【作者】 单娴；

【导师】 姚军；

【作者基本信息】 中国石油大学（华东） ， 油气田开发工程， 2012， 博士

【摘要】 压裂水平井技术已经成为油气藏开发中的重要手段之一，开展压裂水平井数值模拟方法的研究可以为水平井和裂缝的空间展布优化提供理论依据，对提高油气藏的动用储量和采收率具有重要意义。压裂水平井的流动模拟中涉及到多种流动形态，对不同流动形态的对应区域采用不同网格系统进行划分，并耦合求解，能够提高模拟的准确性。论文将油藏-水平井系统划分为远井区域、裂缝区域、近井区域和井筒区域四个部分，按照各区域的流动形态分别建立了相应的数学模型。首先，考虑到油水井附近径向流的流动特征，在近井区域采用径向网格系统，并与油藏区域和裂缝区域笛卡尔网格系统相耦合，推导出各种网格及耦合区域的传导系数，建立了基于混合网格的压裂水平井数值模拟离散模型。其次，考虑平面和垂向渗透率各向异性油藏中水平井周围的椭圆流特征，在近井区域采用椭圆网格系统，并和远井区域及裂缝区域的笛卡尔网格系统耦合，建立了基于混合网格的各向异性油藏压裂水平井数值模拟离散模型。然后，基于水平井井身结构的特殊性以及井筒流体的流动特点，考虑井筒变质量流动的摩擦压降、加速度压降的影响，将井筒压降模型与油藏远井区域和裂缝区域的线性流动、井筒周围的径向流动进行耦合，建立了考虑井筒变质量流的压裂水平井数值模拟模型。以上数值模型均采用预处理正交极小化方法进行求解。将计算结果与通用的数值模拟器对比可以发现，论文中使用的方法具有较高的模拟精度，能够精细地刻画压裂水平井生产过程中各区域的流动特征。以交错五点井网和排状井网为例，运用上述压裂水平井数值模拟方法，对压裂水平井生产动态的影响因素进行了系统分析。通过比较可以看出，油层各向异性系数越小，垂向渗透率越低，流体在垂向上流动阻力越大，同一时刻采出程度越低。处于不同位置处裂缝对压裂水平井产量贡献明显不同。距离注水井较近的裂缝在生产早期产量较高，但含水上升较快，不利于注入水的推进，可以通过降低其长度和导流能力提高波及效率。在距离注水井较远的地方，可以选择较多数目的裂缝，增加其裂缝长度和导流能力，提高压裂水平井的生产能力。更多还原

【Abstract】 Fractured horizontal well technology has been one of the most important techniques forthe reservoir exploration and exploitation. Doing research on the production performance offractured horizontal well is helpful to the optimization of horizontal well and fracturedistribution, which can enhance the oil production and recovery. There are many flow patternsin the flow simulation of fractured horizontal well. Choosing the proper grid technique andcoupling method according to the different flow patterns in different regions, is a challengingtask of important theoretical value. With different flow regulations in different regions, thereservoir is divided into four parts: region far away from the well, fracture region, nearwellbore region, and horizontal wellbore. An integral method is applied to derive the flowequations of the reservoir regions. First, accounting for the radial flow nature in the nearwellbore region, orthogonal curvilinear grid systems are used in the wellbore region, andrectangular grid systems are used in the remaining regions of the reservoir. Thetransmissibility of each grid type and the coupling model of hybrid grid system are derived.Second, for reservoirs with isotropy permeability distribution, the flow nature near thewellbore is elliptical. The reservoir region can be divided into elliptical grids in the nearwellbore region and rectangular grid systems in the remaining regions of the reservoir. Thesplit of the reservoir system generates irregularly shaped blocks at the border of differentregions. Simplified equivalent approach is developed to handle the transmissibility of theirregular blocks. Then, the pressure drop model of variable mass flow in the horizontalwellbore, which can be coupled with the near wellbore model and reservoir model of hybridgrid, is obtained. The coupled model of the hybrid grid system all above is resolved byorthomin iterative method with factorization preconditioner. The numerical model is used tosimulate the production performance of different fracture parameters in five point hybrid wellpattern and row well pattern. The results show that, the lower the isotropy coefficient, thesmaller the vertical permeability. It results in the lower recovery. The production contributionof fractures varies with its location. The water cut of the fracture nearest to the injection wellraises rapid, which is disadvantage to the water injection. The production performance offractured horizontal well can be improved by shorting the length and lowering the flowconductivity of the fractures near the injection well. For regions far away from the injection well, the fracture length, the fracture number, and the flow conductivity of the fractures can belarger to improve the production ability of the fractured horizontal well.更多还原