地球物理学进展 ›› 2016, Vol. 31 ›› Issue (4): 1525-1541.doi: 10.6038/pg20160416

• 空间与固体地球物理 • 上一篇    下一篇

岩浆热场对油气成藏的影响

张旗1,2, 金维浚1, 王金荣3, 陈万峰3, 李承东4, 焦守涛1, 邵国良5   

  1. 1. 中国科学院地质与地球物理研究所, 北京 100029;
    2. 中国科学院地质与地球物理研究所岩石圈演化国家重点实验室, 北京 100029;
    3. 兰州大学地质科学与矿产资源学院, 兰州 730000;
    4. 中国地质调查局天津地质矿产研究所, 天津 300170;
    5. 中国石油华北油田公司勘探开发研究院, 任丘 062552
  • 收稿日期:2015-12-16 修回日期:2016-05-15 出版日期:2016-08-20 发布日期:2016-08-20
  • 作者简介:张旗,男,1937年生,研究员,岩石学和地球化学专业.(E-mail:zq1937@126.com)
  • 基金资助:

    国家自然科学基金重大研究计划(91014001)和中国科学院地质与地球物理研究所岩石圈演化国家重点实验室资助的研究.

Relationship between magma-thermal field and hydrocarbon accumulation

ZHANG Qi1,2, JIN Wei-jun1, WANG Jin-rong3, CHEN Wan-feng3, LI Cheng-dong4, JIAO Shou-tao1, SHAO Guo-liang5   

  1. 1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;
    2. State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;
    3. School of Earth Sciences, Lanzhou University, Lanzhou 370000, China;
    4. Tianjin Institute of Geology and Mineral Resources, China Geological Survey, Tianjin 300170, China;
    5. Research Institute of Petroleum Exploration and Development, Huabei Oilfield Company, PetroChina, Renqiu 062552, China
  • Received:2015-12-16 Revised:2016-05-15 Online:2016-08-20 Published:2016-08-20

摘要:

在油气勘探领域,沉积岩一直是研究的热点和焦点,对火成岩国内外均较少涉及且普遍认为它对油气的生成和聚集成藏有破坏作用.随着研究的进展,人们发现,岩浆侵入和喷出活动对油气成藏具有重要的作用,而且,岩浆岩本身还可能是很好的油气储层.研究表明,由岩浆侵入和喷出带来的热所形成的热场(岩浆热场)与油气成藏的关系几乎是全方位的,它几乎参与了油气生成、演化的全过程,既有有利于油气成藏的积极的一面,也有破坏油气成藏的消极的一面.大体表现在下述5个方面:(1)岩浆热场不仅可以造成围岩的变质和变形,其所带来的大量热和流体对油气的生成、运移、聚集以及油气藏的形成与保存有明显影响.(2)岩浆热场提高了有机质的热演化程度,使生油门限变浅,使烃源岩达到高成熟或过成熟,使烃源岩中残余有机质丰度降低.岩浆热场提高了盆地的地温梯度,使原本成熟度低的烃源岩达到生油窗的温度范围,促进生烃作用进程,加速烃源岩的热成熟,并为油气运移和聚集提供了运移通道、储集空间、封盖遮挡条件和圈闭构造,有利于油气的运移、聚集和成藏.岩浆热场带来的流体主要是由多元组分构成的超临界流体,其上升、对流、循环可使热场范围内的物质与能量发生调整和再分配.在流体上升过程中,可萃取、富集沉积物中的分散有机质,对生烃产生显著的加氢作用,从而为油气的形成补充物源.流体还能与围岩储层发生反应,改善储层的孔渗条件,有利于油气的聚集成藏,抑制烃类的热裂解.(3)岩浆热场还与非常规油气(页岩气、天然气水合物、煤层气等)有关.岩浆热场的作用主要是使泥页岩成熟度提高,岩浆侵入造成的构造压力使泥页岩产生大量裂缝,提高了泥页岩的有机孔隙度以及泥岩对页岩气的吸附力,使位于岩浆热场中的泥页岩生烃强度大、储集性好、吸附能力强,成为页岩气有利的富集区.(4)有机的煤、油、气与无机的金属相伴成矿(成藏)是最具吸引力的.油气田中常伴有各种金属元素,当含上述元素的热液与有机质相遇时,会促使有机质向烃类物质转化.有机与无机矿床(藏)时空上的密切联系,说明有机-无机质相互作用是多种能源矿产共存成藏(矿)的重要因素.有机油、气、煤所具有的吸附作用、还原环境和络合作用对无机铅锌金铜铀的沉淀、富集和成矿有利;同样,在烃类生成过程中,无机组分有时也具有催化剂的作用,也能使有机碳更多的与氢结合生成更多的烃类.(5)岩浆热场还是一把双刃剑,对油气成藏既有有利的一面,也有不利的一面.研究表明,油气大量生成和运移时期以前发生的岩浆活动对油气藏保存无不利影响,油气生成运移期或其以后的岩浆活动,则有可能对油气藏起明显的破坏作用.新形成的高温热场可能吞噬和破坏储油层及其结构,使油气向上散逸.此外,高温岩浆侵入生油层后,还会对周围生油母质及生成的油气进行烘烤使之炭化.

Abstract:

In the oil and gas exploration, sedimentary rock has always been the research hotspot and focus, the igneous rocks are less concerned at home and abroad, and are widely believed that they damaged the generation and accumulation of oil and gas accumulation. With the research, researchers found that magma intrusion and eruption plays an important role in hydrocarbon accumulation, and igneous rock itself may become favorable oil and gas reservoir. Studies have shown that magma thermal field formed by the magma intrusion and eruption is almost involved in the whole oil and gas generation and evolution process. It has both advantages and disadvantages on hydrocarbon accumulation. It is embodied in the following six aspects: (1) Not only can magma thermal field cause metamorphism and deformation of the surrounding rocks, but also bring a lot of heat and fluid. Magmatism have obvious influence on the oil and gas generation, migration, accumulation and reservoir formation and preservation. (2) Magma thermal field improves the thermal evolution degree of organic matter, makes oil threshold becomes shallow, makes hydrocarbon source rocks to reach high mature or over mature, reduces residual organic matter abundance in hydrocarbon source rocks. Magma thermal field improves the basin geothermal gradient, makes originally low maturity hydrocarbon source rocks to the temperature range of the oil window, promotes the hydrocarbon generation process, accelerates the thermal maturity of hydrocarbon source rocks, and provides the migration pathway for oil and gas migration and accumulation, reservoir space and barrier conditions and trap structures, have advantages to the oil and gas migration and accumulation. The fluid is mainly composed of multiple components of supercritical fluid whose rise, convection and cycle can make the matter and energy in adjustment and redistribution within the scope of the thermal field. In the fluid rise, it extracts and enriches the dispersed organic matter in sediments, acts on hydrocarbon hydrogenation significantly, which supplies the oil and gas formation source. Fluid can react with surrounding rock to improve the reservoir permeability, conducive to the oil and gas accumulation, inhibits thermal cracking of hydrocarbon. (3) The magma thermal field affects unconventional hydrocarbon resources (shale gas, gas hydrate, coal bed methane). The magma thermal field can improve the shale maturity. The tectonic stresses caused by magma intrusion make mud shale to produce a large amount of cracks, improve the organic shale porosity and shale gas adsorption. The shale reservoir in magma thermal field is of high hydrocarbon generation intensity and high adsorption ability.(4) Organic coal, oil, gas accompanied by metal mineralization is the most attractive. Oil and gas fields often accompanied by various kinds of metal elements, while hydrothermal fluid contained of these metal elements meet organic, would lead to the transformation of organic matter into hydrocarbons. Organic and mineral deposits are closely linked on the time and space, which shows that the organic-inorganic qualitative interaction is an important factor of a variety of mineral accumulation energy. Adsorption, reduction environment and complex of the oil, gas and coal is favorable to precipitation, enrichment and mineralization of inorganic lead, zinc, gold, copper and uranium; Similarly, in the process of hydrocarbon generation, inorganic components sometimes are of the catalyst function, can also make more organic carbon combines with hydrogen to generate more hydrocarbons. (5) Magma thermal field is a double-edged sword, is of both the advantages and disadvantages to the hydrocarbon accumulation. Studies have shown that the magmatism had no adverse effect on reservoir preservation if it happened before the period of hydrocarbon generation and migration, the magmatism have obvious damage on reservoirs if it happened after generating hydrocarbon migration period . The new high temperature thermal field may engulf and destroy reservoir and its structure, and make oil and gas to escape upwards. In addition, the high temperature magma will intrude into the surrounding source rocks and bake the oil and gas carbonization.

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