Severe Deviation Mitigation
Traditional T and SM couplings both have limitations operating in severely deviated well sections, especially when corrosion is present. SM couplings can better resists corrosion and does not wear easily; however, its higher surface hardness often cause excessive tubing wear. The T coupling is softer and does not cause tubing wear, but under the combined effect of corrosion and abrasion, it does not last long before it has to be replaced. As a result, the operator has to choose between frequent work-over jobs to replace T coupling, or dealing with tubing leaks. Neither is desirable.
EH9 Coupling’s material is a special steel that contains 10%-12% and no carbon. It resists common corrosive agents including H2S, CO2 and bacteria. EH9 outperforms SM couplings even in the harshest environment. At the same time, EH9 maintains the same hardness levelas T grade coupling, 16-23 HRC, and reduces tubing wear risks even in the severely deviated wells with significant amount of side loading.
Dimension, tensile strength, torque performance and other properties of EH9 coupling comply to API11-B specifications.
The copper plated threads and side surfaces ensure easy and reliable makeup and reduced risk of galling. Regular torque cards provided by rod manufacturer should be used to make-up with EH9 coupling. No special procedure is required.
Corrosion Factor for T coupling When Tubing and T coupling rub against each other, the protective corrosion scale is removed in the process, resulting in accelerated corrosion wear, hence shorter run time for T coupling.
| Tensile Strength | Reduction | ||
| ksi | 2”, % | % | (HRA) |
| 95-120 | >16 | >50 | 56-62 |
T Coupling
- Softer than L-80 Tubing
- Doesn’t wear Tubing
- Wears out Coupling
- Susceptible to corrosion
- Less expensive but frequent rod walkovers
SM Coupling
- Harder than L-80 Tubing
- Wears away Tubing
- Coupling doesn’t wear easily
- Resist to corrosion
- Less frequent but more expensive tubing jobs
