For this document, systems approach will be defined as the loads or combination of loads along the length of the well. Generally, these loads are the result of pressure, tension, bending, and compression loads (both dynamic and static) on the components that will be transferred from component to component as these components are connected in the well configuration. These loads generally are transferred to the earth at the shoe through a cemented shoe joint, along the cemented casing and at the wellhead.
Source: API TR 1PER15K-1, Protocol for Verification and Validation of High-pressure High-temperature Equipment, First Edition, March 2013. Global Standards