Operators strive to drill faster and more reliably regardless of the drilling environment. This has increased the demand for more power generation by a mud motor. For shoe-to-shoe drilling performance and improved total well delivery, it is vital for the focus to be on the motor as a system. Historically, the focus on motors has been to improve performance of individual sub-systems or components with little focus on overall system performance. As a result, one of the trends is that the power section has outpaced the rest of the motor in terms of torque capability and horsepower. With advances in elastomer technology and power section design, the industry has developed high-performance power sections that can run at higher flow rate and higher differential pressure resulting in increased horsepower. The transmission and bearing section has now become the weaker link in the chain along with the motor connections. A true system level design requires consideration of the overall bottomhole assembly (BHA), such as motor only or motor-assisted rotary steerable system (RSS); applications (vertical only, curve and lateral, or lateral only); downhole temperatures; and drilling parameters. A clear understanding of the loads on the BHA in various applications and rig constraints in terms of flow rate, pressure and torque capability is critical to ensuring a successful drilling campaign..

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