致密油储层特点与压裂液伤害的关系——以鄂尔多斯盆地三叠系延长组长7段为例  

Relationship between characteristics of tight oil reservoirs and fracturing fluid damage:A case from Chang 7 Member of the Triassic Yanchang Fm in Ordos Basin

作　　者：王明磊[1,2] 张遂安[1] 关辉[2] 刘玉婷[2] 管保山[2] 张福东[2] 崔伟香[2] 

机构地区：[1]中国石油大学(北京)石油工程学院,北京102249 [2]中国石油勘探开发研究院廊坊分院,河北廊坊065007

出　　处：《石油与天然气地质》2015年第5期848-854,共7页Oil & Gas Geology

基　　金：国家科技重大专项(50430503;2011ZX05007-002)

摘　　要：压裂是致密油开发的主要手段，在改造储层的同时又会带来储层伤害。以鄂尔多斯盆地延长组7段为例，依据储层物性、铸体薄片、电镜扫描、X－射线衍射、恒速压汞、核磁共振、CT以及敏感性测试等实验分析，研究致密油储层特点与压裂液伤害的关系。长7段属于典型的致密油储层，填隙物含量高达15％，易于运移和膨胀的伊利石占比大；孔隙、喉道皆为微米－纳米级别，孔喉连通性差，大孔隙常被小喉道所控制。长7段致密油储层属于中等偏弱速敏（岩心渗透率的损害率为0.33～0.48）、强水敏（岩心渗透率的损害率为0.14～0.28）、易水锁的储层，因此宜在压裂液配方中添加粘土稳定剂、防膨剂和助排剂以降低压裂液对储层的伤害；入井压裂液矿化度低于10000 mg／L会产生盐敏伤害；压裂液残渣粒径为2.25～8.39μm，对于致密油储层而言，滤饼、沉积、吸附堵塞和桥堵等伤害现象都存在。综合研究认为，采用低伤害压裂液是降低残渣伤害的主要办法。Fracturing stimulation is the main method for development of tight oil.It can improve reservoir quality,but also can cause damages to reservoirs.Taking the Chang 7 Member of Yanchang Formation in Ordos Basin as an example,the relationship between the characteristics of tight oil reservoirs and fracturing fluid damage is studied based on experimental analysis,such as physical properties of reservoir,casting thin sections,scanning electron microscope（SEM）,X-ray dif-fraction（ XRD） ,rate-controlled mercury penetration,NMR,CT and sensitivity test.The Chang 7 Member is a typical tight oil reservoir in which the content of interstitial materials is as high as 15%.Illite,which is easy to transport and expand, accounts for a large proportion in the interstitial materials;Both pores and pore throats are of micro-nanometer scale, and the pore throats have poor connectivity.Large pores are generally controlled by small throats.The tight oil reservoir of the Chang 7 Member has moderate to weak velocity sensitivity （ the damage rate of core permeability is in the range of 0.33-0.48）,strong water sensitivity（the damage rate of core permeability is 0.14-0.28）,and strong tendency of water blocking.Therefore,clay inhibitors,anti-swelling agents and cleanup additives should be added to the fracturing fluid formula to reduce the damage of fracturing fluid to the reservoir;salt sensitivity damage would occur when the salinity of the fracturing fluid running into the well is lower than 10 ,000 mg/L; the particle size of the fracturing fluid residue is 2.25-8.39 μm.For tight oil reservoirs,various damages such as filter cakes,sediments,absorption blocking and bridge plug can occur.It is considered through integrated study that using low damage fracturing fluids is the main way to reduce the residual damage.

关 键 词：敏感性 压裂液 储层 致密油 延长组 三叠系 鄂尔多斯盆地 

分 类 号：TE348[石油与天然气工程—油气田开发工程]