Abstract:

The stratum is complex in Baoxinggou gold mine,and the rocks suffer intense weathering and alteration generally,therefore,the stratum hole wall is easy to be instability in the process of drilling construction,leading to collapse and block out,and the protection of the borehole wall is difficult,so folder and underground drilling accidents usually occur.Taking ZK0702 drilling as an example,we introduce the main problems and construction difficulties encountered in the process of construction.Through on-site practice,we adopt combined treatment process including hitting,anti,expansion and fishing,using solid-free fluid（PAB）to protect hole wall.Finally,we successfully avoid the drilling accident,and propose specific measures to resolve and prevent accidents,it can provide a reference for the next construction.

Key words: Drilling construction, Solid-free fluid （PAB）, Folder drilling accident, Precaution, Baoxinggou gold mine, Heilongjiang Province