“一点法”产能评价方法的内涵、矿场应用及改进

Connotation,field application and improvement of the"one point method"productivity evaluation method

近年来,在四川盆地气井产能评价实践中发现,针对低渗强非均质性和中高渗储层,常规“一点法”适用性差。为探索并解决该问题,文中系统梳理并总结了“一点法”产能评价方法的不同形式,揭示了其内涵。“一点法”的内涵主要包括均质储层、可靠的稳定经验数、气井现场测试达到拟稳定渗流状态3个方面,围绕这3个方面的内涵,指明了“一点法”的矿场应用偏差。在此基础上,首先深入剖析了“一点法”计算参数的敏感性;其次对矿场应用提出了改进和数据处理方法,建立了稳定经验数与试井地层系数的经验关系式及不同层系试井地层系数与测井储能系数拟合关系式;再次,提出了不同类型气井测试数据评价方法及试油建议;最后应用文中建立的“一点法”改进方法对四川盆地不同气田的31口气井进行了计算对比,验证了方法的可靠性和可行性。该改进方法不仅适用于常规“一点法”的应用领域,也适用于具有低渗强非均质性、中高渗地质特征的气田,弥补了特定地质条件下常规“一点法”确定气井稳定产能误差大的不足,对于气田的开发设计、规模调整和现场生产组织均具有积极意义。

In recent years,it had been found in the practice of gas well productivity evaluation in the Sichuan Basin that the conventional"one point method"has poor applicability for reservoirs with low permeability,strong heterogeneity and reservoirs with medium to high permeability.To explore and solve the problems mentioned above,this article first systematically reviewed and summarized different forms of the"one point method"productivity evaluation method,revealing their connotations.The connotation of the"one point method"mainly includes three aspects:homogeneous reservoirs,reliable stable experience numbers and reaching a pseudo stable seepage state for gas well field testing.Around three aspects of the connotation,the deviation of the"one point method"in field application were pointed out.On this basis,the sensitivity of the"one point method"calculation parameters were deeply analyzed.Secondly,method improvements and data processing methods had been proposed for the field application,establishing empirical relationships formula between stable empirical numbers and well testing formation coefficients,as well as fitting relationships formula between well testing formation coefficients and well logging energy storage coefficients for different layers.In addition,evaluation methods and oil testing recommendations for different types of gas well testing data had been proposed.Finally,the improved"one point method"established in this article were applied to calculate and compare 31 gas wells in different gas fields in Sichuan Basin.The application of examples verified the reliability and feasibility of the method.This improved method is not only applicable to the application fields of the conventional"one point method",but also to gas fields with geological characteristics of low permeability,strong heterogeneity and medium to high permeability.It compensates for the large error in determining the stable productivity of gas wells under specific geological conditions using the conventional"one point method",and has positive significance for the development design,scale adjustment,and on-site production organization of gas fields.