金属网布筛网冲蚀预测几何模型优选

Optimization of geometric model for erosion prediction of metal mesh screen

金属网布筛网是含砂油气田生产最常用的挡砂工具,含砂液流必然会对防砂筛管造成不同程度的冲蚀破坏,严重影响油井或气井的正常生产。针对防砂筛管几何结构复杂、冲蚀模型选择难等问题,基于流场相似理论提出了一种柱状多孔结构简化几何筛网模型,并以油井生产运行工况数据为依据优选了适宜的筛网冲蚀预测模型。在模拟中把油水考虑成均相,油水混合物密度采用含水率的加权平均来计算,油水混合物黏度按照具有较高精度的Mcadams公式计算。模拟结果与筛网喷射冲蚀试验数据进行了对比分析,发现ZHANG模型的计算结果与试验数据误差较小(16.57%),而DNV模型与OKA模型的结果与试验数据误差较大(26.4%和36.34%);DNV和OKA模型冲蚀区域比较集中,与试验结果不符,ZHANG模型下筛网的冲蚀相对发散,与室内试验比较相符。简化的几何筛网模型和优选的ZHANG模型具有较高的可靠性,可为井下筛网的选型、生产工艺设计提供参考。

The metal mesh screen is the most commonly used sand retaining tool in the production of sand-bearing oil and gas fields.The sand-bearing liquid flow will inevitably cause different degrees of erosion damage to the sand control screen,which will seriously affect the normal production of oil and gas wells.In view of the complex geometric structure of the sand control screen and the difficulty in choosing erosion models,a simplified geometric screen model with columnarporous structure was proposed based on the flow field similarity theory,and a suitable erosion prediction model of screen was optimized based on the test data.In the simulation,the oil-water mixture was considered as homogeneous phase,the density of the oil-water mixture was calculated by the weighted average of the water content,and theviscosity of the oil-water mixture was calculated according to the Mcadams formula with high accuracy.The simulation results were compared with the test data of screen jet erosion.It is found that the calculation results of the ZHANG model and the test data have a small error(16.57%),while the results of the DNV model and the OKA model have a large error with the test data(26.4%and 36.34%);The erosion area of DNV and OKA models is relatively concentrated,which does not match the test results.The erosion of the screen mesh under ZHANG model is relatively divergent,which is consistent with the indoor test.The simplified geometric screen model and the optimized ZHANG model have high reliability,which can provide references for the selection of downhole screens and the design of production processes.