This document provides information about side sliding doors (SSDs), including:
1) SSDs are also known as sliding sleeves that provide controlled communication between the tubing and casing annulus.
2) SSDs can be used for applications like fluid displacement, well killing, gas lifting, and chemical injection by opening or closing ports between the annulus and tubing.
3) SSD sleeves can be shifted using wireline methods, coiled tubing methods, pressure darts, or differential pressure application to the annulus.