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most up-to-date version of API RP 11BR at Engineering Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at  API RP 11BR, Recommended Practice for Care and Handling of Sucker.
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However, the reasons for failures need to be investigated and the root cause for this failure must be determined to extend the rod life in the future. Makeup the connection to the hand-tight position. The API does not specify the minimum yield strength for sucker rods. Rod strings should be designed to enable the operator to unseat the pump without yielding any rod in the rod string.
An allowable load or stress curve should be developed to discern during the design of a rod string if it is overloaded, and adjustments should be made to prevent this. The manufacturer of specialty or non-API rods should be consulted for their recommended CD values and makeup procedures.
Inspect the pin and coupling threads for visual damage without removing thread lubricant. The author is solely responsible for the content of the materials.
RP 11BR Archives – Production Technology
Proper running, handling, and makeup procedures should be followed to secure maximum service from a rod string. This page discusses rod types, design of the rod string, couplings, maintenance and replacement.
Replacing a rod string one 11hr at a time is not normally a good operating practice; thus, the economic life of a rod string needs to be considered if rods start to fail. Sucker-rod strings are lifting a great deal of weight every cycle. Corrosion pits aoi have rounded or notched shape; notch-shaped pits are more serious and are more likely to occur in Grade D rods than in Grade C rods.
Corrosion pits are one type of stress raiser. In a noncorrosive environment, the endurance limit of steel is primarily determined by the maximum stress, the range of stresses, and the number of stress reversals. Thus, a full economic analysis should be conducted ai good operating records obtained to determine if use of these rods is cost effective. Regardless of what method or program is used to predict loads, once the equipment is installed and the well has stable production and fluid levels, it is recommended that a dynamometer survey be run with a load-capable dynamometer attached to the polished rod.
Recent discussions have promoted a hyperbolic relationship for allowable load using the Gerber parabola, rather than a straightline relationship.
Maximum tension 40 ksi 1br L. The first number in the column refers to the largest rod size in the string, while the second number refers to the smallest rod size in the string, 11rb representing the size in eighths of an inch. Reviewing this standard shows that temperature, load reversals, and fatigue life have a bigger effect on FRP rods than on steel rods.
If the manufacturer and rod type are known, the actual yield-strength values should be used. Ideally, a rod string should be a continuous taper from top to bottom.
These variables include, but are not limited to: Sucker-rod strings may be composed of a single size or may be tapered, typically to include rods of two and three sizes. A number of manufacturers have developed higher-strength steel rods to compete with other specialty rods.
Preload no axial load 3 2. This includes the original work from Slonneger  and Mills  on vibration effects of rod strings. This is because it has to support the weight of the rest of the small-diameter rod load, the aip and the very large fluid load on the gross seating nipple area. The advent of the personal computer and its continued developments of power and speed allowed more developments of rod-string simulators, including: 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.
The proper design will decrease the stress on the rods above the bottom section. To make up a sucker-rod joint using CD, the pin and 11bg threads should be cleaned and lubricated with a lubricant that has passed the NACE MR screening test.
Zaba  detailed the next refinement of sucker-rod loading, which was the organization of the Sucker Rod Pumping Research Inc. They are under stress on both the downstroke and the upstroke. E due to arc P Worksheet for sec 8.
API RP 11BR Revisions on Sucker Rod Makeup
The development 11vr the wave equation for sucker-rod lift by S. This overtravel 11be equals twice the expected value when using steel sucker-rod strings.
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. A detailed discussion and development of these formulas is provided by Zaba.
The values were determined based upon actual strain gauge readings and resulting stress calculations by an API industry workgroup reference R. The first column of Table I in this reference contains the rod-string size designation. The three main grades of steel rods follow:. This method was provided to the industry in the s, and the design results were developed into the hand-calculation and graphical xpi in API RP 11L. Using four or more sizes of rods in a taper is not normally recommended.
The connectors used at the pump or at the top of the sinker bars were the weakest 11bf of the flexible strand. 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. Stress raisers cause areas of concentrated stresses and may be caused by a number of things.
11bg work used the dynamic effects on the rod’s upstroke and downstroke, along with assumed pumping speeds for varying stroke lengths.
The downhole production strings may fail for a variety of reasons, some of which have been discussed previously. 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 11be, psi for Grade C and K and ofpsi for Grade D should be used.
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