地表油气地球化学勘探中轻烯烃形成机理探讨

发布时间：2018-03-24 15:38

本文选题：油气地球化学勘探　切入点：烯烃　出处：《天然气地球科学》2017年02期

【摘要】：油气藏烃类能够垂向微渗漏到地表是油气地球化学勘探的理论基础。在油气田地表轻烃检测中,高浓度C_1—C_5烷烃常常伴有烯烃(C_2H_4,C_3H_6),众所周知,地下的石油和天然气中是不存在轻烯烃的。目前地表油气地球化学勘探中,土壤中的烯烃普遍被认为是地表原位有机物在一定条件下由微生物生成。油气藏地表烯烃异常的客观存在,如不给出合理的解释,将导致地质界对油气藏地表轻烷烃异常的质疑,影响地球化学勘探技术的应用。通过渤海湾盆地济阳坳陷惠民凹陷南坡临南油田、美国怀俄明州Teapot Dome油田地表地球化学勘探实例发现,油田区地表土壤轻烃异常中含有烯烃,且烯烃与烷烃相关性较好,并与油气区吻合度较高,说明这些烯烃并非来自地表原位有机质的生物作用。为了进一步说明油气藏地表烯烃的来源,对油气藏烷烃类垂向微渗漏到地表的地球化学特征进行了实验模拟,实验结果发现,模拟的地表土壤轻烃异常中含有较高浓度的烯烃,且烯烃与烷烃相关性较高,说明烯烃是在地表环境中由微渗漏的烷烃演化而来,具有油气指示意义。上述研究结果初步阐明了油气田地表轻烯烃异常形成机理,证实了地球化学勘探中轻烃异常对油气藏指示的可信性,同时为轻烯烃作为地表地球化学勘探新指标提供了理论和实践依据。
[Abstract]:The vertical microleakage of hydrocarbon to the surface of oil and gas reservoir is the theoretical basis of oil and gas geochemical exploration. In the detection of light hydrocarbon on the surface of oil and gas field, the high concentration of C_1-C_5 alkanes is often accompanied by alkene C _ 2H _ 4 C _ 2H _ 4C _ 3H _ 6, which is well known to all. There are no light olefins in underground oil and gas. Olefin in soil is generally considered to be in situ organic matter generated by microorganisms under certain conditions. The objective existence of surface olefin anomalies in oil and gas reservoirs, such as failure to give a reasonable explanation, This will lead to the questioning of surface light alkane anomalies in oil and gas reservoirs by geological circles and affect the application of geochemical exploration techniques. Through the Linnan oilfield on the south slope of Huimin depression, Jiyang depression, Bohai Bay Basin, An example of surface geochemical exploration in Teapot Dome oilfield, Wyoming, USA shows that the surface soil light hydrocarbon anomaly contains olefin, which has good correlation with alkane, and is in good agreement with oil gas area. In order to further explain the source of surface olefins in oil and gas reservoirs, the geochemical characteristics of vertical microleakage of alkanes to the surface of oil and gas reservoirs are simulated experimentally. The experimental results show that the simulated soil light hydrocarbon anomaly contains higher concentration of olefin and higher correlation between olefin and alkane, which indicates that olefins evolved from microleakage alkanes in the surface environment. The above research results preliminarily clarify the formation mechanism of light olefin anomalies on the surface of oil and gas fields, and confirm the credibility of light hydrocarbon anomalies in geochemical exploration to the indicators of oil and gas reservoirs. It also provides theoretical and practical basis for light olefin as a new index of surface geochemical exploration.
【作者单位】：中国石化石油勘探开发研究院无锡石油地质研究所;杭州电子科技大学材料与环境工程学院;
【基金】：国家自然科学基金项目(编号:41373121;41072099)联合资助
【分类号】：P618.13;P632

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