缅甸D区块井下复杂原因分析及钻井液技术对策  

Analysis of Downhole Troubles and Drilling Fluid Countermeasures for Block D Myanmar

作　　者：王斌[1,2] 李强[2] 邱光远[2] 张永振 

机构地区：[1]中国地质大学工程技术学院 [2]中石化国际石油勘探开发有限公司 [3]北京温菲尔德石油技术开发有限公司

出　　处：《钻井液与完井液》2010年第2期84-86,共3页Drilling Fluid & Completion Fluid

摘　　要：在缅甸陆上区块的勘探过程中事故发生率高,多数井都因无法处理而提前完钻或弃井,如Yagyi-1井三开井段的最大井径扩大率为70.95%,Yagyi-1和Patolon-1井分别漏失钻井液3092和387m3。分析认为,造成井下复杂最突出的原因是钻井液安全密度窗口窄,这是因为缅甸D区块断层较发育,高陡推覆体构造多,地层挤压破碎严重,地层倾角大,主断层以上地层中存在长的泥岩段,且有高压油气层存在,在同一祼眼内同时存在渗透性好或含有裂隙和微裂隙的层位,从而导致安全密度窗口很窄。而现用的KCl/PHPA/聚合醇钻井液的抑制性不是很强,封堵能力也无法满足要求,其与地层作用后很大程度地缩小了原来的安全密度窗口。通过比较目前常用体系的抑制性,从扩大安全密度窗口的角度入手,提出可以优选具有强抑制性和封堵能力的KCl/硅酸盐钻井液。Onshore drilling in Myanmar has long been experiencing downhole troubles,resulting in abandonment of wells. For example,the well Yagyi-1 had a maximum hole enlargement 70.95%,and mud lost on Yagyi-1 and Patolon-1 were 3,092 and 387 m3,respectively. It is found that the downhole safety mud density is very narrow,because of developed fault zones in the block D,in which these wells were drilled. Fractured formations because of the faulting have very low strength,causing mud losses. Also in these formations there are high pressure gas zones,which need higher mud density to stabilize. Loss zones and high pressure zones may coexist in the same open hole,making drilling operation very difficult. Drilling fluid right now in use is a KCl/PHPA/poly glycol fluid showing weak inhibitive capacity to the clay stones encountered,and plugging capacity was also low,leading to a narrowed safety density window. It is thus proposed a strongly inhibitive and plugging drilling fluid,KCl/silicate mud to improve the narrow safety density of the formations to be drilled.

关 键 词：山前高陡构造 井眼稳定 坍塌 井漏 KCl/硅酸盐钻井液 缅甸D区块 

分 类 号：TE254.3[石油与天然气工程—油气井工程]