Vertical seismic profiling in deviated wells : a study of the signal processing considerations when determining travel times and velocity anisotropy estimates from a vertical incidence and walkaway survey conducted in a deviated production well
Thesis (M.Sc.)--Memorial University of Newfoundland, 2008. Earth Science Includes bibliographical references (leaves 115-118) Travel times are essential for processing and velocity determination from VSP surveys. Even though many wells drilled today are deviated from vertical, there is very limited...
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ftmemorialunivdc:oai:collections.mun.ca:theses4/176746 2023-05-15T17:23:34+02:00 Vertical seismic profiling in deviated wells : a study of the signal processing considerations when determining travel times and velocity anisotropy estimates from a vertical incidence and walkaway survey conducted in a deviated production well McCallum, David Skye, 1973- Memorial University of Newfoundland. Dept. of Earth Science 2008 xvi, 136 leaves : ill. (some col.) Image/jpeg; Application/pdf http://collections.mun.ca/cdm/ref/collection/theses4/id/176746 Eng eng Electronic Theses and Dissertations (18.42 MB) -- http://collections.mun.ca/PDFs/theses/McCallum_DavidS.pdf a2544077 http://collections.mun.ca/cdm/ref/collection/theses4/id/176746 The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries Seismic traveltime inversion Vertical seismic profiling Text Electronic thesis or dissertation 2008 ftmemorialunivdc 2015-08-06T19:22:48Z Thesis (M.Sc.)--Memorial University of Newfoundland, 2008. Earth Science Includes bibliographical references (leaves 115-118) Travel times are essential for processing and velocity determination from VSP surveys. Even though many wells drilled today are deviated from vertical, there is very limited geophysical literature on the effects of well deviation on travel time measurements and processing issues when a VSP is conducted in a deviated well. An investigation of the processing considerations associated with acquiring precise travel times from a vertical incidence and walkaway survey conducted in a deviated well was carried out. Compensation for well deviation by rotating the vertical component in-line with the downgoing P-wave particle motion for each source-receiver pair of the vertical incident survey had a negligible effect on acquired travel times. Rotation of the vertical component in-line with the downgoing P-wave particle motion for each source-receiver pair of the walkaway survey proved to follow conventional practice and the deviation of the well was not an issue. -- The issue of well deviation when acquiring travel times from VSP surveys conducted in deviated wells is a concern when characterizing a reservoir by determining aspects like anisotropic characteristics of a specific rock layer. Using the travel times acquired from both the vertical incidence and walkaway surveys, it is demonstrated, by producing a percent velocity anisotropy estimate of 17.1% for a marine shale, that the travel time-inversion method is well suited for a deviated well setting. This estimate is appropriate when compared to published values and to an independent estimate of 17.9% obtained by modifying the phase-slowness method using the same assumptions that govern the travel time-inversion method. Modifying the phase-slowness method also made it operationally less intense. In general, with the application of reasonable assumptions, velocity anisotropy measurements can be obtained within a deviated well without rigorous computational adjustments. Thesis Newfoundland studies University of Newfoundland Memorial University of Newfoundland: Digital Archives Initiative (DAI) |
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Open Polar |
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Memorial University of Newfoundland: Digital Archives Initiative (DAI) |
op_collection_id |
ftmemorialunivdc |
language |
English |
topic |
Seismic traveltime inversion Vertical seismic profiling |
spellingShingle |
Seismic traveltime inversion Vertical seismic profiling McCallum, David Skye, 1973- Vertical seismic profiling in deviated wells : a study of the signal processing considerations when determining travel times and velocity anisotropy estimates from a vertical incidence and walkaway survey conducted in a deviated production well |
topic_facet |
Seismic traveltime inversion Vertical seismic profiling |
description |
Thesis (M.Sc.)--Memorial University of Newfoundland, 2008. Earth Science Includes bibliographical references (leaves 115-118) Travel times are essential for processing and velocity determination from VSP surveys. Even though many wells drilled today are deviated from vertical, there is very limited geophysical literature on the effects of well deviation on travel time measurements and processing issues when a VSP is conducted in a deviated well. An investigation of the processing considerations associated with acquiring precise travel times from a vertical incidence and walkaway survey conducted in a deviated well was carried out. Compensation for well deviation by rotating the vertical component in-line with the downgoing P-wave particle motion for each source-receiver pair of the vertical incident survey had a negligible effect on acquired travel times. Rotation of the vertical component in-line with the downgoing P-wave particle motion for each source-receiver pair of the walkaway survey proved to follow conventional practice and the deviation of the well was not an issue. -- The issue of well deviation when acquiring travel times from VSP surveys conducted in deviated wells is a concern when characterizing a reservoir by determining aspects like anisotropic characteristics of a specific rock layer. Using the travel times acquired from both the vertical incidence and walkaway surveys, it is demonstrated, by producing a percent velocity anisotropy estimate of 17.1% for a marine shale, that the travel time-inversion method is well suited for a deviated well setting. This estimate is appropriate when compared to published values and to an independent estimate of 17.9% obtained by modifying the phase-slowness method using the same assumptions that govern the travel time-inversion method. Modifying the phase-slowness method also made it operationally less intense. In general, with the application of reasonable assumptions, velocity anisotropy measurements can be obtained within a deviated well without rigorous computational adjustments. |
author2 |
Memorial University of Newfoundland. Dept. of Earth Science |
format |
Thesis |
author |
McCallum, David Skye, 1973- |
author_facet |
McCallum, David Skye, 1973- |
author_sort |
McCallum, David Skye, 1973- |
title |
Vertical seismic profiling in deviated wells : a study of the signal processing considerations when determining travel times and velocity anisotropy estimates from a vertical incidence and walkaway survey conducted in a deviated production well |
title_short |
Vertical seismic profiling in deviated wells : a study of the signal processing considerations when determining travel times and velocity anisotropy estimates from a vertical incidence and walkaway survey conducted in a deviated production well |
title_full |
Vertical seismic profiling in deviated wells : a study of the signal processing considerations when determining travel times and velocity anisotropy estimates from a vertical incidence and walkaway survey conducted in a deviated production well |
title_fullStr |
Vertical seismic profiling in deviated wells : a study of the signal processing considerations when determining travel times and velocity anisotropy estimates from a vertical incidence and walkaway survey conducted in a deviated production well |
title_full_unstemmed |
Vertical seismic profiling in deviated wells : a study of the signal processing considerations when determining travel times and velocity anisotropy estimates from a vertical incidence and walkaway survey conducted in a deviated production well |
title_sort |
vertical seismic profiling in deviated wells : a study of the signal processing considerations when determining travel times and velocity anisotropy estimates from a vertical incidence and walkaway survey conducted in a deviated production well |
publishDate |
2008 |
url |
http://collections.mun.ca/cdm/ref/collection/theses4/id/176746 |
genre |
Newfoundland studies University of Newfoundland |
genre_facet |
Newfoundland studies University of Newfoundland |
op_source |
Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries |
op_relation |
Electronic Theses and Dissertations (18.42 MB) -- http://collections.mun.ca/PDFs/theses/McCallum_DavidS.pdf a2544077 http://collections.mun.ca/cdm/ref/collection/theses4/id/176746 |
op_rights |
The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. |
_version_ |
1766113357156319232 |