Unidades de bombeo

P6-i The Lease Pumper’s Handbook CHAPTER 6 MECHANICAL LIFT A. Pump Operation 1. Application of Mechanical Pumping. 2. How Mechanical Lift Works. 3. Problems Caused by the Cyclic Load Factor. 4. Pumping at the Wrong Speed. Operating and Servicing the Pumping Unit. 1. Mechanical Lift with Electric Prime Movers. 2. Mechanical Lift with Natural Gas Engines. 3. Pumping Schedules. 4. AutomaticControls. 5. Maintaining the Pumping Unit.  The daily inspection.  The weekly inspection.  The monthly inspection.  The three- and six-month inspection.  Pitman arm and gearbox problems. 6. Direction of Rotation. 7. Gearbox Oil. 8. Typical Pumping Unit Problems. Wellhead Design and the Polished Rod 1. Preparing the Well for Pumping Downhole. 2. Pumping Wellheads. 3. Selection of Polished Rods,Clamps, Liners, and Stuffing Boxes.  Polished rod.  The polished rod liner.  The polished rod clamp.  The stuffing box.  The polished rod lubricator.  The rod rotator. 4. Tubing, Casing, and Flow Line Check Valves.  The tubing check valve.  The casing check valve.  The flow line check valve. The Downhole Pump 1. Basic Components of the Pump.  Standing valve.  Barrel tube.

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D.6-ii  Plunger.  Traveling valve.  Holddown seal assembly. Pumps Designs.  Insert pumps.  Tubing pumps.  Other styles of pumps.

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6A-1 The Lease Pumper’s Handbook Chapter 6 Mechanical Lift Section A PUMP OPERATION

There are four types of power that are commonly used to provide artificial lift in the oil field. There are:   Mechanical lift powered by a motor or engine on thesurface Hydraulic lift, where oil or water is pumped down into the well to operate a hydraulic pump Electric submersible pump, where a pump at the bottom of the well is driven by electricity from the surface Gas lift, where natural gas injected into the tubing at intervals lightens the weight of the fluid, helping it rise to the surface

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This system of pumping works well for low productionbecause the surface equipment requires very little daily attention. Each installation is an independent system, is economical to maintain, is easily automated, and is ideal for both intermittent as well as continuous production. Other lift methods may be more appropriate for a specific situation and for higher production rates, but for many applications mechanical lift is ideal, including in shallowoffshore wells. A-2. How Mechanical Lift Works. The mechanical pumping unit works on the same operating principles as a windmill or any water well that has a string of sucker rods, a standing and a traveling ball on the bottom, and power at the top. Figure 1 shows a typical pumping unit. These systems, sometimes called rod pumping units, work with an up and down reciprocating motion.

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Allfour of these systems offer advantages and disadvantages for specific situations. During the life of a well, more than one of these systems may be used. Occasionally the same type of system may be installed a second time on the same well. Mechanical lift is one of the more commonly used forms of artificial lift and is the subject of this section. The other types of lift are discussed in the nextthree chapters. A-1. Application of Mechanical Pumping. The mechanical pumping unit remains as one of the best ways to produce artificial lift wells. It is also satisfactory for marginally producing wells, and the majority of all artificial lift wells use mechanical lift.

Figure 1. A conventional beam-style pumping unit.

6A-2 The crank of the pumping unit is driven in a circular motion by therotation of the sheaves or pulleys, belts, and gearbox. The gearbox is driven by the prime mover, generally a gas-powered engine or an electric motor. The pitman arms are connected to the walking beam, and the rotary action is converted into reciprocating power to the walking beam and the horse head. A set of counterweights offsets the weight of the string of rods and part of the weight of the...