【正文】 ) ? Brake Horsepower or Motor Load ? From the above, Pump Efficiency may be calculated 1 3 6 0 0 0))(( S p g rBPDF e e tPH y d r a u l ic H ?B HPPHy d r a u l i c HE ffic ie n c y ?58 Using the pump curve Example: A well will produce 4000 BPD with a GC3500 pump when the pump produces a TDH (total dynamic head) of 5000 ft. Specific gravity of the produced fluid = How many stages we need? How big the motor should be? 59 Pump Curve GC3500 Single Stage Performance, 3500 RPM SpGr = , 60 Hertz 4000 BPD, 42 ft/stg, HP/stg, 70% efficient 60 Using the pump curve S t a g e sS t a g e s S t a g eL i f tT DH 1 1 9425 0 0 0/ ???2 1 4))((1 1 9))(( ??? S p G rS t a ge sP u m p H P S t ag eB HPSo we need a motor bigger than 214HP, say 255HP. 61 Pump Thrust 62 In Floating Impeller Pumps the Impeller does not ?Float? It is free to move up and down on the pump shaft Impeller Position 64 Under normal operating conditions, fluid circulates on top and underneath the impeller shrouds Pump Thrust Load 65 The impeller discharge pressure is on the upper and lower impeller shrouds Pump Thrust Load 66 The larger cross sectional area on the upper shroud causes the force to be Down Pump Thrust Load This causes the impeller to be moved down This is a positive downward force termed ?Downthrust? 67 Pump Thrust Load At some point the volume of fluid going up into the pump will lift the impeller up, overing the Downthrust pressure This causes the impeller to be moved up 68 Pump Thrust Load The downward force is now reversed (negative), it is termed ?Upthrust? This causes the impeller to be moved up At some point the volume of fluid going up into the pump will lift the impeller up, overing the Downthrust pressure 69 Pump Thrust Load This increases the ?Upthrust? This causes the impeller to be held up This creates a larger cross sectional area on the bottom shroud which increases the pressure underneath 70 Hydraulic Thrust ? Total hydraulic thrust has two ponents, an up thrust ponent and a down thrust ponent ? The up thrust ponent is primarily created by the velocity through the impeller or hydraulic impact force ? The down thrust is primarily created by the pressure generated by the stage ? These two ponents bine to make up total hydraulic thrust ? Fluid viscosity has a dramatic affect on hydraulic thrust 71 Flow from Diffuser Impeller Flow Path Fluid velocity amp。 viscous drag forces add to upthrust. Hydraulic Thrust Pressure generated by the stage 72 Thrust and Impeller Position In normal operation the larger cross sectional area on the upper shroud causes more pressure on top, pushing the impeller down The pump is designed to operate in slight to moderate Downthrust. 73 Washers are fitted to prevent wear: Downthrust washers Upthrust washer Pump Thrust Load 74 Downthrust Washer 75 76 Upthrust Washer 77 Impeller Top Impeller Bottom 78 Hub Upper Shroud Vane Lower Shroud Skirt Eye Upthrust Washer Down thrust Washer Impeller Name the parts: 79 Shaft Thrust Shaft thrust is the result of the pump discharge pressure acting on the cross sectional end of the pump shaft The two things that determine shaft thrust is the pump discharge pressure (or TDH) and the diameter of the pump shaft. This thrust is transmitted directly to the seal section thrust bearing 80 Variable Speed Operation ESPs may also be ran at variable speeds. Changing the speed or frequency of an ESP system follows the “Affinity Laws” … ? New Flow Rate = Old Flow (New Hz/Old Hz) ? New Head = Old Head (New Hz/Old Hz)2 ? New Brake HP = Old BHP (New Hz/Old Hz)3 81 01020304050600 1000 2022 3000 4000 5000 6000Flow, Barrels per day (BPD) Operating Range Head Capacity Pump Efficiency Brake Horse Power Head in Feet BHP Pump Curve 80 60 40 20 1 2 3 Efficiency % Best Efficiency Point (BEP) 82 V a ri a bl e S pe e d O pe ra t i on0204060801001201400 500 1000 1500 2022 2500 3000 3500 4000 4500 5000Flow (BPD)Head (Feet)6 0 H zOperating Range GC2200 Single Stage Performance RPM 60Hz = 3500 (Sg = 1) 83 V a ri a bl e S pe e d O pe ra t i on0204060801001201400 500 1000 1500 2022 2500 3000 3500 4000 4500 5000Flow (BPD)Head (Feet)6 0 H zOperating Range GC2200 Single Stage Performance RPM 60Hz = 3500 (Sg = 1) 84 Fluid Reservoir ?Normal? RPM 85 Fluid Reservoir Fluid Reservoir ?Normal? RPM Slower RPM 86 Fluid Reservoir Fluid Reservoir Fluid Reservoir ?Normal? RPM Slower RPM Faster RPM 87 V a ri a bl e S pe e d O pe ra t i on0204060801001201400 500 1000 1500 2022 2500 3000 3500 4000 4500 5000Flow (BPD)Head (Feet)6 0 H z88 V a ri a bl e S pe e d O pe ra t i on0204060801001201400 500 1000 1500 2022 2500 3000 3500 4000 4500 5000Flow (BPD)Head (Feet)6 0 H z5 0 H z89 V a ri a bl e S pe e d O pe ra t i on0204060801001201400 500 1000 1500 2022 2500 3000 3500 4000 4500 5000Flow (BPD)Head (Feet)7 0 H z6 0 H z5 0 H z90 Variable Speed Operation ? New Flow Rate = Old Flow (New Hz/Old Hz) ? New Head = Old Head (New Hz/Old Hz)2 “ Affinity Laws” … 60Hz – Operating Range Min flow = 1500bpd 54ft BEP flow = 2200bpd 46ft Max flow = 3000bpd 25ft Min flow = 2022bpd 96ft BEP flow = 2933bpd 82ft Max flow = 4000bpd 44ft 80Hz – Operating Range ? 91 V a ri a bl e S pe e d O pe ra t i o