Abstract

Proper tubing size selection is essential to maximize economic reserve recovery in depletion drive gas reservoirs. For wells completed in multiple reservoirs with a wide range of reservoir properties, tubing size selection can become quite complex. This paper presents an approach used to determine optimum tubing size using a model developed by applying Nodal Analysis and Gas Load-Up Technology. A database consisting of 340 gas wells was analyzed and used to determine average parameters for input into the model. The model develops a relationship between Reservoir Abandonment Pressure (P_ab), Permeability Thickness (kh) and tubing size at various operating pressure conditions. The model shows that for high kh (Permeability Thickness) completions, tubing size has only a minor effect on the reservoir abandonment pressure. Actual VICO field data confirms the validity of the model.