Petroleum casing use

Oil casing is an important equipment for oil drilling, and its main equipment includes drill pipe, core pipe and casing, drill collar and small diameter steel pipe for drilling. The domestic casing is made of geological drilling steel by hot rolling or cold drawing, and the steel number is “geological” (DZ), and the common casing steel grades are DZ40, DZ55, DZ753.

1. Use
   Used for oil well drilling.
2. Types
   According to SY/T6194-96 “oil casing”, there are two kinds of short thread casing and its coupling and long thread casing and its coupling.
3. Specification and appearance quality
   (1) Domestic casing according to SY/T6194-96, the length of the casing is variable, the range of 8-13m, but not shorter than 6m casing can be provided, the number of not more than 20%.
   (2) The internal and external surfaces of the casing shall not have folding, hairline, delamination, cracks, rolling folds and scars. These defects shall be completely removed, and the removal depth shall not exceed 12.5% of the nominal wall thickness.
   (3) The outer surface of the joint shall not have defects such as folding, hairline, delamination, cracking, rolling, folding and scarring.
   (4) The surface of casing and coupling threads shall be smooth, and no burrs, tears and other defects sufficient to interrupt the threads and affect the strength and tightness of the connection shall be allowed.
4. Chemical composition inspection
   (1)According to SY/T6194-96. The same steel grade is used for the casing and its coupling. Sulfur content <0.045%, phosphorus content <0.045%.
   (2) according to the provisions of GB222-84 to take chemical analysis samples. Chemical analysis in accordance with the provisions of the relevant part of GB223.
   (3) American Petroleum Institute ARISPEC5CT1988 1st edition regulations. Chemical analysis according to the latest version of ASTME59 sample preparation, chemical analysis according to the latest version of ASTME350.
5. Physical properties inspection
   (1)According to the provisions of SY/T6194-96. Do flattening test (GB246-97) tensile test (GB228-87) and hydrostatic test.
   (2) according to the American Petroleum Institute APISPEC5CT 1988, 1st edition, hydrostatic test, flattening test, sulfide stress corrosion cracking test, hardness test (ASTME18 or E10 latest version of the provisions of the test), tensile test, transverse impact test (ASTMA370, ASTME23 and the latest version of the relevant standards), grain size determination ( ASTME112 latest version or other methods).
6. Main import and export situation
   (1) The main importing countries of oil casing are: Germany, Japan, Romania, Czech Republic, Italy, Britain, Austria, Switzerland, the United States, Argentina, Singapore also have imports. The import standard is mostly referred to the American Petroleum Institute standard API5A, 5AX, 5AC. steel grade is H-40, J-55, N-80, P-110, C-75, C-95, etc.. The specifications are mainly 139.77.72R-2, 177.89.19R-2, 244.58.94R-2, 244.510.03R-2, 244.511.05R-2, etc.
   (2) There are three kinds of lengths specified by API: namely R-1 for 4.88 to 7.62m, R-2 for 7.62 to 10.36m, and R-3 for 10.36m to longer.
   (3) Some of the imported goods are marked with the word LTC, i.e. long silk buckle casing.
   (4) Imported casing from Japan in addition to the use of API standards, there are a small number of implementation of Japanese factory standards (such as Nippon Steel, Sumitomo, Kawasaki, etc.), steel grades are NC-55E, NC-80E, NC-L80, NC-80HE, etc.
   (5) In the claim cases, there have been black buckle, wire buckle damage, tube body folding, broken buckle and thread tightness distance is over poor, joint J value is over poor and other appearance defects and casing brittle crack, low yield strength and other intrinsic quality problems.
7. Packaging
   According to SY/T6194-96, domestic casing should be bundled with steel wire or steel belt. The exposed part of each casing and coupling thread should be screwed on the protection ring to protect the thread.
   8.Other
   According to the American Petroleum Institute standard APISPEC5CT1st edition in 1988, the casing steel grade is divided into H-40, J-55, K-55, N-80, C-75, L-80, C-90, C-95, P-110, Q-125, a total of 10 kinds.
   The casing shall be supplied with threads and clamps, or with any of the following pipe ends.
   Flat end, round thread without or with coupling, offset trapezoidal thread with or without coupling, direct thread, special end processing, seal ring structure.