Application of ultralong im horizontal hole drilling technology in Bozhong 19-4 Oilfield

Because of the high content of goeschwitzite and montmorillonite in Bozhong Minghuazhen reservoir of Bohai Sea, there happened serious hydrate expansion and mud property was hard to control.Therefore,it was difficult to run φ240.6 mm casing after φ311.2 mm borehole landing.In order to decrease the operating difficulty,φ152.4 mm horizontal borehole operation was conducted after φ215.9 mm borehole landing and φ177.8 mm tail pipe running.The successful example of well BZ19-4-B10 h set good practice ground for later operation in well structure,make up of string,bit type selection,hydraulics,mud property and so on.