考虑井筒摩阻损失后的Joshi公式

The Joshi formula considering the friction loss of well bore

刘子雄 汪亚蓉 黄 凯 郑齐义

中海油田服务股份有限公司，天津 300450 长江大学石油工程学院，湖北 荆州 434023 大庆油田有限责任公司采油工程研究院，黑龙江 大庆 163453

China Oilfield Services Limited, CNOOC, Tianjin 300450, China College of Petroleum Engineering, Yangtze University, Jingzhou 434023, China Production Engineering Research Institute, Daqing Oilfield Company Limited, CNPC, Daqing 163453, China

目前在设计水平井段长度时，采用的各种水平井产能计算公式均很难找出最优水平段长度。在目前的研究与应用中，普遍使用的Joshi公式忽略了井筒内摩阻损失，从而出现了在无限大的地层中，水平井段的长度与其产能关系曲线基本上呈线性，也就是说水平段长度越长越好，这一点与实际情况不符。通过对目前大多数水平井段中原油的流动状态，即层流的研究，考虑了层流情况下水平井井筒内摩阻的影响，修正了水平井产能计算公式，从而使其能够更加全面及准确地用于计算水平井的产能。

It is difficult to find out the optimal horizontal length by using various formulas of production calculation in design of horizontal well length. In the present study and application, the widely used Joshi formula has ignored the friction loss of well bore, which appeared that the relation between the length of horizontal section and its production ability is basically a linear curve in the formation of infinite length, that is to say, the longer horizontal length will be better, which does not match the actual situation. Through the study on the flow of most horizontal section, which considered the influence of friction within the horizontal section in
laminar flow conditions, the Joshi formula is modified with considering the friction loss of well bore on this flowing condition. Accordingly it is more suitable for designing the length of horizontal well and calculating production.