水平井水平段长度计算及影响因素分析

由于水平井水平段的流动是变质量流,因此在水平井水平段存在流动压降,特别是当水平段较长时,会导致水平段井筒末端油藏和井筒的压降很小甚至为零。因而研究水平井水平段有效长度对水平井设计具有重要意义。在考虑水平段流动阻力的情况下,对水平段流动进行了简化,建立了计算水平井水平段长度的模型。对于一定的生产压差和预期达到的产量,利用该模型可以计算出所需水平段长度;反之,对于一定的生产压差和预期的水平段长度,利用该模型可以计算水平井所能达到的产量;并可利用该模型对影响水平井产量的因素进行敏感性计算分析。井例计算表明,对于具体油藏中的具体水平井存在一个最优的水平段长度。

Horizontal Section Length Computation and Effect Factor Analysis for Horizontal Wells

Considering the variable mass flow in horizontal well,the pressure drop exists in horizontal section.The long horizontal section will cause very small or zero pressure difference between the formation and the toe of wellbore.Therefore,study on effective wellbore length is very important to development program design of horizontal well.Considering the horizontal flow resistance,the horizontal flow was simplified,and the model to calculate the horizontal length was created.For specified drawdown and expected production,horizontal wellbore length can be calculated;and for specified drawdown and expected horizontal wellbore length,horizontal well production rate can be calculated.The sensitivity studies of parameters impacting the horizontal production rate are conducted.The simulated results indicate that there exists an optimized horizontal length for specified horizontal well.