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Classification and Function of Petroleum Casing Pipe

Date:2020-04-08    keywords:casing pipe,petroleum,classification
The oil layer casing is the production casing, and the tail pipe technology is only one kind of cementing technology. It is a method of hanging the casing on the upper casing only by the open hole section of the lower oil casing and the technical casing. For details, please refer to the following knowledge, please adopt if you are satisfied.

Petroleum casing is abbreviated as casing, which is a kind of petroleum pipe. The pipes used in petroleum are collectively called petroleum pipes. Petroleum pipes include finished oil casings, drill pipes, drill collars, couplings and short rods.

1. Classification and function of casing
The casing is a steel pipe that supports the walls of oil and gas wells. Each well will use several layers of casing according to different drilling depths and geological conditions. Cement is used to cement the casing after it goes down the well. It is different from tubing and drill pipe and cannot be reused. It is a disposable material. Therefore, the casing consumption accounts for more than 70% of all oil well pipes. The casing pipe can be divided into: casing, surface casing, technical casing and oil layer casing according to the usage.
① Guide bush: mainly used for drilling in oceans and deserts to separate seawater and sand to ensure smooth drilling. The main specifications of this layer of casing are: ∮762mm (30in) × 25.4mm, ∮762mm (30in) × 19.06mm.

② Surface casing: It is mainly used for the first drilling, drilling the soft ground layer to the bedrock, in order to seal this part of the formation from collapse, it needs to be sealed with surface casing.
The main specifications of the surface casing: 508mm (20in), 406.4mm (16in), 339.73mm (13-3 / 8in), 273.05mm (10-3 / 4in), 244.48mm (9-5 / 9in), etc. The depth of the downpipe depends on the depth of the soft formation, generally 80 ~ 1500m. Its external pressure and internal pressure are not large, generally K55 steel grade or N80 steel grade.

③ Technical casing
Technical casing is used in the drilling of complex formations. When it encounters complex parts such as collapse layer, oil layer, gas layer, water layer, loss layer and salt-gypsum layer, it needs to be sealed with technical casing, otherwise drilling will be impossible. get on. Some wells are deep and complex, and the downhole depth is several kilometers. This deep well requires several layers of technical casing. Its mechanical properties and sealing performance requirements are very high, and the steel grade used is also high. Most of them use N80 and P110 steel grades, some deep wells also use Q125 or even higher non-API steel grades such as V150.

The main specifications of the technical casing are: 339.73mm (13-3 / 8in), 273.05mm (10-3 / 4in), 244.48mm (9-5 / 8in), 219.08mm (8-5 / 8in) 193.68mm ( 7- 5 / 8in), 177.8mm (7in), etc.

④ Oil layer casing
When the drilling reaches the target layer (oil and gas-bearing horizon), the oil and gas layer and the upper exposed stratum are all sealed with an oil layer casing. Inside the oil layer casing is the oil layer. Reservoir casing has the deepest downhole depth in various casings, and its mechanical and sealing performance requirements are also the highest. Steel grades include K55, N80, P110, Q125, V150, etc.
The main specifications of the oil layer casing are: 177.8mm (7in), 168.28mm (6-5 / 8in), 139.7mm (5-1 / 2in), 127mm (5in), 114.3mm (4-1 / 2in) and so on.

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