摘要
这是位于松辽盆地南部叠置在元古代及古生代变质岩基底之上的中、新生代沉积区,面积为3.2×10~4km^2,最大沉积厚度约4500m,属断-坳型坳陷。侏罗系与白垩系的构造成因、变形程度和构造展布方向均异。该区可分为5个一级构造单元,14个次级构造单元。有三种含油气组合形式;上侏罗统为主要目的层;陆家堡坳陷及哲中坳陷中的保安、奈曼旗凹陷等含油远景最佳。
Kailu Region in the south part of the Songliao Basin is a Meso-Cenozoic sedimentaryprovince that covers an area of 3.2×10~4 km^2 and developed the Upper Jurassic Series,Cretaceous and part of Tertiary Systems. The sediments that overlaid on Proterozoic-Paleozoic metamorphic basement reached the maximum thickness of 4500 m. Kailu Re-gion underwent four tectonic evolution stages that are tensional faulting, fault--subsiding,depressing and compresson--shearing, and can be divided into 5 first order tectonic unitsand 14 secondary tectonic units. A series of elongated contemporaneous normal faults that stretches NNE or NW withbig vertical throws and a group of separate graben-like lake basins in which igneous rocksdeveloped in the early stage and shore--shallow lake sediments in the late stage formed inthe Jurassic due to the underthrusting of the Pacific Plate and the updoming of mantle.Faulting basically stopped in the Early Cretaceous and the whole region subsided underisostutic effect, resulting in stable extensive shore-shallow lake deposits. From Late Creta-ceous to Tertiary, the variation of regional stress field caused horizontal compression onthe southeast margin, thus forming northeast trend surface folds and causing particularnormal faults to reversal. There are thick dark mudstones in the Jurassic (occupying 60-90% of the totalthickness), which has rich organi matter (organic carbon 2-3% ), type--Ⅰ and type--Ⅱ of kerogen and widespread oil-gas shows. The threshold depth for oil generation is1300m. It is considered that the Jiufotang and Shahai Formations are the main oil-generating intervals, and the Lujiabao Depression, Bao'an and Naimanqi Sags in theZhezhong Depression are the most prospective regions for hydrocarbon exploration.
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
1991年第1期42-51,共10页
Oil & Gas Geology
