水平井渗流模型分析评价及发展方向

为了进一步发展水平井技术以应对目前老油田产能下降及新增低渗储量比例不断提高的状况，需要对水平井理论进行进一步的深入研究。从最基础的渗流理论出发，总结分析国内外有关水平井的多种渗流模型，将这些模型按照所对应的渗流状态分为稳态渗流模型、拟稳态渗流模型、非稳态渗流模型以及井筒与地层耦合流动模型4类。通过对各类模型的适用条件及优缺点进行分析评价，认为稳态模型具开创性意义，但假设过于理想，与实际相差较远；拟稳态模型形式简单，却只描述了一个很短时间的形态；非稳态模型具有普遍性，但没有考虑到近井地带井筒流动的影响；而耦合模型在实际和精度方面具有优势，但却存在计算复杂的问题。在此项研究的基础上，提出了模型下一步发展方向，即以井筒与地层耦合模型为基础，进一步引入实际参量，并根据实际条件对参量进行拟合，固定部分计算参量的数值，在保证精度的前提下简化计算过程；同时，结合追踪流线与矢量井网等方法的应用，丰富研究手段。

Analysis and evaluation on horizontal well seepage models and their developing trends

As productivity of mature oilfields lowers and the proportion of reserves in low-permeability reservoirs increases,horizontal-well theory needs to be improved to innovate horizontal well technologies. Beginning with the basic see-page flow theory,this paper reviews different seepage models of horizontal wells at home and abroad.These models are divided into 4 types,including steady state model,pseudo steady state model,unsteady state model and wellbore-reservoir coupled flow models.The applicable conditions as well as advantages and disadvantages of every model are analyzed and evaluated.The results show that the steady state model is of pioneering significance,but their assumptions are too ideal to be in accordance with the actual situations;the pseudo steady state model is simple in forms,but can only describe see-page flow in a short-period;the unsteady state model is universal,but does not take the influences of wellbore flow in near wellbore areas into consideration; the wellbore-reservoir coupled flow model is high in accuracy,but also high in complexity of computation.Based on the study above,the paper presents the trend of seepage model development.Actual parameters will be introduced based on the wellbore-reservoir coupled flow model and will be fitted according the actural conditions.Some of the parameters will be determined to simplify the calculation procedure.Moreover,methods such as tracking streamline and vector well pattern will be incorporated to enrich research tools.