连续管钻小井眼水平井水力学分析

水力学分析是连续管钻井的重要内容。建立了连续管钻水平井水力学计算方法并对其规律进行了分析,结果表明:连续管弯曲会增加压耗,增加幅度随排量增加而增大。推荐现场采用50.8 mm和60.3 mm直径的连续油管进行钻井。从控制环空压耗(ECD)角度考虑,建议连续管钻井设计时应使连续管外径与井径比小于0.5;偏心使环空压耗减小,环空尺寸越小,偏心的影响越明显。岩屑床使环空压耗梯度增加,岩屑床高度越大,增加幅度越大。常规钻井时随测深增加,泵压逐渐增加,而连续管钻进时泵压基本保持不变,甚至在某些情况下还会略有减小。

Hydraulics Analysis of Horizontal Slimhole Using Coiled Tube Drilling Method

Hydraulics analysis is the key of hydraulics design when drilling coiled tube wells. Based on the exiting researches, a method of hydraulics analysis when drilling horizontal slimholes with coiled tube is proposed and some cases are calculated and analyzed. The results show that, bending the coiled tube will increase the pressure loss and the increasing degree will increase with the increase of pump rate. The tube with 50.8 and 60.3 millimeters outside diameter are recommended to drilling coiled tube wells. To control the annular pressure loss, the rate of outside diameter of tube to borehole diameter had better be smaller than 0.5. Eccentricity decreases pressure loss and cuttings bed has the reverse effect. And the influence will be more obvious relevantly as the annular size is smaller and the cuttings bed height is bigger. When drilling a regular well the pump pressure increases with the increase of depth while the pump pressure almost remains stationary or decreases slightly in some case during coiled tube drilling.