大庆兴城南部火山岩储层发育控制因素

Control Factors of the Volcanic Reservoir in South Xingcheng Area,Daqing

大庆兴城气田主力储层为营城组火山岩。地球化学和岩石学研究表明,该区营城组以中酸性火山岩为主。利用岩心、薄片分析资料,对兴城南部火山岩储层进行了研究。熔岩中储集空间以气孔和脱玻化孔为主,火山碎屑岩中则主要以粒内、粒间孔和溶孔为主。火山岩储层物性差异显著,储层发育状况受火山岩岩性和火山岩相、成岩作用及构造作用影响。火山岩岩石类型与火山岩相决定了储层原生孔隙的发育状况;成岩作用对原生孔隙进行了改造;构造作用产生构造裂缝,对储层起到有效的疏导作用。综合分析认为,近火山口相带火山岩储层物性好,是天然气勘探开发的有利区域。

Volcanic rocks of the Yingcheng Formation are main reservoirs in Xingcheng gas field.Geochemical and petrological research shows that neutral and acid volcanic rock is the major type of volcanic rocks in the Yingcheng Formation.Core and thin section study reveals that gas pore and devitrification pore are the main accumulating spaces in lava as well as intergranular pore,intragranular pore and dissolved pore in volcaniclastic rock.Core analyses show low porosity and permeability characteristics of the volcanic reservoirs.The control factors of volcanic reservoirs are analyzed based on the data of core and thin section.Types of volcanic rocks and volcanic facies control the development of original pores,and diagenesis modifies original pores and fissures,and tectonic action leads to the formation of structural fissure,which contribute a lot to effective drainage of volcanic reservoirs.It is concluded that favorable volcanic facies near the volcanic crater are the pay zones in gas explor ation and development.