川中地区蓬莱1井超高压气水层的安全钻井技术

Safe drilling technology for high pressure water-bearing gas zones in the well Penglai-1,central Sichuan Basin

川中地区蓬莱1井在第四次开钻钻进过程中，用密度1．97g／cm^3的钻井液钻至下三叠统嘉陵江组嘉二段，遇高压气水显示，用密度2．14g／cm^3钻井液压井后仍不能平衡，将钻井液密度逐步加重至2．55g／cm^3。由此导致了在钻进过程中泵压高、易粘卡、钻井液性能维护难等问题，同时还出现了起钻灌钻井液困难、溢流、不能正常起下钻等井控问题。针对这些难题，在试验探索的基础上，采用HHH塞封隔技术、超高钻井液密度维护技术、特高压井控技术和加重钻井液防粘附卡钻等技术，最终安全顺利地完成了这口超高压井的钻井工作，并获得高产油气流，取得了超高钻井液密度情况下的钻井经验。

High pressure water-gas indication was observed during the fourth spud-in of drilling the well Penglia-1 at the central Sichuan Basin,when drilling came to the second member of the Jialingjiang Formation of the Lower Triassic with the 1.97 g/cm3 drilling fluid.Then the 2.14 g/cm3 drilling fluid was used to kill the well without avail,so the density of the fluid was increased up to 2.55 g/cm3.However,this resulted in great difficulties in well control,such as a high pump pressure during drilling,sticking potential and hard drilling fluid maintenance,as well as hard feeding of drilling fluid during tripping out,overflows and no smooth trips,etc.Through investigation and tests,many technical measures like HHH plug isolation,special maintenance techniques for super-high-density drilling fluid,well control under super-high pressure and weighted drilling fluids,were presented and tried out with success in this super-high pressure well with a high productivity of oil and gas.This success is of great value in providing good drilling experiences in drilling wells with such super-high density drilling fluid.