Abstract: In this paper,the 3D steady state pressure distribution of oil flow in a reservoir due to a horizontal well is derived for several cases of common reservoir type and a new formula of calculating pressure drop along the horizontal wellbore is also derived based on the principle of conservation of matter and momentum theorem.The effect of influx into the horizontal wellbore from the reservoir on pressure drop in the wellbore has been considered in the formula.A mathematical model coupling fluid flow in the reservoir with the flow in the horizontal wellbore is developed and the method for solving the model is presented.Example calculations showed that the precision of calculating productivity using the model is high,that performance of the well can be influenced by pressure drop in the horizontal wellbore,that the total well rate does not increase with increasing well length for lengths exceeding a certain value and that production index per unit length for every interval along horizontal well axis is not equal.

Key words: horizontal well, steady state flow, 3D, pressure distribution, pressure drop, well bore flow, mathematical model, coupling

摘要： 针对几种常见油藏类型情况,导出了水平井生产时单相原油三维稳态流动的压力分布,并根据质量守恒原理及动量定理导出了水平井筒内压降计算新公式。它考虑了沿程流入对井筒内压降的影响。提出了把油层中的渗流与水平井筒内的流动耦合的数学模型及求解方法。实例计算表明:用此模型计算产能,精度高;井筒内压降对水平井生产动态有影响。当生产井段长度超过某一值后,产量不再随井长增加而增加;沿水平井筒长度方向各段单位长度的采油指数并不相等。

关键词: 水平井, 稳态流动, 三维, 压力分布, 压力降, 井筒流动, 数学模型, 耦合