水平井变质量管内流动损失的数值研究(一):单支孔流动

NUMERIC SIMULATION STUDY OF FLOW LOSS FOR VARIABLE MASS FLOW IN HORIZONTAL WELL: PART ONEFLOW IN SINGLE HOLE

水平井采油是石油工程中新的重大课题之一 ,尤其对于开采稠油、低渗、裂缝性、底水和气顶油藏以及老井的后期挖潜有明显效益。由于水平井与油藏接触段较长 ,井内压降较大 ,其沿程压降对产油量有很大影响。因此 ,掌握水平段的流动损失和压降规律 ,对优化水平井长度及开采工艺设计、准确预测水平井产油量是非常重要的。在实际水平井中 ,沿程不断有流体从管壁孔眼流入井筒 ,这是一种变质量流动 ,这种流动比常规的管道流动复杂得多。文中采用数值方法研究壁面注入对管流压降及壁面摩擦阻力的影响 ,给出单支管流动损失并总结压降系数与壁面注入速度及截面雷诺数的变化规律。多支管流动损失将在《水平井变质量管内流动损失的数值研究 (二 ) :多支孔流动》中介绍。

Horizontal well production is one of the most challenging new research projects in petroleum engineering. It is very clear that horizontal well has its advantage in the development of viscosity oil, low permeable, fractural, bottom water, gas cap reservoirs and in the applications to dig out oil production potential of developed wells. Oil production rate is influenced greatly by the pressure drop along the well bore, because of longer distance of horizontal interval and higher pressure drop in the well. Therefore, it is very important to have a better understanding of mechanism for flow loss and pressure drop along the horizontal interval, and the principle can be used to optimize horizontal interval, to design production technologies and to predict production rate of horizontal wells. In a real horizontal well, the fluid flow from different perforations is added to the main flow along the horizontal interval continuously. This kind of flow is variable mass flow and its flow mechanism is more complex than that of normal tube flow. This paper describes numeric simulation approach which is used to study the flow pressure drop and influence of friction caused by the injection from well wall. It also supplies single hole flow and summarizes the relationship among the pressure drop, injection rate from perforations and well bore section Reynolds number. The loss of multi-hole flow will be introduced in Part two, Muti-hole flow of Numeric Simulation Study of Flow Loss for Variable Mass flow in Horizontal Well.\;