Effects Of A Borehole Environment And Residual Hydrocarbon On Stoneley Wave Amplitude And Reflectivity
In recent years, borehole Stoneley wave amplitude and reflectivity have been used for estimating formation permeability based on the strong correlation between Stoneley wave attenuation, reflectivity and formation fluid conductivity. There are other factors, however, that may cause substantial St...
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| Other Authors: | |
| Format: | Technical Report |
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Massachusetts Institute of Technology. Earth Resources Laboratory
2012
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| Online Access: | http://hdl.handle.net/1721.1/75320 |
| _version_ | 1811093529431113728 |
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| author | Tao, Guo Cheng, C. H. |
| author2 | Massachusetts Institute of Technology. Earth Resources Laboratory |
| author_facet | Massachusetts Institute of Technology. Earth Resources Laboratory Tao, Guo Cheng, C. H. |
| author_sort | Tao, Guo |
| collection | MIT |
| description | In recent years, borehole Stoneley wave amplitude and reflectivity have been used for
estimating formation permeability based on the strong correlation between Stoneley
wave attenuation, reflectivity and formation fluid conductivity. There are other factors,
however, that may cause substantial Stoneley attenuation and reflection in a borehole
environment. To make better use of Stoneley measurements for formation permeability
estimation, it is desirable to identify and quantify those causes of Stoneley attenuation
and reflection that do not directly result from formation permeability. In this study,
a simplified Biot-Rosenbaum model developed by Tang et at. (1991) is adopted to systematically model Stoneley attenuation and reflection in various borehole environments
and formation configurations. By changing pore fluid, formation porosity, lithology,
bed boundaries and thickness in the modeling, the sensitivity of Stoneley wave propagation to these conditions are quantitatively assessed. It is found that the presence of a light hydrocarbon in the formation, especially a natural gas residual in the immediate vicinity of the borehole wall, even with only 5% contained in pore fluid, may also cause substantial Stoneley attenuation and reflection. This phenomenon, on the other hand, can be used to evaluate a nonfractured, low permeability gas reservoir when combined with shear wave velocity data. For the full gas-saturated zone, Stoneley wave reflection may be observed even when the permeability is as low as a few milliDarcies. Compared to the effects of pore fluid, the effects due to lithology contrasts at the boundaries and the changes of nonfracture porosity are insignificant in the cases studied here. For a residual gas-bearing zone of moderate permeability, Stoneley wave attenuation and reflection may be observed if the zone is thicker than 0.5 meter. |
| first_indexed | 2024-09-23T15:46:33Z |
| format | Technical Report |
| id | mit-1721.1/75320 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T15:46:33Z |
| publishDate | 2012 |
| publisher | Massachusetts Institute of Technology. Earth Resources Laboratory |
| record_format | dspace |
| spelling | mit-1721.1/753202019-04-10T23:56:53Z Effects Of A Borehole Environment And Residual Hydrocarbon On Stoneley Wave Amplitude And Reflectivity Tao, Guo Cheng, C. H. Massachusetts Institute of Technology. Earth Resources Laboratory Tao, Guo Cheng, C. H. In recent years, borehole Stoneley wave amplitude and reflectivity have been used for estimating formation permeability based on the strong correlation between Stoneley wave attenuation, reflectivity and formation fluid conductivity. There are other factors, however, that may cause substantial Stoneley attenuation and reflection in a borehole environment. To make better use of Stoneley measurements for formation permeability estimation, it is desirable to identify and quantify those causes of Stoneley attenuation and reflection that do not directly result from formation permeability. In this study, a simplified Biot-Rosenbaum model developed by Tang et at. (1991) is adopted to systematically model Stoneley attenuation and reflection in various borehole environments and formation configurations. By changing pore fluid, formation porosity, lithology, bed boundaries and thickness in the modeling, the sensitivity of Stoneley wave propagation to these conditions are quantitatively assessed. It is found that the presence of a light hydrocarbon in the formation, especially a natural gas residual in the immediate vicinity of the borehole wall, even with only 5% contained in pore fluid, may also cause substantial Stoneley attenuation and reflection. This phenomenon, on the other hand, can be used to evaluate a nonfractured, low permeability gas reservoir when combined with shear wave velocity data. For the full gas-saturated zone, Stoneley wave reflection may be observed even when the permeability is as low as a few milliDarcies. Compared to the effects of pore fluid, the effects due to lithology contrasts at the boundaries and the changes of nonfracture porosity are insignificant in the cases studied here. For a residual gas-bearing zone of moderate permeability, Stoneley wave attenuation and reflection may be observed if the zone is thicker than 0.5 meter. Massachusetts Institute of Technology. Borehole Acoustics and Logging Consortium ERL/nCUBE Geophysical Center for Parallel Processing United States. Dept. of Energy (Contract DE-FG02-86ER13636) 2012-12-10T17:59:34Z 2012-12-10T17:59:34Z 1996 Technical Report http://hdl.handle.net/1721.1/75320 Earth Resources Laboratory Industry Consortia Annual Report;1996-04 application/pdf Massachusetts Institute of Technology. Earth Resources Laboratory |
| spellingShingle | Tao, Guo Cheng, C. H. Effects Of A Borehole Environment And Residual Hydrocarbon On Stoneley Wave Amplitude And Reflectivity |
| title | Effects Of A Borehole Environment And Residual Hydrocarbon On Stoneley Wave Amplitude And Reflectivity |
| title_full | Effects Of A Borehole Environment And Residual Hydrocarbon On Stoneley Wave Amplitude And Reflectivity |
| title_fullStr | Effects Of A Borehole Environment And Residual Hydrocarbon On Stoneley Wave Amplitude And Reflectivity |
| title_full_unstemmed | Effects Of A Borehole Environment And Residual Hydrocarbon On Stoneley Wave Amplitude And Reflectivity |
| title_short | Effects Of A Borehole Environment And Residual Hydrocarbon On Stoneley Wave Amplitude And Reflectivity |
| title_sort | effects of a borehole environment and residual hydrocarbon on stoneley wave amplitude and reflectivity |
| url | http://hdl.handle.net/1721.1/75320 |
| work_keys_str_mv | AT taoguo effectsofaboreholeenvironmentandresidualhydrocarbononstoneleywaveamplitudeandreflectivity AT chengch effectsofaboreholeenvironmentandresidualhydrocarbononstoneleywaveamplitudeandreflectivity |