松辽盆地青山口组湖相灰岩特征及油气地质意义

Lacustrine limestone characteristics and its petroleum geology implication in Qingshankou formation of Songliao Basin

松辽盆地中央坳陷带龙虎泡-大安阶地与西部泰康隆起的交界处青山口组(Qn2+3)发现了特殊的淡水碳酸盐岩沉积——核形石灰岩与叠层石灰岩。典型的核形石产在杜30井高二砂岩组,典型的叠层石产在杜402井高三砂岩组。通过对此种灰岩的岩电特性、结构组分、沉积特征和主要岩石类型进行的系统性研究,进而对其沉积环境提出了初步认识。该区湖相灰岩的平面分布规律及生油、储油物性研究表明,泰康地区大面积的湖相灰岩具有较强的生油能力,且产在大型油气田的储集岩系之中,对今后新类型储层的寻找具有重要实际意义。

Fresh water carbonate sedimentation,oncolitic limestone and stromatolithic limestone,had been found in Qingshankou formation (Qn2+3) at the juncture of Longhupao-Da’an terrace and west Taikang uplift in the central depression of Songliao Basin.Typical oncolite was found in the second member of Gaotaizi formation in Well Du 30,and typical stromatolite was found in the third member of Gaotaizi formation in Well Du 402.Such limestone has been systematically studied in respects of litho-electro property,composition,sedimentary characteristics and rock types on which basis a preliminary understanding of sedimentary environment is presented.The study of the distribution of lacustrine limestone and petroleum generation and preservation in this area shows that the extensive lacustrine limestone in Taikang had a high oil-generating potential and occurred in a large reservoir rock system,therefore is of great significance to exploration of new type of reservoirs.