Oil casing is an important piece of equipment for oil drilling. Its main equipment also includes drill pipes, core pipes and casings, drill collars, and small-diameter drilling steel pipes. The domestic casing is made of hot-rolled or cold-drawn steel for geological drilling. The steel grade is represented by “geology” (DZ). Commonly used casing steel grades include DZ40, DZ55, and DZ753.
1. Used for oil well drilling.
2. Type According to SY/T6194-96 “Petroleum Casing”, it is divided into two types: short threaded casing and its couplings and long threaded casing and its couplings.
3. Specifications and appearance quality
(1) Domestic casing is stipulated in SY/T6194-96. The length of the casing is not fixed, and its range is 8-13m. However, a casing not shorter than 6m can be provided, and its quantity shall not exceed 20%.
(2) The internal and external surfaces of the casing shall be free of folds, hairlines, separation layers, cracks, folds, and scars. These defects should be completely removed to a depth not exceeding 12.5% of the nominal wall thickness.
(3) The outer surface of the coupling shall not have defects such as folding, hair lines, separation layers, cracks, rolling, and scarring.
(4) The thread surface of the casing and coupling should be smooth, and no burrs, tears, or other defects sufficient to interrupt the threads will affect the strength and tight connection.
4. Chemical composition inspection
(1) According to the provisions of SY/T6194-96. The casing and its couplings are of the same steel grade. Sulfur content <0.045%, phosphorus content <0.045%.
(2) Take chemical analysis samples according to the provisions of GB222-84. Carry out chemical analysis according to the relevant provisions of GB223.
(3) American Petroleum Institute ARISPEC5CT1988 1st edition regulations. Chemical analysis was carried out according to the latest version of ASTME59 for sample preparation and chemical analysis according to the latest version of ASTME350.
5. Physical performance inspection
(1) According to the provisions of SY/T6194-96. Conduct flattening test (GB246-97), tensile test (GB228-87), and hydraulic pressure test.
(2) Hydrostatic pressure test, flattening test, sulfide stress corrosion cracking test, hardness test (conducted according to the latest version of ASTME18 or E10), tensile test, and transverse impact test ( ASTMA370, ASTME23 and the latest version of relevant standards), grain size determination (ASTME112 latest version or other methods).
6. Main import and export situations
(1) The main importing countries of oil casing are Germany, Japan, Romania, the Czech Republic, Italy, the United Kingdom, Austria, Switzerland, the United States, Argentina and Singapore also import. Import standards mostly refer to the American Petroleum Institute standards API5A, 5AX, and 5AC. Steel grades are H-40, J-55, N-80, P-110, C-75, C-95, etc. The main specifications are 139.77.72R-2, 177.89.19R-2, 244.58.94R-2, 244.510.03R-2, 244.511.05R-2, etc.
(2) API specifies three lengths: R-1 is 4.88~7.62m, R-2 is 7.62~10.36m, and R-3 is 10.36m or longer.
(3) Some imported goods are marked with LTC, which means long threaded casing.
(4) In addition to API standards, casing imported from Japan also adopts Japanese factory standards (such as Nippon Steel, Sumitomo, Kawasaki, etc.). The steel numbers are NC-55E, NC-80E, NC-L80. NC-80HE etc.
(5) In the claim cases, there have been appearance defects such as black buckles and threaded buckle damage, folding of the pipe body, broken buckles, excessive thread tightness, excessive coupling J value, and internal defects such as casing brittleness and low yield strength. quality problem.
7. Packaging According to the regulations of SY/T6194-96, domestic casing should be bundled with steel wire or steel belts. A protective ring should be screwed on the exposed portion of each casing and coupling thread to protect the thread. 8. Others according to the American Petroleum Institute standard APISPEC5CT 1988 1st edition, casing steel grades are H-40, J-55, K-55, N-80, C-75, L-80, C-90, C-95 , P-110, Q-125, a total of 10 types. The casing should be supplied with threads and couplings, or in any of the following pipe end forms: plain end, round thread without coupling or with coupling, trapezoidal thread with or without coupling, direct connection Type thread, special end processing, sealing ring structure.
Post time: Jan-19-2024