闵桥地区火山岩油气储层特征及油气成藏规律分析

Oil and gas reservoir characteristics of volcanic rocks and hydrocarbon accumulation regularity in Minqiao area

江苏油田闵桥地区火山岩油藏为典型多期次喷出玄武岩油藏,通过岩心观察和实验分析,认为研究区发育熔岩和火山沉积岩两大类火山岩,火山岩储层发育原生和次生两类储集空间,并具有中-低孔隙度、低渗透率、强非均质性等特点。通过单井和剖面等研究,认为研究区火成岩发育多个期次,每个期次又可划分为4种岩相类型,不同岩相具有不同的孔隙特征。在断层发育、裂缝分布等的分析基础上认为,研究区正断层不仅控制着火山岩的厚度,并且控制了构造裂缝的发育,裂缝的出现沟通了气孔、溶孔等孔隙,形成了火山岩的有效储层,最终来自于深凹的油气通过断层在该处火山岩聚集,在此认识基础上提出了研究区断-缝-孔成藏模式。

Volcanic oil reservoir of MinQiao area in Jiangsu oilfield is a typical basalt reservoir with more extrusive periods.Through core observation and experimental analysis,the results indicate there are two kinds of volcanic lava and igneous sedimentary rock developed in the area.The igneous rock reservoir developed the two types of reservoir space,the primary and secondary ones,with the characteristics of medium-low porosity,low permeability,strong heterogeneity,etc.After research on single well and profiles analysis,the igneous rock developed multiple periods and each period can be divided into four types of lithofacies.Different lithofacies are of different porosity characteristics.Based on faults development and fracture distribution analysis,the normalfaults not only control the thickness of the igneous rocks but also control the development of structural fracture.The fractures communicate the the pores and solution pores,forming the effective reservoirs for the igneous rocks.Finally the hydrocarbon from the deep sag accumulated through the faults.Based on this understanding,the accumulation pattern of fault-fracture-pore has been provided.