterns, namely slug, bubble, churn, dispersed bubble, and annular flow. In order to predict wellbore pressure, a steady state model was developed to predict flow patterns, pressure gradient, and liquid holdup for gasliquid flow in vertical annulus and drill string. The model included flow pattern transition models and hydrodynamic models for individual flow pattern. The model equations along with appropriate constitutive relations formed a system of coupled drift flux, momentum, and energy equations, which were solved using the well known iterative Newton Raphson method. All model equations were implemented in a computer program named Fortran 95. The effect of gas and liquid flow rates, and choke pressure on the wellbore pressure, particularly in the BHP was evaluated numerically. In order to validate the results of the developed model, they were compared with actual field data and the results of the WELLFLO software using different mechanistic models. The results revealed that the two phase model developed can accurately predict wellbore pressure, particularly BHP, wellbore temperature, gas/liquid velocities, and two phase flow patterns. 2015-11 Thesis http://eprints.utm.my/id/eprint/54684/ http://eprints.utm.my/id/eprint/54684/1/RezaCheraghiKootianiPFChE2015.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:94672 phd doctoral Universiti Teknologi Malaysia, Faculty of Chemical Engineering Faculty of Chemical Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TP Chemical technology
spellingShingle	TP Chemical technology Kootiani, Reza Cheraghi Wellbore pressure prediction after pipe connection operation in underbalanced drilling
description	In underbalanced drilling (UBD), bottom hole pressure (BHP) must be maintained in the defined limit. Maintaining underbalanced drilling conditions after pipe connection operation is required for the success of underbalanced drilling operations. Modeling and simulation of gas-liquid two phase flow in an UBD operation is very significant in order to accurately predict the wellbore pressure and other parameters of two phase flow. After pipe connection operation in UBD, upon restarting mud circulation system, frictional pressure influenced the BHP and the fluid slugs in the drill string are transferred into the annulus. Therefore, the hydrostatic pressure will increase and UBD pipe connection operations create a BHP vibration, which is a critical point. This particular time can reduce the benefits obtained to drill the well in an underbalanced environment. In this study, a mechanistic steady state gas-liquid two phase flow model was used to simulate the two phase flow after pipe connection operation in UBD. Simulation was carried out to predict the parameters; such as wellbore pressure, liquid holdup, and velocities of the two phases at different flow patterns, namely slug, bubble, churn, dispersed bubble, and annular flow. In order to predict wellbore pressure, a steady state model was developed to predict flow patterns, pressure gradient, and liquid holdup for gasliquid flow in vertical annulus and drill string. The model included flow pattern transition models and hydrodynamic models for individual flow pattern. The model equations along with appropriate constitutive relations formed a system of coupled drift flux, momentum, and energy equations, which were solved using the well known iterative Newton Raphson method. All model equations were implemented in a computer program named Fortran 95. The effect of gas and liquid flow rates, and choke pressure on the wellbore pressure, particularly in the BHP was evaluated numerically. In order to validate the results of the developed model, they were compared with actual field data and the results of the WELLFLO software using different mechanistic models. The results revealed that the two phase model developed can accurately predict wellbore pressure, particularly BHP, wellbore temperature, gas/liquid velocities, and two phase flow patterns.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Kootiani, Reza Cheraghi
author_facet	Kootiani, Reza Cheraghi
author_sort	Kootiani, Reza Cheraghi
title	Wellbore pressure prediction after pipe connection operation in underbalanced drilling
title_short	Wellbore pressure prediction after pipe connection operation in underbalanced drilling
title_full	Wellbore pressure prediction after pipe connection operation in underbalanced drilling
title_fullStr	Wellbore pressure prediction after pipe connection operation in underbalanced drilling
title_full_unstemmed	Wellbore pressure prediction after pipe connection operation in underbalanced drilling
title_sort	wellbore pressure prediction after pipe connection operation in underbalanced drilling
granting_institution	Universiti Teknologi Malaysia, Faculty of Chemical Engineering
granting_department	Faculty of Chemical Engineering
publishDate	2015
url	http://eprints.utm.my/id/eprint/54684/1/RezaCheraghiKootianiPFChE2015.pdf
_version_	1747817702402031616

Wellbore pressure prediction after pipe connection operation in underbalanced drilling

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