顺北区块辉绿岩井段井壁稳定性分析

发布时间：2018-04-09 21:23

本文选题：辉绿岩　切入点：井壁稳定性　出处：《中国海上油气》2017年05期

【摘要】：顺北地区多口井在钻进奥陶系桑塔木组辉绿岩侵入体时掉块严重,导致井下频繁蹩钻、阻卡,上提钻井液密度后多次引发井漏,多次堵漏但效果不明显。基于辉绿岩的微观结构特性分析,通过开展辉绿岩理化性能测试和岩石力学实验,结果表明:辉绿岩基岩矿物主要以斜长石为主,缝间填充物矿物主要包括石英、斜长石和黏土矿物,水化不易分散、稳定性好、水化膨胀应变非常小,不易造成井壁坍塌失稳;辉绿岩具岩石硬脆性、强度高而弹塑性差的力学特征,微裂缝发育的弱理面效应导致辉绿岩岩体整体强度降低易造成井壁坍塌失稳。根据裂缝对辉绿岩强度的影响规律,建立了辉绿岩地应力与坍塌压力剖面,从而得出了辉绿岩合理钻井液密度窗口,并在顺北1-3、顺北1-6H等后续钻井中取得成功应用,具有推广应用价值。
[Abstract]:Based on the analysis of the microstructure of diabase, the physical and chemical properties of diabase and the rock mechanics experiments are carried out. The results show that the minerals of diabase bedrock are mainly plagioclase, and the interseam filling minerals mainly include quartz.Plagioclase and clay minerals are not easily dispersed in hydration, have good stability, and the hydration expansion strain is very small, which is not easy to cause collapse and instability of wellbore; diabase has the mechanical characteristics of hard brittleness, high strength but poor elastic-plastic properties.The weak surface effect of microfracture development leads to the decrease of the overall strength of diabase rock mass, which can easily lead to the collapse instability of wellbore.According to the influence of fracture on diabase strength, the ground stress and collapse pressure profile of diabase is established, and the reasonable drilling fluid density window is obtained, which has been successfully applied in subsequent drilling such as Shunbei 1-3, Shunbei 1-6H, etc.It has the value of popularization and application.
【作者单位】：中国石化西北油田分公司;中国石化石油工程技术研究院;
【基金】：“十二五”国家科技重大专项“顺北1井区钻完井评价与优化研究(编号:2011ZX05049-002-002)”部分研究成果
【分类号】：TE21

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