Diaa Hamed ShaatMohammad Al- Bakheet Ali Abu Al-Haj Omar Rababa’h Hala Al-Adwan Machine Design Laboratory – Semester Project Supervised By Dr. Mohammad Dado History and development of the walking beam pumping units Figure 1. The first Oil Pumping unit in History .. Interesting ! 1 Figure 2. Figure 1. Lufkin pumping unit from the early 1920s 2 Figure 3. The 1926 Lufkin Crank-Balanced Pumping Unit is still in service today with only slight modification. However. a means of Artificial Lift is used to lift the oil from the reservoir to the surface. the oil flows naturally to the surface. when the reservoir does not have enough pressure to produce by natural energy. Beam Pumping is the most common type of artificial lift-some estimates claim that as many as 71 % of artificial lift wells are occupied with beam pumps.Application and usage of beam pumping Units When the pressure in an oil producing reservoir is high. 3 . Usage percentages of oil Artificial left methods worldwide.Figure 4. 4 . Source: world oil 2005. operation. Specifications.Structure. and classification of Beam Pumping systems Figure 5. A diagrammatic drawing of a sucker rod pumping unit. 5 . 6 Specifications Typical Values Gear reducer output shaft speed (depending on well characteristics and fluid properties) 4-40 rpm Stroke lengths of conventional pumping units 12-200 in Polished rod loads 3000-35000 Ib . 7 . The polished rod and stuffing box combine to maintain a good liquid seal at the surface and.The rotary motion of the crank arm is converted to an oscillatory by means of the walking beam through a pitman arm. The horse’s head and the hanger cable arrangement is used to ensure that the upward pull on the sucker rod string is vertical at all times (thus. no bending moment is applied to the stuffing box). The output shaft of the gear reducer drives the crank arm at a lower speed . thus. force fluid to flow into the ‘‘T’’ connection just below the stuffing box. Operation of the Pumping unit: The power from the prime mover is transmitted to the input shaft of a gear reducer by a V-belt drive. Sketch of three types of pumping units: (a) conventional unit (b) Lufkin Mark II Unit (c) air-balanced unit 8 .Figure 6. Position Analysis The pumping unit can be modeled as a 4-bar mechanism. = 20 degrees). Taking the loop ADE. 3) The pumping angle of the output link oscillates from -30 to 30 degrees (assuming a Grashofian mechanism). Mobility analysis shows that 1 input is required to control the motion of the mechanism M = 3(L-1) – 2J = 3(4-1) – 2(4) = 1. Assumptions: 1) The ground link AE equals 10 m at an angle 20 degrees (d1= 10 m. 9 . 2) The length of the output link DE equals 7 m (d4 = 7m). Figure 7. 10 . Sketch of the pumping unit. Deriving the equation which relates theta 2 (input) with theta 4 (output): 11 . Deriving the equation which relates theta 3 (walking beam) with theta 2 and theta 4: 12 . Dimensions of the pumping unit From the geometric constrains of the upper and lower positions of the output link. and the pitman arm BD (d3) are determined. the lengths of the input crank AB (d2) . Figure 8. The lower limiting position 13 . Figure 9. so it is a grashofian mechanism of the crank-rocker type. 14 . The upper limiting position Note that d1 + d4 > d2 + d3 . which means the input does a full rotation and the output oscillates. 396 rad/sec = velocity of output walking beam. And the velocity of the input crank = 29. 15 . Assuming 14 stroke / min * 3.Velocity Analysis The equation which relates the velocity of the input and output links is: Note: the output link velocity is MAX when = 180 degrees.4 rad/s.14 stroke length *6 m / 60 = 4. And = Zero at the limiting positions ( = and = + pi . 988 kg 16 B . From the standard tables for steel: Mass = 194 kg/m Length of output link = 13 m Then the Mass = 2522 kg D B For beam 3 (the walking beam) [ Rectangular cross section ]. From the standard tables for steel: Mass = 23.51 m Then the Mass = 129.Masses of the beams For beam 4 (the output) [ I cross section ].6 kg/m D Length of walking beam link = 5. D = 838 mm. B= 292 mm. D = 300 mm. B= 10 mm. For beam 2 (the input link) [ Rectangular cross section ].3 kg 17 .6 kg/m Length of walking beam link = 2. B= 10 mm.17 m Then the Mass = 51. D = 300 mm. From the standard tables for steel: Mass = 23. Production Analysis and Rope Design 18 Result Value Strokes / min 14 Barrel / day 1700 Stroke length 3.4 cm Mass of oil 13670 N Mass of barrel 1324.14 m Stroke diameter 7.1 Mpa .6 cm Factor of safety 6 Stress acting on the wire section 22.35 N Mass of the rod Neglected Total force acting on the wire 15000 N Barrel diameter 27. Production Analysis and Rope Design 19 . Production Analysis and Rope Design Selecting the suitable rope and the material (lang lay 6*37) Manganese steel. 20 . Production Analysis and Rope Design 9 cm = the rope diameter 21 . 22 .Determining the life of the rod. the force in link 3 (two force member) is found to be 4230.36 deg.223 N (compression). Taking a FBD of the walking beam. 23 .Torque Calculations Taking the critical position when the walking beam is Horizontal to calculate the MOMENT required to be supplied by the motor. and theta 3 = 34.77 deg. At this position theta 2 = 171. m 4230.77deg 34. the moment is found to be 21.223 N 2.5 KN.36 deg 10000 N 24 M .1730 m 171.Torque Calculations Taking a FBD of the input crank. 25 .Stress Analysis of the walking beam Figure 10. Shear force diagram. Stress Analysis of the walking beam Result Value Maximum Sear stress + 27.108 KN at 7 m Second moment of area 2434380214 mm^4 First moment of area 3354188.298 mm^3 Web thickness 14 mm = 2.6678 Mpa (maximum) 26 . Bearings selection Calculation Value Fd + 27.36 KN 27 .108 KN / 2 Ld 8760 hour (yearly) Nd 14 rpm Lr 10^6 C10 = 26. Bearings selection 28 . Bearings selection 29 Result Value 2 bearings @ E Bore = 40 mm 2 bearings @ D Bore = 20 mm .
Report "Design and Analysis of a Sucker Rod Oil Pumping Unit"