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Line 46: − + − ! colspan="3" | Characteristics of dry, freshly broken surfaces at 20× magnification − ! rowspan ="2" | Permeability − + − ! Pinpoint − ! Consolidation − + − − − − − + − − − − − + − − − − Line 94:
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Sandstone permeability estimation from cuttings (view source)
Revision as of 17:19, 6 April 2022
, 17:19, 6 April 2022added Category:Treatise Handbook 3 using HotCat
| 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
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
{| class = "wikitable"
{| class = "wikitable"
|-
|-
! Type
! Type || 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.
|}
|}
{| 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
|-
|-
! Visible
! Visible || 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
|}
|}
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 />.
# 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.
# Estimate consolidation using the scheme described in the preceding table.
# 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.)
# Predict permeability for the formation in prospective areas where petrophysical characteristics are believed to be similar
==See also==
==See also==
[[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]]