Drilling Technology of Horizontal-opposing Communicated Well in Soft and Low Permeability Thin Coal Seam

Abstract:

Coal reservoir of Wulan mine has the characteristics of soft & loose property, large inclined angle in drilled formation and shallow target bed, well trajectory control is difficult with serious leakage and cementing problem. Effective technical measures were adopted in well structure design, equipment selection, drill assembly, drilling parameter, well trajectory control, drilling fluid, casing and cementing; long-distance horizontal well in thin and soft-low permeability coal seam was realized (with the longest distance of 223.73m), which was successfully connected to the vertical well. Based on the analysis on the construction technology of coal bed methane horizontal opposing well in Wulan mine, the paper summed up the construction experience of horizontal opposing well in thin and soft-low permeability coal seam.

Key words:soft; thin and soft-low permeability coal seam; horizontal opposing well; well drilling; PE case