This section will discuss the concept of a well. This domain introduction is provided so that the reader will be familiarized with the basic concepts in order to understand and use the Well data model. This is not an exhaustive introduction. References to more complete domain information will be provided.
What is a well?
At the highest level, a well is a collection of boreholes that all have the same surface location. In common language, a well consists of the surface facilities for handling of the reservoir fluid and the borehole from which these fluids come.
How a well is defined
A well is composed of surface equipment, boreholes and the casings/liners within them. The main piece of equipment on the surface is called the Wellhead. A wellhead is the surface termination of a borehole that incorporates facilities for installing casing hangers during the well construction phase. The wellhead also incorporates a means of hanging the production tubing and installing the Christmas tree and surface flow-control facilities in preparation for the production phase of the well.
Wellhead Components
For a well under production, the Christmas tree sits on the top of the wellhead. In oilfield terms, a Christmas tree is an assembly of valves, spools, pressure gauges, and chokes fitted to the wellhead of a completed well to control production. Christmas trees are available in a wide range of sizes and configurations, such as low- or high-pressure capacity and single- or multiple-completion capacity.
Once the Casing is placed in the borehole, it is cemented in place and then completed. For a mode detailed description on well completions see the documentation on Production.