Abstract The sharp decline in oil or gas production has been observed in many multi-fractured horizontal wells (MFHW) within only one or two years’ development. How to determine production rate distribution of MFHW becomes significant for enhancing hydrocarbon productivity. However, the effect of non-uniform production distribution of horizontal sections and fractures on pressure-transient response are hardly considered for the available well-testing models of MFHW, leading to erroneous interpretation results. The aim of this work is to present a novel approach to investigate the non-uniform production distribution along horizontal wellbore in a relatively economical way. An analytical model was developed to better characterize flow in fractures and horizontal wellbore. To better calculate the pressure drops in hydraulic fractures, we modeled the fluid flow in fractures with finite conductivity by considering variable-mass-linear flow for fluid far from wellbore and radial flow for fluid near wellbore. Meanwhile, horizontal wellbore was divided into multiple horizontal sections, and each segment is considered as a cylindrical source. As a result, an analytical pressure solution was developed. The analytical solution was further compared with numerical model in Saphir to verify the accuracy. A new horizontal line before pseudo-radial flow was observed (the second radial flow)) on pressure-derivative curves. It would lead to incorrect interpretation results of parameters if the new regime is regarded as the pseudo-radial flow.

中文翻译：

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分析多级压裂水平井产量分布的新型试井模型

摘要 许多多级压裂水平井（MFHW）在短短一两年的开发过程中就发现油气产量急剧下降。如何确定MFHW的产率分布对于提高油气产能具有重要意义。然而，现有的MFHW试井模型几乎没有考虑水平剖面和裂缝产量分布不均匀对压力瞬态响应的影响，导致解释结果错误。这项工作的目的是提出一种新方法，以相对经济的方式研究沿水平井眼的非均匀产量分布。开发了一种分析模型以更好地表征裂缝和水平井眼中的流动。为了更好地计算水力压裂中的压降，我们通过考虑远离井筒的流体的可变质量线性流动和接近井筒的流体的径向流动，对具有有限电导率的裂缝中的流体流动进行建模。同时，水平井筒被划分为多个水平段，每个段被视为一个柱状源。结果，开发了分析压力解决方案。解析解进一步与Saphir中的数值模型进行比较，以验证其准确性。在压力导数曲线上观察到伪径向流之前的新水平线（第二个径向流）。如果将新流态视为伪径向流，将导致参数解释结果不正确。