The development of a new sonic correlation for UCS estimation from drilling data

One of the most important characteristics of rocks in drilling operations is unconfined rock strength (UCS), which is critical in different aspects of drilling operations. Several laboratory-based correlations have been generated for specific rocks to estimate UCS from physical properties (such as t...

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Main Authors: Mostofi, Masood, Rahimzadeh, H., Shahbazi, K.
Format: Journal Article
Published: 2011
Online Access:http://hdl.handle.net/20.500.11937/42250
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author Mostofi, Masood
Rahimzadeh, H.
Shahbazi, K.
author_facet Mostofi, Masood
Rahimzadeh, H.
Shahbazi, K.
author_sort Mostofi, Masood
building Curtin Institutional Repository
collection Online Access
description One of the most important characteristics of rocks in drilling operations is unconfined rock strength (UCS), which is critical in different aspects of drilling operations. Several laboratory-based correlations have been generated for specific rocks to estimate UCS from physical properties (such as transient time, porosity, and Young's modulus) of the rocks. In drilling analysis, when UCS information is required and direct methods for estimation of UCS are not available, it is common to use correlations that have been developed for other formations with the same or similar lithology. Obviously, the results of estimations based on UCS correlations for other formations will not be accurate and can affect subsequent analyses. Therefore, it is highly recommended to generate a correlation for the formation of interest, though it is not always possible to reach this goal from experimental works on core samples retrieved from the formation. In this study, a sonic correlation that shows that it can provide relatively better global estimation of UCS for limestone rocks is modified for one of the Iranian carbonate formations by determining new coefficients for the correlation based on drilling data. For this purpose, the drilling information recorded in mud logging data is analyzed to backward simulate the drilling process based on a modified penetration rate model and calculate the rock strengths of the formation. The apparent rock strength log generated from this calculation proceeds quality-controlled steps according to statistical and pattern recognition methods to eliminate the noises and fluctuations that normally exist while working with field data. Then, a new correlation is developed from the formation response to sonic logs and apparent rock strength log. Because this new correlation is originally generated for the formation of interest, UCS is estimated more accurately and analyses dependent on UCS show fewer errors. Copyright © Taylor & Francis Group, LLC.
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spelling curtin-20.500.11937-422502017-09-13T14:19:39Z The development of a new sonic correlation for UCS estimation from drilling data Mostofi, Masood Rahimzadeh, H. Shahbazi, K. One of the most important characteristics of rocks in drilling operations is unconfined rock strength (UCS), which is critical in different aspects of drilling operations. Several laboratory-based correlations have been generated for specific rocks to estimate UCS from physical properties (such as transient time, porosity, and Young's modulus) of the rocks. In drilling analysis, when UCS information is required and direct methods for estimation of UCS are not available, it is common to use correlations that have been developed for other formations with the same or similar lithology. Obviously, the results of estimations based on UCS correlations for other formations will not be accurate and can affect subsequent analyses. Therefore, it is highly recommended to generate a correlation for the formation of interest, though it is not always possible to reach this goal from experimental works on core samples retrieved from the formation. In this study, a sonic correlation that shows that it can provide relatively better global estimation of UCS for limestone rocks is modified for one of the Iranian carbonate formations by determining new coefficients for the correlation based on drilling data. For this purpose, the drilling information recorded in mud logging data is analyzed to backward simulate the drilling process based on a modified penetration rate model and calculate the rock strengths of the formation. The apparent rock strength log generated from this calculation proceeds quality-controlled steps according to statistical and pattern recognition methods to eliminate the noises and fluctuations that normally exist while working with field data. Then, a new correlation is developed from the formation response to sonic logs and apparent rock strength log. Because this new correlation is originally generated for the formation of interest, UCS is estimated more accurately and analyses dependent on UCS show fewer errors. Copyright © Taylor & Francis Group, LLC. 2011 Journal Article http://hdl.handle.net/20.500.11937/42250 10.1080/10916460903452025 restricted
spellingShingle Mostofi, Masood
Rahimzadeh, H.
Shahbazi, K.
The development of a new sonic correlation for UCS estimation from drilling data
title The development of a new sonic correlation for UCS estimation from drilling data
title_full The development of a new sonic correlation for UCS estimation from drilling data
title_fullStr The development of a new sonic correlation for UCS estimation from drilling data
title_full_unstemmed The development of a new sonic correlation for UCS estimation from drilling data
title_short The development of a new sonic correlation for UCS estimation from drilling data
title_sort development of a new sonic correlation for ucs estimation from drilling data
url http://hdl.handle.net/20.500.11937/42250