阻塞流现象对稠油泵排量系数的影响

EFFECT OF CHOCKED FLOW ON DISCHARGE COEFFICIENT OF HEAVY OIL PUMP

由于H油田的稠油油藏具有“浅、薄、稠、松、散”的特点，地层能量低，原油流动性差，含水率高，开采难度大，稠油井在开采过程中普遍存在泵排量系数偏低的现象。为了寻找引起H油田稠油泵排量系数偏低的真正原因，提高稠油井的采收率，通过对泵排量系数影响因素以及稠油泵特殊结构的分析，发现阻塞流现象是引起泵排量系数偏低的一个重要因素。根据现场数据计算也表明，考虑阻塞流现象后，理论计算的排量系数与实际排量系数比较吻合，说明H油田稠油泵在抽汲稠油的过程中确实存在阻塞流现象。同时，通过阻塞条件分析表明，增大吸入阀孔径，合理设计阀和泵内部结构，减小阀和泵的流动损失，有助于防止阻塞流现象，提高泵的排量系数，为进一步研究稠油井增产措施提供了理论依据。

With the characteristics of ＂shallow, thin, heavy, loose and unconsolidated＂, heavy oil reservoirs in H Oilfield have some problems including low energy, poor mobility of oil, high water cut and difficulty of production. So, pump discharge coefficient of heavy oil well is commonly low during the development. In order to find real cause for low coefficient and to increase recovery of heavy oil well, through analysis on affecting factor of pump discharge and special structure of heavy oil pump, it is found that choked flow is an important factor which causes low coefficient. Field data calculation shows that, with consideration of choked flow, discharge coefficient of theoretical calculation basically coincides with actual value, which proves that choked flow exists indeed during the pumping of heavy oil from well in H Oilfield. Choked flow provision analysis shows that, enlarging valve aperture, reasonable design of valve and pump, and decreasing flow loss of value and pump can be helpful to prevent choked flow and increase discharge coefficient, providing theoretical foundation for further study of heavy oil well stimulation.