Determination of safe mud weight windows for drilling deviated wellbores: A case study in the North Perth Basin

Drilling non-vertical wells, which is commonly used to enhance production, in particular in unconventional reservoirs with very low permeability, is subjected to rock mechanics related issues namely wellbore instabilities. Drilling in the same formation but with different deviations and at different...

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Bibliographic Details
Main Authors: Le, K., Rasouli, Vamegh
Other Authors: Prof Fuad Khoshnaw
Format: Conference Paper
Published: WITS Press 2012
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/4434
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author Le, K.
Rasouli, Vamegh
author2 Prof Fuad Khoshnaw
author_facet Prof Fuad Khoshnaw
Le, K.
Rasouli, Vamegh
author_sort Le, K.
building Curtin Institutional Repository
collection Online Access
description Drilling non-vertical wells, which is commonly used to enhance production, in particular in unconventional reservoirs with very low permeability, is subjected to rock mechanics related issues namely wellbore instabilities. Drilling in the same formation but with different deviations and at different directions would not result in similar response in terms of rock failures. This is due to the rotation of the induced stresses around the wellbore wall along its trajectory. The type of instabilities that the formation experiences around the wellbore is a function of formation’s mechanical properties and the status of in-situ stresses. It is clear that none of these natural parameters can be controlled or changed during drilling operation. However, the density of the mud weigh which is used to drill the wellbore could be optimised in order to mitigate or stop wellbore instability issues in the form of tensile failure or fracturing in case of using high mud density or shear failure or breakouts when a low mud weigh is used. Therefore, a safe mud weight window (MWW) can be determined for optimum drilling in terms of having the least issues related to wellbore instabilities. This MWW will change as the wellbore deviation changes. In this paper, the concept of constructing the rock mechanical model (RMM) which includes the rock mechanical properties as well as in-situ stress profiles is briefly presented. Then the RMM output corresponding to vertical well Arrowsmith-1 which is a shale gas well drilled in the North Perth Basin of Australia will be used to calculate the safe MWW for drilling wellbores in different azimuth and deviation in the field. The results indicate how the MWW changes as a function of wellbore trajectory.
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spelling curtin-20.500.11937-44342017-09-13T16:01:58Z Determination of safe mud weight windows for drilling deviated wellbores: A case study in the North Perth Basin Le, K. Rasouli, Vamegh Prof Fuad Khoshnaw insitu stresses Arrowsmith-1 breakouts mud weight windows fracturing wellbore instability Drilling non-vertical wells, which is commonly used to enhance production, in particular in unconventional reservoirs with very low permeability, is subjected to rock mechanics related issues namely wellbore instabilities. Drilling in the same formation but with different deviations and at different directions would not result in similar response in terms of rock failures. This is due to the rotation of the induced stresses around the wellbore wall along its trajectory. The type of instabilities that the formation experiences around the wellbore is a function of formation’s mechanical properties and the status of in-situ stresses. It is clear that none of these natural parameters can be controlled or changed during drilling operation. However, the density of the mud weigh which is used to drill the wellbore could be optimised in order to mitigate or stop wellbore instability issues in the form of tensile failure or fracturing in case of using high mud density or shear failure or breakouts when a low mud weigh is used. Therefore, a safe mud weight window (MWW) can be determined for optimum drilling in terms of having the least issues related to wellbore instabilities. This MWW will change as the wellbore deviation changes. In this paper, the concept of constructing the rock mechanical model (RMM) which includes the rock mechanical properties as well as in-situ stress profiles is briefly presented. Then the RMM output corresponding to vertical well Arrowsmith-1 which is a shale gas well drilled in the North Perth Basin of Australia will be used to calculate the safe MWW for drilling wellbores in different azimuth and deviation in the field. The results indicate how the MWW changes as a function of wellbore trajectory. 2012 Conference Paper http://hdl.handle.net/20.500.11937/4434 10.2495/PMR120081 WITS Press unknown
spellingShingle insitu stresses Arrowsmith-1
breakouts
mud weight windows
fracturing
wellbore instability
Le, K.
Rasouli, Vamegh
Determination of safe mud weight windows for drilling deviated wellbores: A case study in the North Perth Basin
title Determination of safe mud weight windows for drilling deviated wellbores: A case study in the North Perth Basin
title_full Determination of safe mud weight windows for drilling deviated wellbores: A case study in the North Perth Basin
title_fullStr Determination of safe mud weight windows for drilling deviated wellbores: A case study in the North Perth Basin
title_full_unstemmed Determination of safe mud weight windows for drilling deviated wellbores: A case study in the North Perth Basin
title_short Determination of safe mud weight windows for drilling deviated wellbores: A case study in the North Perth Basin
title_sort determination of safe mud weight windows for drilling deviated wellbores: a case study in the north perth basin
topic insitu stresses Arrowsmith-1
breakouts
mud weight windows
fracturing
wellbore instability
url http://hdl.handle.net/20.500.11937/4434