7/31/2019 tech_bull_10

1/2

T E C H N I C A L B U L L E T I N N O . 10

Pumping unit alignment is critical in pre-

venting polished rod failures. Shut the unit

down, blow down tubing and unscrew the

stuffing box. Rod must be as close to per-

fect alignment in the center of the tee. If

alignment is off, check to make sure pad is

level, pumping unit is level, unit bridle is

centered on the horsehead, and head of

unit for worn or unadjusted hinges.

StuffingBoxesMisaligned boxes create rod stress at the pol-

ished rod and shorten the packing life. Over-

tightening of the stuffing box will shorten

packing life, as well as distorting load cell

readings, so proper installation of the stuff-

ing box is a must.

Pumping Unit

AlignmentWellheadAlignmentThe wellhead should be secured to insure

no movement occurs. Alignment of all fit-

tings and tubing should be as close to ver-

tical as possible so that alignment of the

polished rod in the tee and tubing can be

achieved (see Fig. 2). A string and plumb

bob hung from the carrier bar down beside

the tee and tubing can assist in alignment.

Preventing

Polished Rod FailuresR&M Energy Systems has investigated numerous field failures, compiled data, and found

several areas that are critical in preventing polished rod breaks. This issue of New Era News

contains a summary of these findings. The complete research findings, procedures and conclusions,

written by Larry Angelo of R&M Energy Systems, were presented at the Southwestern Petroleum

Short Course in Lubbock, Texas. For a copy of this paper, contact R&M Energy Systems Customer

Service office at 1-800-858-4158. And also ask for your pocket-sized, laminated instruction guide.

R&M Energy Systems has

found several areas critical in pre-

venting polished rod breaks.

Almost all polished rod

breaks are fatigue failures.

(see Fig.l)

Proper alignment of the

wellhead, pumping unit and

stuffing box is crucial.

(see Fig. 2)

Carrier bars, rod clamps and

polished rods should be chosen

& checked carefully.

(see Fig. 3)

Proper installation of load

cells and centering of the pulling

unit is very important.

SUMMARY

Fig. 1

Fig. 2

7/31/2019 tech_bull_10

2/2

Carrier BarCarrier bars should be checked for flat and

smooth surface on top where equipment

(polished rod clamp, rotator, load cells)

sets. Come carrier bars should be modified

to insure that a flat, level area exists to min-

imize wobbling of equipment above (seeFig. 3). Leveling plates should be installed

on top of the carrier bar and underneath the

equipment to assist with leveling. When

using Huber load cells, the polished rod

clamp must set level and be centered on the

cell. Carrier bar swinging on the up and

down stroke should be minimized. Wells

that sand up or have downhole conditions

that don t allow the polished rod clamp to

ride the carrier bar on the downstroke

should be evaluated to insure system align-

ment is correct and clamp segments are level.

Load CellsInstall load cells very carefully. The cell

should never be dropped, but instead low-

ered slowly into position on the leveling

plate. The clamp should ride the cell with

both segments level to insure proper opera-

tion, while also extending the cell s life.

Excellence Through Innovation

Borger PlantCustomer Service

P.O. Box 2871Borger, Texas 79008

Ph. (806) 274-5293 Fax (806) 274-34181-800-858- 4158

R&M Energy Systems CanadaCustomer Service9830 45th Avenue

Edmonton, Alberta Canada T6E 5C5Ph. (780) 437-6316 Fax (780) 435-3074

1-800-661-5659

R&M Energy Systems

Polished RodsPolished rods should be selected properly,

according to the taper API (86, 76, 66) and

weight of the rod string. Run API RP1 1 pre-

dictive calculations on all installations andcheck the string analysis for maximum rod

loads on polished rods. The formula to calcu-

late linear speed is: stroke length x SPM =

linear speed. If using sprayed metal polished

rods, place the clamp above the sprayed

metal, never on the sprayed metal.

When hauling polished rods, it is recom-

mended that the handling be the same as

sucker rods, specified in API recommended

practices RP1 1BR. Inspection of rods deliv-

ered to locations is also recommended.

Rod ClampCheck clamp for bent hinges or bolts. Follow

manufacturer s recommended torque for each

clamp. Never use extension devices to tight-

en clamps and after tightening, make sure

both segments are still level on the carrier

bar (see Fig. 3). Always check used clampsprior to installation. A safety clamp should

be installed below the carrier bar on wells

with a history of polished rod failures.

LiftingThe Rod StringPulling units can cause a permanent bend

in the polished rod at the polished rod

clamps, a condition that can lead to pol-

ished rod fatigue failures when the well is

put back on pump.

Proper centering of the pulling unit and the

use of long pony rods to lift the rod strings

are recommended. Keep the pulling unit

blocks away from the horsehead when

pulling the rod string.

Sucker RodsIf used rods are utilized, establish a program

to evaluate all suspect rods and then place

these rods in less critical pumping wells.

Contact R&M Energy Systems Customer Service Department in Borger, Texas to schedule a

Proper Care and Maintenance Seminar for your R&M Energy Systems stuffing boxes.

1-800-858-4158

R&M Energy Systems CommitmentR&M Energy Systems utilizes a solution-oriented systems approachthat optimizes the well operation.

Fig. 3