摘要
基于大量露头实测和卫星影像资料,探讨了塔里木盆地西克尔地区奥陶系溶洞系统特征及主要控制因素。根据溶洞系统成群、成层状分布特征,提出了溶洞群的观点。并以溶洞充填物为主要依据,将研究区内溶洞群分成碎屑物质充填型和热液矿物充填型两大类。平面上,溶洞群是多个单一溶洞系统的组合,溶洞主体呈雁列式排列,溶洞系统中的缝、洞连片分布形成统一整体,其中,单个溶洞以岩溶管道和厅堂2种形态为主;纵向上,溶洞群由多个单一溶洞成层状有规律地分布,多级次裂缝沟通了不同溶洞主体,其中单个溶洞主体形状以圆形、椭圆形和扁豆状为主。在此基础上,综合溶洞系统宏观特征及分布特点、充填物岩石学特征、充填物碳、氧同位素和87Sr/86Sr值等多种因素,明确了研究区溶洞系统充填期次,得出溶洞系统的分布受控于古气候、溶蚀沟道和断裂系统,其中,古气候是溶洞系统发育的基础,而溶蚀沟道和断裂系统对溶洞发育的后期改造起重要作用,且以断裂系统控制为主。为此,提出了断裂系统控制下溶洞系统发育的2种过程模式,以期为塔北覆盖区溶洞型岩溶储层预测提供理论依据。
Based on the outcrop and satellite image,this paper discussed the characteristics of Ordovician ca- ve system and its main controlling factors in Xekar,Tarim Basin. As paleokarst cave system was distributed grouped and layered, view of cavern system groups is put forward. And cavern system groups of the re- search area were divided into a single fracture-cavity system and cavern group system based on the detailed observation of cavern fillings. On the planar,the shape of single fracture-cavern was as single hole and hall, but the shape of cavern group was the combination o{ multiple single cave system. On the cross section, cavern system group is the combination of multiple single cave system distributed into a layer regularly. Different karst caves were connected by multiple scale fractures, in which shape of a single cavity body is mainly circular, elliptic and lenticular. With the analysis of fracture-cavern shape and their distribution characteristics, also various geochemical analysis data, such as carbon and oxygen isotopes, strontium iso- tope （~7Sr/86Sr）,we conclude that the distribution of paleokarst cave system in study area is dominated by climate,unconformity,channel system and fault system. Climate and unconformity are foundation for the development of fracture-cavity system, and the channel system and fault system, especially fault system, play significant role in later reformation of cave. The development model and mechanism of fracture-cavity system dominated by unconformity-channel system and the development process and model of fracture-cave dominated by facture system are generalized systematically,which is expected to provide theoretic basis for paleokarst cave system reservoir predication in the subarea of north Tarim Basin.
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2014年第2期167-177,共11页
Natural Gas Geoscience
基金
国家科技重大专项(编号:2011ZX05004)资助
关键词
西克尔
溶洞系统
奥陶系
溶洞群
控制因素
形成机理
Xekar
Cave system
Ordivieian
Cavern system groups
Controlling factor
Formation mechanism
