Changes

Although shale-gas resource plays were slow to spread from the Barnett Shale into other United States and Canadian plays, a worldwide surge in interest has occurred since about 2006. The primary activity outside North America has been in Europe, where several companies including major oil and gas companies have secured land deals and have started drilling and testing of these plays. Key countries in this pursuit are Germany, Sweden, and Poland.

Although shale-gas resource plays were slow to spread from the Barnett Shale into other United States and Canadian plays, a worldwide surge in interest has occurred since about 2006. The primary activity outside North America has been in Europe, where several companies including major oil and gas companies have secured land deals and have started drilling and testing of these plays. Key countries in this pursuit are Germany, Sweden, and Poland.

The lower Saxony Basin of Germany has been studied extensively over the years. In the 1980s, the research organization KFA in Julich, Germany, was funded to drill shallow core holes into the lower Jurassic Posidonia Shale. In the Hils syncline area of the lower Saxony Basin, thermal maturity ranges from 0.49% to about 1.3% Ro (Rullkotter et al., 1988; Horsfield et al., 2010). These cores and their published data provide a wealth of information on this Lower Jurassic source rock and potential resource play. The TOCo values average about 10.5%, with GOC values averaging 56% of the TOCo. Given the high oil saturations reported in the Posidonia Shale (Rullkotter et al., 1988), there may be potential for shale-oil resource plays in the oil window parts of the basin.

The lower Saxony Basin of Germany has been studied extensively over the years. In the 1980s, the research organization KFA in Julich, Germany, was funded to drill shallow core holes into the lower Jurassic Posidonia Shale. In the Hils syncline area of the lower Saxony Basin, thermal maturity ranges from 0.49% to about 1.3% Ro.<ref name=Rllkttr>Rullkotter, J., et al., 1988, Organic matter maturation under the influence of a deep intrusive 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.M</ref> (Horsfield et al., 2010). These cores and their published data provide a wealth of information on this Lower Jurassic source rock and potential resource play. The TOCo values average about 10.5%, with GOC values averaging 56% of the TOCo. Given the high oil saturations reported in the Posidonia Shale,<ref name=Rllkttr /> there may be potential for shale-oil resource plays in the oil window parts of the basin.

Data for the Lower Cretaceous Wealden Shale is more difficult to locate, but some published TOC and Rock-Eval data on immature samples are available (Munoz et al., 2007). These data suggest perhaps four different organofacies for the Wealden Shale, ranging in HIo from 500 to 700 mg HC/g TOC with variable TOCo contents ranging from about 4.5% to 8.0%. Generation potentials and TOC values for select samples from the Wealden and Posidonia shales are shown in [[:File:M97FG8.jpg|Figure 8]], with the highlighted red area being indicative of the core gas-producing area values for Barnett Shale in Fort Worth Basin, Texas. These data indicate that these shales are not highly converted, at least in this data set. Given this level of conversion, some liquids would be expected with gas, thereby having higher Btu values than other areas of the basin where maturities are higher. Certainly, once the areas of gas window thermal maturity are identified, it becomes necessary to assess other risk factors such as mineralogy, petrophysics, rock mechanics, and fluid sensitivities, for example.

Data for the Lower Cretaceous Wealden Shale is more difficult to locate, but some published TOC and Rock-Eval data on immature samples are available (Munoz et al., 2007). These data suggest perhaps four different organofacies for the Wealden Shale, ranging in HIo from 500 to 700 mg HC/g TOC with variable TOCo contents ranging from about 4.5% to 8.0%. Generation potentials and TOC values for select samples from the Wealden and Posidonia shales are shown in [[:File:M97FG8.jpg|Figure 8]], with the highlighted red area being indicative of the core gas-producing area values for Barnett Shale in Fort Worth Basin, Texas. These data indicate that these shales are not highly converted, at least in this data set. Given this level of conversion, some liquids would be expected with gas, thereby having higher Btu values than other areas of the basin where maturities are higher. Certainly, once the areas of gas window thermal maturity are identified, it becomes necessary to assess other risk factors such as mineralogy, petrophysics, rock mechanics, and fluid sensitivities, for example.

* Railroad Commission of Texas, 2011, [http://www.rrc.state.tx.us/meetings/ogpfd/RangePFD.PDF&sa=U&ei=WIAQT9DPA6Xu0gGBxlC_Aw&ved=0CAcQFjAB&client=internal-uds-cse&usg=AFQjCNHn-_WOT9BMMdwJJalA1JclwbfUfw Texas Railroad Commission hearing, 2011, Docket No. 7B-0268629] - Commission called hearing to consider whether operation of the Range Production Company Butler unit well no. 1H (RRC No. 253732) and the Teal unit well no. 1H (RRC No. 253779), Newark, East (Barnett Shale) Field, Hood County, Texas, are causing or contributing to contamination of certain domestic water wells in Parker County, Texas, v. 1, 123 p.

* Railroad Commission of Texas, 2011, [http://www.rrc.state.tx.us/meetings/ogpfd/RangePFD.PDF&sa=U&ei=WIAQT9DPA6Xu0gGBxlC_Aw&ved=0CAcQFjAB&client=internal-uds-cse&usg=AFQjCNHn-_WOT9BMMdwJJalA1JclwbfUfw Texas Railroad Commission hearing, 2011, Docket No. 7B-0268629] - Commission called hearing to consider whether operation of the Range Production Company Butler unit well no. 1H (RRC No. 253732) and the Teal unit well no. 1H (RRC No. 253779), Newark, East (Barnett Shale) Field, Hood County, Texas, are causing or contributing to contamination of certain domestic water wells in Parker County, Texas, v. 1, 123 p.

* Raseroka, L., and I. R. McLachlan, 2009, [http://www.searchanddiscovery.net/documents/2009/10196raseroka/index.htm?q=%2Btext%3Araseroka The petroleum potential of South Africa's onshore Karoo basins (abs.)]: AAPG International Conference and Exhibition, Cape Town, South Africa, October 26–29, 2008, Search and Discovery Article 10196, 3 p.

* Raseroka, L., and I. R. McLachlan, 2009, [http://www.searchanddiscovery.net/documents/2009/10196raseroka/index.htm?q=%2Btext%3Araseroka The petroleum potential of South Africa's onshore Karoo basins (abs.)]: AAPG International Conference and Exhibition, Cape Town, South Africa, October 26–29, 2008, Search and Discovery Article 10196, 3 p.

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* Zou, C.-n., S.-z. Tao, X.-h. Gao, Y. Li, Z. Yang, Y.-j. Gong, D.-z. Dong, X.-j. Le, et al., 2010, [http://www.searchanddiscovery.net/abstracts/pdf/2010/annual/abstracts/ndx_caineng.pdf Basic contents, geological features and evaluation methods of continuous oil/gas plays in China]: AAPG Search and Discovery Article 90104, 7 p.

* Zou, C.-n., S.-z. Tao, X.-h. Gao, Y. Li, Z. Yang, Y.-j. Gong, D.-z. Dong, X.-j. Le, et al., 2010, [http://www.searchanddiscovery.net/abstracts/pdf/2010/annual/abstracts/ndx_caineng.pdf Basic contents, geological features and evaluation methods of continuous oil/gas plays in China]: AAPG Search and Discovery Article 90104, 7 p.