致密油/凝析油中的轻烃地球化学特征 ——以美国伍德福德￣密西西比油气区带为例

Geochemical characteristics of light hydrocarbons in tight oil /condensate oil：a case study of Woodford-Mississippian oil play in U.S.A.

张冬琳 Matthew Coffey 唐友军 王霆 3

长江大学油气资源与勘探技术教育部重点实验室， 湖北 武汉 430100 美国德文能源有限责任公司， 俄克拉荷马 俄克拉荷马城 73102 美国俄克拉荷马大学地质与地球物理学院， 俄克拉荷马 诺曼 73019

Key Laboratory of Exploration Technologies for Oil and Gas Resources, Ministry of Education, Yangtze University, Wuhan 430100, China Devon Energy Corporation, Oklahoma City 73102, U.S.A. School of Geology and Geophysics, University of Oklahoma, Norman 73019, U.S.A.

密西西比（Mississippian）石灰岩致密储层特征的变化反映了所产油气化学性质的不同，这通常被解释为油气可能来源于不同的烃源岩。文中对产自密西西比石灰岩和伍德福德（Woodford）页岩致密储层中的原油样品的轻烃、分子标志物进行了气相色谱（GC）和气相色谱￣质谱（GC￣MS）测试。结果显示：源自密西西比石灰岩的原油具有独特的地球化学指纹特征，如丰富的长链三环萜烷和独特的庚烷星图展布特征，这些特征指示了有机质来源和热成熟度等信息；原油分子组成特征的差异揭示了可能有2套烃源岩层，分别是伍德福德页岩和密西西比石灰岩。该研究为阿纳达科盆地泥盆系￣密西西比系油气系统中的油气运移提供了地球化学方面的证据和启示，减小了勘探开发的地质风险。

The variations of tight reservoir characteristic of Mississippian Limestone reflect the chemical property differences of the oil and gas produced, which are usually explained by different possible source rocks. This study conducted GC and GC-MS test on light hydrocarbon and molecular markers in crude oil(condensate oil) samples produced in tight reservoir of Mississippian Limestone and Woodford Shale. The results show that the crude oil from Mississippian Limestone has distinct geochemical fingerprint characteristics such as the abundance of extended tricyclic terpanes and unique heptane star diagrams. Such characteristics are indicative of the organic matter sources and thermal maturity. Based on molecular composition difference of crude oil, two possible source rocks were identified including the Woodford Shale and Mississippian Limestone. These geochemical parameters shed light on petroleum migration within Devonian-Mississippian petroleum systems in Anadarko Basin, which mitigate geological risk in exploring and developing petroleum reservoirs.

10.6056/dkyqt202004006