摘要
基于岩心和薄片观察、裂缝充填物包裹体分析、围岩及裂缝充填物碳氧同位素组成和微量元素分析,研究了渤海湾盆地富台油田寒武系—奥陶系碳酸盐岩潜山裂缝充填物的成因和分布。富台油田潜山储集层发育多种成因裂缝,裂缝多为方解石充填,充填率达60%以上,且多数为一期结晶的亮晶方解石。裂缝充填方解石中包裹体均一温度高于潜山储集层温度,而且裂缝充填方解石中发育含油包裹体,说明裂缝方解石充填与油气成藏同期;碳氧同位素和稀土元素组成分析表明,充填裂缝的方解石矿液既带来深层热液,又溶蚀潜山中的灰岩和白云岩,再在潜山浅部裂缝中沉淀形成方解石等物质。裂缝充填物的热液成因,有助于解释裂缝充填物的分布,即富台潜山靠近埕南和埕南二台阶等断层的裂缝充填程度高、远离断层的裂缝充填程度较低。
Genesis and distribution of fracture fillings of the Cambrian-Ordovician carbonate buried-hill in Futai Oilfield of Bohai Bay Basin were investigated based on observation of core samples and thin sections, analysis of inclusions in fracture fillings, stable isotopic compositions of carbon and oxygen as well as trace element compositions in the fillings and surrounding rocks. There are many kinds of fractures developed in Futai buried-hill structure. Generally, the fracture spaces are filled over 60% by calcite, mostly sparry calcite and formed once time in the fractures. The homogenization temperatures of inclusions in calcite fillings in the fractures are higher than those in the buried-hill reservoirs. Oil-bearing fluid inclusions were found in the calcite fillings in the fractures, which means that the fracture filling is at the same time as oil-pool formation. Analysis of compositions of stable carbon and oxygen isotopes and rare earth elements showed that calcite mother fluids（including oil-pool forming fluid） were hydrothermal fluids coming from deep strata in the basin, and the hydrothermal fluids dissolved the limestone and dolomite and then deposited calcite in the fracture networks in the shallow part of the buried-hill structure. The hydrothermal genesis of calcite fillings in the fractures is useful in understanding the distribution of the calcite filling contents in the buried-hill structure, that is, the fractures near Chengnan and Chengnan Ertaijie faults have higher filling contents, while the fractures far from these faults have fewer fillings.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
2015年第4期454-462,共9页
Petroleum Exploration and Development
基金
国家重点基础研究发展计划(973)项目(2011CB201001)
国家油气重大专项(2011ZX05014-004)
关键词
碳酸盐岩潜山
裂缝充填机制
深层热液
富台油田
渤海湾盆地
carbonate buried-hill
fracture filling mechanism
deep thermal fluid
Futai Oilfield
Bohai Bay Basin
