Optimization of the gas production rate by marginal cost analysis: Influence of the sales gas pressure, gas price and duration of gas sales contract

• Marginal cost analysis to optimize natural gas production rate.
• Increasing sales gas pressure and gas price will increase optimum gas rate and maximum profit.
• Increasing duration of sales contract will reduce optimum gas rate.
• Increasing duration of sales contract will reduce or increase profit depending on reservoir type.

The development of a gas field requires accurate planning, but the gas production rate is one of the main challenges in determining the feasibility of a gas project. An optimum gas production rate is determined not only by the gas reserve and reservoir characteristics but also by the consumer's requirements of the sales gas pressure, duration of the gas sales contract and gas price. This paper presents a gas production optimization model based on the marginal cost approach to maximize economic profit using a case study in the Donggi gas field. The results reveal that increasing the sales gas pressure and gas price raises the optimum gas production rate and increases the maximum profit; meanwhile, increasing the duration of a gas sales contract will reduce the optimum gas production rate and reduce or increase the maximum profit depending on the gas reserve and reservoir characteristics. This work clearly shows the relationship between the user's requirements and optimum gas production rate, which is an important piece of information for negotiating the gas price and planning production.