天然气开发战略规划风险量化评价方法研究

Quantitative risk evaluation methods in natural gas development strategic planning

天然气开发战略规划编制过程中许多指标都具有不确定性,有可能会导致实施过程中存在较大的风险,为了更好地规避风险,充分发挥战略规划的引领作用,对风险进行量化评价就显得十分必要。为此,系统开展了天然气开发战略规划风险因素识别、目标模拟方法和风险综合评价标准研究。天然气开发战略规划风险因素主要有7类,即资源规模、开发地质、规划部署、技术水平、经济效益、管道市场和宏观政策风险;考虑不同风险因素对规划目标的作用机理,建立了产量评价数学模型,即以资源规模和开发地质作为产量规模评价的基础,以技术水平、管道市场、宏观政策和规划部署风险为约束条件,以经济效益最大化为优化目标的天然气产量最优化预测模型;引入蒙特卡洛随机模拟方法,实现了产量概率模拟;综合考虑产量目标实现概率和离散程度两个指标建立了风险等级评价矩阵,并针对客观风险和决策风险特点分别建立了"概率曲线扫描法"和"概率曲线位移法"两种风险因素敏感评价方法。实例应用效果表明,该风险量化评价模型能够量化战略规划风险大小、主要风险点及其分布特征,可以为辨识和降低战略规划风险、制定规避措施提供科学依据。

Uncertainties existed in the process of compiling strategic plan of natural gas development will lead to rather high risks in ac- tual implementation. Therefore, quantitative risk evaluation is important in avoiding those risks and exerting the effective role of strategic planning. Hence, systematic research was conducted on risk factors identification, target simulated methodology, and assessment criteria in gas development strategic planning. In terms of risk factors identification, seven types of risks are summarized： resource scale, devel- opment geology, plan deploying, technology level, economic benefits, pipeline-market constraints and macro policies. Considering the mechanisms of different risks affecting strategic planning, an optimal gas-output forecasting model was established. This is a prediction model based on resource scale and development geology, and constrained by technology level, pipeline-market constraints, macro poli- cies and plan deploying, and targeting for economic benefits maximization. In this model, the Monte Carlo stochastic simulation method was introduced to stimulate gas-output probability, and then risk grade assessment matrix was built considering both the probability for achieving the yield target and its dispersion degree. Finally, based on the evaluation objective and decision-making risks, two sensitivity analysis methods （＂probability-curve scanning method＂ and ＂probability-curve shifting method＂） were established. Case histories demon- strated that this quantitative risk assessment model can figure out the risk sizes in strategic planning, identify main risk types, and provide support for implementing measures to reduce risks.