Steerable BHAs drill storage wells with difficult trajectories. [Bottom Hole Assembly]

The use of steerable downhole motor assemblies allows greater variation in well bore trajectory for drilling gas and oil storage wells in salt domes in areas with surface site restrictions. With modern directional drilling tools, the cavern wells are drilled vertically, kicked off in an S turn, and then finished with a vertical section. The last 100 m of a cavern well above the last cemented casing shoe must be vertical because of the technical demands of brining and completion. To date, Kavernen Bauund Betriebs-GmbH has successfully drilled and completed three directional cavern boreholes in Germany. These directional drilling techniques have also been used successfully for vertical boreholes with strict deviation limits. The paper describes this technology.