预防卡钻及提高排阻成功率之研究.PDF

預防卡鑽及提高排阻成功率之研究* * A study of stuck pipe prevention and enhanced free pipe technology 1 2 1 2 W.L. Wang M.C. Lee Dr ill pip e may get stuck in the borehole for several reasons: part of the borehole collapsing on to the drill pipe; high angle dogleg; or high borehole/ formation pressure differential. Th e most com mon r ea son for th e b or ehole collap sing on t o th e p ip e i s th at th e for m at ion interstitial salt water forming a bond with the water in the dr illing mud . Th is can cau se the sh ale to U exp and and slough off into the b orehole cau sing Pipe-lax stuck pipe. The drill pipe can also get stuck in the borehole when b orehole pressure is much higher than the formation pressure. The high pressure differential can build up thick mud cake that may cau se stuck 1. 2 . collars during tripping out. 3. If the dr ill pip e get s stuck at a dogleg, it is probably because the drilling angle deviated slightly in the drilling process. When the drill stem is pulled from the hole, the drill pipe or the slightly larger drill collars get stuck at the dogleg. Since the borehole is seldom straight, the opportunity for dogleg stuck pipe is always present.