大邑构造浅部井段钻具失效分析及预防

Analysis and precaution of drilling tools failure in shallow section of Dayi structure

大邑构造浅部地层砂岩和泥岩交错,局部夹杂砾石层,可钻性差。近年来在该地区共部署了13口深井,在浅部井段共发生了42次钻具失效,造成了重大的经济损失。为了避免钻具失效在大邑浅部地层的频繁发生,对前期的失效情况进行了统计,并开展了室内微观和腐蚀实验,发现其频繁失效的主要原因是由于地层软硬交错导致钻具易发生疲劳,现场未及时进行无损探伤,钻进时转速过高加剧了钻具疲劳失效。在此基础上,提出了合理控制钻井参数,及时做好无损探伤工作等预防钻具频繁失效的对策,现场应用效果较好。

Sandstone and mudstone stagger in shallow formation of Dayi structure with gravel layers locally,so the drillability is poor.In recent years,13 deep wells were deployed in the area,while a total of 42 time drilling failures happened in shallow section,causing significant economic loss.In order to avoid frequent drilling failure in Dayi shallow strata,the early failures were collected,and indoor micro and corrosion tests were conducted.The main reason of the failure is that soft and hard staggered formation easily leads to drilling tools fatigue,with no nondestructive testing in time,and drilling rotation speed is too high,causing the probability of occurrence of fatigue failure increases.The measures to prevent drilling failure are proposed,which are properly adjusting drilling parameters and timely nondestructive testing.Good results have been achieved at the scene through the use of these measures.