摘要
塔里木盆地寒武系盐下白云岩作为重要的战略接替区已成为近年来的研究热点。前人主要集中对寒武系白云岩的形成机制和膏盐岩的封盖作用进行了研究,而关于膏盐岩对白云岩储层的影响则少有涉及。本文总结了塔里木盆地寒武系白云岩储层特征,同时探讨了膏盐岩对白云岩储层的影响机制,以期为寒武系盐下白云岩勘探提供指导。塔里木盆地寒武系白云岩主要分为结晶白云岩和微生物白云岩两大类,其中结晶白云岩又可分为泥微晶白云岩、晶粒白云岩和颗粒白云岩,微生物白云岩又可分为凝块石白云岩、叠层石白云岩和泡沫绵石白云岩。受膏盐岩影响的白云岩储层类型可划分为膏溶孔型白云岩储层、晶间孔型白云岩储层和溶蚀孔型白云岩储层。蒸发潮坪环境中,膏盐岩的沉淀有利于克服白云石化的Mg2+的动力学障碍而形成白云岩,同时,微生物作用下SO24-的还原会促进白云石的沉淀。膏盐岩对白云岩储层孔隙的影响主要体现在:含硬石膏结核泥粉晶白云岩易于形成膏溶孔型白云岩储层;膏盐层较高的热导率有利于倒退溶蚀作用的发生;近地表低温条件下硫酸盐的溶解有利于白云石的沉淀;热化学硫酸盐还原作用形成酸性气体有利于深埋溶蚀作用,形成溶蚀孔型白云岩储层。
The Cambrian dolomite in Tarim Basin has become focus in recent years as the significant strategic area.Previous studies have mainly focused on the dolomitization mechanism and the capping effect of salt rock. However,studies of the impact of salt rock on the dolomitization and reservoir formation are very rare. In this study,the authors summarized the dolomite reservoir characteristics of Cambrian Tarim basin and discussed the impact of salt rock on the subsalt dolomite. The Cambrian dolomite in Tarim basin can be classified into two major types,i. e.crystalline dolomite and microbial dolomite. The crystalline dolomite can further be divided into dolomicrite,crystal dolomite and granular dolomite. The microbial dolomite can be divided into thrombolites dolomite,stromatolite dolomite and foamite dolomite. Influenced by salt rock,the dolomite reservoir can be classified into anhydrite dissolved pores type reservoir,intercrystalline pores type reservoir and intercrystalline dissolved pores type reservoir. The salt rock mainly exerted impact on the dolomitization process and the formation of reservoir pores. The precipitation of gypsum and anhydrite in evaporated flat settings increased the Mg2+/Ca2+ratio in the formation fluid,which was favorable for the dolomitization. Besides,the reduction of SO24-influenced by microbial action promoted the precipitation of dolomite. In the aspect of impact on reservoir,the anhydrite dissolved pores were normally good reservoir space,the relative high thermal conductivity was favorable for the retrograde solution of dolomite,the dissolution of sulfate in near-surface condition was favorable for the precipitation of dolomite,and thermochemical sulfate reduction produced sour gas to form dissolved pores.
作者
刘丽红
高永进
王丹丹
白忠凯
张远银
韩淼
LIU Li-hong;GAO Yong-jin;WANG Dan-dan;BAI Zhong-kai;ZHANG Yuan-yin;HAN Miao(Oil&Gas Survey,China Geological Survey,Beijing 100083,China)
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2021年第1期109-120,共12页
Acta Petrologica et Mineralogica
基金
国家自然科学基金青年基金资助项目(41802173)
地质调查项目(DD20190106,DD20190708,DD20190090)。
作者简介
刘丽红(1982-),女,工程师,研究方向油气储层地质学,E-mail:liulihong713@163.com;通讯作者:王丹丹(1982-),女,高级工程师,主要从事油气调查和石油地质综合研究工作,E-mail:ddwangcn@163.com。
