Changes

  | 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  = 9-21

  | topg    = 9-156

  | topg    = 9-21

  | 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

==Connectivity==

==Connectivity==

Even very large pores contribute nothing to fluid flow unless they connect to other pores. Connectivity increases with the size of pore throats and with increasing number of pore throats surrounding each pore. The number of pore throats that connect with each pore is the '''coordination number'''.<ref name=ch09r64>Wardlaw, N., C., Cassan, J., P., 1978, Estimation of recovery efficiency by visual observation of pore systems in reservoir rocks: Bulletin of Canadian Petroleum Geology, vol. 26, no. 4, p. 572–585.</ref>

Even very large pores contribute nothing to fluid flow unless they connect to other pores. Connectivity increases with the size of pore throats and with increasing number of pore throats surrounding each pore. The number of pore throats that connect with each pore is the '''coordination number'''.<ref name=ch09r64>Wardlaw, N. C., and J. P. Cassan, 1978, Estimation of recovery efficiency by visual observation of pore systems in reservoir rocks: Bulletin of Canadian Petroleum Geology, vol. 26, no. 4, p. 572–585.</ref>

==Pore shape, throat size, and throat abundance==

==Pore shape, throat size, and throat abundance==

Pore systems are easily characterized by size using pore throat size. Pore throat sizes can be measured using [[capillary pressure]] curves. A capillary pressure curve is converted to a distribution profile of pore throat size, and a pore throat size that characterizes the rock is determined by picking a certain saturation level.

Pore systems are easily characterized by size using pore throat size. Pore throat sizes can be measured using [[capillary pressure]] curves. A capillary pressure curve is converted to a distribution profile of pore throat size, and a pore throat size that characterizes the rock is determined by picking a certain saturation level.

Which saturation level should we use? Work by Dale Winland and Ed Pittman<ref name=ch09r46>Pittman, E., D., 1992, [http://archives.datapages.com/data/bulletns/1992-93/data/pg/0076/0002/0000/0191.htm Relationship of porosity to permeability to various parameters derived from mercury injection–capillary pressure curves for sandstone]: AAPG Bulletin, vol. 76, no. 2, p. 191–198.</ref> shows a statistical correlation between optimal flow through rocks and the radius of the pore throats when 35% of the pore space of a rock is saturated by a nonwetting phase during a capillary pressure test. They call the size of pore throats at 35% nonwetting phase saturation r₃₅, also called '''port size'''. Port size is convenient for characterizing the size of a pore system. Pore systems can be subdivided into “port types” by port size. (See [[Characterizing rock quality]] for a discussion of port size and r₃₅.) The table below shows port types and size ranges for those port types.

Which saturation level should we use? Work by Dale Winland and Ed Pittman<ref name=ch09r46>Pittman, E. D., 1992, [http://archives.datapages.com/data/bulletns/1992-93/data/pg/0076/0002/0000/0191.htm Relationship of porosity to permeability to various parameters derived from mercury injection–capillary pressure curves for sandstone]: AAPG Bulletin, vol. 76, no. 2, p. 191–198.</ref> shows a statistical correlation between optimal flow through rocks and the radius of the pore throats when 35% of the pore space of a rock is saturated by a nonwetting phase during a capillary pressure test. They call the size of pore throats at 35% nonwetting phase saturation r₃₅, also called '''port size'''. Port size is convenient for characterizing the size of a pore system. Pore systems can be subdivided into “port types” by port size. (See [[Characterizing rock quality]] for a discussion of port size and r₃₅.) The table below shows port types and size ranges for those port types.

{| class = "wikitable"

{| class = "wikitable"

[[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]]