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Situation awareness and safety in offshore drill crews
Published in Eduardo Salas, Aaron S Dietz, Situational Awareness, 2017
Anne Sneddon, Kathryn Mearns, Rhona Flin
Once this is complete, flow of the oil up through the well is allowed by placing tubing (a smaller-diameter pipe) into the casing, and a packer down the outside of this (this forms a seal round the tubing, and also sets the production level). At the top of the tubing, a ‘Christmas tree’ is attached—this contains a number of valves which allows the drill crew to control the resulting flow of oil from the well. Owing to the pressures at which the oil is found, ‘blow-outs’ are possible, and are another added risk in the process. Blow-outs occur when the gas pressure inside the well suddenly forces the oil up and out at forces which can have the potential to destroy the rig if not controlled. While blow-out valves are placed on the seabed in order to stabilise the pressure and control the well when necessary, the potential for a catastrophic situation is very real for the drill crew.
Work In The Sea
Published in Robert A. Ragotzkie, J. Robert Moore, Man and the Marine Environment, 2018
The next stage after exploration is the “completion” of the oil well. The work a diver does in completing an oil well is not in itself unique, but it deserves special mention because of where it fits into the scheme of offshore oil production. “Completion” is the step involved in connecting the oil well with equipment for separating oil, gas, and water, and for piping the oil either to shore or to a place where it can be loaded onboard a tanker. A “Christmas tree” is placed on the well, adjusted, and connected to a pipeline system that gathers oil from several wells.
Completions Engineering
Published in Nwanosike-Warren Quinta, Oil and Gas Engineering for Non-Engineers, 2022
A Christmas tree or production tree is a device placed at the surface at the wellhead to regulate flow of fluids into pipelines that take hydrocarbons to processing facilities. It can be used to shut down production from the well for repairs. Some Christmas trees can be remotely monitored and operated.
Calculation method for the vertical bearing capacity of a riser-surface casing composite pile
Published in Ships and Offshore Structures, 2021
In recent years, the cost of offshore oilfield exploitation has gradually increased in the Bohai Sea. The tasks of some old platforms have become increasingly heavy, and the exploitation difficulty has continued to increase (Wang et al. 2019). The bearing capacity design of some jacket platforms can no longer meet the increasing demands of the exploitation tasks. Furthermore, to improve economic benefits, in addition to the conventional large oil fields, increasingly marginal, low-capacity, and inefficient block oil fields, including small marginal oil fields, need to be developed (Yang 2003; Permata and Hatzignatiou 2011; Carpenter 2014; Zhao et al. 2016). To save development costs, some simple platform structures have been developed. Whether involving a traditional jacket platform or a simple platform, the indispensable part of the platform structure is the oil well. The oil wells of offshore platforms generally include risers and surface casings. The riser is a steel pipe that runs from the offshore drilling platform to the shallow seabed during the drilling process. Its main function is to isolate the well from seawater, form a circulation channel for drilling fluid, and provide structural support for the Christmas tree and blowout preventer. The surface casing is usually used to isolate the well from the shallow surface water layer and the shallow complex bottom layer.