二连盆地基底石炭系碳酸盐岩油藏的发现及地质特征

Discovery and Geologic Characteristics of Carboniferous Basement Carbonate Reservoir in Erlian Basin

赛汉塔拉凹陷赛51井首次发现了基底石炭系碳酸盐岩油藏,酸压试油获得日产油226m3。这是二连盆地自1979年大规模石油勘探以来获得的最高产量,也是在中国东部地区石炭系碳酸盐岩中的首次发现,为中国东部开辟了一个重要的油气勘探新领域。赛51油藏位于赛汉塔拉凹陷缓坡一侧的扎布断阶带上,紧邻主生油洼槽,具有不整合面与断层两种供油方式,油气源充足;同时,有利的背斜圈闭形态、孔缝洞十分发育的石炭系碳酸盐岩储层、良好的以致密火山岩为主的盖层条件等,是该油藏形成并高产富集的关键因素。赛51油藏的发现对类似地质条件的地区具有重要的指导意义。

A basement Carboniferous carbonate reservoir is discovered with production rate of 226 m^3/d through acid-fracturing production test in Well Sai-51 in Saihan Tal Sag, Erlian Basin. It has been the highest production rate since large-scale petroleum exploration was initiated in Erlian basin in 1979 and it also becomes an important new field of oil and gas exploration as the first discovery in eastern China. Sai-51 reservoir is located at a multiplefault zone on the gentle slope of the sag that is adjacent to the main oil-generating trough through which hydrocarbon is sufficiently supplied by two kinds of oil supplying modes including unconformity surface and faults. Favorable anticlinal traps and developed pores, fractures and caves are common in the Carboniferous carbonate reservoir that is capped by tight volcanic andesite rock, which is the key for rich hydrocarbon accumulation in the reservoir and high oil yield. The discovery of Sai-51 reservoir plays an important role for the areas with similar geologic settings.