乌北南二段输导层油气运移优势路径演化研究

EVOLUTION OF DOMINANT OIL-GAS MIGRATION PATHWAYS OF TRANSPORTING LAYER IN SOUTHERN MEMBER 2, THE NORTH OF WUERXUN DEPRESSION

根据输导层内油气运移优势路径的形态特征,将油气运移优势路径划分为汇聚型、发散型和平行型3种形式。通过乌尔逊凹陷北部南二段输导层特征分析,在古埋深恢复的基础上,利用油气运移优势路径研究原理和方法对乌尔逊凹陷北部南二段输导层各地质时期的油气运移优势路径进行了研究。得到该区各地质时期南二段输导层油气运移优势路径的分布具有相似特征,主要有5个汇聚区,以苏1井、苏21井和乌8井汇聚区油气运移优势路径密度大,苏21井汇聚区位于生烃灶的边部,苏1井和乌8井汇聚区位于生烃灶内,有利于油气的运聚成藏。西部两个汇聚区油气运移优势路径密度小,且位于生烃灶之外,不利于油气聚集成藏。该区目前的工业油气流井不是分布在油气运移优势路径的汇聚点处,就是在其优势路径上,这是该区南二段油气成藏的重要条件。

According to the pattern characteristics of dominant oil-gas migration pathways of transporting layer, the patterns of dominant oil-gas migration pathways are divided into three types of coalescence, divergence and parallel patterns. Through the analysis of characteristics of transporting layer of southern member 2 in the north of Wuerxun depression, the oil-gas migration pathways of southern member 2 transporting layer in the north of Wuerxun depression in each geological period are studied based on the reconstruction of ancient burial depth. The direction and distribution pattern of dominant oil-gas migration pathways of transporting layer in the member has similar characteristics in different geological periods. There are five coalescence areas. The cealescance density of dominant oilgas migration pathways in well Su 1,Su 21 and Wu 8 is big, the cealescence area of well Su 21 is at the edge of hydrocarbon kitchen, the cealescence areas of well Su 1 and Wu 8 is in the hydrocarbon kitchen, which is favorable for oil-gas to accumulate and form oilgas reservoirs. The cealescence density of oil-gas migration pathways in the two cealescence areas of the west of this region is small, they are outside the hydrocarbon kitchen, which is not favorable for oilgas to accumulate and form oilgas reservoirs. The industrial oilgas wells now are either in the cealesence areas of oilgas migration pathways or on dominant oilgas migration pathways, which is the important condition for forming oilgas reservoirs.