固井纤维水泥射孔实验研究

为进一步了解纤维水泥改善水泥石射孔后出现脆裂的情况,通过实弹射孔及射钉枪射孔实验,研究了纤维对射孔后水泥石的阻裂机理,并利用电镜扫描的手段对射钉枪射孔后留下的孔道以及孔道周围的裂缝进行了分析,研究表明:小试件条件下,实弹射孔试验过程中无纤维水泥试件形成毁坏性的破碎,而纤维水泥在射孔后可以保留完整的孔道,证明了纤维水泥有助于射孔完井作业的成功;纤维水泥石受到射孔冲击后,纤维可以吸收外来冲击波的作用,减缓水泥石的变形,从而破坏强度不至于任其裂纹发展形成脆性破坏;在孔的壁面上可以明显看到纤维对裂纹的阻裂作用;纤维的桥联作用增加了水泥材料本身的临界能量释放率,这使得纤维水泥石在完成钢钉枪射孔后孔内剖面比较完好。

Perforation experiment of fiber cement for cementing

In view of cracking problems of cement after perforated completion,ball perforation and nailgun perforation on fiber cement are studied in this paper.Pore passage and rupture around pore passage are analyzed by electron microscope scanning and interpreted by fracture mechanics.The results show that there is destructive fracture on the non-fiber cement,while fiber cement can retain integral pore passage which contributes to perforation completion.After fiber cement is pounded by perforation,the fiber can absorb the shock wave and slow down the cement deformation,so the breaking strength will not be enough to the cement brittle rupture.It is shown that fiber cement has crack arresting affect on cleavage from the pore wall,and the fractional release G of critical energy is increased by coordinate bridging action which makes the inner section of fiber cement retains undamaged after completion of nailgun perforation.