Geological Steering of Horizontal Wells

Horizontal well technology has evolved rapidly. The most difficult concerns have changed from borehole stability and drilling techniques to completion, stimulation, and formation evaluation. Tomorrow's challenge lies in steering the well path precisely by use of formation geologic and geophysical information. This geosteering technique is credited with major improvements in drilling results. One definition of geosteering is the planned interactive navigation of a wellbore using geological criteria. Geosteering implies feedback, with all available data continuously entered into the model of the well path and reservoir. Potential gains in production must be balanced with additional drilling and formation evaluation costs. Proper characterization requires knowledge of where the well path is located, where the current trajectory will take the well path, and where the wellbore should go. Uncertainty in geological modeling and the need to maximize profitability require an interdisciplinary team approach.