单井气藏改建储气库的经济评价方法——以川西北地区WC1井为例

Economic evaluation method of rebuilding single well into underground gas storage:A case study on Well WC1 in the northwestern Sichuan Basin

储气调峰能力不足是当前我国天然气产运储销体系建设的短板之一。由于地下储气库建设存在选址难度大、建设周期长等特点,为满足更多区域调峰需求,单井气藏改建储气库作为一种新模式应运而生,成为地下储气库的重要补充。为了解决单井气藏改造成储气设施的经济性论证问题,结合单井改建储气库的技术经济特征,在评价末期回收垫底气,建立与之相适应的经济评价方法。研究结果表明:①以川西北地区WC1井为例论证了考虑垫底气回收经济评价方法的可行性,项目整体内部收益率为6.78%,高于6%的基准收益率,从财务评价角度证实方案经济可行;②对比了评价方法对方案效益的影响,不考虑垫底气回收情况下,方案整体内部收益率为6.17%,低于考虑垫底气回收时6.78%的收益率。最后,提出两点建议:①推广单井气藏改建储气库的建库新模式,尤其是在选址难度大,但是又有调峰需求的资源地,可充分利用区域内现有的产能和枯竭气藏资源,开展单井气藏改造储气库的探索;②推荐经济评价时考虑回收垫底气,以解决改造项目的经济性论证难题。

Insufficient capacity of gas storage and peak shaving is one of the short boards in the construction of domestic natural gas production,transportation,storage and sales system.The construction of underground gas storage(UGS)is characterized by great site selection difficulty and long construction cycle,so in order to meet the need of peak shaving in more areas,single-well UGS emerges as a new mode at the proper time to act as an important supplement to UGS.In order to demonstrate the economics of rebuilding single-well gas reservoir into gas storage facility,this paper establishes the corresponding economic evaluation method by considering recycling cushion gas at the end of the evaluation period based on the technical and economic characteristics of rebuilding single well into UGS.And the following research results are obtained.First,the feasibility of the economic evaluation method considering the recycling of cushion gas is demonstrated with Well WC1 in the northwestern Sichuan Basin as an example.It is shown that the overall internal rate of return(IRR)of the project is 6.78%,which is higher the basic rate of return(6%),which proves the economic feasibility of the scheme from the perspective of financial evaluation.Second,the influences of evaluation methods on scheme benefits are compared.It is indicated that the overall IRR of the scheme without considering the recycling of cushion gas is 6.17%,which is lower that considering the recycling of cushion gas 6.78%.Third,two suggestions are recommended.First,it is recommended to popularize the new UGS construction mode of rebuilding single well into UGS,and especially in the resource areas with great site selection difficulty and peak shaving demand,existing productivity and depleted gas reservoir resources in the areas shall be used sufficiently to explore the rebuilding of single-well gas reservoir into UGS.Second,it is recommended to consider the recycling of cushion gas during economic evaluation,so as to solve the difficulty in the economic demonstration of rebuilding project.