三凝水泥浆体系在深井、超深井固井中的应用

APPLICATION OF THREE-STAGE CEMENTING SLURRY SYSTEM IN DEEP AND ULTRADEEP WELLS

川东北地区φ177.8mm尾管固井存在裸眼井段地层承压能力低、高低压力系统同存、气显示层段多、温差大、喇叭口附近水泥浆易发生超缓凝、强度不够的固井技术难题。针对固井技术难题,提出采用三凝水泥浆体系分别封固油气层、非油气层的技术思路;套管重合段采用常规密度水泥浆封固,能有效地防止高温水泥浆超缓凝现象。该体系在七北103井固井中的应用,取得了固井质量优为30.98%,中为39.54%,差为29.48%的良好效果。对比同一构造同一套管层次固井作业,尤其是套管重合段,该体系保证了悬挂器处封固质量,注水泥后井口没有出现喇叭口附近窜气冒气现象,有效地防止了气窜的发生。声波测井结果表明,复杂井段的封固质量达到了防气窜的目的。

The φ177.8 mm liner cementing in the northeastern Sichuan basin was facing challenges like low bearing pressure capability at open hole section,both high and low pressure systems existed,multiple intervals having gas indication,large temperature differential,cement slurry over-retarded near the bell mouth,insufficient cement strength,etc.To solve these problems,a 3-stage cementing slurry system was put forward,which was to cement payzones and non-payzones respectively,and the casing lapping section to be cemented with conventional slurry to effectively prevent the over-retarding problem of high-temperature slurry system.This system was tried on the well Qibei-103 with a good result as 30.98% of the cementing job being excellent,39.54% being moderate,and 29.48% being poor.Compared with other cementing jobs conducted in the same size casing at the same structure,the cementing quality at the casing lapping area was guaranteed,no gas leakage near the bell mouth at the wellhead,and the gas channeling was effectively prevented,and the acoustic logging proved the cementing quality at the problem section would not allow the occurrence of gas channeling.