It is very important to choose available grade for the sucker rod.
As we know, the sucker rod is one important part in the artificial lift system, so the correct grade for sucker rod plays essencial role in the well operation.
There are 3 grades specified in API 11B Specification, they are grade C, K and D. The grade C sucker rod is used in light load and no corrosive oil wells, and the grade K sucker rod is used in light load, but badly corrosive oil wells. Grade D sucker rod is used in heavy load oil wells. With regarding to grade D, the grade D special sucker rod is another branch for it, which is used in heavy load and badly corrosive oil wells.
So the first element to choose sucker rod grade is confirming the oil wells condition.
