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| | part = Predicting the occurrence of oil and gas traps | | | part = Predicting the occurrence of oil and gas traps |
| | chapter = Predicting reservoir system quality and performance | | | chapter = Predicting reservoir system quality and performance |
− | | frompg = 9-1 | + | | frompg = 9-48 |
− | | topg = 9-156 | + | | topg = 9-48 |
| | author = Dan J. Hartmann, Edward A. Beaumont | | | author = Dan J. Hartmann, Edward A. Beaumont |
| | link = http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm | | | link = http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm |
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| [[file:predicting-reservoir-system-quality-and-performance_fig9-29.png|500px|thumb|{{figure number|1}}Resistivity profiles of formations with fresh and saltwater mud filtrate invasion.]] | | [[file:predicting-reservoir-system-quality-and-performance_fig9-29.png|500px|thumb|{{figure number|1}}Resistivity profiles of formations with fresh and saltwater mud filtrate invasion.]] |
| | | |
− | During the drilling process, filtrate water from the drilling fluid invades the formation. Its resistivity (R<sub>mf</sub>) is either greater than, less than, or equal to R<sub>t</sub> and can distort deep resistivities. Distortions to resistivities due to invasion must be corrected to get a valid R<sub>t</sub> value. The diagram in [[:file:predicting-reservoir-system-quality-and-performance_fig9-29.png|Figure 1]] shows resistivity profiles of formations with fresh and saltwater mud filtrate invasion. | + | During the drilling process, filtrate water from the drilling fluid invades the formation. Its [[Resistivity of mud filtrate|resistivity (R<sub>mf</sub>)]] is either greater than, less than, or equal to R<sub>t</sub> and can distort deep resistivities. Distortions to resistivities due to invasion must be corrected to get a valid R<sub>t</sub> value. The diagram in [[:file:predicting-reservoir-system-quality-and-performance_fig9-29.png|Figure 1]] shows resistivity profiles of formations with fresh and saltwater mud filtrate invasion. |
| | | |
| ==Obtaining a valid r<sub>t</sub> value== | | ==Obtaining a valid r<sub>t</sub> value== |
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| {| class="wikitable" | | {| class="wikitable" |
| |- | | |- |
− | ! If… | + | ! If… || Then… |
− | ! Then…
| |
| |- | | |- |
− | | Bed is < 20 ft thick for an [[Basic open hole tools#Induction|induction log]] or < 4 ft thick for a [[Basic open hole tools#Laterologs|laterolog]] | + | | Bed is < 20 ft thick for an [[Basic open hole tools#Induction|induction log]] or < 4 ft thick for a [[Basic open hole tools#Laterologs|laterolog]] || Correct for this bed using appropriate service company chart |
− | | Correct for this bed using appropriate service company chart | |
| |- | | |- |
− | | Shallow, medium, and deep investigating tools measure different resistivities (i.e., log has step profile) | + | | Shallow, medium, and deep investigating tools measure different resistivities (i.e., log has step profile) || Correct for invasion using appropriate service company tornado chart |
− | | Correct for invasion using appropriate service company tornado chart | |
| |} | | |} |
| | | |
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| [[Category:Predicting the occurrence of oil and gas traps]] | | [[Category:Predicting the occurrence of oil and gas traps]] |
| [[Category:Predicting reservoir system quality and performance]] | | [[Category:Predicting reservoir system quality and performance]] |
| + | [[Category:Treatise Handbook 3]] |