Control of multiple tubing string well systems

A computer-executable method, comprising:

• modeling a well system of multiple tubing strings as segments;
• modeling each segment as one or more equations describing one or more characteristics of a fluid resource associated with the segment;
• establishing multiple control points in the well system;
• solving the equations to convergence to predict flow rates, pressures, and flow of energy to satisfy production or injection targets and to satisfy selected constraints for the control points;
• wherein the constraints further comprise a steam trap constraint for forcing at least one segment of the well into a sub-cooled condition and a steam production constraint for limiting production from at least one segment of the well based upon one or more water vapor inflow values;
• applying different operating strategies for determining the constraints, each operating strategy associated with a triggering criterion to modify a topology of the well system to improve a production of the well system or to balance a production of the well system;
• and
• wherein modifying the topology includes one of opening a well, closing a completion, or changing a boundary condition of the well system.

A non-transitory computer-readable storage medium, containing instructions, which when executed by a computer perform a process, comprising:

• modeling a multi-segment well system of multiple tubing strings as equations, each equation associated with a segment and each equation describing one or more physical characteristics of a fluid resource associated with the segment;
• modeling a node and a pipe of each segment individually to accommodate chords and devices affecting pressure and rate flow;
• assigning an open chord to selected nodes to create multiple control points;
• solving the equations to convergence to predict a flow of fluids and energy to satisfy a production target subject to user-specified constraints for the control points;
• and
• applying the converged equations to improve a production of the fluid resource;
• calculating surface phase volumes for each phase of the fluid resource;
• establishing stages of a separator chain at different temperatures and pressures;
• flashing component molar rates of surface phase volumes to thermodynamic equilibrium at a first stage in the separator chain;
• directing an outlet stream from a phase outlet for each of the equilibrated phases to subsequent stages in the separator chain or to an overall separator outlet for the individual phase;
• wherein a fluid from a phase outlet of any separator stage can be split and sent to different downstream stages;
• and
• wherein the split can be based on a volume fraction or volume rate for each phase outlet.