摘要
介绍了从古流体的角度对海相碳酸盐岩区油气保存条件研究的新思路、方法、原理和实例。利用古流体对保存条件进行动态评价,是在建立流体活动事件序列的基础上,对每一期流体尤其是那些关键性流体进行地质与地球化学示踪,确定古油气藏盖层以上的地层中是否有来自于古油藏或古气藏中的流体,或者储层中是否有大气淡水的注入,从而就盖层对流体的封盖能力进行评价。采用这一方法,对川中安平1井、高科1井和合12井的油气保存条件进行了分析,恢复了古油气藏的形成-破坏过程。研究表明,研究区生油窗之前下组合内部的流体相互连通,下组合内部的泥质岩和膏盐岩对下伏流体不具有封隔能力。生油窗期、生气窗期保存条件相对较好,形成了古油藏和古气藏。燕山期-喜马拉雅期以来的隆升,使保存条件变差、热裂解气逸散和水溶气脱溶;古气藏之中的盐水流体由下向上发生垂向流动迁移到上覆寒武系-二叠系之中,古气藏被完全破坏。向上运移的热裂解气和水溶气有可能在上覆三叠系海相碳酸盐岩中重新聚集成藏。
New ideas,methods,principles and examples about hydrocarbon preservation research based on paleo-fluid geochemistry in marine carbonate rock areas are reported in detail.Based on the reconstruction for the sequence of multi-episodic fluid rechargings and geological and geochemical traces of fluid source for each stage＇s fluid,especially the key fluid,it is necessary to determine whether the fluid infillings in strata overlying on seals are from ancient oil and gas reservoirs or whether there are meteoric water to recharge in the ancient hydrocarbon reservoirs.The sealing capability for ancient hydrocarbon reservoirs can be evaluated according to the fluid source in strata overlying on the seal,and this makes dynamic evaluation for hydrocarbon preservation become possible.Making use of the above idea,the sealing capabilities about Well Anping 1,Well Gaoke 1 and Well He 12 are discussed and the process of development and destruction of ancient oil and gas reservoirs are reconstructed.The research indicates that the fluid infillings before oil window were interconnected in the lower association from Sinian to Silurian,and that the sealing capability of pelite and gypsum in the lower association was worse.A good sealing capability for hydrocarbon formed the ancient oil and gas reservoir during oil window and gas window.After gas window,the uplift since Yanshan destroyed the sealing capability of seals,the thermal cracking gas effused upward and the water soluble gas was separated from water in the ancient gas reservoir,the saline fluid under gas-water interface migrated upward and filled into the different strata from Cambrian to Permian,and the ancient gas reservoir was destroyed entirely.It is possible for the thermal cracking gas and water soluble gas migrated upward to form a new gas reservoir in Triassic carbonate rocks.
出处
《成都理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2009年第6期631-644,共14页
Journal of Chengdu University of Technology: Science & Technology Edition
基金
国家重点基础研究发展计划“973”项目(2005CB422106)
“矿物学、岩石学、矿床学”国家重点(培育)学科建设项目(SZD0407)
关键词
古流体
地球化学示踪
内源流体
外源流体
保存条件
paleo-fluid geochemical trace endogenetic fluid introduced fluid hydrocarbon preservation
