3. Chemical Composition Inspection
(1) According to the regulations of SY/T6194-96. The casing and its couplings shall be 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 part of GB223.
(3) The first edition of ARISPEC5CT1988 of the American Petroleum Institute. The chemical analysis shall be prepared according to the latest version of ASTME59, and the chemical analysis shall be carried out according to the latest version of ASTME350.
4. Physical performance test
(1) According to the regulations of SY/T6194-96. For flattening test (GB246-97), tensile test (GB228-87) and hydraulic test.
(2) Hydrostatic pressure test, flattening test, sulfide stress corrosion cracking test, hardness test (as specified in the latest version of ASTME18 or E10), tensile test, transverse impact test ( ASTMA370, ASTME23 and the latest version of relevant standards), grain size determination (the latest version of ASTME112 or other methods).
5. Main import and export situation
(1) Oil casing pipes are mainly imported from Germany, Japan, Romania, Czech Republic, Italy, the United Kingdom, Austria, Switzerland, the United States, Argentina, and Singapore. Import standards mostly refer to American Petroleum Institute standards API5A, 5AX, 5AC. Steel grades are 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 types of API-specified 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, that is, long threaded sleeve.
(4) In addition to adopting API standards for casings imported from Japan, there are also a small number of Japanese factory standards (such as Nippon Steel, Sumitomo, Kawasaki, etc.), and the steel grades are NC-55E, NC-80E, NC-L80, NC-80HE etc.
6. Packaging
According to the regulations of SY/T6194-96, domestic bushings should be bound with steel wire or steel belt. The exposed portion of each casing and coupling thread shall be screwed with a protective ring to protect the thread.
7. Other
According to the first edition of American Petroleum Institute standard APISPEC5CT1988, 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.
Casing shall be supplied with threads and couplings, or with any of the following pipe ends:
Plain end, round thread without coupling or with coupling, partial trapezoidal thread with coupling or without coupling, direct connection type thread, special end processing, sealing ring structure.
8.Purpose and category of special oil pipe
Oil pipes are mainly used for the drilling of oil and gas wells and the transportation of oil and gas. It includes oil drilling pipe, oil casing, oil extraction pipe. Oil drill pipe is mainly used to connect drill collars and drill bits and transmit drilling power. The oil casing is mainly used to support the well wall during the drilling process and after the well completion, so as to ensure the drilling process and the normal operation of the entire oil well after the well completion. The oil suction pipe mainly transports the oil and gas at the bottom of the oil well to the surface.
The oil casing is the lifeline to maintain the operation of the oil well. Due to the different geological conditions, the downhole stress state is complex, and the combined effects of tension, compression, bending and torsional stress act on the pipe body, which puts forward higher requirements on the quality of the casing itself. Once the casing itself is damaged for some reason, it may lead to a reduction in production of the entire well, or even scrap it.
According to the strength of the steel itself, the casing can be divided into different steel grades, namely J55, K55, N80, L80, C90, T95, P110, Q125, V150, etc. Different well conditions and well depths require different steel grades. In a corrosive environment, the casing itself is also required to have corrosion resistance. In places with complex geological conditions, the casing is also required to have anti-collapse performance.
|
outer diameter
|
theoretical weight
|
wall thickness
|
inside diameter
|
nomrmal diameter
|
Coupling outer diameter
|
thread type
|
Grade
|
Length
|
|
139.7
（5-1/2）
|
20.85（0.244）
23.09（15.50）
25.32（17.00）
29.79（20.00）
34.26（23.00）
|
6.20(0.244)
6.98(0.275)
7.72(0.304)
9.17(0.361)
10.54(0.415)
|
127.3(5.012)
125.7(4.950)
124.3(4.892)
121.4(4.778)
118.6(4.670)
|
124.1(4.887)
122.6(4.825)
121.1(4.767)
118.2(4.653)
115.4(4.545)
|
153.7
(6.050)
|
round thread
Ladder thread
|
j55
n80
p110
|
8m -12m
(2602-39.4)
|
|
177.8
（7）
|
25.52917.00）
29.79（20.00）
34.26（23.00）
38.73（26.00）
43.20（29.00）
47.66（32.00）
52.13（35.00）
56.60（38.00）
|
5.87(0.231)
6.91(0.272)
8.05(0.317)
9.19(0.362)
10.36(0.408)
11.51(0.453)
12.65(0.498)
13.72(0.540)
|
166.1(6.538)
164.2(6.456)
161.7(6.366)
159.4(6.276)
157.1(6.180)
154.8(6.090)
152.5(6.004)
150.4(5.430)
|
162.9(6.413)
160.8(6.331)
158.5(6.204)
156.2(6.151)
153.9(6.059)
151.6(5.969)
149.3(5.879)
147.2(5.795)
|
194.5
(7.656)
|
round thread
Ladder thread
|
j55
n80
p110
|
8m -12m
(2602-39.4)
|
|
219.1
（8-5/8）
|
35.75（24.00）
41.71（28.00）
47.66（32.00）
53.62（36.00）
59.58（40.00）
|
6.71(0.264)
7.72(0.304)
8.94(0.352)
10.16(0.400)
11.43(0.450)
|
205.7(8.093)
203.7(8.020)
201.2(7.927)
198.8(7.827)
196.2(7.724)
|
202.5(7.972)
200.5(7.894)
198.0(7.795)
195.6(7.701)
193.0(7.598)
|
244.5
(9.625)
|
round thread
Ladder thread
|
j55
n80
p110
|
8m -12m
(2602-39.4)
|
|
244.5
（9-5/8）
|
48.11(32.30)
53.62（36.00）
59.58（40.00）
64.79（43.50）
70.01（47.00）
71.69（53.50）
|
7.92(0.312)
8.94(0.352)
10.03(0.395)
11.05(0.435)
11.99(0.472)
13.84(0.545)
|
328.7(9.001)
236.6(8.921)
224.4(8.835)
232.4(8.755)
320.5(8.681)
216.8(8.535)
|
244.7(8.845)
222.6(8.765)
220.4(8.679)
218.4(8.599)
216.5(8.525)
212.8(8.379)
|
269.6
(10.6250
|
round thread
Ladder thread
|
j55
n80
p110
|
8m -12m
(2602-39.4)
|
|
273.0
（10-3/4）
|
48.78（32.75）
60.32（40.50）
67.77（45.50）
75.96（51.00）
82.67（55.50）
|
7.09(0.279)
8.89(0.350)
10.26(0.400)
11.43(0.450)
12.57(0.495)
|
258.9(10.192)
255.3(10.050)
252.7(9.950)
250.2(9.850)
247.9(9.760)
|
254.9(10.035)
251.3(9.894)
248.8(9.794)
246.2(9.694)
243.9(9.604)
|
298.5
(11.752)
|
round thread
Ladder thread
|
j55
n80
p110
|
8m -12m
(2602-39.4)
|
|
339.7
（13-3/8）
|
71.50（48.00）
81.18（54.50）
90.86（61.00）
101.69（68.00）
|
8.38(0.330)
9.65(0.380)
10.92(0.430)
12.19(0.480)
|
322.9(12.715)
320.4(12.615)
317.9(12.515)
315.3(12.415)
|
319.0(12.559)
316.5(12.459)
313.9(12.359)
311.4(12.259)
|
365.1
(14.374)
|
round thread
Ladder thread
|
j55
n80
p110
|
8m -12m
(2602-39.4)
|
|
73.0
（2-7/8）
|
9.53（6.40）
11.62（7.90）
12.81（8.60）
|
5.51(0217)
7.01(0.276)
7.82(0.308)
|
62.00(2.441)
59.00(2.323)
57.40(2.259)
|
59.61(2.347)
56.62(2.229)
54.99(2.165)
|
88.9
(3.500)
|
round thread
|
j55
n80
|
8.5m -9.5m
(27.9-31.2)
|
|
88.9
（3-1/2）
|
11.47（7.70）
15.19（10.20）
|
5.49(0.216)
7.34(0.289)
|
77.9(3.067)
76.0(2.992)
|
24.25(2.943)
21.04(2.797)
|
107.95
(4.250)
|
round thread
|
j55
n80
|
8.5m -9.5m
(27.9-31.2)
|
|
114.3
（4-1/2）
|
18.77（12.60）
|
6.88(0.271)
|
100.5(3.957)
|
97.37(3.833)
|
132.08
(5.200)
|
round thread
|
j55
n80
|
8.5m -9.5m
(27.9-31
|
|
|
|
|
|
|
|
|
|
|
Oil casing with special threads is mainly used in wells where traditional API threads are not suitable. Traditional API threads have problems such as sealing and tensile strength. Traditional API threads have poor gas sealing performance. For wells containing hydrogen sulfide, carbon dioxide and chloride ions It is not suitable for wells in different positions, and special threads can effectively overcome these shortcomings. In addition, some high-grade steel pipes (such as Q125 and above steel grades) generally use special threads.
37Mn5----J55
The buckle types of API5CT oil casing include STC (short round buckle), LTC (long round buckle), BTC (ladder buckle), VAM (short round buckle) and other buckle types. API5CT oil casing length R1, R2, R3
DZ40.DZ50.DZ80.H40.J55, K55, N80, L-80, C-90, C-95, P-110, Q-125
st52 is equivalent to Q345B
4.88-7.62M for R1 7.621-10.36M for R2 10.36-14.63M for R3
】SY/T6194-96
The domestic casing is made of hot-rolled or cold-drawn steel for geological drilling, and the steel number is indicated by "geological" (DZ).
There are DZ40, DZ55, DZ753 types
STC (short round buckle), LTC (long round buckle), BTC (ladder buckle), VAM buckle
