API RP 11AR:2000(R2020) pdf download

API RP 11AR:2000(R2020) pdf download.Recommended Practice for Care and Use of Subsurface Pumps.
5.2.2 Stationary Barrel Bottom Anchor Pump (Figure 5)
5.2.2.1 Advantages
a. The stationary barrel, boflom anchor pump is the first pump to consider in deep wells, Like the traveling-barrel pump. it has the advantage of having the hydrostatic tubing pressure applied to the outside of the barrel without the disadvantage o the column loading on the plunger bowing the pull tube on the downstroke.
b. The stationary barrel. bottom anchor pump is normally recommended for wells with low static fluid level, since the production tubing may be run in with only a short pcrtirated nipple or mud anchor below the seating nipple. Thus, if required. the standing valve of the pump may be less than two feet from the bottom of the well.
c. The stationary barrel. bottom anchor pump is supenor to the traveling barrel, bottom anchor pump for low fluid level wells, because the fluid has only to pass the larger standing valve located irnmedbtely above the seating nipple in order to be pumped. The top anchor pump shares this advantage.
d. The stationary barrel, bottom anchor pump is excellent for gassy wells when run in conjunction with a good liquid gas separator or gas anchor. The short rise required for the fluid to pass the standing valve and enter the pump minimizes the tendency to foam and thus reduce efficiency.
5.2.2.2 Limitations
a. It is not a good practice to run a stationary-barrel. bottom. anchor pump in a sandy well because sand can settle in the annulus between the pump and the tubing and stick it tightly in the joint.
b. It also has the disadvantage on intermittent operation that sand or other foreign material can settle past the barrel rod guide and on top of the pump plunger when the well is shut down, with the possibility of sticking the pump when it is put back on production.
5.2.3 Stationary Barrel Top Anchor Pump (Figure 6)
5.2.3.1 Advantages
a. The top anchor pump is recommended in sandy wells where a bottom anchor pump may become sanded in and cause a stripping job. l’he amount of sand that can seule over the seating ring or top cup is limited to a maximum of about three inches. since the fluid discharge from the guide cage keeps it washed free above this point. In this respect. it is even superior to the traveling barrel, bottom anchor pump. since if a travel barrel pump is spaced too high. sand can settle around the pull wbe up to the lowest point reached by the pull plug on the downstroke.
5.2.3.2 Umitations
a. The outside of the pump barrcl of a top anchor pump is at suction pressure. Consequently. it is more subject to bursting or parting the barrel tube than a bottom anchor pump. Well depth and the possibility of fluid pound should be carefully considered before running a top-anchored pump with a thin wall barrel, lithe depth of the well is within the depth recommendations, a top-anchor pump is a good general purpose installation.
5.3 TO OBTAIN OPTIMUM PERFORMANCE
5.3.1 Pump Sumergence
The energy to fill a pump during the upstroke must be supplied by the well formation. Therefore, it is essential the pump he installed as low in the well bore as possible to maintain minimum hack pressure on the fonnation. The pump intake should be placed below the perforations, or as close above them as possible.
5.3.2 Gas Separation
Gas production through the pump severely reduces pump efficiency. Where gas interference is a problem. a properly designed gas separator should be instal led as a part of the sub— surface pumping assembly. Various styles are available with each having merits for particular well conditions. It is important to keep the back pressure on the annulus at the wellhead at a minimum.
5.3.3 Installations Where Formation Sand Can Be a Problem
A pump will inherently have problems if sand is allowed to enter. Therefore, it is best to utilize some method of sand control to prevent entrance of sand into the well bore. Gravel packs, screens, and chemical bonding agents are frequeinly used for this purpose.