单螺杆泵是一种螺旋渐进容积式泵，单螺杆泵的主要工作部件：一根单头旋转的转子和一个通常用弹性材料制成的具有双头螺旋的定子，螺杆泵工作时，液体被吸入后就进入螺纹与泵壳所围的密闭空间，当主动螺杆旋转时，螺杆泵密封容积在螺牙的挤压下提高螺杆压力，并沿轴向移动。由于螺杆等速旋转，所以液体流出流量也是均匀的。也正是基于这种特性，单螺杆泵适合于以下各工况的工作： 1.输送高粘度介质：根据泵的大小不同，可以输送粘度从1mPas--3百万mPas的介质。 
1、井下螺杆泵的工况，即井筒流体进入敞开腔室的流量大小与敞开腔室的压差和流体粘度等因素有关。1. The working conditi of the downhole screw pump, that is, the flow of the wellbore fluid into the open chamber, is related to the pressure difference of the open chamber and the viscosity of the fluid.Ａ、压差对工况的影响The effect of A and pressure difference on the working condition如果忽略流体的蒸汽压力、井筒动液面和泵吸入口的摩阻损失，则打开一个敞开的腔室所建立的生产压差为0.1Mpa，只要在吸入口及腔室之间的压降小于形成一个腔室所建立的压差，井筒流体将全部充满腔室，则螺杆泵可以达到其理论摄排量。
Ｂ、流体粘度对工况的影响The effect of B and fluid viscosity on the working condition随着流体粘度的增加，由于产生较高的压降使泵的排量下降。As the viscosity of the fluid increases, the displacement of the pump decreases as a result of high pressure drop.Ｃ、泵磨损影响Effect of C and pump wear螺杆泵的工作转速通常为40至500r/min，为减少由于磨损而带来的维修工作量，应当随流体的磨蚀性增加而降低泵的转速。研究表明，泵的磨损与流体流速成正比，但是低的转速对井下泵的使用寿命又产生不利的影响。The working speed of the screw pump is usually 40 to 500r/min. In order to reduce the maintenance workload caused by wear, the speed of the pump should be reduced with the increase of the abrasive wear of the fluid. The study shows that the wear of the pump is proportional to the flow velocity of the fluid, but the low speed of the pump has a negative effect on the life of the downhole pump.