声电成像测井在北黄海盆地中生界油气勘探中的应用

北黄海盆地是海域油气勘探新区,经历了多期次的构造演化,地质条件复杂、勘探难度大.利用声电成像测井资料对该盆地东部坳陷某区块的岩性、层理类型、裂缝、古水流及地应力方向进行了分析研究.结果表明：区内中生界岩性主要为砂砾岩、细砂岩、粉砂岩和泥岩;泥岩段水平层理发育,砂岩段则多见楔状交错层理、板状交错层理、小型波状层理;下白垩统、侏罗系的古水流方向在不同并区差异小,总体上呈东偏南向;中生界裂缝不甚发育,多数集中在侏罗系,倾角普遍较大,主要分布于泥岩或泥质粉砂岩,多属无效缝;地应力分析结果指示,研究区最大水平主应力为近东西向.上述研究为该区进一步勘探部署提供了可靠的基础资料.

Application of Acoustic-electric Imaging Logging in Exploration of Mesozoic in North Yellow Sea Basin

The North Yellow Sea Basin is a new offshore oil and gas exploration area, with multiphase tectonic evolution, and the geological conditions are very complicated. Therefore, the HC exploration in this area is rather difficult. Based on acoustic-electric imaging logging data, analysis has been conducted on lithology, the types of bedding, fractures, palaeocurrent direction and in-situ formation stress orientation in the study area of the eastern depression of North Yellow Sea Basin. The study results indicated that the lithologies of Mesozoic in this area consists mainly sandy conglomerate, fine grained sandstones, siltstones and mudstones. Horizon- tal bedding is well developed in mudstone intervals, and wedge cross-bedding, tabular cross-bedding and small wave bedding is often found in sandstone intervals. The palaeocurrent direction of lower Cretaceous and Jurassic was east to south, with no great change in different well-blocks. The dip angle of the Mesozoic is large. Fractures are poor developed in Mesozoic, and most of fractures are in Jurassic, mainly developed in mudstone or argillaceous siltstone. Therefore, most of the fractures are invalid. The analyzing results on in-situ stress indicated that the maximum horizontal principal stress orientation in study area is near east-west. The study results can provide reliable basic data for further oil and gas exploration in this area.