By analyzing the relationship between measured values of pressure loss in a high-pressure hose and calculated values of metal tubing pressure loss formula under the same condition, a calculation formula of pressure loss in a high-pressure hose is revised on the basis of the existing formula, and a model of calculating the circulating pressure loss in coiled tubing ultra-short radius radial drilling technology is established by theoretical derivation. The effects of tubing diameter, tubing length, pump delivery and fluid dynamic viscosity on each part of pressure loss in circuiation system are studied by the pressure loss calculating model. The pressure loss in coiled and straight parts of 0.025 4 m (1 in) coiled tubing is about 8-10 times bigger than the pressure loss of 0.038 1 m (1.5 in) coiled tubing, and the pressure loss in high-pressure hose accounts for a large proportion in circulation system, about 86% in this study; and with drag reducer added in clear water, the pressure loss is about half of clear water pressure loss under the same condition.%通过分析相同条件下高压软管段压耗实测值与已有金属直管压耗公式计算值之间的关系,提出了高压软管段压耗计算公式,经理论推导建立了完整的连续油管侧钻径向水平井循环系统压耗计算模型.利用所建压耗计算模型研究了管径、管长、泵排量和流体动力黏度等参数对循环系统各部分压耗的影响规律.结果表明:0.0254m(1in)连续油管的螺旋段、直管段压耗都明显大于0.0381m(1.5in)连续油管,约为后者的8～10倍；高压软管段压耗在循环系统总压耗中占有较大比重,文中算例结果为86％；相同条件下,清水加减阻剂后压耗约为清水压耗的1/2.
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