• directional drilling
    Drilling

    Directional Drilling Glossary

    Directional Drilling The glossary of terms used in directional drilling has been developed by the API Subcommittee on Controlled Deviation Drilling under the jurisdiction of the American Petroleum Institute Production Department’s Executive Committee on Drilling and Production Practice. The most frequently used terms listed below. Angle of inclination (angle of drift). The angle, in degrees, taken at one at several points of variation from the vertical as revealed by a deviation survey, sometimes called the inclination or angle of deviation. Angle of twist. The azimuth change through which the drillstring must be turned to offset the twist caused by the reactive torque of the downhole motor. Anisotrospic formation theory. Stratifiedor…

  • oil well
    Drilling

    Well Pressure Control

        Basically all formations penetrated during drilling are porous and permeable to some degree. Fluids contained in pore spaces are under pressure that is overbalanced by the drilling fluid pressure in the well bore. The borehole pressure is equal to the hydrostatic pressure plus the friction pressure loss in the annulus. If for some reason the borehole pressure falls below the formation fluid pressure, the formation fluids can enter the well. Such an event is known as a kick. This name is associated with a rather sudden flowrate increase observed at the surface. SURFACE EQUIPMENT A formation gas or fluid kick can be efficiently and safely controlled if the…