【摘要】 为了消除制约琼东南盆地深水区坡折带陵水B构造区油气勘探进程的地层速度规律不清、构造圈闭评价受限、不同地质体交互沉积、岩性圈闭难以刻画等问题,本文提出了基于地质沉积与构造共同约束的高精度叠前深度偏移速度建模方法,从大、中、小三种尺度研究了琼东南盆地深水坡折带少井区地层速度变化规律,并开展了基于气藏模式的单砂体速度验证及校正;针对深水区不同沉积地质体互相影响的岩性圈闭,从井点出发,结合沉积演化规律与叠前地震反演结果,精细刻画了不同沉积体的砂泥岩分布情况,并通过镂空技术立体化展示了不同地质体间的砂泥岩空间分布情况,实现了由点、线、面、体多维度评价岩性圈闭有效性。应用效果表明,深水坡折带陵水B构造区4 000 m埋深的深度误差仅为2～5 m,该构造区梅山组第三期海底扇西块、北块和东块砂体等3个岩性圈闭有效性较好,是较为有利的钻探目标,其中第三期海底扇西块LS7井区对应水道内富泥沉积的T40A砂体钻遇厚气层,首次在梅山组海底扇获得工业气流,在该盆地深水区打开了新的勘探领域。更多还原

【Abstract】 In order to solve the problems that restrict the oil and gas exploration process in Lingshui B structural area of slope break zone in deep-water area of Qiongdongnan basin, such as unclear formation velocity law, limited evaluation of structural traps, interactive deposition of different geological bodies and difficult description of lithologic traps, a high-precision prestack depth migration velocity modeling method based on the constraints of geological deposition and structure is proposed in this paper to study the variation law of formation velocity in the few well area of deep-water slope break zone in Qiongdongnan basin on large, medium and small scales, and verify and correct the velocity of single sand body based on gas reservoir mode. Aiming at the lithologic traps affected by different sedimentary geological bodies in deep-water area, starting from the well point, and combined with the sedimentary evolution law and prestack seismic inversion results, the distribution of sand shale in different sedimentary bodies is finely described, and the spatial distribution of sand shale among different geological bodies is stereoscopically displayed through hollowing out technique, realizing a multi-dimensional evaluation of lithologic trap effectiveness from point, line, surface and body. The application results show that the depth error of 4 000 m buried depth in Lingshui B structural area of deep-water slope break zone is only 2～5 m. Three lithologic traps such as sand bodies of west, north and east blocks of submarine fan in the third stage of Meishan Formation in this structural area have good effectiveness and are favorable exploration targets. Among them, the T40 A sand body with rich mud sediments in the channel corresponding to the LS7 well area in the west block of the third stage submarine fan encountered a thick gas reservoir, obtaining industrial gas flow in the submarine fan of Meishan Formation for the first time, which opened a new exploration field in the deep-water area of the basin.更多还原