低切力高密度无土相油基钻井液的研制  

Development of a clay-free oil-based drilling fluid with a low shearing force and high density

作　　者：张小平[1] 王京光[1] 杨斌[1] 吴满祥[1] 王勇强[1] 

机构地区：[1]低渗透油气田勘探开发国家工程实验室.中国石油川庆钻探工程公司钻采工程技术研究院

出　　处：《天然气工业》2014年第9期89-92,共4页Natural Gas Industry

摘　　要：传统的油基钻井液采用有机土作为增黏剂来增加悬浮重晶石的能力,是一种含土相的油基钻井液,高密度条件下含土相油基钻井液流变性控制困难限制了其应用的范围。为此,以新研制的复合型乳化剂(G326-HEM)为核心,构建了无土相油基钻井液体系,并对该配方进行了优选和性能实验。结果表明:1无土相油基钻井液体系无须使用辅乳化剂、润湿剂,具有配方简单,高密度条件下流变性好等特性;2与含土相钻井液相比,高密度条件下塑性黏度、终切力低,降低了高密度钻井液因黏切高诱发井漏的风险,可节省10%的基础油;3塑性黏度和动切力随着油水比的降低而升高,不同密度下的油基钻井液选用不同的油水比;4无土相油基体系配方对基础油的适应性较广,可广泛应用于合成基、矿物油基钻井液。结论认为,该成果较好地解决了无土相体系在高密度条件下的电稳定性弱、悬浮稳定性差的难题,为页岩气及其他非常规气藏规模开发提供了技术保障。A traditional clay oil-base drilling fluid is added with organic soil as a tackifier to increase its sufficient barites-suspension properties.However,due to its high density,its rheological properties are difficult to control,which restricts its wide application.Therefore,a clay-free oil-based drilling fluid system was established with the focus on a newly-developed composite emulsifier （G326-HEM）,and the optimization and performance tests were performed on this formula.The test results indicated that：（1） neither auxiliary emulsifiers nor wetting agents were necessary,and this drilling fluid was featured by a simple formula and a good rheological property even with high density; （2） compared with a clay drilling fluid with high density,this clay-free oil-based drilling fluid had a low plastic viscosity and a shearing force to reduce a potential circulation loss caused by high viscous shearing,which saved the base oil by 10％ ; （3） the plastic viscosity and dynamic shear force increased with the decrease of oil-water ratios and different oilwater ratios were selected to prepare oil-base drilling fluids with different densities; （4） the formula of the clay-free oil-base system was greatly adaptable to base oil and could be used for compounding based and mineral oil-base drilling fluid.This fluid can not only solve such problems as weak electrical stability and poor suspension stability of clay-free system under high density but provide technical support for the scale development of shale gas and other unconventional gas reservoirs.

关 键 词：油基 钻井液 页岩气 水平井 乳化剂 无土相 电稳定性 悬浮稳定性 

分 类 号：TE254[石油与天然气工程—油气井工程]