The Check Valve (CV) is used to prevent fluid drainage from the tubing string, thereby eliminating backspin (reverse rotation) of the ESP unit upon shutdown. The check valve provides high integrity, allowing the operator to perform tubing pressure tests.
Based on the closure element design, the Check Valve can be either poppet type or ball type.
The valve is typically installed two joints above the ESP fishing head.
In some cases, it is permissible to increase the number of tubing joints between the ESP and the Check Valve. For instance, in wells with a high gas-liquid ratio (GLR), the specific installation depth is determined by specialized engineering services.