E&P
Tackpoint Delivers Custom Bearings for Extreme Downhole Applications Most companies servicing the oil and gas industry have their origins tied to creating a product or providing a service to fill a need in the market. Tackpoint has filled the need for specialized thrust bearings in sealed directional drilling mud motors since 1998.
Photo: DynaBearing compared to Machined Bronze Thrust Bearing
Although the original directional drilling mud motors originated in Europe and Texas in the 1970’s, Edmonton Alberta became a hot bed for design and development of the oil sealed directional mud motors in the 1980’s and 1990’s. The original mud motors utilized 4 point contact stacked ball bearings which had drilling mud flow through the bearing stack. These motors had limited weight on bit capacities and drilling rates due to the stacked ball bearings. The stacked bearings would fracture balls or races once the capacities and life were exceeded. Oil sealed drilling motors allowed the use of cylindrical roller thrust bearings which have higher capacities than ball stack bearings due to line contact of the cylindrical rollers vs. point contact of the bearing balls. Since cylindrical rolling elements can not operate in a drilling mud environment, the mud motor bearing assemblies must be sealed with oil. The companies that were producing the sealed mud motors in Edmonton began using catalog thrust bearings from traditional bearing manufacturers. Shaft and housing sizes were designed around catalog size thrust bearings which would then compromise shaft and other component designs in the motor. These catalog thrust bearings were made from either machined bronze with a steel band around the outside to retain the rollers, or a polyamide plastic moulded cage. The bronze cage construction resulted in fewer rollers and a lower capacity than the polyamide cage due to the amount of bronze required between the rollers to maintain cage strength. Although the polyamide cages had higher capacities, they were limited to 140 °C which was not sufficient for most downhole applications. The thrust washers for both types of cages were made from through
hardened 52100 bearing steel which provides excellent wear properties, however the material will fracture when subjected to repeated shock loading, which occurs in drilling motors.
“Each year the market for custom bearings continues to grow as the traditional bearing companies are unable to produce or react to small run special bearings with short lead times.”
In 1998 a small group of bearing industry salesmen and engineers worked together to develop a unique custom thrust bearing design with features specifically for the downhole drilling motor industry. The result was the patented DynaBearing cylindrical roller thrust bearing assembly. The two piece cage was made from steel and was held together with a positive engagement snap mechanism.
The design allowed increased oil circulation between the maximum number of rollers and the largest rollers possible for any cross section that the customer required. The DynaBearing design allowed for more rollers than the polyamide cage yet was able to operate in temperatures up to 200 °C. The thrust washers in the DynaBearing were made from impact resistant case carburized 8620 which provided extra insurance in hard drilling formations. The DynaBearing could also be produced in small or large quantities with 4 to 6 weeks lead time, with each component engraved for traceability which is a requirement for the downhole industry. Sixteen years after the introduction of the DynaBearing into the market, Tackpoint continues to design and produce custom thrust bearings for downhole sealed mud motor manufacturers around the world. Tackpoint has also expanded its custom bearing designs and solutions well beyond the original DynaBearing. Each year the market for custom bearings continues to grow as the traditional bearing companies are unable to produce or react to small run special bearings with short lead times. This has created new opportunities for special radial needle bearings, thin section ball bearings, mud lube stack bearings and combination radial / thrust bearings. These new bearing solutions challenge the Tackpoint team to continue to raise the bar with innovation in both design and manufacturing. The Tackpoint engineering team consists of a group of bearing engineers with combined bearing industry knowledge of nearly 70 years. The group uses advanced bearing calculation programs and Finite Element Analysis to analyze and create innovative