New Type Of Coupling Developed To Reduce Metal-To-Metal Contact
When two shafts have to be joined together at their ends to transmit power, a coupling is necessary to prevent disconnection of the shafts during operation. When the couplings are carefully selected, installed and maintained, you can expect substantial savings in terms of repair and maintenance including the dreaded downtime.
New wells are being drilled in the Permian Basin but the process has become more complex because of the trend towards longer laterals, enhanced completions and higher initial production rates. Because of the increased complexities, the integrity of the wells is challenged particularly the horizontal wells.
The material provider, Materion Corp. from Ohio is working with the producers to develop a new coupling for the oilfield that will reduce failure in the wells that are prone to extreme rod string buckling and wear deep in the wells. In order to minimize metal to metal contact that results into tubing wear, the new ToughMet3 Valve Rod Guide Bushing Coupling was developed.
If metal to metal contact is reduced, tubing leaks and production interruptions in artificial lift systems can be significantly prevented. The new coupling is an offshoot of the sucker rod coupling that was developed by Hess and launched in 2016.
The number reason for failure in rod strings is holes in the tubing. Since traditional couplings and tubing are made from steel, there is always a steel-to-steel friction which must be mitigated. Spray metal couplings usually wear out the tubing so that a material was developed to prevent the coupling and tubing to be sacrificed. ToughMet3 material is a low friction alloy that has good bearing characteristics and can withstand high impact loads from rod buckling.
Holes are particularly challenging in horizontal wells and deviated sections. The new coupling is designed for the drop into the well as a replacement coupling so that the field projects will not be changed since it conforms to API standards.
The most common reasons why coupling is used for shafts are to provide for the misalignment of shafts or to introduce mechanical flexibility. Shaft couplings are used in machinery to reduce the transmission of shock loads from one shaft to the other.
