What is a sucker rod?
The single length of the sucker rod is 7.62 or 8 meters, 9.14 meters, and the material is generally low-carbon alloy steel after quenching and tempering treatment. It is connected one by one with internal thread hoops in the oil pipe and extends to the piston at the underground oil layer. The oil is pumped by reciprocating motion. The length of the current oil well is generally about two kilometers. Take Shengli Oilfield as an example, the deepest is more than three thousand meters.
The sucker rod is an important part of the rod pumping equipment, which transmits the power of the pumping unit to the downhole oil pump. The sucker rod string is made up of dozens or hundreds of sucker rods connected by couplings. In the process of oil production, the sucker rod string is subjected to asymmetric cyclic loads, and the working medium is well fluid (oil and mine water), and the well fluid of many pumping wells contains corrosive medium. Therefore, the main failure mode of sucker rod is fatigue fracture or corrosion fatigue fracture. The breakage of the sucker rod will seriously affect the oil production, increase the workover cost, and increase the oil cost.
Sucker rod has a history of nearly a hundred years. The most primitive brine extraction rod is made of rattan. The Metal Sucker Rod Patent (U.S. 528168) was issued to Samuel M. Jones of Ohio on October 30, 1894. In the past 20 years, many new materials, new equipment, new technologies and new processes have been adopted in the manufacture of sucker rods at home and abroad, such as the use of multi-element alloy steel and fiberglass; Forging, adopts intermediate frequency induction heating and quenching device and infrared light guide intelligent temperature measuring instrument, production line for non-rotating sucker rod head, automatic production line for coupling; and advanced forging die design technology, sucker rod external thread rolling process, pumping Oil rod variable diameter elbow, coupling internal thread half cutting and half extrusion process, friction welding process, shot peening process, surface induction hardening process, etc., greatly improve the manufacturing level and product quality of sucker rod.
In order to meet the needs of large pump intensive production, small pump deep pumping, heavy oil wells, high wax wells, corrosion wells and inclined wells, many special sucker rods have been developed at home and abroad, such as ultra-high-strength sucker rods, FRP oil pumping Rods, hollow sucker rods, KD grade sucker rods, continuous sucker rods, electric heating sucker rods, wire rope sucker rods and aluminum alloy sucker rods, etc., and researched many accessories for sucker rod strings, such as long stroke High-strength polished rod, toothless polished rod clamp, rotary rod device, shock absorber, graphite adjustable center polished rod sealing box, roller coupling, centralizer, wax scraper, weighted rod, anti-dropping device, disconnecting device, magnetic anti-waxing It further improves the service life and application range of the sucker rod.
