非确定性决策分析和经济评价方法在油气项目投资中的应用和案例分析

The application of non-deterministic decision analysis and economic evaluation methods in oil and gas project investment and case analysis

国际大石油公司对油气勘探开发项目进行经济评价,已经从基于确定性模型的经济评价和决策向非确定性决策分析和经济评价方法转变。当前较受认可且有适用价值的非确定性决策分析和经济评价方法包括:决策树模型、VOI方法、蒙特卡洛模拟以及当前国际石油公司流行的S曲线分析方法。决策树模型和期望货币价值充分考虑了项目的多阶段性、各阶段的各种可能情形和不确定性以及实际测算中的合理性。VOI方法适用于从已知事件的条件概率推导到需要评价事件的条件概率,通过增量经济评价判断是否值得投资。蒙特卡洛模拟通过概率分布描述和量化模型中不确定性的变量或风险,通过采样完成对测算目标的计算,结果是目标的概率分布以及均值、方差、累计概率等。S曲线分析方法在评估油气勘探开发项目的经济性和风险性时较为全面和科学,易于形成通用的决策分析和经济评价体系,目前流行于国际大石油公司并构成了决策分析体系的基础。这些决策分析和经济评价方法适应了衡量项目不确定性和量化投资风险的要求。

The economic evaluation of oil and gas exploration and development projects of major international oil companies has shifed from economic evaluation and decision-making based on deterministic models to non-deterministic decision-making analysis and economic evaluation methods.The currently accepted and applicable non-deterministic decision analysis and economic evaluation methods include decision tree model,VOI method,Monte Carlo simulation,and the S-curve analysis method currently popular among intermational oil companies.The decision tree model and EMV(Expected Monetary Value)fully consider the multistage nature of the project,various possible scenarios and uncertainties at each stage,as well as the reasonableness of actual measurement.The VOI method is suitable for deriving the conditional probability of a known event to the conditional probability of the event that needs to be evaluated and then determining whether it is worth investment through incremental economic evaluation.Monte Carlo simulation uses probability distribution to describe and quantify uncertain variables or risks in the model and completes the calculation of the measured target through sampling.The output is not a single value,but rather the probability distribution of the measured target and statistical results such as mean,standard deviation,and cumulative probability etc.The S-curve analysis method is more comprehensive and scientific in evaluating the economics and risks of oil and gas exploration and development projects and is easy to form a universal decision analysis and economic evaluation system.It is currently popular in major international oil companies and forms the basis of their decision analysis systems.These decision analysis and economic evaluation methods meet the requirements of measuring project uncertainties and quantifying investment risks.