TYPES OF PUMPS There is a difference in the pumps used in the Western and iu the Eastern hard rock fields.
The loose sand of California necessitates a plunger pump (see Fig. 51, page 123). The pump used in the Eastern hard-rock fields consists of a plain bored cylinder with a simple bottom or stationary valve and top or traveling valve which has leather packers or rings like the standing valve. In the California pumps there is a garbut rod which is attached to the bottom valve so it can be readily pulled if the well sands up or gives trouble. With the Eastern pumps, however, there is little need for pulling rods often, so that the garbut rod is eliminated as is also the hollow steel plunger.
California type of pump used in California consists essentially of a cast-iron cylinder highly polished inside called the working barrel. (See Fig. 51, page 123). A hollow steel plunger fits the working barrel very snugly. A traveling valve fits on top of the steel plunger. This valve is of the ball and seat type. A square nut with a hole bored through it is screwed on the lower end of the plunger. The garbut rod extending from the bottom or standing valve (see Fig. 51, page 123) passes through the hole in the nut into the plunger cylinder. On the top end of the garbut rod is a wing nut. The garbut rod is extremely useful where it is necessary to replace parts of the standing valve. Also when the valves sand-up they can often be pulled loose from their seats, and washed by being raised and lowered in the oil in the tubing above the working barrel. As the plunger is raised the nut on the plunger engages the wing nut on the garbut rod. A slight jerk on the garbut rod will free the standing valve. How ever, the sand sometimes packs so tight that it is not possible to pull the standing valve. When such is the case the tubing is pulled.
The cost of California pumps is a large item. Wells are pulled several times a month and new pumps placed in the well. Such pumps cost $35. If three pumps a month are used, as frequently happens, the cost is $105 per well.
Vacuum pumps in oil fields are used on old wells after the gas pressure is nearly exhausted.
They temporarily increase the yield of oil from old wells, and also increase the yield of casing-head gasoline. Vacuums as low as 25 inches of Mercury are obtained, but 15 to 16 inches is more general.
There has been considerable question over the use of vacuum pumps, and in some states there are laws against them. Un doubtedly the operator who uses such pumps has an advantage over the man who does not•. •
Pulling cost of pulling oil wells is measured not only by the cost of the labor, and of the material used, but also by the loss of production due to pulling the wells.
If a well makes 150 bbls. per day and it requires a day to pull a pump and replace it, then the production lost is 75 bbls. for day. There is, however, a relationship, that does not occur to many men, between the wear of a pump and the time it should be replaced. A careful lease man will note that a new well after the first month's run declines slowly as the pump begins to wear. A pump that handles 150 bbls. of oil will drop slowly in production due to wearing of the pump and consequent slip page. If one notes that the well is off 5 bbls. from normal the rule of some lease-men is to pull at once and replace. On the other hand some lease men say, "Do not disturb a pumping well." Of the two, the first is preferable. If the trouble is merely due to a defective valve, a few hours will remedy the fault and only part of a day's production will be lost. The best policy is to pull the valves and see what the trouble may be. If the valves are defective change them, if not, let the well pump awhile longer.
Tubing Catcher.—In all oil fields more or less trouble results from difficulty with breaking or parting of tubing. This may rip a hole in the casing, or may punch a hole through the bottom water plug and thus cause nasty fishing jobs. This results in the expense of a "shut down " well, of fishing operations, and in some cases abandon ment. Figure 52, page 125, shows some tubing fished from a well. Such troubles can be pre vented 'by either putting an anchor of tubing below the pump which will rest on bottom and support the tubing string if it breaks, or by means of a tubing catcher, like that in Fig. 53, page 126. The tubing B runs clear through the catcher; the head C holds the slips D which are free to slide upward. The string of tubing is placed above A, and the pump below A'. If the tubing parts, the weight of the tubing causes the tubing to drop so rapidly that the striker H which is held on the spring 1 due to its inertia will not obtain any acceleration due to the drop. As a result the lower controlling ring of the slips will strike the top of the striker H and be forced outward. The slips at once engage the casing and check the fall of the tubing. The device is very efficient as well as ingenious.