松辽盆地南部隐蔽圈闭及有利地区预测

松辽盆地南部可划分出河道砂体、前积朵叶砂体、断层-岩性圈闭、构造-岩性圈闭 4种类型的岩性圈闭和复合圈闭。在地震剖面上,河道砂体表现为强振幅、低频率的前倾或下凹反射,河岸较陡时的河床可依据水平反射终止点确定,点砂坝呈现微凸、河道呈现下凹的特征;前积朵叶体的前积反射结构则表现为平缓下超或顶超,三角洲席状砂体可由前积层上翘部位或顶超尖灭层上翘部位确定,通过振幅、波形和结构的异常可识别分流河道砂体,三角洲前积层系中振幅和波形的变化与砂体关系密切。经综合分析,大情字井地区、东南物源区为油气有利区,乾安-孤店地区为油气较有利区。

SUBTLE TRAPS AND PREDICATION OF FAVORABLE AREAS IN SOUTHERN SONGLIAO BASIN

Southern Songliao basin can be divided into 4 types of litho-trap and composite trap namely,channel sandbody,progradational leafy sandbody,fault-litho-trap and structural-litho-trap.Channel sandbody in seismic profile displays strong amplitude,preclination of low frequency and down concave reflection.If river bank is steep,the river bed can be defined by termination point of horizontal reflection,point sandbar showing slightly convex while channel displaying the characteristic of concave.Progradational reflection configuration of the progradational leafy body shows gentle downlap or toplap.Deltaic sheet sandbody can be defined by warped part of progradatioal bed or warped part of toplap pinch out bed.Branch channel sandbody can be identified by the abnormality of structure and waveform through amplitude.Changes for amplitude and waveform in strata series of deltaic progradation are closely connected with the sandbody.Daqingzijing area and southeasthern source area are believed to be favorable prospecting oil and gas reservoirs while Qianan-Gudian area is considered to be relatively favorable prospecting oil and gas reservoir.