<?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>Qilong Fu</dc:contributor>
  <dc:contributor>Xun Sun</dc:contributor>
  <dc:contributor>Paul C. Hackley</dc:contributor>
  <dc:contributor>Lucy Tingwei Ko</dc:contributor>
  <dc:contributor>Deyong Shao</dc:contributor>
  <dc:creator>Tongwei Zhang</dc:creator>
  <dc:date>2021</dc:date>
  <dc:description>&lt;p class="abstractnoin"&gt;Typical meter-scale lithofacies cycles from the Wolfcamp A in the Delaware and Midland Basins comprise basal carbonate facies overlain by calcareous or siliceous mudrocks. Siliceous mudstones are the most organic-rich facies with high total organic carbon (&lt;i&gt;TOC&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&amp;gt; 3 wt. %), whereas thin carbonate beds have the lowest organic matter (OM) content among the lithofacies present (&lt;i&gt;TOC&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;TOC, programmed pyrolysis analysis, and residual gas analysis from rock crushing.&lt;/p&gt;&lt;p&gt;Oil saturation index (&lt;i&gt;OSI&lt;/i&gt;) (the amount of free oil normalized by&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;TOC&lt;/i&gt;;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;OSI&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;=&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;S&lt;/i&gt;&lt;sub&gt;&lt;i&gt;1&lt;/i&gt;&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;× 100/&lt;i&gt;TOC&lt;/i&gt;) is used as an indicator of oil enrichment or depletion in the reservoir, where&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;S&lt;/i&gt;&lt;sub&gt;&lt;i&gt;1&lt;/i&gt;&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;is volatile oil in programmed pyrolysis (temperature = 300°C). Both&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;TOC&lt;/i&gt;-lean carbonate and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;TOC&lt;/i&gt;-rich mudstone lithofacies have high&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;OSI&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;in these meter-scale cycles (average&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;OSI&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;is 124.5 mg HC/g&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;TOC&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;for carbonate beds), indicating that migrated oil is present. Residual gas analyses show lower dryness values (C&lt;sub&gt;1&lt;/sub&gt;/C&lt;sub&gt;1–5&lt;/sub&gt;) and higher oil indicator values (100 × C&lt;sub&gt;4+5&lt;/sub&gt;/C&lt;sub&gt;1–5&lt;/sub&gt;) in&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;TOC&lt;/i&gt;-lean carbonate beds compared to the&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;TOC&lt;/i&gt;-rich mudstones, likely indicating a cumulative oil and gas charging effect through source rock maturation. Oil and gas generated at different stages of thermal maturation were partially expelled from OM-rich siliceous/calcareous mudstones into adjacent OM-lean carbonate beds. This study shows oil expulsion from source to adjacent carbonate beds is a key factor in variations of oil saturation in the Wolfcamp A.&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1306/01152120065</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>American Association of Petroleum Geologists</dc:publisher>
  <dc:title>Meter-scale lithofacies cycle and controls on variations in oil saturation, Wolfcamp A, Delaware and Midland Basins</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>