Then it represents the compounding method and management requests of slurry and brings forward the operation points of operation with driller.

Development and application of downhole hole-closure device in the overall process of underbalanced drilling operation;

The drilling construction experience of mud and sand seam

Combined with the survey and geologic background of concrete project,it introduces the construction preparation,construction method,and construction gradation in the drilling construction in this project,analyzes the reasons generating the common problems in the water-seal process with purdah,and represents the corresponding solving methods in order to ensure the project quality.

In view of difficulties encountered in pile foundation construction process of bridge in Chongyang reservoir,from the erection of working platform,embedment of steel casing,drilling construction and other aspects the construction of pile foundation in deep water and in riverbed without overburden is introduced.

With the fountain terra of Shili river Yuanshang country to Meijiayao country in Zuoyun county Shanxi province as example,this paper introduces the art features and essentials of different drilling techniques both in drilling construction and completed well in shallow ground water fountain terra.