连续油管水平井压裂携砂液流动压降及敏感性

连续油管压裂过程中携沙压裂液流动摩阻压降是压裂设计的重要内容,也是现场压裂施工成功的关键。压裂过程中携砂压裂液流经螺旋管、非螺旋段(垂直段+水平段)、环空压裂段,预测压裂流动压降难度大,现场设计数据与实际出入较大。在前人研究的基础上,以大庆某外径60.3 mm、壁厚2.769 mm的连续油管压裂数据为例,对连续油管水平井压裂携砂液流动压降进行分析。结果表明:螺旋段是连续油管在整个压降系统中最敏感部分,且这种敏感性会随着排量的增大而增强;环空压裂段摩阻压降与排量、环空管径比正相关;整体上压降随岩屑体积分数的增加而增加,但在此过程中会出现短暂下降窗口。

FLOW PRESSURE DROP AND SENSITIVITY OF THE SAND-LADING FLUID FOR THE HORIZONTAL WELL WITH THE COILED TUBING

Flow friction pressure drop of the sand-lading fracturing fluid in the process of the coiled-tubing fracturing is the important content of the fracturing design,it is also the key to the success of the fracturing operation.In the process of the fracturing,the fracturing fluid flows through the spiral pipe section,the non-spiral section (including the vertical section and the horizontal section) and the annular fracturing section,these flows make the prediction of the fracturing pressure loss very complex and furthermore the field design data are somewhat different from the actual engineering practice.Based on the previous researches,taking Daqing coiled tubing fracturing data (60.3 mm outer diameter and 2.769 mm thickness ） as the example,the flow pressure drop was analyzed for the sand-lading fracturing fluid in the coiled-tubing fractured horizontal well.The results show that the spiral section of the coiled tubing is the most sensitive part for the pressure drop system and this sensitivity is enhanced with the increase of the discharge;there are the positive correlations between the pressure drop in the annular section and the discharge and annulus diameter;on the whole,the pressure drop increases with the rise of the volume fraction of the debris,but in the process there will be a short time of the reduction.