摘要
四川盆地西北部须二段以致密砂岩储层为主,但4000 m以下仍发育优质储层。深层优质储层主要发育残余原生粒间孔、粒间溶孔、粒内溶孔和裂缝。研究认为:优质储层的形成与原始沉积条件、成岩作用、地层超压和裂缝有关。原始沉积条件是优质储层形成的前提和基础,母岩性质及三角洲前缘沉积不仅造成原始沉积物中碳酸盐含量低,还形成大面积发育的高成份成熟度和结构成熟度石英砂岩和岩屑石英砂岩,从而有效抵抗上覆地层压实作用;石英颗粒早期发育绿泥石衬边,可以抑制次生石英的形成,同时抵消了部分上覆压力的增加,原生孔隙得以保存;欠压实作用有效削弱了正常压实作用对储层孔隙度的影响,从而有利于深层优质储层的形成;裂缝可构成良好的储集空间,有效沟通各类孔隙,增加孔隙流体的流动性。
In northwestern Sichuan Basin, the Xujiahe 2 Member dominantly belongs to tight sandstone reservoirs. Some high-quality Xujiahe reservoirs may be still found below 4000 m of burial depth. Residual primary intergranular pore, intergranular dissolution pore, intragranular pore, and fracture are developed in these deep and high-quality reservoirs with. Our study demonstrates that(1) to form these reservoirs is related to original deposition condition, diagenesis, formation overpressure, and fracture;(2)original deposition condition is the basis and premise to form high-quality reservoirs- the property of parent rock and the detatic frontal deposition not only bring about low content of carbonate in original deposits but also generate a large-scale welldeveloped quartzose sandstone and lithic quartzose sandstone with high texture and composition maturity, thereby to effectively stand up to compaction from overlying strata;(3)chlorite lining was developed in most quartz grains during an early stage in order to control the forming of secondary quartz and conceal an increase of overlying pressure, finally resulting in keeping primary pore;(4)undercompaction may decease the effect of normal compaction on porosity, which is favorable for forming these deep and high-quality reservoirs; and(5)facture, as the better reservoir space, may connect pore very effectively and increase the mobility among pore fluid.
出处
《天然气勘探与开发》
2016年第2期1-5,25,共6页
Natural Gas Exploration and Development
基金
国家科技重大专项(2011ZX05001-005)"四川盆地岩性油气藏富集规律与目标评价"
关键词
原生孔隙
地层超压
深层优质储层
须家河组
四川盆地西北部
primary pore
formation overpressure
deep high-quality reservoir
Xujiahe 2 Member
northwestern Sichuan Basin
作者简介
赵正望，男，1975年出生，硕士，工程师；从事油气地质综合研究工作；地址：（610041）四川省成都市高新区天府大道北段12号；电话：（028）86015672；E-mail：zhao_zw@petrochina．com．cn
