压裂气井产量影响因素及压裂设计优化方法研究

Experiment on Influential Factors for Fractured Gas Well and Optimization in Fracturing Design

在单、双相非达西流裂缝导流能力室内实验的基础上,测定了不同工况下的裂缝渗透率和非达西流系数,建立了产量预测方法,研究了气井压裂后产量的影响因素及敏感程度。研究表明,闭合应力和铺砂浓度是影响产量的两个最主要因素,随着闭合应力增加,产量降低;随着铺置浓度增加,产量升高。而同样的参数变化比例下,闭合应力对产量的影响程度明显大于铺置浓度。两相流的存在对产气量影响非常大。压裂井一旦气水同产,气产量将明显降低,对于压后产水的井,有必要尽可能提高铺砂浓度。在此基础上,建立了新的压裂设计的优化方法。

The conductivity of artificial fractures and coefficient of non-Darcy gas flow in gas wells are affected by many factors.It is difficult to predict them accurately through mathematical methods.To get a more accurate value through the experiments of actual fracture conductivity,laboratory tests are conducted to measure fracture permeability and non-Darcy flow coefficientβ under different conditions.Computational formula of productivity based on the experimental data is established and the influential factors of the production of the artificial fractured gas well are studied.The results show that closure pressure and sanding concentration are the most important factors affecting the productivity and that gas-water production will greatly decrease the productivity of the gas well.The optimization methods in fracturing design based on the experimental data is set, that is：obtaining fracture permeability and non-Darcy flow coefficient β under different conditions through non-Darcy flow experiments and two-phase flow experiments,and then using them to forecast the productivity of fractured gas well,finally optimizing the fractured length,sanding concentration and other parameters accordingly.