摘要
KL3-2油田开发井中东营组下段和沙河街组泥页岩易剥落掉块,导致严重的井下复杂情况。通过X射线衍射、扫描电镜、孔径分布测试、理化性能分析、岩样浸泡实验、岩样自吸水实验等,分析了该地层井壁失稳机理。结果表明：该地层脆性矿物含量高达60%以上,膨胀性黏土矿物含量低,基质微孔隙、微裂缝、层理发育,属于典型的硬脆性泥页岩。钻井液滤液在毛细管力和压差作用下沿微裂缝侵入地层内部,微裂缝、微裂隙的延伸、扩展是泥页岩地层井壁失稳的主要原因。钻井液技术对策为加强微孔、微裂缝的封堵,加强抑制,研选了微纳米封堵剂HSM和页岩抑制剂胺基硅醇HAS,构建了防塌钻井液体系。评价表明,该体系能够有效地封堵泥页岩微孔、微裂缝,阻缓压力传递。现场应用表明,微纳米封堵钻井液能显著改善滤饼质量,降低滤失量,大大减少了钻井液滤液由于压差作用侵入地层,防止由其引起微裂缝、微裂隙延伸、扩展而导致井壁不稳定和各种井下复杂情况的发生。
Sloughing of shale in the lower Dongying Formation and Shahejie Formation caused serious downhole troubles in the Block KL3-2.Laboratory study of the drilled cuttings with X-ray,SEM,pore size distribution,physic-chemical property analysis etc.showed that brittle mineral content in the cuttings sample taken from the formation of interest was more than 60%.Swelling clay content was relatively low.Micro fissures,fractures and beddings were quite developed in the samples studied,showing that the formations are hard and brittle shale.When in contact with drilling fluids,mud filtrates infiltrate along the bedding plane into the formation under the action of capillary force and differential pressure,causing the micro fissures and micro fractures to expand,thus resulting in borehole sloughing.To control this kind of borehole instability,HSM,a micro nano plugging agent,and HAS,an amino silanol shale inhibitor,were selected to formulate an inhibitive drilling fluid,which can effectively plug micro fissures,micro fractures in shales and retard the transmission of pressure in formation.In field use,HSM remarkably improved the quality of the filter cake and reduced filter loss of the mud.The application of this inhibitive drilling fluid helped in controlling borehole wall instability and minimizing downhole troubles related to the hard brittle shales.
出处
《钻井液与完井液》
CAS
北大核心
2015年第2期6-10,97,共5页
Drilling Fluid & Completion Fluid
基金
十二五国家科技重大专项（2011ZX05030-005-07）
中央高校基本科研业务费专项资金（13CX06033A）
山东省博士后创新项目专项资金（201303060）联合资助
关键词
井壁稳定
硬脆性泥页岩
微纳米封堵
胺基硅醇
防榻钻井液
Micro nano plugging agent
Hard and brittle shale
Inhibition
Borehole stabilization
Drilling fluid
作者简介
邱正松，教授，博士生导师，1964年生，现从事井壁稳定理论及应用、钻井液处理剂研发、油气层保护等教学科研工作。地址：山东省青岛市开发区长江西路66号中国石油大学（华东）；邮政编码266580；E-mail：qiuzs63@sina．com。
