煤层气井牛顿流体压裂压力损失预测模型

为准确预测牛顿流体连续管压裂作业时沿程管柱内的压力损失，根据我国煤层气井压裂所采用压裂液的特点，运用流体力学理论与方法，建立了基于牛顿流体流变学基本特征的混砂液在连续油管内流动过程中的压力损失预测模型；对不同施工排量、砂比、连续管径和入井长度比等参数对管内压力损失的影响规律进行了分析。提出: a .牛顿流体在管内流动压力损失的主控因素为流体与管壁的摩擦，因此，降低牛顿流体管内压力损失的有效途径是合理选择连续油管直径与优化施工排量； b .为降低管内摩擦压力损失，应参考入井长度比值等参数，合理优选连续油管长度； c .在满足连续管工作压力和保证携砂液性能的前提下，牛顿流体压裂时应尽可能采用大管径、大排量、中砂比施工。 

Pressure loss prediction model of newtonian fluid hydraulic fracturing in coalbed methane well

In order to predict accurately the pressure loss within coil tube during newtonian fluid coiled tubing fracturing and according to the newtonian fluid rheological characteristics of fracturing fluid used in coalbed methane wells in China, a pressure loss prediction model of slurry based on newtonian fluid in coiled tubing is established. The effect of operation discharge rate, proppant concentration, diameter of coiled tubing and set down ratio on pressure loss in tubing is analyzed. Some suggestions are put forward:(1) friction pressure loss is a major part in pressure loss along the tubing which can be decreased by optimization of tubing diameter and discharge rate; (2) to decrease friction pressure loss, the length of coiled tubing should be reasonably selected according to the set down ratio; (3) large diameter of coiled tubing, large discharge rate and medium proppant concentration should be selected as much as possible under preconditions of meeting the operating pressure of coiled tubing and ensuring proppant carrying ability of water.