考虑变质量流水平井筒稠油携砂能力研究

Research of sand carrying capacity of heavy oil considering variable mass flow in horizontal wellbore

与浆体管输不同,水平井筒从趾部到根部随着地层流体的流入,井筒内流体流量逐渐增大,井筒内各个部位的流态随着井筒内流量的变化而变化。根据液固两相稳态流流态理论,流态依次从非均质悬浮流加固定床或流动床组合到单个非均质悬浮流。流态的变化引起了井筒内压力梯度、固定床层或流动床层高度等流动参数的变化,从而造成稠油携砂能力的变化。根据上述理论,建立了考虑变质量流水平井筒稠油携砂机理模型,并用其计算得到了井筒内压力梯度、固定床层或流动床层高度分布,为评价水平井筒稠油携砂能力提供了依据。

Compared with the transportation of slurry,the flow of mixture of heavy oil and sand in horizontal wellbore is different.From the toe to the root of wellbore with the inflow of formation fluid,the flow rate of wellbore gradually increased,which make the flow condition in the horizontal wellbore alter with the increase of flow rate.According to the method of liquid-solid two phase flow,the flow pattern in horizontal wellbore change in turn from the combination of heterogeneous suspension layer,moving bed layer and stationary bed layer to heterogeneous suspension layer.With the alternation of flow pattern,the flow parameters in wellbore such as pressure gradient,the height of moving bed layer and stationary bed layer will also change,which make the sand carrying capacity of heavy oil change.Based on above-mentioned theories,this paper sets up a sand carrying model of heavy oil considering variable mass flow in horizontal wellbore,and calculates the distribution of pressure gradient,the height of moving bed layer and stationary bed layer in wellbore,which help to appraise the sand carrying capacity of heavy oil.