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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 = 9-96 |
− | | topg = 9-156 | + | | topg = 9-98 |
| | 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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| From examination of cuttings, sandstone permeability can be predicted using the following petrophysical descriptions: | | From examination of cuttings, sandstone permeability can be predicted using the following petrophysical descriptions: |
| | | |
− | * Grain size and sorting | + | * [[Grain size]] and [[Core_description#Maturity|sorting]] |
| * Degree of rock consolidation | | * Degree of rock consolidation |
| * Volume percent of clays | | * Volume percent of clays |
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| {| class = "wikitable" | | {| class = "wikitable" |
| |- | | |- |
− | ! Type | + | ! Type || Description |
− | ! Description
| |
| |- | | |- |
− | | I | + | | I || Rocks with pores capable of producing gas without natural or artificial fracturing. |
− | | Rocks with pores capable of producing gas without natural or artificial fracturing. | |
| |- | | |- |
− | | II | + | | II || Rocks with pores capable of producing gas with natural or artificial fracturing and/or interbedded with type I rocks. |
− | | Rocks with pores capable of producing gas with natural or artificial fracturing and/or interbedded with type I rocks. | |
| |- | | |- |
− | | III | + | | III || Rocks too tight to produce at commercial rates even with natural or artificial fracturing. |
− | | Rocks too tight to produce at commercial rates even with natural or artificial fracturing. | |
| |} | | |} |
| | | |
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| {| class = "wikitable" | | {| class = "wikitable" |
| |- | | |- |
− | ! rowspan ="2" | Pore type | + | ! rowspan ="2" | Pore type || colspan="3" | Characteristics of dry, freshly broken surfaces at 20× magnification || rowspan ="2" | Permeability |
− | ! colspan="3" | Characteristics of dry, freshly broken surfaces at 20× magnification
| |
− | ! rowspan ="2" | Permeability
| |
| |- | | |- |
− | ! Visible | + | ! Visible || Pinpoint || Consolidation |
− | ! Pinpoint
| |
− | ! Consolidation
| |
| |- | | |- |
− | | I | + | | I || Abundant to common; interconnection visible on many pores || Very abundant to common || Needle probe easily dislodges many grains from rock surface || ''Type I Subclasses''<br>IA:>100md<br>IB: 10–100 md<br>IC: 1–10 md<br>ID: ±0.5–1 md |
− | | Abundant to common; interconnection visible on many pores | |
− | | Very abundant to common | |
− | | Needle probe easily dislodges many grains from rock surface | |
− | | ''Type I Subclasses''<br>IA:>100md<br>IB: 10–100 md<br>IC: 1–10 md<br>ID: ±0.5–1 md | |
| |- | | |- |
− | | II | + | | II || Scattered || Abundant to common || Needle probe can only occasionally dislodge a grain from rock surface || ± 0.5–1.0 md (depending on particle size, sorting, and clay mineral content) |
− | | Scattered | |
− | | Abundant to common | |
− | | Needle probe can only occasionally dislodge a grain from rock surface | |
− | | ± 0.5–1.0 md (depending on particle size, sorting, and clay mineral content) | |
| |- | | |- |
− | | style=white-space:nowrap | III | + | | III || None to very isolated || None to a few pores || Usually very well consolidated and/or pores filled with clays or other pore-filling material || Too tight to produce gas at commercial rates even when fractured or interbedded with type I rocks |
− | | None to very isolated | |
− | | None to a few pores | |
− | | Usually very well consolidated and/or pores filled with clays or other pore-filling material | |
− | | Too tight to produce gas at commercial rates even when fractured or interbedded with type I rocks | |
| |} | | |} |
| | | |
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| The procedure below is for predicting the permeability of sandstones from cuttings using 20× magnification<ref name=ch09r57 />. | | The procedure below is for predicting the permeability of sandstones from cuttings using 20× magnification<ref name=ch09r57 />. |
| | | |
− | {| class = "wikitable"
| + | # Estimate grain size and sorting using standard size-sorting comparators, thin section and SEM photomicrographs, and rock photographs. |
− | |-
| + | # Estimate volume percentages using Terry-Chillingar charts made for volume estimates. |
− | ! Step
| + | # Estimate consolidation using the scheme described in the preceding table. |
− | ! Action
| + | # Describe the visible and pinpoint [[porosity]] and interconnectedness. |
− | |-
| + | # Estimate permeability from rocks on comparators and/or using rock characteristics described in the preceding table. (Comparators can be made or purchased.) |
− | | 1
| + | # Predict permeability for the formation in prospective areas where petrophysical characteristics are believed to be similar |
− | | Estimate grain size and sorting using standard size-sorting comparators, thin section and SEM photomicrographs, and rock photographs.
| |
− | |-
| |
− | | 2
| |
− | | Estimate volume percentages using Terry-Chillingar charts made for volume estimates.
| |
− | |-
| |
− | | 3
| |
− | | Estimate consolidation using the scheme described in the preceding table.
| |
− | |-
| |
− | | 4
| |
− | | Describe the visible and pinpoint [[porosity]] and interconnectedness.
| |
− | |-
| |
− | | 5
| |
− | | Estimate permeability from rocks on comparators and/or using rock characteristics described in the preceding table. (Comparators can be made or purchased.)
| |
− | |-
| |
− | | 6
| |
− | | Predict permeability for the formation in prospective areas where petrophysical characteristics are believed to be similar
| |
− | |}
| |
| | | |
| ==See also== | | ==See also== |
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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]] |