松辽盆地下白垩统沉火山碎屑岩优质储层特征和形成机理  

Characteristics and formation mechanisms of high quality reservoir of volcaniclastic sedimentary rocks of Early Cretaceous in Songliao Basin

作　　者：唐华风[1] 孔坦 刘祥[2] 杨迪[1] 霍宏宇[2] 黄玉龙[1] 

机构地区：[1]吉林大学地球科学学院,吉林长春130061 [2]中国石油吉林油田公司勘探开发研究院,吉林松原138000

出　　处：《石油学报》2016年第5期631-643,共13页Acta Petrolei Sinica

基　　金：国家重点基础研究发展计划(973)项目(2012CB822002);国家自然科学基金项目(No.41472304);和吉林大学优秀青年教师培养计划项目资助

摘　　要：松辽盆地王府断陷沉火山碎屑岩中发现了高丰度气藏,但对该类优质储层分布规律和形成机制的认识还不清楚。以王府断陷CS6井区沙河子组为例,利用铸体薄片、压氦法、压汞法和核磁共振方法研究了储集空间类型、储层物性、孔喉和孔隙直径,探讨了优质储层的形成机理和主控因素。研究结果表明优质储层岩性为沉集块岩和沉角砾岩,为向上变粗的序列。进一步识别出3类7种储集空间类型,其中具有丰富原生孔隙的岩屑内气孔是沉火山碎屑岩优质储层独有特征,为大孔隙-小喉道型储层;沉集块岩孔渗稍高于沉角砾岩、二者均明显高于沙河子组沉积岩,其孔隙度与埋深关系密切。沉火山碎屑岩储层形成机理为母岩挥发分逸出、颗粒支撑、溶蚀和构造改造作用,其中前两者为主控因素。研究区优质储层主要分布在沉火山碎屑岩扇体平面位置的中部,其中颗粒支撑、颗粒粗、岩屑内气孔碎屑含量高和埋深小于3 000 m的沉火山碎屑岩最为有利。The prolific gas reservoir of volcaniclastic sedimentary rocks of Early Cretaceous of Wangfu fault sag （WFS） in SongliaoBasin （SB） was found in 2011. However, the characteristics and formation mechanisms of high quality reservoirs in volcaniclasticsedimentary rocks of SB is not well understood. In this paper, volcaniclastic sedimentary rocks of Shahezi Formation of well blockCS6 in WFS of SB is taken as an example of high quality reservoirs. The void space,porosity-permeability, pore throat and pore diameterare discussed using the following method; thin sections impregnated with blue epoxy resin, helium （He） injection, mercury（ Hg） injection and nuclear magnetic resonance respectively. The formation mechanism and main controlling factors of high qualityreservoirs are analyzed based on all the above methods. The result shows that the high quality reservoirs are reworked lapilli andbreccia,and exhibits the coarsening-upward successions. Primary and secondary porosity and secondary fracture porosity has been identted.The intragranular vesicular of primary porosity are distinguished void space of high quality reservoirs. It has the characteristicsof large pore and small throat. The porosity and permeability of reworked breccia is higher than reworked lapilli, and both displayrelatively higher porosity and permeability than the sedimentary rocks in Shahezi Formation. The porosity is correlated to burialdepth. The formation mechanism of volcaniclastic sedimentary rocks reservoir are gas released in parent rocks, grain-support contacts,alteration by organic acid and tectonic deformation. The main controlling factors of reservoirs formation are gas released in parentrocks and the grain-support. The high quality reservoirs are distributed in the middle part of alluvial fan of volcaniclastic sedimentaryrocks. Volcaniclastic sedimentary rocks with grain-support, coarse particle, highly percentage of volcaniclasts with intragranularvesicle and burial depth less than 3 3 0 m are the favorable target of explora

关 键 词：沉火山碎屑岩 储层形成机理 有利勘探目标 沙河子组 王府断陷 松辽盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]