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印缅俯冲增生楔位于印度板块与欧亚板块俯冲前缘,是深水油气勘探的重要地带。重新审视深水油气勘探潜力、认识增生楔地区油气成藏模式和机理是当前研究热点。印缅俯冲带增生楔提供了一个良好实例和研究契机,它不仅是一个斜向俯冲增生楔,而且是一个气烟囱发育的增生楔。本文基于高精度地震资料,应用地震波组和频谱扫描、地震属性检测以及基于多层感知器的非线性神经网络技术,识别出该区气烟囱具有分带性,且在增生楔斜坡和海沟盆地气烟囱发育。气烟囱总体表现出向海渐新、期次递减的特征,即增生楔斜坡以全新世和中新世两期发育的断层型气烟囱为主,纵向上横跨渐新统至更新统;海沟盆地以全新世发育的背斜型气烟囱为主,纵向上横跨中新统至全新统。气烟囱发育的动力来源为渐新统和中新统烃源岩持续生烃形成的超压,幕式构造活动产生气源通道,古近系和新近系中的泥页岩等提供封盖条件。气烟囱与油气成藏关系密切,具有振幅、频率、相位等地震异常并伴有亮点、平点等地震反射的相关伴生构造是油气运聚的有利目标。结合气烟囱的气源特征,本文提出混源断层型、生物气源断层-背斜型、生物气源背斜型等三种气烟囱成藏模式,指出海沟盆地气烟囱地震异常体具有较好的浅层天然气勘探前景,下覆烃源岩内幕构造、岩性圈闭是另一个有利的油气勘探领域。
The Indosinian subduction accretionary wedge is located on the leading edge of the subduction of India and Eurasia plates and is an important area for deepwater oil and gas exploration. It is the current research focus to reexamine the potential of deepwater oil and gas exploration and understand the hydrocarbon accumulation pattern and mechanism in the area of the Pleistocene wedge. The Indo-Myanmar subduction zone accretion wedge provides a good example and a research opportunity. It is not only a diagonal subduction accretion wedge, but also a accretion wedge with a gas chimney development. Based on the high-precision seismic data, the application of seismic wave sets and spectral scanning, the detection of seismic attributes and the nonlinear neural network based on multi-layer perceptron, this paper identifies the zonal gas chimney in this area, Chimney development. The gas chimneys generally show a trend toward seaward and declining, ie, the accretionary wedge slopes are mainly fault-type gas chimneys developed during the Holocene and Middle Miocene and longitudinally across the Oligocene to the Pleistocene. The Trench Basin The anticline gas chimney developed in the Holocene mainly extends longitudinally from the Miocene to the Holocene. The source of the gas chimney development is the overpressure of continuous hydrocarbon generation in the Oligocene and Miocene source rocks, the source channel in the episode tectonic activity, the shale in Paleogene and Neogene, etc. . Gas chimneys are closely related to the hydrocarbon accumulation. The associated structures with seismic anomalies such as amplitude, frequency and phase accompanied by bright spots and flat spots are favorable targets for hydrocarbon migration and accumulation. Combining with the characteristics of gas source of gas chimney, this paper presents three gas chimney accumulation models of mixed source fault type, biogenic gas source fault-anticline type and biogas source anticline type. It is pointed out that the gas chimney seismic anomalies in Tugou Basin are better Of the shallow gas exploration prospects, underlying the source rock insider structure, lithologic traps is another favorable field of oil and gas exploration.