Changes

==Tools and methods==

==Tools and methods==

The extremely low permeability of tight gas reservoirs severely restricts the ability of gas to migrate appreciable distances. Consequently, the most important geological characteristic of this type of reservoir is the nature and distribution of [[porosity]] and permeability (Table 1). The most common reason for the minimal permeabilities is the occlusion of interstitial pore throats by detrital or authigenic clays or cement (see [[Rock-water interactions: formation damage]]). Thus, a proper geological evaluation of tight gas reservoirs requires a multidisciplinary approach to assess the depositional and diagenetic controls on [[reservoir quality]] and heterogeneity.

The extremely low permeability of tight gas reservoirs severely restricts the ability of gas to migrate appreciable distances. Consequently, the most important geological characteristic of this type of reservoir is the nature and distribution of [[porosity]] and permeability (Table 1). The most common reason for the minimal permeabilities is the occlusion of interstitial pore throats by detrital or authigenic clays or cement (see [[Rock-Water interactions: formation damage]]). Thus, a proper geological evaluation of tight gas reservoirs requires a multidisciplinary approach to assess the depositional and diagenetic controls on [[reservoir quality]] and heterogeneity.

===Facies determinations===

===Facies determinations===