深水褶皱冲断带的构造变形和油气地质特征

DEFORMATION IN DEEPWATER FOLD AND THRUST BELTS AND ITS BEARING ON HYDTOCARBON ACCUMULATION

深水褶皱冲断带是目前全球油气勘探的重要领域,其构造变形和油气地质特征是勘探研究的主要内容。通过对不同地区深水褶皱冲断带的地震剖面解释和综合分析,结合沉积特征对其构造样式、变形特征和石油地质特征进行了研究。研究表明,在主动大陆边缘和被动大陆边缘存在4种不同构造样式的深水褶皱冲断带,即:主动大陆边缘型深水褶皱冲断带;被动大陆边缘背景下的泥岩滑脱型、盐岩滑脱型和重力垮塌滑动型深水褶皱冲断带。由于他们具有不同的驱动机制、构造特征和演化特征,导致了其含油气性差别较大。主动大陆边缘背景下发育的深水褶皱冲断带主要发育倾向陆地的逆冲断层、叠瓦构造以及相关的褶皱构造,缺乏有效的烃源岩和储层。被动大陆边缘背景下发育的深水褶皱冲断带可以划分为伸展区、过渡区和挤压区3部分,并发育相关构造,其中泥岩滑脱型和盐岩滑脱型深水褶皱冲断带已经有大量的油气发现。

Deepwater fold and thrust belts are important targets of oil and gas exploration in the world, and the structural deformation and its geological characteristics are the main concerns of oil and gas geologists. Based on seismic interpretation and comprehensive analysis, as well as the characteristics of sedimentation, we made the research on structural style and deformation of deepwater fold and thrust belts and their bearing on petroleum accumulation. There are four kinds of structural styles in the deepwater fold and thrust belts in both the active and passive continental margins, namely, the active continental margin type under subduction, the mudstone detachment,the salt detachment and the gravitational collapse types of deepwater fold and thrust belt under passive continental margins. There are different driving mechanisms, structural characteristics and evolutionary histories, leading to various hydrocarbon accumulation modes. Thrust, imbricate and associated folds dipping landward are well developed in the deepwater fold and thrust belt in the active continental margin, where effective source rocks and reservoirs are lack. The deepwater fold and thrust belt in passive continental margin is further divided into the extensional, transitional and compressional zones, with relevant structures. Besides, there are a large number of oil and gas discoveries in the mudstone detachment and salt detachment deepwater fold and thrust belts under passive continental margins.