渤海海域前新生代基底特征及其油气勘探意义

基于渤海钻井资料和三维地震资料,梳理了渤海海域前新生代基底岩性、地层、结构、构造特征。将渤海基底划分为前寒武系、古生界、中生界三个构造层,论述了各个构造层残余地层分布特征,并将基底结构分为三种类型,单层型、双层型、三层型。基底构造演化表现为“垂直升降→强烈挤压→局部伸展→强烈伸展反转→整体隆升→‘伸展+走滑’复合改造”6大阶段。结合薄片及物性资料探索了基岩储层发育规律,单层型前寒武系变质岩、双层型顶部的碳酸盐岩或火山岩、三层型顶部中生界火山岩为有利的勘探目标。围绕在富烃凹陷周边的潜山,在岩性和供油窗口耦合的情况下,具有良好的勘探前景。

Characteristics of Pre-Cenozoic Basement in Bohai Sea and its Significance in Oil and Gas Exploration

Based on the Bohai drilling and 3D seismic data, lithology, stratigraphy and structural features of the Pre-Cenozoic basement in the Bohai sea have been integrated. The Bohai sea basement is divided into three structural layers: Pre-Cambrian, Paleozoic and Mesozoic. Distribution characteristics of the residual layers in each structural layer are discussed, and the basement structure is divided into three types: single, double and three level. Tectonic evolution of the basement comprises six stages: vertical rise and fall, strong extrusion, local extension, strong extension and inversion, overall uplift, stretch and strike-slip compound transformation. Combining the rock sheet and material data, the development regularity of the basement reservoir is explored. Precambrian metamorphic rocks of the single-layer type, carbonate or volcanic rocks at the top of the double-layer type, and Mesozoic volcanic rocks at the top of the three-layer type are favorable exploration targets. Buried hill around the hydrocarbon rich sag has a good exploration potential under the coupling of lithology and oil-supply window.