A typical SKF mud motor contains between eight and 12 rows of bearings. When the bearing is new, most of the load is taken by the first few rows. As each row begins to wear, the load is shifted to the next row and the next until all the rows are worn equally. Then, the load is shifted back to the first row and the process is repeated. 

Because every situation is different, SKF brings to bear a specific set of tools to customize the mud stack bearings for each project depending on space limitations, fluctuating demands in drilling operations, depth and direction of drilling and geological conditions. These tools include in-house testing, some field testing, and reviewing process and operating parameters; the box explains more on this. 

With a predicted surge in worldwide drilling activity over the coming years, increased reliability will translate to extended mean time before failure and the improved performance offered by companies like SKF provides a critical advantage for oil producers looking to gain an edge in this ferociously competitive market.