Changes

[[File:M97Ch1.2FG18.jpg|thumb|500px|{{figure number|18}}Database of the Ordovician Utica and Devonian Marcellus shales showing the oil crossover effect on select samples. S1 = Rock-Eval measured oil contents.]]

[[File:M97Ch1.2FG18.jpg|thumb|500px|{{figure number|18}}Database of the Ordovician Utica and Devonian Marcellus shales showing the oil crossover effect on select samples. S1 = Rock-Eval measured oil contents.]]

The Devonian Marcellus Shale is regarded as becoming the largest shale-gas resource system in the United States, but areas are also present in western New York and West Virginia where the shale is in the oil window. Wells in these areas show the oil crossover effect. Data from the State Museum of New York show OSI values more than 100 mg oil/g TOC in Erie, Livingston, Allegany, Chautauqua, and Otsego counties and also to the south in northwestern West Virginia (Nyahay et al., 2007).

The Devonian Marcellus Shale is regarded as becoming the largest shale-gas resource system in the United States, but areas are also present in western New York and West Virginia where the shale is in the oil window. Wells in these areas show the oil crossover effect. Data from the State Museum of New York show OSI values more than 100 mg oil/g TOC in Erie, Livingston, Allegany, Chautauqua, and Otsego counties and also to the south in northwestern West Virginia.<ref>Nyahay, R., J. Leone, L. Smith, J. Martin, and D. Jarvie, 2007, [http://www.searchanddiscovery.com/20047/07101nyahay/index.htm Shale gas potential in New York: Result from recent NYSERDA-sponsored research], AAPG Annual Meeting, Long Beach, California, April 1–4, 2007, AAPG Bulletin.</ref>

Similarly, the Ordovician Utica Shale shows oil crossover in parts of New York, Pennsylvania, Ohio, and Michigan.

Similarly, the Ordovician Utica Shale shows oil crossover in parts of New York, Pennsylvania, Ohio, and Michigan.

===Western Canada Sedimentary Basin===

===Western Canada Sedimentary Basin===

Although the Doig Phosphate and Montney Shale are discussed as a shale-gas resource system, they can also produce substantial liquid petroleum depending on the location. What is interesting about the Montney Shale is the overridingly low TOC values reported, suggesting it as only a poor to fair source rock (see part 1 of this chapter). Furthermore, Riediger et al. (1990) correlate several known oil accumulations in the Montney Formation to be sourced by either the Doig Phosphate or the Jurassic Nordegg Formation. Regardless, both gas and oil production is ongoing in the Montney Formation, and it can be described in a variety of ways as a tight resource system with petroleum sourced internally by more organic-rich Montney Shale or by secondary migration from the overlying Doig Phosphate, or by tertiary migration from the Nordegg Formation.

Although the Doig Phosphate and Montney Shale are discussed as a shale-gas resource system, they can also produce substantial liquid petroleum depending on the location. What is interesting about the Montney Shale is the overridingly low TOC values reported, suggesting it as only a poor to fair source rock (see part 1 of this chapter). Furthermore, Riediger et al.<ref>Riediger, C. L., M. G. Fowler, P. W. Brooks, and L. R. Snowdon, 1990, Triassic oils and potential Mesozoic source rocks: Peace River arch area, Western Canada Basin: Organic Geochemistry, v. 16, no. 1–3, p. 295–305, doi:10.1016/0146-6380(90)90049-6.</ref> correlate several known oil accumulations in the Montney Formation to be sourced by either the Doig Phosphate or the Jurassic Nordegg Formation. Regardless, both gas and oil production is ongoing in the Montney Formation, and it can be described in a variety of ways as a tight resource system with petroleum sourced internally by more organic-rich Montney Shale or by secondary migration from the overlying Doig Phosphate, or by tertiary migration from the Nordegg Formation.

A database of Montney Shale wells was obtained from the Geological Survey of Canada.<ref name=Jrv2011 /> This database consists of data from 24 wells with 192 Montney Shale samples. Average TOCpd is 1.02% over a range of 0.25 to 4.79%, with a standard deviation of 0.70% indicative of a much lower TOC value overall than most of the shale resource plays, except for perhaps the Lewis Shale of the San Juan Basin, New Mexico. Calculated HIo values are highly variable, ranging from less than 100 mg HC/g TOC to upward of 700 mg HC/g TOC. However, the very high HIo samples account for only 8% of the database with more than 70% at values less than 100 mg HC/g TOC. Some sourcing of petroleum by the Montney Shale occurs, but it does not appear to have the petroleum-generation potential to have sourced the high amounts of gas and oil in the Montney Formation.

A database of Montney Shale wells was obtained from the Geological Survey of Canada.<ref name=Jrv2011 /> This database consists of data from 24 wells with 192 Montney Shale samples. Average TOCpd is 1.02% over a range of 0.25 to 4.79%, with a standard deviation of 0.70% indicative of a much lower TOC value overall than most of the shale resource plays, except for perhaps the Lewis Shale of the San Juan Basin, New Mexico. Calculated HIo values are highly variable, ranging from less than 100 mg HC/g TOC to upward of 700 mg HC/g TOC. However, the very high HIo samples account for only 8% of the database with more than 70% at values less than 100 mg HC/g TOC. Some sourcing of petroleum by the Montney Shale occurs, but it does not appear to have the petroleum-generation potential to have sourced the high amounts of gas and oil in the Montney Formation.

</gallery>

</gallery>

Recently, the Paris Basin of France is described as having shale-oil resource potential (Toreador Resources, 2010). Substantiating this, it has been recently announced that Vermillion Energy has achieved oil flow of 32 to 38deg API oil in Paris Basin Toarcian Shale (Vermillion Energy, 2010). The company reported porosity as high as 12%.

Recently, the Paris Basin of France is described as having shale-oil resource potential.<ref>Toreador Resources: 2010, [http://www.toreador.net/images/presentations/Toreador_Unconventional_Oil_2010.pdf Paris Basin shale oil: Toreador taking the lead], Unconventional Oil 2010, October 12, 2010, London.</ref> Substantiating this, it has been recently announced that Vermillion Energy has achieved oil flow of 32 to 38deg API oil in Paris Basin Toarcian Shale.<ref>Vermillion Energy, 2010, [http://www.vermilionenergy.com/files/Presentations/November%20Investor%20Presentation_web.pdf November 2010 investor report]</ref> The company reported porosity as high as 12%.

Average Toarcian Shale data from Espitalie et al.<ref name=Esptl1988 /> demonstrate the oil crossover effect (Figure 20). Furthermore, a geochemical log of a well from the Donnemarie field was constructed to illustrate the shale-oil system play (Figure 21). This log illustrates two reservoir systems: one proven conventional and an unproven unconventional. The oil crossover effect in this well is obvious between 3020 and 3240 m (sim9908–10,630 ft), where conventional Triassic sandstone production exists. Uphole from this conventional ongoing production, immediately below the organic-rich Toarcian Shale, a thick organic-lean interval is present in this well from 2465 to 2609 m (sim8087.2–8559.7 ft) where oil crossover occurs, indicative of an untested, but potential, hybrid shale-oil resource production. Given the source rock type, a marine shale, and conventionally produced oil quality elsewhere in the basin, oil in this interval would be expected to be more than 35deg API oil. The Toarcian Shale immediately above this zone of crossover has an average TOC of almost 2.00% and is in the earliest oil window at about 0.75% Roe (from Tmax). In addition, a Toarcian Shale sample at 2270 m (7447.8 ft) is organic rich (4.47% TOC) and exhibits very high oil content and oil crossover indicative of active generation and expulsion. A sample at 2530 m (8300.5 ft) does not show crossover, so it could be a seal between two free oil-saturated zones.

Average Toarcian Shale data from Espitalie et al.<ref name=Esptl1988 /> demonstrate the oil crossover effect (Figure 20). Furthermore, a geochemical log of a well from the Donnemarie field was constructed to illustrate the shale-oil system play (Figure 21). This log illustrates two reservoir systems: one proven conventional and an unproven unconventional. The oil crossover effect in this well is obvious between 3020 and 3240 m (sim9908–10,630 ft), where conventional Triassic sandstone production exists. Uphole from this conventional ongoing production, immediately below the organic-rich Toarcian Shale, a thick organic-lean interval is present in this well from 2465 to 2609 m (sim8087.2–8559.7 ft) where oil crossover occurs, indicative of an untested, but potential, hybrid shale-oil resource production. Given the source rock type, a marine shale, and conventionally produced oil quality elsewhere in the basin, oil in this interval would be expected to be more than 35deg API oil. The Toarcian Shale immediately above this zone of crossover has an average TOC of almost 2.00% and is in the earliest oil window at about 0.75% Roe (from Tmax). In addition, a Toarcian Shale sample at 2270 m (7447.8 ft) is organic rich (4.47% TOC) and exhibits very high oil content and oil crossover indicative of active generation and expulsion. A sample at 2530 m (8300.5 ft) does not show crossover, so it could be a seal between two free oil-saturated zones.

===Other Worldwide Locales for Shale-oil Resource System Production===

===Other Worldwide Locales for Shale-oil Resource System Production===

Elsewhere in Europe, there may also be shale-oil potential in various regions that are being explored for shale-gas resource systems. Many of the basins have an oil window as well as a gas window, so the opportunity likely exists in many basins. For example, data from the lower Saxony Basin of Germany, lower Hils syncline, show vitrinite reflectance values ranging from 0.49 to 1.3% Ro (Rullkotter et al., 1988). Both the Wealden and Posidonia shales could be potential shale-oil resource systems. Similarly, in one of the hot areas for shale-gas activity, Poland, shale-oil resource potential also exists, given modest levels of conversion of the organic-rich shales in select areas.

Elsewhere in Europe, there may also be shale-oil potential in various regions that are being explored for shale-gas resource systems. Many of the basins have an oil window as well as a gas window, so the opportunity likely exists in many basins. For example, data from the lower Saxony Basin of Germany, lower Hils syncline, show vitrinite reflectance values ranging from 0.49 to 1.3% Ro.<ref>Rullkotter, J., et al., 1988, Organic matter maturation under the influence of a deep instrusive heat source: A natural experiment for quantitation of hydrocarbon generation and expulsion from a petroleum source rock (Toarcian Shale, northern Germany), Advances in Organic Geochemistry 1987: Organic Geochemistry, v. 13, no. 1–3, p. 847–856, doi:10.1016/0146-6380(88)90237-9.</ref> Both the Wealden and Posidonia shales could be potential shale-oil resource systems. Similarly, in one of the hot areas for shale-gas activity, Poland, shale-oil resource potential also exists, given modest levels of conversion of the organic-rich shales in select areas.

With its abundant oil production, the oil-saturated organic-rich source rocks in Saudi Arabia are likely targets. Both the Tuwaiq Mountain and Hadriya Formation, the latter of which is being tested, are likely targets for possible production from shale-oil resource systems.

With its abundant oil production, the oil-saturated organic-rich source rocks in Saudi Arabia are likely targets. Both the Tuwaiq Mountain and Hadriya Formation, the latter of which is being tested, are likely targets for possible production from shale-oil resource systems.

==References cited==

==References cited==

{{reflist}}

{{reflist}}