摘要
通过对春风油田22口井微体化石分析,首次在该地区见到了丰富的介形类和轮藻化石,分别建立了2个介形类化石组合和2个轮藻化石组合:Ⅰ.Cypridea tuguluensis-Djungarica stolida组合,Ⅱ.Cyprideis littoralis-Ilyocypris errabundis组合,Ⅲ.Aclistochara(Caucasuella)shaqiuheensis-Aclistochara(Caucasuella)changjiensis组合,Ⅳ.Hornichara lagenalis-Nitellopsis obtuse组合,第Ⅱ和第Ⅳ组合时代为新近纪,第Ⅰ和第Ⅲ组合时代为早白垩世。根据化石组合特征确定了春风油田上部主力油层归属新近系沙湾组,为油气埋藏的认识和储量规模的确定提供了依据。依据微体古生物的生态特征,分析认为K_1tg为一种开阔平静的淡水湖泊相沉积环境,N_1s为一种较动荡的辫状河三角洲相至湖相的沉积环境。
Through the microfossil analyses of 22 wells in Chunfeng Oilfield, abundant ostracods and charophytes are detected for the first time in this area. Two ostracode assemblages and two charophyta assemblages are established： Ⅰ . Cypridea tuguluensis-Djungarica stolida ostracode assemblage and Ⅱ. Cyprideis littoralis-Ilyocypris errabun- dis ostracode assemblage Ⅲ. Aclistochara （ Caucasuella ） shaqiuheensis-Aclistochara （ Caucasuella ） changjiensis charcr phyta assemblage and IV. Hornichara lagenalis-Nitellopsis obtuse charophytal assemblage. The geologic age of as- semblage Ⅱ and IV are Neogene, the geologic age of Ⅰ and Ⅲ are Early Crataceous. According to the microfossil as- semblages, the major reservoirs of upper layer in the Chunfeng Oilfield are determined as Shawan Formation of Neo- gene, which provided the recognition and evidence of reserve size. By analysis of ecological characteristics of micro- palaeontology, it is considered that the sedimentary environment of the early Cretaceous（K1ts） was open calm fresh- water lake facies, while Neogene（N1g） was turbulent braided river delta to lake facies.
出处
《微体古生物学报》
CSCD
北大核心
2015年第4期372-383,共12页
Acta Micropalaeontologica Sinica
基金
中国石油化工股份有限公司科学技术研究开发项目(P12028)准西北地区超剥带成藏规律及勘探目标~~
