As gas and oil fields mature their operation becomes increasingly more complex, due to complex process dynamics, like slugging, gas coning, water breakthrough, salt or hydrate deposition. Moreover these phenomena also lead to production constraints in the upstream facilities. This complexity asks for operator support in how to optimally operate such an asset.
In this paper we explore how, based on physical models of reservoirs, wells and top side separation and compression equipment, real-time optimization may be used in optimal operation of a maturing asset showing complex dynamic behavior and top side compressor constraints. In a joint industry project of Wintershall, GDF, EBN, Siemens and TNO the applicability of Real-Time Optimization is explored.
Real-time optimization will be demonstrated on a maturing North Sea off-shore gas production asset consisting of eight wells and two separator and compression trains.
The current results show how the optimization problem has been defined and implemented in a real-time architecture. First results are shown realizing the gas production set point and minimizing compressor power, while the production of individual wells suffer from degrading performance and (unplanned) shut-ins.
The optimizer computes how the production must be dynamically distributed over the wells and how the compressor trains must be operated.
Dynamic optimization strategies have been exploited successfully in downstream operations. A similar development is happening in upstream industry, while having to cope with the higher uncertainties typically present in upstream processes. As the paper shows Dynamic Optimization may lead to large benefits in Real-Time Operation of upstream production facilities.