Changes

==Reservoir Permeability==

==Reservoir Permeability==

[[File:Average permeability.jpg|300px|thumbnail|right|{{figure number|1|}}Average permeability for various producing fields on the UK and Norwegian continental shelves.<ref>Spencer, S. J., M. L. Somers, W. V. Pinczewski, and I. D. Doig, 1987, Numerical simulation of gas drainage from coal seams: SPE Paper 16857, 1987 SPE Annual Technical Conference and Exhibition, Dallas, Texas, p. 27-30.</ref><ref>Abbots, I. L., ed., United Kingdom Oil and Gas Fields, 25 Years Commemorative Volume: Geological Society (London) Memoir 14</ref> (Gluyas et al. 2004; Abbots 1991; Gluyas et al. 1992; Oxtoby et al. 1995).]]

[[File:Average permeability.jpg|300px|thumbnail|right|{{figure number|1|}}Average permeability for various producing fields on the UK and Norwegian continental shelves.<ref>Spencer, S. J., M. L. Somers, W. V. Pinczewski, and I. D. Doig, 1987, Numerical simulation of gas drainage from coal seams: SPE Paper 16857, 1987 SPE Annual Technical Conference and Exhibition, Dallas, Texas, p. 27-30.</ref><ref>Abbots, I. L., ed., United Kingdom Oil and Gas Fields, 25 Years Commemorative Volume: Geological Society (London) Memoir 14</ref><ref>Gluyas, J. G., S. M. Grant, and A. G. Robinson, 1993, Geochemical evidence for a temporal control on sandstone cementation, ''in'' A. D. Horbury and A. G. Robinson, eds., Diagenesis and basin development: AAPG Studies in Geology 36, p. 23-34.</ref><ref>H. N. Oxtoby, W. A. Mitchell, and J. Gluyas, 1995, The filling and emptying of the Ula oilfield (Norwegian North Sea), ''in'' J. M. Cubitt and W. A. England, eds., The geochemistry of reservoirs: Geological Society (London), p. 141-158</ref> (Gluyas et al. 2004).]]

Permeability is an intrinsic property of a material that determines how easily a fluid can pass through it. In the petroleum industry, the Darcy (D) is the standard unit of permeability, but milidarcies (1 mD = 10-3 D) are more commonly used. A Darcy is defined as a flow rate of 10-2 ms-1 for a fluid of 1 cp (centipoise) under a pressure of 10-4atm m-2. Permeability in reservoir rocks may range from 0.1 mD to more than 10 D.<ref name=gluyas2004 />

Permeability is an intrinsic property of a material that determines how easily a fluid can pass through it. In the petroleum industry, the Darcy (D) is the standard unit of permeability, but milidarcies (1 mD = 10-3 D) are more commonly used. A Darcy is defined as a flow rate of 10-2 ms-1 for a fluid of 1 cp (centipoise) under a pressure of 10-4atm m-2. Permeability in reservoir rocks may range from 0.1 mD to more than 10 D.<ref name=gluyas2004 />