鄂尔多斯盆地大牛地地区致密砂岩石英溶解作用及其对优质储集层的影响  

Dissolution of Quartz in Tight Sandstones of the Daniudi Area,Ordos Basin,and Its Influence to High Quality Reservoirs

作　　者：邱隆伟[1,2] 徐宁宁 周涌沂 高青松[3] 张向津[1] 宋璠 马晓芸 

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]山东省高校盆地分析与油气储层地质重点实验室,山东青岛266580 [3]中国石油化工股份有限公司华北分公司,郑州450006

出　　处：《矿物岩石地球化学通报》2015年第1期38-44,2,共7页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家重点基础研究发展计划项目(2014CB239002);"十二五"国家油气重大专项(2011ZX05009-002);国家自然科学基金重点项目(U1262203)

摘　　要：储集层孔隙成因机制是致密砂岩储集层评价和预测必须解决的基本问题。本文以储集层微观分析为基础,对鄂尔多斯盆地大牛地气田石炭-二叠系致密砂岩储集层孔隙成因类型及其和优质储集层成因的关系进行了研究。结果表明,研究区致密砂岩储集层中碎屑石英颗粒存在明显的直接溶解现象,并形成了以石英溶解为主的储集空间类型,这种石英溶解是碱性成岩环境作用的结果,致密砂岩储集层的发育程度仍然和孔隙度以及组分的溶解作用有密切关系,碱不稳定矿物的溶蚀量一般为1%~23%,石英溶解型孔隙对储集层孔隙的贡献率一般可以达到60%~90%,碱溶蚀量达到5%以上时有利于优质储集层的形成;石英溶解作用较强的位置主要是颗粒边部的粒间孔隙周围,这种类型的溶解形成于储集层经历较强的压实成岩改造之后,所形成的溶解孔隙在后期的持续性压实过程中损失程度较低;石英溶解作用的强弱决定了储集层物性的最终发育程度以及优质储集层的形成。Based on microscopic observations of reservoirs,this paper studied genetic types of pores in Carboniferous-Permian tight sandstone reservoirs in the Daniudi Gasfield,Ordos basin,and investigated their relationships with the genesis of high-quality reservoirs. This study presented observations of the microscopic evidences of reservoir spaces forming directly by the dissolution of detrital quartz grains in tight sandstone reservoirs to demonstrate that characteristics of reservoirs in tight sandstones still closely related with the porosity and dissolution of mineral constituents. The results also showed that 1% ~ 23% of alkaline unstable minerals had been corroded,pores directly from quartz dissolving accounted for more than 60% ~90% of the total pores,high-quality reservoirs were favorably formed when the alkaline corrosion were more than 5%,dissolutions of quartz mainly happened in inter-particle-pores near the edges of grains and the damage degree of such formed pores is relatively low during the later continuous compaction since they were formed after strong diagenetic transformation of reservoirs. In summary,this study indicated that corrosion degree of quartzdetermined the final development process of the reservoir physical property and the formation of high-quality reservoirs.

关 键 词：致密砂岩 石英溶解孔隙 优质储集层 形成机理 大牛地气田 

分 类 号：P618.13[天文地球—矿床学]