<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>M.J. Pawlewicz</dc:contributor>
  <dc:creator>Michael Lewan</dc:creator>
  <dc:date>2025</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;New data including measured reflectance (%&lt;/span&gt;&lt;i&gt;R&lt;/i&gt;&lt;sub&gt;o&lt;/sub&gt;&lt;span&gt;), programmed open-system pyrolysis data, and kerogen elemental analyses obtained on the Mississippian Barnett Shale in the Fort Worth Basin, Texas, indicate that secondary-gas generation starts at 1.5%&amp;nbsp;&lt;/span&gt;&lt;i&gt;R&lt;/i&gt;&lt;sub&gt;o&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and not at the previously prescribed 1.1%&amp;nbsp;&lt;/span&gt;&lt;i&gt;R&lt;/i&gt;&lt;sub&gt;o&lt;/sub&gt;&lt;span&gt;. Oil-cracking kinetic parameters derived from pyrolysis experiments in the presence and absence of water indicate that secondary-gas generation will not occur at a thermal maturity as low as 1.1%&amp;nbsp;&lt;/span&gt;&lt;i&gt;R&lt;/i&gt;&lt;sub&gt;o&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and requires a minimum thermal maturity of 1.5%&amp;nbsp;&lt;/span&gt;&lt;i&gt;R&lt;/i&gt;&lt;sub&gt;o&lt;/sub&gt;&lt;span&gt;. This difference is especially important in using the Barnett Shale as an analog for evaluating other possible shale-gas plays. The new reflectance measurements have a good relationship with hydrogen indices (HIs) and compare well with other published data sets. However, the relationship does not compare well with the previously published data used to prescribe 1.1%&amp;nbsp;&lt;/span&gt;&lt;i&gt;R&lt;/i&gt;&lt;sub&gt;o&lt;/sub&gt;&lt;span&gt;&amp;nbsp;as the start of secondary-gas generation in the Barnett Shale. This discrepancy is attributed to differences in measured %&lt;/span&gt;&lt;i&gt;R&lt;/i&gt;&lt;sub&gt;o&lt;/sub&gt;&lt;span&gt;&amp;nbsp;values and not attributed to differences in the HI values. Lack of publicly available information on the previously reported %&lt;/span&gt;&lt;i&gt;R&lt;/i&gt;&lt;sub&gt;o&lt;/sub&gt;&lt;span&gt;&amp;nbsp;values makes it difficult to ascertain the reason for their lower values. These lower %&lt;/span&gt;&lt;i&gt;R&lt;/i&gt;&lt;sub&gt;o&lt;/sub&gt;&lt;span&gt;&amp;nbsp;values also have impact on the previously prescribed relationship for estimating %&lt;/span&gt;&lt;i&gt;R&lt;/i&gt;&lt;sub&gt;o&lt;/sub&gt;&lt;span&gt;&amp;nbsp;from the temperature at maximum yield by programmed open-system pyrolysis (&lt;/span&gt;&lt;i&gt;T&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt;&lt;span&gt;). As a result, the new data do not agree with a previously described relationship, and the considerable scatter makes the new relationship unreliable. However, the relationship between the HI and %&lt;/span&gt;&lt;i&gt;R&lt;/i&gt;&lt;sub&gt;o&lt;/sub&gt;&lt;span&gt;&amp;nbsp;has less scatter, which indicates that HI offers a better proxy in calculating %&lt;/span&gt;&lt;i&gt;R&lt;/i&gt;&lt;sub&gt;o&lt;/sub&gt;&lt;span&gt;&amp;nbsp;than&amp;nbsp;&lt;/span&gt;&lt;i&gt;T&lt;/i&gt;&lt;sub&gt;max&lt;/sub&gt;&lt;span&gt;&amp;nbsp;for the Barnett Shale. Comparison of various programmed open-system pyrolysis methods (i.e., Rock-Eval II, Rock-Eval 6, Source Rock Analyzer, and Hawk) indicates that variations in HI are within ±10% of one another. An HI of at least 44 mg/g total organic carbon is prescribed as a more certain limit for the start of secondary-gas generation and prospective in situ gas-shale accumulations.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1306/01251716053</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>American Association of Petroleum Geologists</dc:publisher>
  <dc:title>Reevaluation of thermal maturity and stages of petroleum formation of the Mississippian Barnett Shale, Fort Worth Basin, Texas</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>