Buy API 11BR: RECOMMENDED PRACTICE FOR THE CARE AND HANDLING OF SUCKER RODS from SAI Global. Find the most up-to-date version of API RP 11BR at Engineering Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at  API RP 11BR, Recommended Practice for Care and Handling of Sucker.
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Beforepercentages were calculated so that the unit stress on the top rod of each section from the weight of the rods in air plus the weight of the produced fluids on the gross plunger area is equal. Thus, a full economic analysis should be conducted and good operating records obtained to determine if use of these rods is cost effective.
API RP 11BR Revisions on Sucker Rod Makeup
xpi This coupling type, however, decreases the coupling area available for supporting the pumping loads. A hand-tight position is attained when full shoulder abutment is made and a 0. They also are standardized in size and performance by API Spec. Care should be taken when recommending the SM couplings, even though they have longer wear life than T couplings. This is impractical, not only because of the manufacturing difficulties involved, but also because the lower rods must have sufficient stiffness to support the entire string in the tubing if failures occur high up in the string.
However, this rod type may be more notch-sensitive and may require better handling and corrosion protection than normal API-type rods. Usually, wells of the same type in a field can be grouped together and the necessary calculations do not have to be performed for each well.
This type of rod string was less expensive than a normal API steel string and was found useful for unloading gas wells.
Pony rods are sucker rods shorter than 25 ft, and they vary in length. Thus, when placing the rod string with new suckers, new pony rods should be used. This hardness is normally accomplished by the spray-metal process. Additionally, RP 11L,  discusses the need to reduce the allowable load or stress on used rods.
Any variation in lubricants or in the surface finish of the threads or mating surfaces drastically changes these percentages, indicating that torque could never be a precision makeup method for sucker rods. Additionally, Hermanson  provides discussion and photographs of different rod failures.
This 11b the original work from Slonneger  and Mills  on vibration effects of rod strings. The high-strength group is generally harder and higher strength than Grade D and may be more susceptible to hydrogen embrittlement and notch effects that may then decrease run life. Maximum compression -5 ksi 3. The sucker-rod string is often highly stressed and usually fails because of the repeated load reversals. If the manufacturer and rod type are known, the actual yield-strength values should be used.
Companies used this graphical chart and calculation method for many years, with some refinements and changes to the practice, to account for tapered-rod strings and rod percentages, apj provide equal loading in each section of a string. These new methods utilize computerized rod tongs to measure applied torque and either the number of turns or the final displacement of the coupling to the pin ali.
These rods are normally made from protruded fiberglass. The advantage of this rod is its ability to pull wpi entire rod string in one piece with a special pulling unit. Clean and inspect the pin and coupling threads. The proper design will decrease the stress on the rods above the bottom section.
RP 11BR Archives – Production Technology
Despite having high strength and a small cross-sectional area, it was expensive and ran into field support problems similar to those of flexible strands and CORODs. Preload no axial load 3 2.
They should be selected for wells in which operating stresses do not exceed 50, psi. Typically, the rod-string section will be replaced after two or three failures, while the entire rod string may be replaced after three or four failures. Further work by Hermanson  using the area relationships and allowable strength of the different grades of steel rods resulted in different derating factors, which are included in API RP 11BR.
Buoyancy of the rod string is not taken into account. The Sponsoring Organizations cannot and do not warrant the accuracy of these documents beyond the source documents, although we do make every attempt to work from authoritative sources. Class T through hardened coupling has a Rockwell C hardness range of minimum 16 and maximum 23, and Class SM surface hardened has a minimum Rockwell C surface hardness of Where the yield strength of a rod string is necessary in calculations, it is recommended that if the manufacturer is not known, a minimum yield of 60, psi for Grade C and K and ofpsi for Grade D should be used.
A study of several FRP string-design analyses indicate that rod-string overtravel may be approximately equal to the following:.
This method was provided to the industry in the s, and the design results were developed into the hand-calculation and graphical method in API RP 11L. The API does not specify the minimum yield strength for sucker rods. Corrosion pits are one type of stress raiser. Fatigue of a;i also was considered in The tensile strength is generally greater thanpsi, while the yield strength is generally greater thanpsi; therefore, these rods could not be classified as API Grade D.
Apply the appropriate CD value for the rod size and grade. Thus, slimhole couplings are not as strong as the full size. Tapered rod strings that use different segments of different-sized rods ali commonly used to save unnecessary weight and to distribute the loading on long strings of rods used in deep wells.
These rods have a special heat treatment that should put the 11bd in a compressive set. The following is a summary of the normal rod-string spi and typical reasons for failure:. The top rod in the bottom section normally has the highest stress in the string because it has the smallest cross-sectional area.
The development of the wave equation for sucker-rod lift by Wpi. However, a high tubing-casing-annulus fluid level decreases the load on the rod string when attempting to unseat a pump. The differences lead to the conclusion that an accurate rod string design should be based on calculations using actual pumping conditions.
The most common rods in use will meet API specifications and will probably be in ft lengths. Effectively inhibited systems apo be considered noncorrosive, which would limit the surface pitting of the steel rods or components.
Because of the increased hardness and lower coefficient of friction, if properly surface treated, coupling-on-tubing wear is transferred from the rods—which are easy and less expensive to replace—to the softer tubing, which is more expensive to replace.