摘要
对层状风化壳模式的认识一度支撑着塔里木盆地下古生界深层碳酸盐岩油气勘探,但这类深层碳酸盐岩储层显示出的强烈非均质性使得勘探风险愈来愈大。研究以塔里木盆地塔河地区中—下奥陶统碳酸盐岩储层为典型实例,重点论述了成岩作用和构造—热流体复合作用对储层的制约,并结合表生岩溶等其它要素开展了储层分布综合解释。研究认识到:①奥陶系碳酸盐岩正常深埋藏成岩作用的主要效应是碳酸盐的沉淀而不是碳酸盐的溶解,建设性改造主要与表生岩溶作用(古喀斯特)或构造—热流体作用有关,并导致了碳酸盐岩储层强烈的非均质性。②从中下奥陶统到上奥陶统,下部碳酸盐岩地层热流体活动迹象明显优于上部地层。③奥陶系碳酸盐岩构造—热流体的建设性改造作用主要发生在中—晚泥盆世与二叠纪叠加改造的断裂构造交汇区,以及中—晚奥陶世、前石炭纪形成的表生岩溶发育区;有效储层与高能沉积相带关系有限。为此,提出了奥陶系碳酸盐岩构造—流体作用与储层形成概念模式,这为进一步认识储层的形成分布规律提供了新的线索。
The understanding for layered weathering crust model once sustained oil and gas exploration of the Lower Paleozoic deep-buried carbonate in the Tarim Basin.However,strong heterogeneous characteristics of the carbonate reservoir types increases exploration risk in the study area.As a case study,The Middle-Lower Ordovician carbonate reservoirs of Tahe area,Tarim basin,are studied in this paper,with focuses on superposition effect of burial diagenesis and structurally controlled thermal-fluid,on reservoir formation.Finally,combined with other elements including epigenetic karst process and so on,a comprehensive explanation on reservoir distribution is given in this research.The main recognition includes：① Normal deep-buried diagenesis of Ordovician carbonates mainly resulted in precipitation rather than dissolution,and constructive modification primarily related to the epigenetic karstification（paleo-karst）or structurally controlled thermal-fluid flow and led to strong heterogeneity of carbonate reservoirs.② From the Lower Ordovician to Upper Ordovician,thermal fluid flow evidence in the lower carbonate strata is stronger than that of the upper carbonate strata.③ The constructive modification of structural-thermal fluid flow in Ordovician carbonate mainly occurred in structural intersection of superimposed faults developed during Middle-Late Devonian and Permian,respectively,and the strong pre-existed epigenetic karstification area formed at Middle-Late Ordovician and pre-Carboniferous periods.The most efficient carbonate reservoirs have limited genetic relation with high-energy depositional facies in the study area.This paper puts forward a conceptual model about structural-geofluid processes and related reservoir formation for the Ordovician carbonates in Tahe area,which provides a new clue for further understanding formation and distribution of the studied reservoirs.
出处
《沉积学报》
CAS
CSCD
北大核心
2010年第5期969-979,共11页
Acta Sedimentologica Sinica
基金
国家基础研究发展规划项目(编号:2006CB202304)
国家重大专项(编号:2008ZX05008-003)资助
