基于平衡流速的水平井砾石充填α波砂床平衡高度预测与试验

Prediction and experiment for α wave equilibrium sand bed height in horizontal well gravel-packing based on equilibrium velocity

基于Gruesbeck,Oroskar和Penberthy 3种固液两相管流平衡砂床上部平衡流速经验公式,考虑复杂的井底管柱结构和筛管偏置等情况,提出水平井砾石充填α波砂床平衡高度预测方法;利用自行研制的水平井砾石充填全尺寸试验模拟装置进行筛管偏置度、流量、砂体积分数对α波砂床平衡高度影响的试验。结果表明：基于Penberthy与Oroskar平衡流速经验公式的砂床平衡高度计算结果与试验值偏差较大,基于Gruesbeck经验公式的预测模型的计算结果与试验结果比较吻合,进行必要的修正后可用于水平井砾石充填α波砂床平衡高度预测;筛管偏置趋向于增大砂床高度,在实际施工过程中,应尽量避免筛管偏置下垂情况的发生;试验中砂体积分数为2%-8%,属于较低值范围,试验条件下砂床平衡高度随砂体积分数的增大而增大。

Considering the complicated downhole string structure and screen bending in horizotal well gravel-packing, an integrated α wave sand bed height model and its calculation method were evolved based on Gruesbeck, Oroskar and Penberthy empirical formulas for equilibrium velocity above the sendiment bed in solid-liquid flow in pipeline. A self-designed experimental system for inside-casing gravel-packing simulation was used to analyze the effects of screen bending degree, flow rate and sand percentage by volume on α wave sand bed height and verify the mathematical model. The results indicate that the α wave sand bed height models based on Penberthy and Oroskar equilibrium velocity formulas are not feasible to calculate the α wave sand bed height of horizontal well gravel-packing because of their high error to experimr.ntal results. The model based on Gruesbeck formulas is relatively accordant to the experimental data and more reasonable to predict α wave sand bed height o by necessary rectification. Screen bending helps to increase the sand bed height, which is negative to complete packing job. The sand percentage by volume is lower of 2% -8% in this experiment, and the α wave sand bed height increases with the sand percentage by volume increasing.