致密砾岩储层与CO_(2)作用机理及控制因素实验研究  

Experimental study on reaction mechanism between tight conglomerate reservoir and CO_(2) and its controlling factors

作　　者：彭东宇 唐洪明[2] 王子逸 唐浩轩 董海海[3] 滕梨 任旭[3] PENG Dongyu;TANG Hongming;WANG Ziyi;TANG Haoxuan;DONG Haihai;TENG Li;REN Xu(Zhanjiang Branch of CNOOC(China),Zhanjiang City,Guangdong Province,524057,China;Southwest Petroleum University,Chengdu City,Sichuan Province,610500,China;Research Institute of Exploration and Development,Xinjiang Oilfield Company,PetroChina,Karamay,Xinjiang,834000,China)

机构地区：[1]中海石油(中国)有限公司湛江分公司,广东湛江524057 [2]西南石油大学,四川成都610500 [3]中国石油新疆油田公司勘探开发研究院,新疆克拉玛依834000

出　　处：《油气地质与采收率》2023年第2期94-103,共10页Petroleum Geology and Recovery Efficiency

摘　　要：新疆油田530井区克下组致密砾岩储层具有复杂的复模态孔隙结构,富含火山凝灰岩,铁质含量高,目前CO_(2)驱矿场试验效果难预测。以该储层为研究对象,利用铸体薄片、矿物组分、元素分析、离子浓度分析、核磁共振等手段,通过室内实验,对比了岩石碎块、岩石粉末、岩心段塞与CO_(2)反应前后矿物组分、孔隙结构、流体离子浓度等参数的变化,并从岩石矿物组分、粒径、物性及孔隙结构和反应时间等方面对反应控制因素进行探讨。研究结果表明:CO_(2)的注入对储层的影响整体较小。矿物组分的变化表现为石英、黏土矿物相对含量增加,长石、碳酸盐矿物相对含量减少,以及铁质矿物溶解后再次沉淀;元素和孔隙结构变化较小,孔隙度平均变化小于0.5%;液相中Ca^(2+)和Mg^(2+)质量浓度变化相对较大,新增的Al^(3+),Fe^(3+),Si^(4+)等质量浓度变化较小。CO_(2)与储层岩石间相互作用机理为长石、方解石的溶蚀以及铁质矿物的先溶蚀后沉淀。储层岩石方解石含量越高,反应后孔隙结构变化越大;反应后Ⅱ类储层孔隙结构变化大于Ⅲ类储层;岩石粉末反应速率强于岩石碎块;随时间的推移,反应在0~7 d内达到平衡,期间以溶蚀作用为主,反应在7~30 d内各组分变化较小,存在Al(OH)_(3)和Fe(OH)_(3)的沉淀作用。As the conglomerate reservoir of Lower Karamay Formation in Well530 Area of Xinjiang Oilfield has a complex multi-modal pore structure,rich volcanic tuff,and high iron content,it is difficult to predict the effect of CO_(2) flooding field test.With the Lower Karamay Formation reservoir as the research object,the changes in mineral composition,pore structure,fluid ion concentration,and other parameters before and after the reaction of rock fragments,rock powder,core slugs with CO_(2) were compared through cast thin section,XRD,XRF,ICP ion concentration analysis,NMR,etc.The controlling factors of the reaction were discussed from the aspects of mineral composition,grain size,physical properties,pore structure,and reaction time.The results show that the impact of CO_(2) injection on the reservoir is small.The change in mineral composition shows that the relative content of quartz and clay increases while feldspar and carbonate minerals decrease,and iron minerals precipitate again after dissolution.Elements and pore structure change little,and the average change of porosity is less than 0.5%.The concentration of Ca^(2+) and Mg^(2+) in the liquid phase changes relatively greatly,and the newly added Al^(3+),Fe^(3+),Si^(4+)changes slightly.The interaction mechanism between CO_(2) and reservoir rocks is the dissolution of feldspar and calcite as well as the first dissolution and then precipitation of iron minerals.As the calcite content of reservoir rock is higher,the variation of pore structure after the reaction is greater.After the reaction,the change in the pore structure of classⅡreservoir is greater than that of classⅢreservoir.The reaction rate of rock powder is stronger than that of rock fragments.The reaction reaches equilibrium within 0-7 days,during which the main action is dissolution.The components of the reaction change little within 7-30 days,and there is the precipitation of Al(OH)_(3) and Fe(OH)_(3).

关 键 词：致密砾岩储层 CO_(2)驱 沉淀与溶解 孔隙结构 克下组 

分 类 号：TE341[石油与天然气工程—油气田开发工程]