油井内波纹板表面结垢规律及预测模型

Surface Scale Law and Prediction Model of Corrugated Plates in Oil Wells

针对油田开发过程中井下抽油泵结垢问题,采用波纹板作为泵前预结垢装置的结垢元件,分析其结垢规律。基于Kern-Seaton结垢速率模型,推导了结垢沉积的半经验公式;运用湍流-化学相互作用模型和DPM模型模拟了CaCO_(3)颗粒在管道内波纹板表面的结垢过程,定量分析了温度、流速和颗粒质量浓度的倍数对结垢速率的影响规律;复配井下产出液,进行了室内结垢试验。试验结果表明:数值模拟和室内试验有着较好的一致性,温度上升颗粒质量浓度增加,对碳酸钙的结垢沉积具有促进作用;而流速的升高则能抑制碳酸钙的结垢沉积。在实际生产过程中,井内温度和结垢离子的质量浓度不可控,可以通过适当降低产出液的流速,增加波纹板表面的结垢量,以此达到减轻抽油泵结垢的目的。所得结论可为油田防垢、除垢提供理论依据和新思路。

In order to solve the scaling problem of downhole pump in oilfield development,the corrugated plate was used as the scaling component of pre-scaling device in front of the pump,and its scaling law was analyzed.Based on the Kern-Seaton scaling rate model,a semiempirical formula for scale deposition was derived.Then,the turbulence-chemical interaction model and DPM model were used to simulate the scaling process of CaCO_(3)particles on the surface of corrugated plate in pipeline,and quantitatively analyze the influence of temperature,flow rate and particle mass concentration multiple on the scaling rate.Finally,the downhole produced fluid was prepared for laboratory scaling experiment.The results show that there is a good consistency between numerical simulation and laboratory experiment.The increase in temperature and particle mass concentration promotes the scale deposition of calcium carbonate,while the increase in flow rate inhibits the scale deposition of calcium carbonate.In the actual production process,the temperature and concentration of scale-forming ions in the well are uncontrollable.Therefore,the scaling of downhole pump can be alleviated by appropriately reduce the flow rate of produced fluid and thus increase the amount of scale buildup on the surface of the corrugated plate.The conclusions provide theoretical basis and new ideas for scale prevention and removal in oilfields.