氮气欠平衡钻井技术在定向深探井中的应用

Application of nitrogen underbalanced drilling technology in drilling deep directional wells

川西3000m以深井段普遍存在机械钻速慢、储层保护技术单一等问题，常规欠平衡钻井均不能很好地解决以上问题。为了更好地保护和发现油气藏，提高深井勘探成功率，西南分公司引进了氮气钻井技术，通过大量地质工程论证，在DY1井四开4652．26～4775．56m产层段进行了氮气欠平衡钻井技术应用试验。试验表明，在深井段采用氮气钻井技术可大幅度提高钻井速度，该层段平均机械钻速达8．36m／h，与邻井相比提高8～9倍，在提高钻速的同时还直观有效地发现了一个裂缝性气层。该技术在深探井中的成功应用加快了气体钻井技术向深层推广的步伐，对同类地区的钻井具有较高借鉴意义。

The traditional underbalanced drilling technology cannot solve the problems of the low penetration rate and simple reservoir protecting measures in the west Sichuan interval of more than 3000 m. The Southwest Subsidiary Company introduces nitrogen drilling technology to better protect and discover hydrocarbon reservoirs and advance the success rate of deep well exploring. Based on large amounts of geological and engineering appraisal, application test of nitrogen drilling technology is conducted in the producing interval of 4652.26～4775.56 m during the fourth spudding in DY1 well. The test shows that the application of the new technology has brought good effect and greatly increased the drilling speed. The average rate of penetration of the interval reaches as high as 8.36 m/h, 8~9 times higher than that of the offset well, meanwhile, a fractured gas reservoir is discovered. The successful application of the new technology in exploring deep wells accelerates the popularization of the gas drilling technology and can be a good reference for drilling in similar regions.