Well Design Using a Computer Model

Summary In this study, the theory of nonlinear optimization is used to develop a well-design computer model to determine the optimum directional parameters to minimize drilling depth and reduce drilling costs. The model uses the sequential unconstrained minimization technique (SUMT) to minimize drilling-depth objective function. Also, the model is used to calculate well surveys, simulate bit walk, and determine optimum lead angle to kick a well off. The minimum drilling depth is achieved at the minimum values for kickoff point, inclination, and angle-buildup and -dropoff rates. These minimum parameters reduce the dogleg severity, which, in turn, reduces the chances for operational problems like high torque and drag. The computer model has been validated by comparing a conventional design and an optimized design for a well drilled in the Gulf of Suez. The optimization model produced less drilling depth and lower inclination and dogleg severity.