松辽盆地滨北地区油气运移输导体系分析

Pathway Systems for Hydrocarbon Migration to Binbei District,Songliao Basin,Northeast China

传统的围绕生烃洼陷的油气勘探在滨北地区受到了严峻的考验,面积占整个松辽盆地1/3的滨北地区的油气勘探一直没有取得突破性进展。分析认为滨北地区存在三大背斜构造带(绥棱背斜带、乾元背斜带和克山—依龙背斜带)和滨州走滑断裂带所构成的输导体系。三大背斜带的形成和定型均早于盆地青山口组主力烃源岩大规模生排烃时间(白垩纪末),并分别倾没于齐家—古龙凹陷北部、黑鱼泡凹陷和三肇凹陷,凹陷生烃潜力的差异决定了紧邻输导体系油气勘探潜力的差异,其中齐家北凹陷和三肇凹陷已经发现了较丰富的油气资源,决定了绥棱背斜带和克山—依龙背斜带油气勘探的潜力较大。乾元背斜带临近黑鱼泡凹陷,由于黑鱼泡凹陷烃源岩成熟度低,烃源岩没有进入大规模生排烃阶段,因此勘探潜力有限;滨州走滑断裂带横穿齐家-古龙凹陷和三肇凹陷,断裂活动时间与烃源岩成熟时间一致,有利于油气的定向运移,同时晚期构造活动西段强而东段弱,从油气保存的角度看,有可能东段优于西段,但从油气的垂向运移看,西段更有可能形成垂向上多层系含油的复式油气聚集带,因此沿整个滨州走滑断裂带是有利的勘探领域。

The Binbei District lies in the northeast of the Songliao Basin, covering 1/3 of the total area. Conventional hydrocarbon exploration around local pod of active source rocks has never come to a prominent progress. Hence, a new idea to direct the hydrocarbon exploration is necessary for the oil exploration in this district. The investigation of the hydrocarbon migrated from the main active source pod developed in the south of the Songliao Basin indicates that the pathway system is the key problem. It is discovered that two kinds of pathway systems are composed of anticline and strike-slip fault respectively. Three big anti- clines formed by tectonic reversal plunged into the west depression of the Qijia-Gulong Depression, the Heiyupao Depression and the east Depression of Sanzhao respectively, all of which are the main hydrocarbon generating depressions. The anticline of the Suileng plunged into the Sanzhao Depression formed earlier than the maturation of the source rock, indicating a good exploration potential. While the anticline of Keshan plunged into the west Qijia-Gulong Depression formed synchronizedly with the maturation of the source rock, also indicating a rather good exploration potential. The two big pathway systems composed of strike-slip faults have different exploration potential. The anticline of Qianyuan plunged into the depression of Heiyupao, a local hydrocarbon generating depression, has limited hydrocarbon exploration potential. The fault of Binzhou intersects both hydrocarbon generating depression of Qijia-Gulong and Sanzhao, determining its good exploration potential. The activity of the Binzhou Fault is synchronous with the maturation of the source rock, but its late-stage activity is segmented. While the west part of the fault is more active and much stronger than that of the east part, which favors hydrocarbon migration instead of hydrocarbon preservation.