A Note on Optimization of Deviated Well Drilling Angles

A simple illustration is employed to show that the optimal angle one should use to drill an exploration well is dependent on two major factors: (i) the depth distribution anticipated for hydrocarbon-beating reservoirs in a particular exploration setting; (ii) whether the borelength, L, approved for drilling is long enough to more than encompass the depth, H, at which the anticipated reservoir distribution reaches its average value. If both conditions are estimated to be satisfied, then one should drill a deviated hole at an angle θ with respect to the vertical given by cosθ =H/L. This angle minimizes the probability that one will not encounter a hydrocarbon-bearing reservoir. If the second condition is not expected to be satisfied, then a vertical borehole represents the best chance of minimizing the probability of not encountering a reservoir. Using the general procedure illustrated here, historical databases in analogous geological settings can be used to sharpen the estimate of optimized drilling angle.