How do oil rigs function?

Answer 1

There are basically 2 types of rigs.

1) Drilling Rig

The function of this rig is drilling a well down to the production zone then installs a casing in it. There are various types for offshore drilling and there are types for onshore drilling.

2) Production Platform (Offshore)

The function of this rig is for producing oil. It consists of not only a single well like on an onshore pad, but I have seen platforms with 20 to 50 wells. They are not drilled straight down like most onshore wells, but they are deviated and get drilled in and arc, away from the platform and ends up being somewhat horizontal. Wells can be anything from 1000+ and up to a few thousand feet deep.

A work-over rig on the platform uses equipment to perforate the casing at the desired production zone and a screen is installed to minimize sand flowing into the well. Pumps are installed into wells to produce the oil.

Depending on how far the platform is located from land, a pipe line can tranport the oil to land or in most cases where platforms are to far offshore, the surrounding platforms pump the oil to a FPSO which is basically a huge oil tanker that transfers oil to oil tanker ships.

Onshore operations are different. A well is drilled and a wellhead is installed. Piping from the wellhead leads to a manifold which is connected to the surrounding wells. From there oil gets pumped to gathering stations then to refineries.