An Integrated Production Modelling workflow for CSG production forecasting and optimisation

An Integrated Production Model (IPM) predicts the coupled response of the reservoir, producer wells and surface facilities ensuring that proper boundary conditions are honored at all times. Traditional IPM approaches typically employ time-dependent type curves for modelling the reservoir-well behavior to reduce computational effort and time. However, these approaches have limited accuracy and applicability because changes in the reservoir pressure or well production variations as a function of the surface network back pressure are ignored. This paper presents the implementation of an automated workflow to replace time-dependent type curves by pressure-dependent reservoir-well models for honoring pressure and flow constraints, controlling the IPM optimizer and efficiently generating a fully constrained CSG production forecast. The automated workflow approach provides a framework for reducing simulation time, improving accuracy and handling scenario analysis being tested using field data of two real integrated production systems of increasing complexity involving 250 wells (single compressor station) and 500 wells (multiple compressor stations), respectively, with pre or post dewatering periods. The results show the time required to manually generate long-term production forecasts is reduced by up to 68% model whereby the system was accurately solved to meet demand or to maximize production by satisfying hydraulic constraints and boundary conditions. This approach has been applied for Optimisation and Debottlenecking of which case studies are presented.