A New Method of Gas Plateau Rate Optimisation: A Win-Win Solution for the Gas Field Operator and the Government as the Owner

摘要

A gas field company concern is to seek the highest gas plateau rate as possible for a contract rate of sale gas to obtain the most economics field development scenario. On the other hand, the higher plateau rate causes more gas reserve left underground after end of the plateau rate for the rest of the life of a field, and this reserve left would be the government concern as the owner to maximize the field ultimate recovery. Having this fact, a new concept has been brought up to solve this optimization problem to find a meeting point between the two concerns by figuring the performance of the Recovery Factor (RF) at the end of the plateau rate or until the end of the contract; we name it Contractor Concern Recovery Factor (CCRF), and the performance of Remaining Recovery Factor (RFR) after the contract ends until the Field Ultimate Recovery Factor; we name it Government Concern Recovery factor (GCRF), with respect to Rate of Return (ROR), at which the two performances behave oppositely. We define this meeting point of CCRF and GCRF the optimum for both parties, a win-win solution for the gas field company as an operator and the government as the owner. Having this optimization concept, a reservoir model of a real gas field is run for a sensitivity analysis study and Design of Experiment (DoE) of important parameters for the optimum gas plateau flow rate, and the results suggest that Original Gas in Place, is the most influencing parameter followed by average permeability and gas relative permeability. Finally, a correlation is introduced by applying the Least- Square method to find a relationship between the optimum gas plateau flow rate with the parameters, and the resulted correlation has an acceptable accuracy.