LC threaded coupling connections for casing pipes

 

Application

Coupling connection for casing pipes with a thread of round (triangular) profile without shoulders is intended for construction and operation of vertical wells in oil, gas, and gas-condensate fields.

 

Design description

The peculiar design feature of casing pipes with the thread of round (triangular) profile is that the thread fits along the lateral sides of the triangular profile. The required tightness of the connection is ensured by thread-lubricant sealing of clearances during the mechanical make-up. The thread profile has the angle of 60°, pitch of 3.175 mm, taper of 1:16. The LC connection with elongated thread features greater tightness and resistance to tensile loads in comparison with the STC short thread.

 

The tightness is ensured by the thread-sealing grease pressure in design clearances of the thread connection profile.

Make-up control

In case of correct mechanical make-up, the coupling face moves up to the surface of pipe thread run-out end.

Main features of the LC connection

Pipe Coupling
Outer diameter D, mm Wall thickness S, mm  Inner diameter d, mm Weight* of 1 m pipe, kg Outer diameter Dc, mm Min. coupling length Lc, mm Weight*, kg
1 2 3 4 5 6 7
114,30 6,35 101,65 16,91 127,00 177,80 4,15
7,37 99,56 19,44
8,56 97,18 22,32
127,00 6,43 114,14 19,12 141,30 196,85 5,75
7,52 111,96 22,16
9,19 108,61 26,70
11,10 104,80 31,73
12,14 102,72 34,39
12,70 101,60 35,80
139,70 6,98 125,74 25,85 153,67 203,20 6,42
7,72 124,26 25,13
9,17 121,36 29,52
10,54 118,62 33,57
168,28 7,32 153,64 29,06 187,71 222,25 11,34
8,94 150,40 35,13
10,59 147,10 41,18
12,06 144,16 46,46
177,8 8,05 161,70 33,70 194,46 228,60 10,83
9,19 159,42 38,21
10,36 157,08 42,78
11,51 154,78 47,20
12,65 152,50 51,52
13,72 150,36 55,52
193,68 8,33 177,02 38,08 215,90 234,95 15,63
9,52 174,64 43,24
10,92 171,84 49,22
12,70 168,28 56,68
14,27 165,14 63,14
15,11 163,46 66,54
15,88 161,92 69,63
219,08 8,94 201,20 46,33 244,48 254,00 21,67
10,16 198,76 52,35
11,43 196,22 58,53
12,70 193,68 64,64
14,15 190,78 71,51
244,48 8,94 226,60 51,93 269,88 266,70 25,45
10,03 224,40 57,99
11,05 222,40 63,61
11,99 220,50 68,75
13,84 216,80 78,72
15,11 214,25 85,47
* — estimated value