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. Horizontal 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.