一种非渗透钻井完井液对裂缝性储层保护能力实验评价  

EXPERIMENTAL EVALUATION OF NON-PENETRATIVE DRILLING/COMPLETION FLUID PROTECTION ABILITY TO FRACTURED RESERVOIR

作　　者：王永恒[1] 康毅力[1] 兰林[2] 徐兴华[3] 

机构地区：[1]西南石油大学油气藏地质及开发工程国家重点实验室 [2]中国石化西南分公司 [3]中国石化西南石油局

出　　处：《钻采工艺》2007年第1期101-104,共4页Drilling & Production Technology

基　　金：油气藏地质及开发工程国家重点实验室基金项目(PLN9720);四川省青年科技基金项目(02ZQ026-042)。

摘　　要：非渗透钻井完井液是近年发展起来的一项新技术，以往主要采用砂床试验来研究其对孔隙性储层的保护能力，尚未涉及到对不同宽度级别裂缝的保护。文章选取四川盆地致密砂岩岩心，人工造出不同宽度级别的裂缝，用非渗透钻井完井液开展高温高压动态损害实验，主要评价其对裂缝的暂堵能力、滤饼强度和返排恢复率。研究表明，3．5MPa正压差下非渗透钻井完井液对400μm以内不同宽度级别的裂缝有很好的封堵效果，能够在1～5min内形成暂堵率为99．999％的滤饼，60min内累积滤失量均小于1ml；返排恢复率多在40％以下，并且观察到非渗透钻井完井液沿裂缝侵入较深，有时可以贯穿裂缝；对于宽度大于50μm裂缝，所形成的滤饼强度小于5MPa，很容易在井筒液柱压力发生变化时被破坏，导致钻井完井液进一步侵入和滤饼重复形成，这会影响中途测试和井壁稳定，对裸眼完成的井需采取滤饼清除措施来解除近井带损害。Non-penetrative drilling/completion fluid is one new technology developed in recent years. The core samples selected form Sichuan basin tight sandstone with different widths artificial fracture were carried out HPHT dynamic damage experiment by using non-penetrative drilling completion fluid. The paper evaluated temporary plugging ability of non-penetrative drilling/completion fluid to fracture, filter cake strength and flowback recovery ratio. The experimental results showed that the non-penetrative drilling/completion fluids had a good plugging capacity to less than 400m slot width samples under 3.5MPa positive pressure differential, and it can form filter cake with 99.999% temporary plugging ratio during 1 to 5 minutes, and the cumulative filter loss are all less than 1ml in 60 minutes. But the most flowback recovery ratios are under 40%. At the same time, the non-penetrative drilling/completion fluids invaded deeply along sample fracture and sometimes it may pass through the entire fracture. The filter cake intensity is less than 5MPa when the fracture width reaches more than 50m. It can induce repeated forming filter cake and further formation damage when fluids column pressure changed and will impact DST and wellball stability.

关 键 词：非渗透钻井完井液 储层损害 滤液侵入 固相侵入 滤饼 储层保护 

分 类 号：TE257[石油与天然气工程—油气井工程]