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. (Gluyas et al. 2004; from Spencer et al. 1987; 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 name=gluyas2004 /><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>]]

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 />

All types of rock (igneous, sedimentary, metamorphic) can act as reservoir rocks if it can accommodate and drain hydrocarbons. Reservoir rocks around the world is dominated by sedimentary rocks because generally it has primary porosity. [[Igneous]] and metamorphic rocks can be reservoir if there are in fracturing state (secondary porosity).

All types of rock (igneous, sedimentary, metamorphic) can act as reservoir rocks if it can accommodate and drain hydrocarbons. Reservoir rocks around the world is dominated by sedimentary rocks because generally it has primary porosity. [[Igneous]] and metamorphic rocks can be reservoir if there are in fracturing state (secondary porosity).

[[File:Klasifikasi reservoir.jpg|650px|center|thumbnail|{{figure number|2|}}Scheme of classification of reservoir rocks. (Adapted from Nichols, 2009, from lecture handout by Alamsyah <ref name=Alamsyah2015 >Alamsyah, M.N., 2015, Konsep Petroleum System (Handout Kuliah): Universitas Brawijaya</ref> )]]

[[File:Klasifikasi reservoir.jpg|650px|center|thumbnail|{{figure number|2|}}Scheme of classification of reservoir rocks. (Adapted from Nichols,<ref>Nichols, G., 2009, Sedimentology and Stratigraphy. Blackwell Science Ltd., London, 335 p.</ref> from lecture handout by Alamsyah<ref name=Alamsyah2015 >Alamsyah, M.N., 2015, Konsep Petroleum System (Handout Kuliah): Universitas Brawijaya</ref> )]]

===Siliciclastic Reservoir===

===Siliciclastic Reservoir===

On this type of reservoir, it was formed by the accumulation of  lacustrine sediments. Very fine grain sediment rocks.

On this type of reservoir, it was formed by the accumulation of  lacustrine sediments. Very fine grain sediment rocks.

[[File:Diagrammatic cross sections of depositional units within deltas.jpg|500px|thumbnail|center|{{figure number|5|}}Diagrammatic cross sections of depositional units within deltas. (A) Delta Concept of Gilbert (1885) showing topset, foreset, and bottomset beds; (B) Deltaic and neritic facies from Frazier (1967); (C) Sediment types and depositional units of an idealized delta.<ref>Berg, R.R., 1985, Reservoir Sandstones, Prentice Hall College Div.</ref>]]

[[File:Diagrammatic cross sections of depositional units within deltas.jpg|500px|thumbnail|center|{{figure number|5|}}Diagrammatic cross sections of depositional units within deltas. (A) Delta Concept of Gilbert<ref>Gilbert, G. K., 1885, The topographic features of lake shores: U.S. Geological Survey Annual Report 5, p. 75– 123.</ref> showing topset, foreset, and bottomset beds; (B) Deltaic and neritic facies from Frazier<ref>Frazier, D. E., 1967, Recent deltaic deposits of the Mississippi River; their development and chronology: Gulf Coast Association of Geological Societies Transactions, v.17, p. 287-315</ref>; (C) Sediment types and depositional units of an idealized delta.<ref>Berg, R. R., 1985, Reservoir Sandstones: Prentice Hall College Div.</ref>]]

===Carbonate Reservoir===

===Carbonate Reservoir===

====Clastic Limestone====

====Clastic Limestone====

Clastic limestone usually associated with oolit and become a pretty good reservoir. Limestone associated with oolit often referred to as calcarenite. The Deposition is in shallow marine environments along the coast with high energy (strong wave currents). Porosity may be extremely high because of the dissolution, but permeability is not far from 5 milidarcy. It is called clastic because oolit associated with limestone is present through the transport process before finally deposited.

Clastic limestone usually associated with oolit and become a pretty good reservoir. Limestone associated with oolite often referred to as calcarenite. The deposition is in shallow marine environments along the coast with high energy (strong wave currents). Porosity may be extremely high because of the dissolution, but permeability is not far from 5 mD. It is called clastic because oolite associated with limestone is present through the transport process before finally being deposited.

====Dolomite====

====Dolomite====

==Another Type of Reservoir==

==Another Type of Reservoir==

Although the porosity and permeability are poor, shale, silt stone, limestone can even act as reservoir due to fractures in the rock body (secondary porosity – secondary permeability). For example, an oil field in Florence, Colorado which is having shale (Lower – Upper Cretaceous) as reservoir rock.

Although the porosity and permeability are poor, shale, silt stone, limestone can even act as reservoir due to fractures in the rock body (secondary porosity – secondary permeability). For example, an oil field in Florence, Colorado which is having shale (Lower–Upper Cretaceous) as reservoir rock.

Then, it shows that for other than sedimentary rocks (igneous – metamorphic) could be reservoir rock if there are in fracturing state. For example, in Cuba, the oil is obtained from ultra-base igneous rock or volcanic rock that has fractured. There are eight oil fields in Cuba in 1964 that produce 710 barrels oil per day.<ref>Koesoemadinata, R.P.,1980, Geologi Minyak -Dan Gasbumi, Institut Teknologi Bandung.</ref> Reservoir from this type has a very small percentage compared to the reservoir from sedimentary rock (about 1% of the overall reservoir in the world).

Then, it shows that for other than sedimentary rocks (igneous – metamorphic) could be reservoir rock if there are in fracturing state. For example, in Cuba, the oil is obtained from ultra-base igneous rock or volcanic rock that has fractured. There are eight oil fields in Cuba in 1964 that produce 710 barrels oil per day.<ref>Koesoemadinata, R. P., 1980, Geologi Minyak: Dan Gasbumi, Institut Teknologi Bandung.</ref> Reservoir from this type has a very small percentage compared to the reservoir from sedimentary rock (about 1% of the overall reservoir in the world).

   

   

[[File:Comparison of reservoir rock types.jpg|700px|thumbnail|center|Figure 8- Comparison of reservoir rock types around the world in 1956 (based on Knebel & Rodriguez, 1956 in Koesomadinata, 1980)]]

[[File:Comparison of reservoir rock types.jpg|700px|thumbnail|center|{{figure number|8|}}Comparison of reservoir rock types around the world in 1956 (based on Knebel & Rodriguez<ref>Knebel, G. M., and G. Rodriguez-Eraso, 1956, Habitat of some oil: AAPG Bulletin, v. 40, no. 4, p. 547-561</ref>)]]

Volcanic rocks are igneous rocks that formed on the earth surface (extrusive igneous rock). Volcanic rock can be formed from mafic minerals such as olivine, pyroxene, amphibole, and biotite, or felsic minerals such as feldspar, muscovite, and [[quartz]].<ref> Noor, D., 2009, Pengantar Geologi, Universitas Pakuan Bogor.</ref> For example, oil obtained in Jatibarang (West Java, Indonesia), produced from fractures that occur in volcanic rock (tuff). Oil production from volcanic rock reservoir shows higher production in initially, and then shows a rapid decline in production.

Volcanic rocks are igneous rocks that formed on the earth surface (extrusive igneous rock). Volcanic rock can be formed from mafic minerals such as olivine, pyroxene, amphibole, and biotite, or felsic minerals such as feldspar, muscovite, and [[quartz]].<ref> Noor, D., 2009, Pengantar Geologi, Universitas Pakuan Bogor.</ref> For example, oil obtained in Jatibarang (West Java, Indonesia), produced from fractures that occur in volcanic rock (tuff). Oil production from volcanic rock reservoir shows higher production in initially, and then shows a rapid decline in production.