压后水平气井生产动态预测模型

A prediction model of dynamic production of post-fractured horizontal gas wells

通常压裂后气井产能的计算模型都是针对稳态渗流过程的,倾向于计算无阻流量和稳态产量,而对于整个动态生产过程的模拟则较少被提及。为此,根据复位势理论和势的叠加原理,再结合压裂后水平气井的裂缝形态和气体的流动过程,用严格的渗流力学方法推导出了具有较广泛适应性的压裂水平气井生产动态预测公式。该预测公式既能用于存在缝间干扰的情况,又能够在压裂水平气井裂缝两翼非对称、间距不相等、方位角任意的情况下使用。应用该公式对吉林油田某水平气井进行了实例计算,计算值和实际值的误差为2.6%,并且通过预测公式能够很好地模拟分析裂缝方位、裂缝条数、裂缝长度、裂缝导流能力、裂缝间距等裂缝参数对压裂水平气井的产量影响,能够满足现场预测产量的需求。

Generally,productivity calculation models for post-fractured gas wells are formulated with reference to steady seepage and they tend to calculate only the open flows and stable outputs,without adequate simulation of the entire dynamic production process.In view of this,a formula with greater applicability is deduced for predicting the dynamic production of the fractured horizontal gas wells by the stringent seepage mechanics methodology,based on the complex potential theory and the superposition principle of potentials and in combination with the fracture form of post-fractured horizontal gas wells and the flow process of gases.This formula is not only applicable to well conditions with interaction among fractures,but also can be used for horizontal gas wells under circumstances of asymmetrical wings,unequal spaces and arbitrary azimuth angles.This formula is used for the calculation of a horizontal gas well in the Jilin Oil Field,with the error between the calculated and actual values of 2.6%.In addition,the formula can be used to simulate and analyze the impact of various parameters of fractures,such as position,number,length,division performance and spacing,on the output of the fractured horizontal gas wells to meet the demand of on-site output prediction.