准噶尔盆地车排子凸起火山岩储层特征及主控因素

Characteristics and main controlling factors of igneous reservoirs in Chepaizi uplift,Junggar Basin

准噶尔盆地石炭系火山岩油气勘探取得重大突破,火山岩储层特征研究成为深化井位部署的重要依据.文章通过岩心观察、薄片鉴定、物性测试和测录井资料分析等技术手段,对准噶尔盆地车排子凸起东部火山岩的岩相分布、储层特征及主控因素进行研究.结果表明:火山岩相可划分为近火山口相、爆发相、喷溢相、火山沉积相,储层岩性为凝灰质砂岩、火山角砾岩、凝灰岩、安山岩和玄武岩;近火山口相火山角砾岩储层具有最高的孔隙度,爆发相凝灰岩储层具有最高的渗透率;储集空间为原生孔隙、次生孔隙和裂缝,微裂缝和粒内溶孔占总孔隙类型的77.4%.近火山口相和爆发相要优于其他岩相,渗流层和潜流层中储层受溶蚀作用最为强烈,裂缝对各类孔隙起到重要的连通作用,且是影响溶蚀孔发育的重要因素.

The lithofacies distribution,reservoir characteristics and main controlling factors of igneous rocks in the eastern Chepaizi uplift of Junggar Basin are studied,by means of core observation,thin section identification,physical property testing and logging data analysis.It is considered that volcanic lithofacies can be divided into near Crater facies,explosive facies,eruptive facies and volcanic sedimentary facies,and that reservoir lithology includes tuffaceous sandstone,volcanic breccia,tuff,andesite and basalt;volcanic breccia reservoir with near-crater facies has the highest porosity and tuff reservoir with explosive facies has the highest permeability;reservoir space includes primary pore,secondary pore and fracture;micro-fracture and intragranular solution pore account for 77.4%of the total pore type;near-crater facies and explosive facies are superior to other lithofacies,and reservoirs in seepage and subsurface are eroded.Fractures play an important role in connecting all kinds of pores,and they are important factors affecting the development of dissolution pores.