Difference between revisions of "Displacement pressure estimation from pore size"

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  | part    = Critical Elements of the Trap
 
  | part    = Critical Elements of the Trap
 
  | chapter = Evaluating top and fault seal
 
  | chapter = Evaluating top and fault seal
  | frompg  = 10-1
+
  | frompg  = 10-74
  | topg    = 10-94
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  | topg    = 10-74
 
  | author  = Grant M. Skerlec
 
  | author  = Grant M. Skerlec
 
  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch10/ch10.htm
 
  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch10/ch10.htm
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==Method==
 
==Method==
  
Displacement pressure can be estimated from pore size using Washburn's<ref name=ch10r90>Washburn, E., W., 1921, Note on a method of determining the distribution of pore sizes in a porous material: Proceedings of the National Academy of Science, vol. 7, p. 115–116.</ref> equation,
+
[[Displacement pressure]] can be estimated from pore size using Washburn's<ref name=ch10r90>Washburn, E., W., 1921, Note on a method of determining the distribution of pore sizes in a porous material: Proceedings of the National Academy of Science, vol. 7, p. 115–116.</ref> equation,
  
 
:<math>\mbox{P}_{\rm d} = \frac{-2\gamma \cos \theta}{\mbox{r}}</math>
 
:<math>\mbox{P}_{\rm d} = \frac{-2\gamma \cos \theta}{\mbox{r}}</math>
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Pore throat radius, ''r'', can be estimated in three ways:
 
Pore throat radius, ''r'', can be estimated in three ways:
  
* Thin-section analysis of pore throats<ref name=ch10r20>Dullien, F., A., L., Dhawan, G., K., 1974, Characterization of pore structure by a combination of quantitative photomicrography and mercury porosimetry: Journal of Colloid and Interface Science, vol. 47, no. 2, p. 337–349., 10., 1016/0021-9797(74)90265-3</ref>Etris et al., 1988<ref name=ch10r53>Macdonald, I., F., Kaufmann, P., Dullien, F., A., L., 1986, Quantitative image analysis of finite porous media 2: Specific genus of cubic lattice models and Berea sandstone: J. Microscopy, vol. 144, p. 297–316., 10., 1111/jmi., 1986., 144., issue-3</ref><ref name=ch10r88>Wardlaw, N., C., 1990, Quantitative determination of pore structure and application to fluid displacement in reservoir rocks, in Kleppe, J., Berg, E., W., Buller, A., T., Hjemeland, O., Torsaeter, O., eds., North Sea Oil and Gas Reservoirs: London, Graham & Trotman, p. 229–243.</ref>
+
* Thin-section analysis of pore throats<ref name=ch10r20>Dullien, F., A., L., Dhawan, G., K., 1974, Characterization of pore structure by a combination of quantitative photomicrography and mercury porosimetry: Journal of Colloid and Interface Science, vol. 47, no. 2, p. 337–349., 10., 1016/0021-9797(74)90265-3</ref><ref>Etris, E. L., D. S. Brumfield, R. Ehrlich, R. and S. J. Crabtree, 1988, Relation between pores,
* Thin-section analysis of grain size and assumptions of spherical grains and rhombohedral packing<ref name=ch10r5>Berg, R., R., 1975, [http://archives.datapages.com/data/bulletns/1974-76/data/pg/0059/0006/0900/0939.htm Capillary pressure in stratigraphic traps]: AAPG Bulletin, vol. 59, no. 6, p. 939–956.</ref>
+
throats and permeability: a petrographic/physical analysis of some carbonate grainstones and packstones: Carbonates Evaporites, volume 3, 17–32.</ref><ref name=ch10r53>Macdonald, I F., P. Kaufmann, and F. A. L. Dullien, 1986, Quantitative image analysis of finite porous media 2: Specific genus of cubic lattice models and Berea sandstone: J. Microscopy, vol. 144, p. 297–316.</ref><ref name=ch10r88>Wardlaw, N. C., 1990, Quantitative determination of pore structure and application to fluid displacement in reservoir rocks, in J. Kleppe, E. W. Berg, A. T. Buller, O. Hjemeland, and O. Torsaeter, eds., North Sea Oil and Gas Reservoirs: London, Graham & Trotman, p. 229–243.</ref>
* Empirical correlation of [[permeability]], [[porosity]], and pore throat radius<ref name=ch10r89>Wardlaw, N., C., Taylor, R., P., 1976, Mercury [[capillary pressure]] curves and the interpretation of pore structure and capillary behavior in reservoir rocks: Canadian Petroleum Geology Bulletin, vol. 24, no. 2, p. 225–262.</ref><ref name=ch10r94>Wells, J., D., Amafuele, J., O., 1985, Capillary pressure and permeability relationships in tight gas sands: SPE/DOE paper 13879.</ref><ref name=ch10r88 /><ref name=ch10r63>Pittman, E., D., 1992, [http://archives.datapages.com/data/bulletns/1992-93/data/pg/0076/0002/0000/0191.htm Relationship of porosity and permeability to various parameters derived from mercury injection-capillary pressure curves for sandstone]: AAPG Bulletin, vol. 76, no. 2, p. 191–198.</ref>
+
* Thin-section analysis of [[grain size]] and assumptions of spherical grains and rhombohedral packing<ref name=ch10r5>Berg, R. R., 1975, [http://archives.datapages.com/data/bulletns/1974-76/data/pg/0059/0006/0900/0939.htm Capillary pressure in stratigraphic traps]: AAPG Bulletin, vol. 59, no. 6, p. 939–956.</ref>
 +
* Empirical correlation of [[permeability]], [[porosity]], and pore throat radius<ref name=ch10r89>Wardlaw, N. C., and R. P. Taylor, 1976, Mercury [[capillary pressure]] curves and the interpretation of pore structure and capillary behavior in reservoir rocks: Canadian Petroleum Geology Bulletin, vol. 24, no. 2, p. 225–262.</ref><ref name=ch10r94>Wells, J. D., and J. O. Amafuele, 1985, Capillary pressure and permeability relationships in tight gas sands: SPE/DOE paper 13879.</ref><ref name=ch10r88 /><ref name=ch10r63>Pittman, E. D., 1992, [http://archives.datapages.com/data/bulletns/1992-93/data/pg/0076/0002/0000/0191.htm Relationship of porosity and permeability to various parameters derived from mercury injection-capillary pressure curves for sandstone]: AAPG Bulletin, vol. 76, no. 2, p. 191–198.</ref>
  
Although these methods can estimate the P<sub>d</sub> of sands, they do not apply easily to shales and finer grained rocks that comprise top seals. The assumptions of spherical grains and rhombohedral packing used to infer pore throat radius to not apply to shales that contain plate-like clay minerals.<ref name=ch10r5 /> Nor is the pore-size distribution easily determined from thin sections of fine-grained shales<ref name=ch10r44>Krushin, J., 1993, Entry pore throat size of nonsmectite shales, in Ebanks, J., Kaldi, J., Vavra, C., eds., Seals and Traps: A Multidisciplinary Approach: AAPG Hedberg Research conference, unpublished abstract.</ref> Use of permeability and porosity is thwarted by the lack of a distinct apex in the mercury injection data of low-permeability rocks<ref name=ch10r63 /> as well as the difficulty of measuring the permeability of shales.
+
Although these methods can estimate the P<sub>d</sub> of sands, they do not apply easily to shales and finer grained rocks that comprise top seals. The assumptions of spherical grains and rhombohedral packing used to infer pore throat radius to not apply to shales that contain plate-like clay minerals.<ref name=ch10r5 /> Nor is the pore-size distribution easily determined from thin sections of fine-grained shales<ref name=ch10r44>Krushin, J., 1993, Entry pore throat size of nonsmectite shales, in J. Ebanks, J. Kaldi, and C. Vavra, eds., Seals and Traps: A Multidisciplinary Approach: AAPG Hedberg Research conference, unpublished abstract.</ref> Use of permeability and porosity is thwarted by the lack of a distinct apex in the mercury injection data of low-permeability rocks<ref name=ch10r63 /> as well as the difficulty of measuring the permeability of shales.
  
 
==Theory and experiment==
 
==Theory and experiment==
Predicting top seal capacity is difficult—even in idealized experiments in which all variables are known to a degree unobtainable in practical prospect assessment. The predicted height of hydrocarbon columns calculated from pore throat diameters in uniform glass bead packs is 160–500T larger than heights actually observed in experiments.<ref name=ch10r12>Catalan, I., Xiaown, L., F., Chatzis, I., Dullien, F., A., L., 1992, [http://archives.datapages.com/data/bulletns/1992-93/data/pg/0076/0005/0000/0638.htm An experimental study of secondary oil migration]: AAPG Bulletin, vol. 76, no. 5, p. 638–650.</ref> If we cannot predict the height of hydrocarbon columns trapped in a controlled experiment with uniform glass beads and known variables, then we must be cautious in prospect analysis.
+
Predicting top seal capacity is difficult—even in idealized experiments in which all variables are known to a degree unobtainable in practical prospect assessment. The predicted height of hydrocarbon columns calculated from pore throat diameters in uniform glass bead packs is 160–500T larger than heights actually observed in experiments.<ref name=ch10r12>Catalan, I., L. F. Xiaown, I. Chatzis, and F. A. L. Dullien, 1992, [http://archives.datapages.com/data/bulletns/1992-93/data/pg/0076/0005/0000/0638.htm An experimental study of secondary oil migration]: AAPG Bulletin, vol. 76, no. 5, p. 638–650.</ref> If we cannot predict the height of hydrocarbon columns trapped in a controlled experiment with uniform glass beads and known variables, then we must be cautious in prospect analysis.
  
 
==See also==
 
==See also==
* [[Estimating displacement pressure]]
+
* [[Measuring displacement pressure using mercury injection]]
* [[Measuring Pd using mercury injection]]
+
* [[Estimating displacement pressure from sedimentary facies and well logs]]
* [[Estimating Pd from sedimentary facies and well logs]]
 
  
 
==References==
 
==References==

Latest revision as of 22:55, 2 February 2016

Exploring for Oil and Gas Traps
Series Treatise in Petroleum Geology
Part Critical Elements of the Trap
Chapter Evaluating top and fault seal
Author Grant M. Skerlec
Link Web page
Store AAPG Store

Method

Displacement pressure can be estimated from pore size using Washburn's[1] equation,

Techniques for estimating r

Pore throat radius, r, can be estimated in three ways:

Although these methods can estimate the Pd of sands, they do not apply easily to shales and finer grained rocks that comprise top seals. The assumptions of spherical grains and rhombohedral packing used to infer pore throat radius to not apply to shales that contain plate-like clay minerals.[6] Nor is the pore-size distribution easily determined from thin sections of fine-grained shales[10] Use of permeability and porosity is thwarted by the lack of a distinct apex in the mercury injection data of low-permeability rocks[9] as well as the difficulty of measuring the permeability of shales.

Theory and experiment

Predicting top seal capacity is difficult—even in idealized experiments in which all variables are known to a degree unobtainable in practical prospect assessment. The predicted height of hydrocarbon columns calculated from pore throat diameters in uniform glass bead packs is 160–500T larger than heights actually observed in experiments.[11] If we cannot predict the height of hydrocarbon columns trapped in a controlled experiment with uniform glass beads and known variables, then we must be cautious in prospect analysis.

See also

References

  1. Washburn, E., W., 1921, Note on a method of determining the distribution of pore sizes in a porous material: Proceedings of the National Academy of Science, vol. 7, p. 115–116.
  2. Dullien, F., A., L., Dhawan, G., K., 1974, Characterization of pore structure by a combination of quantitative photomicrography and mercury porosimetry: Journal of Colloid and Interface Science, vol. 47, no. 2, p. 337–349., 10., 1016/0021-9797(74)90265-3
  3. Etris, E. L., D. S. Brumfield, R. Ehrlich, R. and S. J. Crabtree, 1988, Relation between pores, throats and permeability: a petrographic/physical analysis of some carbonate grainstones and packstones: Carbonates Evaporites, volume 3, 17–32.
  4. Macdonald, I F., P. Kaufmann, and F. A. L. Dullien, 1986, Quantitative image analysis of finite porous media 2: Specific genus of cubic lattice models and Berea sandstone: J. Microscopy, vol. 144, p. 297–316.
  5. 5.0 5.1 Wardlaw, N. C., 1990, Quantitative determination of pore structure and application to fluid displacement in reservoir rocks, in J. Kleppe, E. W. Berg, A. T. Buller, O. Hjemeland, and O. Torsaeter, eds., North Sea Oil and Gas Reservoirs: London, Graham & Trotman, p. 229–243.
  6. 6.0 6.1 Berg, R. R., 1975, Capillary pressure in stratigraphic traps: AAPG Bulletin, vol. 59, no. 6, p. 939–956.
  7. Wardlaw, N. C., and R. P. Taylor, 1976, Mercury capillary pressure curves and the interpretation of pore structure and capillary behavior in reservoir rocks: Canadian Petroleum Geology Bulletin, vol. 24, no. 2, p. 225–262.
  8. Wells, J. D., and J. O. Amafuele, 1985, Capillary pressure and permeability relationships in tight gas sands: SPE/DOE paper 13879.
  9. 9.0 9.1 Pittman, E. D., 1992, Relationship of porosity and permeability to various parameters derived from mercury injection-capillary pressure curves for sandstone: AAPG Bulletin, vol. 76, no. 2, p. 191–198.
  10. Krushin, J., 1993, Entry pore throat size of nonsmectite shales, in J. Ebanks, J. Kaldi, and C. Vavra, eds., Seals and Traps: A Multidisciplinary Approach: AAPG Hedberg Research conference, unpublished abstract.
  11. Catalan, I., L. F. Xiaown, I. Chatzis, and F. A. L. Dullien, 1992, An experimental study of secondary oil migration: AAPG Bulletin, vol. 76, no. 5, p. 638–650.

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