Changes

==Effect of pressure==

==Effect of pressure==

The main effect of pressure is compaction. The process of porosity loss with depth of burial is slowed by overpressures. Basing his findings mainly on North Sea sandstones, Scherer<ref name=ch09r53>Scherer, M., 1987, Parameters influencing porosity in sandstones: a model for sandstone porosity prediction: AAPG Bulletin, vol. 71, no. 5, p. 485–491.</ref> notes sandstones retain approximately 2% porosity for every [[pressure::1000 psi]] of overpressure during compaction. He cautions this figure must be used carefully because the influence of pressure on porosity depends on the stage of compaction at which the overpressure developed.

The main effect of pressure is compaction. The process of porosity loss with depth of burial is slowed by overpressures. Basing his findings mainly on North Sea sandstones, Scherer<ref name=ch09r53>Scherer, M., 1987, [http://archives.datapages.com/data/bulletns/1986-87/data/pg/0071/0005/0450/0485.htm Parameters influencing porosity in sandstones: a model for sandstone porosity prediction]: AAPG Bulletin, vol. 71, no. 5, p. 485–491.</ref> notes sandstones retain approximately 2% porosity for every [[pressure::1000 psi]] of overpressure during compaction. He cautions this figure must be used carefully because the influence of pressure on porosity depends on the stage of compaction at which the overpressure developed.

==Effect of age==

==Effect of age==