• (#22) is a section of large diameter pipe fitted to the top of the that the attaches to via a side outlet, to allow the to flow back to the .• (BOPs) (#23 and #24) are devices installed at the wellhead to prevent fluids and gases from unintentionally escaping from the . #23 is the annular (often referred to as Hydril named after a manufacturer), and #24 is the pipe rams and blind rams.
[pdf] This article lists the main components of a onshore . rigs have similar elements, but are configured with a number of different drilling systems to suit drilling in the marine environment. The equipment associated with a rig is to some extent dependent on the type of rig but typically includes at least some of the items listed below.
[pdf] A shallow well generally refers to a design drilled to a relatively shallow depth compared to other types of wells. Operations often drill these wells where oil deposits are close to the surface or within shallo. Barge rigs work in shallower waters, usually less than 20 feet deep. After being floated to the drilling location, the hull is brought to rest on the ocean floor, creating a stable platform for drilling. Many barge rigs operate in the Gulf of Mexico and around the world.
[pdf] 
