堵漏技术在也门水井几种钻井作业中的实践与应用

也门水井项目是长城钻井公司独自开发的国际项目中较早的一个，业主是也门国家水电部。该项目合同内容是为也门萨那市钻15口水井，解决城市居民用水问题。钻井施工中最大的困难是井漏和因井漏引起的上部地层垮塌，并因此造成井的报废，发生井漏的原因是地下水层含有丰富的活动水，因钻井目的是为了居民饮用，因而处理井漏的技术条件有限，在生产水层发生井漏不能用水泥堵漏．不能用对水有污染性的化工原料，增加了处理井漏问题的难度。为此，对非生产水层井漏以水泥堵漏或石膏堵漏为主，目的是一定要封住水层，保证下步施工顺利进行；对生产水层的漏失以桥接堵漏和盲钻强行钻进技术为主，关键是必须要安全钻进，保证钻井成功率。新的技术措施，加快了钻井进度，钻井周期从三个月降低到一个月；钻井成功率由36％提高到100％。证明新的钻井技术措施在也门萨那地区是有效可行的。

Practice and Application of Loss Circulation Control Technique in Yemen Water Well

The water well project in Yemen is an early international drilling project that carried out by Great Wall Drilling Co. solely. Loss circulation and the upper bore collapsed caused by mud losing were the most troubles in the drilling program and thus the abandoned well occurred. The reason for this is that there were a lot of moving water in the water zone under formation. Because the purpose of drilling wells is to get drinking water for the city, it is not completely free of limitations to take measures for treating Loss circulation. Loss circulation happened, cementing plug with cement was forbidden in producing water zone, and so did the chemical materials that may be polluted the water. All of these made the well loss difficulty getting more and more. Therefore, cement plugging or gypsum plugging was to be taken to seal the water formation in non-producing water zone, to make sure next step. Bridge plugging and blind drilling (drilling ahead without mud circulation) should be chose in producing water zone, the key problems in this program is to ensure drilling safely and successfully. Taking new technical measures sped up the drilling program, the well period reduced from three months down to one, the rate of well succeed increased from 36% up to 100%. This proves the new drilling technique is valid and availably in drilling water well in Sana'a, Yemen.