Changes

==Effect of quartz overgrowths==

==Effect of quartz overgrowths==

In general, as quartz cement precipitates, the pore:pore throat size ratio approaches 1.<ref name=Harris1985>Harris, P. M., C. G. St.-C. Kendall, and I. Lerche, 1985, Carbonate cementation—a brief review, in N. Schneidermann and P. M. Harris, eds., Carbonate Cements: SEPM Special Publication 36, p. 79–95.</ref> Throats are reduced less than pore space; therefore, [[permeability]] is affected less than porosity. During cementation, the size of the pore spaces between the pore-filling crystals decreases until it approaches the size of the pore throats. Throats become more tabular or sheet-like. Sandstone porosity may be quite low (<5%) and still have some permeability (<10 md) where cemented with quartz. (See also [[Connectivity and pore throat size]].)

In general, as quartz cement precipitates, the pore:pore throat size ratio approaches 1.<ref name=Harris1985>Harris, P. M., C. G. St.-C. Kendall, and I. Lerche, 1985, Carbonate cementation—a brief review, in N. Schneidermann and P. M. Harris, eds., Carbonate Cements: SEPM Special Publication 36, p. 79–95.</ref> Throats are reduced less than pore space; therefore, [[permeability]] is affected less than [[porosity]]. During cementation, the size of the pore spaces between the pore-filling crystals decreases until it approaches the size of the pore throats. Throats become more tabular or sheet-like. Sandstone porosity may be quite low (<5%) and still have some permeability (<10 md) where cemented with quartz. (See also [[Connectivity and pore throat size]].)

==Effect of fractures==

==Effect of fractures==