PUMPING METHODS The main methods of lifting oil are: 1. By the walking beam.
2. By pumping-jacks.
3. By individual motors at well.
4. By compressed air lift.
the system the walking-beam and engine used in drilling may be employed as power to lift the pump rods. However, the drilling well may be replaced by a smaller steam engine; or a gas engine or an electric motor may be installed. Gas engines are more eco nomical than steam, and it is now found that electricity is even cheaper than gas.
The walking-beam system is used more especially for wells over 1500 ft. in depth, and where it is desirable to keep heavy engines for pulling rods and cleaning wells.
Jack 1500 ft. the jack system is generally used. In this system power is furnished from a central station. A "power" is located in this station. It usually consists in an eccentric which is fastened to a vertical shaft (see Figs. 47 and 48). The shaft is driven by a belt connecting with a pulley driven by a steam engine, gas engine, or electric motor. This eccentric (or eccentrics) has connections to which shackle rods are attached. These shackle rods in turn are connected to the pump rods by a pumping device styled a jack (see Fig. 49a and 49b). Such a jack is in reality a simple lever. The point of application of power is at A, the fulcrum at B and the weight lifted at C. The frame supports the fulcrum. The pull may be over as in Fig. 49a or under as in Fig. 49b. Jacks are used where the stroke is regular and slow, and for efficiency one well must be balanced against the other, so that the rods falling in well #1 will lift the rods in well #2 with a minimum of energy from the power Plant. Several wells may be pumped from one jack-plant so long as each well is counterbalanced by weights equal to the weight of the string of rods to be lifted.
Individual pumping motors for wells (see Fig. 50) are used where electric wires can be readily installed. These motors are useful in wells that are placed in river beds or in lakes, where it is difficult to operate steam or gasoline engines.
Electric drive practically eliminates most of the shut-downs chargeable to engines due to rod breakage; water clogged steam lines or trouble with the engine itself.
Rod breakage is greatly reduced since the motor during the pumping stroke does not pick up the rods with a jerk as is the case with steam or gas engines, the speed of the band wheel being practically constant during the entire revolution. The rods are therefore less liable to crystallize.
In pulling and cleaning a well, a motor will pull the first stand of tubing as fast as the last one, practically regardless of the load to be lifted, while with engines the speed is considerably reduced on the heavier work. Quicker work can be done with motors in spotting rods and tubing when screwing up, since no delay is caused by overtravel when hoisting and lowering. On the lease of the Birch Oil Company, near Fullerton, the cleaning gang using a standard 15/30 pumping and cleaning motor equipment, pulled sixty 60-ft. stands of V1-in. rods in 55 minutes.
One of the most noticeable savings effected by the use of electric pumping equipment is in the item of labor or attendance charges. Because a motor can always be depended upon to pump the well at a given constant speed on the same point of the con troller, thus obviating the possibility of speed fluctuations encountered with steam or gas engines, and because the motor is provided with protective devices to guard against possibility of damage in emergencies, one pumper can look after a greater number of wells, with the assurance that the possibility of the engine running away and its constant damage, due to parting of the rods or breaking of the band wheel belt, is absolutely eliminated.
times it is found advantageous to weigh or balance the walking beam. One arm of the balance weight is swung on the post, the other is attached near the end of the beam on the pitman side. In other cases the weight is hung on the end of the walking beam and fastened to the brace between the engine block and the sand reel. Such weights counterbalance the weight of the rods and make pumping easier. There is a decided saving, as less power is needed to lift the oil. Vibration is also less, which eliminates the wear and tear on all the pump ing machinery.