中文摘要：

低渗透致密储层进行大规模压裂改造在地层中形成多条裂缝及复杂裂缝网络是获得经济产能的主要手段，通过有效的方法对压裂水平井裂缝分布评价、压裂改造体积及压裂后产能预测对压裂施工效果分析具有重要意义。为此，在充分结合致密油储层特点和压裂改造设计思路的基础上，针对压裂措施后形成的分级多簇的裂缝排布及裂缝有限导流渗流特征，建立了水平井体积压裂三线性流数学模型，应用Laplace变换，求得定产条件下封闭边界单条裂缝的拉氏空间解；通过Stehfest数值反演及多裂缝叠加原理，得到了体积压裂水平井井底压力和产量的表达式；同时，结合美国巴肯致密油储层生产特征参数对模型的正确性进行了验证。对产能影响因素研究结果表明，裂缝排布方式对储层改造体积影响较大，级簇比越大累积产油量越高；增加裂缝条数可以有效提高储层动用效率，在进行水平井体积压裂措施设计时应充分考虑裂缝级数或簇数增加导致产量下降问题。研究结果对致密油储层水平井体积压裂设计及产能评价具有重要意义。

英文摘要：

For low-permeability tight oil/gas reservoirs ,economic development is viable only after high-volume hydraulic fracturing which can create multiple fractures and complex network consisting of natural and induced hydraulic fractures . Consequently ,fracture arrangement evaluation ,prediction of stimulated reservoir volume and well productivity are critical to well stimulation analysis .In combination with the characteristics of tight reservoir and the basics of hydraulic fracture design ,we proposed a trillinear flow mathematical model for volume-fractured horizontal wells which can reflect the finite conductivity flow behavior inside hydraulic fractures and massive fractures arrangement .The solution of single fracture at closed boundary condition can be obtained through Laplace transformation .Meanwhile,Stehfest numerical inversion and fracture superposition principle were applied to get formulas of bottom hole pressure and well production for volume -frac-tured horizontal wells .The model has been valid by using Bakken tight oil production curves .Sensitivity to various para-meters such as fracture arrangement ,stimulated reservoir volume ,number of fractures have been investigated .The result shows that the pattern of fracture distribution has a great influence on the stimulated reservoir volume ;the higher ratio of fracture stage and cluster is ,the higher the cumulative oil production of fractured horizontal well is;increasing the num-bers of fractures can improve producing efficiency ,however ,interference between fractures possibly cause the decrease of production .The study results are of great significance for the volume-fracturing design and well productivity evaluation of horizontal wells in tight oil reservoirs .