准噶尔盆地白垩系储集层特征

准噶尔盆地白垩系储集层总体具有“低成分成熟度、低胶结物含量、高结构成熟度和粘土膜发育”的岩石学特征。岩石类型以长石岩屑砂岩和岩屑砂岩为主；颗粒之间多为点接触关系，薄膜-孔隙式胶结；长石相对含量高，普遍含方沸石胶结物是区别于侏罗系储集层的男一特点。成岩怍用总体较弱，主要处于早成岩A—B阶段；剩余啄生粒间孔是白垩系最主要的孔隙类型；次生溶蚀孔隙主要发育于吐谷鲁群底部砂砾岩中；岩性愈粗，孔隙结构愈好。除卡因迪克地区外，白垩系储集层普遍较优。塑性岩屑和填隙物含量低是形成比质储集层的内因；低古地温梯度、弱成岩强度和晚期深埋方式有利于孔隙的保存。砂岩成岩压实怍用是储集层孔隙损失的主要因素；砂岩粒径是影响储集层性质的重要因素；沉积环境造成了岩石类型的差异；溶蚀是白垩系砾岩和砂砾岩的主要增孔因素；粘土膜发育是形成白垩系油层低电阻率的主要原因。

Characteristics of Cretaceous Reservoir Rocks in Junggar Basin

The Cretaceous reservoir in Junggar basin is on the whole characterized by low component maturity,low cement con-tent,high textural maturity and developed clay film in lithology.The rock types are dominated by feldspathic litharenite and lithic sandstone with point contact relations among grains,film-pore cementation.Relative high content of feldspar and commonly exist-ing analcite cements are another features different from Jurassic reservoir.In diagenesis,most part is week,primarily in early phase of diagenetic A-B;residual primary intergranular pores are the most important type of Cretaceous system;while secondary dissolution porosity is mostly developed in glutenite of Tugulu group bottom;and the coarser the lithology,the better the pore configuration.In exception of Kayindike area,the quality of Cretaceous reservoir is generally high.The high quality reservoir is due to low content of plasticlast and fillers.The low paleo-geothermal gradient,weak diagenesis and late deep buried pattern are favorable for preservation of porosity.The sandstone diagenetic compaction is the main reason for loss of reservoir porosity,the sand partical size is an important factor affecting reservoir quality.In addition,it is sedimentary environment that results in the difference of rock types;solution is major factor of incremental porosity in Cretaceous conglomerate and glutenite;developed clay film is major reason for forming low resistivity of Cretaceous oil zones.