松辽盆地青山口组三段底界不整合面的发现及石油地质学意义

Identification of Uncomformity Plane at the Bottom(K_2qn^3) of Qingsan Member in the Songliao Basin and Its Implication for Petroleum Geology

基于地震资料、岩芯观察、测井资料,并结合微体古生物和地球化学分布特征,通过开展高分辨率层序地层学研究,在松辽盆地北部的西部斜坡区、泰康隆起带、龙虎泡阶地以及滨北地区,发现青三段底界发育一区域性不整合面。该不整合面可作为松辽盆地南、北两大探区(大庆、吉林探区;松辽盆地南部的西部斜坡区和红岗阶地也发育大规模区域不整合面)青二、三段划分和对比的标志,同样也可作为三级层序划分的重要理论依据。该不整合面的形成由差异沉积速率和地壳的差异沉降作用共同控制,属于沉积型不整合面。该不整合面控制青二、三段高频层序的时空分布;宏观控制沉积相带分布;控制青二段高位域砂体在水下的分布,进一步控制油藏类型的形成和油气规模的分布。青三段底界不整合面的发现和提出无疑具有重要的地质理论和油气勘探实践意义。

Based on the seismic, core and logging data, integrated with the characteristics of micro-paleophyte and geochemistry, this study carried out research on high resolution stratigraphy for the Qingshankou Formation, and a regional unconformity of K2qn^3 bottom was found in the west slope block, Taikang uplift zone, Longhupao terrace and Binbei block of Songliao basin. The unconformity can be regarded as an important mark for formation correlation of K2qn^2 and K2qn^3 in the north and south of Songliao basin and an important theory evidence of the 3rd sequence division. Formation of the unconformity was controlled jointly by differential deposit velocity, and depression velocity of earth crust, belonging to deposition uniformity. The unconformity of K2 qn^3 bottom controls the distribution of high resolution of Ks qn2 and K2qn^3, the macro-distribution of sedimentary facies, under water sand-body of HST in Ks qn^2, and oil reservoir styles and the distribution scale of oil. Identification and development of the unconformity of K2qn^3 bottom is no doubt of important significance both in theory and exploration for oil.