Table 19 – The evaluation of efficiency of different variants of drill rods according to the expense during the drilling of the well with the depth 500 m
|
Variant of the design |
The brief |
Extreme condition |
Extreme bending moment |
Extreme |
Average mechanical speed |
Resource of rods in hours during the drilling on the bottom |
Drilled for the resource of the column |
Consumption R. |
|||
|
on fatigue |
on wear |
of the rod/ tool joint |
of the rod with the tool joint |
of the rod/ tool joint |
of the rod with the tool joint |
||||||
|
I |
Drill rod 50x5.5 |
Thread of the rod |
Surface of the tool joint and the rod |
650 |
400 |
2.12 |
3000/ 1200 |
- |
12720 |
4.3/ 10.7 |
- |
|
II |
The same (50x6.5); |
The same |
The same |
746 |
425 |
2.25 |
8300/ 1500 |
- |
37350 |
1.42/ 11.2 |
- |
|
III |
Upset drill rod 63.5х6.5. with the tool joint Z-50; |
Thread |
Thread |
1156 |
404 |
2.14 |
- |
1550 |
6634 |
- |
8.2 |
|
IV |
Drill rod 63.5x6.0; |
Body of the rod |
Surface of the tool joint and the rod |
1350 |
535 |
2.84 |
- |
10200 |
57936 |
- |
0.9 |
Note:
1. Values Mextreme for variants I and IV are received on the basis of bench tests of samples in reversed bending and for variants II and III - by taking into account the conversion ratio coefficients the real stress concentration and scale factor for carbon and alloy steels, and the availability (lack of) of the thread’s durability.
2. Resources values of rods for variants I and IV are received on the basis of acceptance tests and for the variants II and III by converting them with taking into account the ration of the material hardness of rods.
3. Tool joints’ resources according to the SS R 7918-75 for variants I and II are due, mainly, with the wear of surface because the thread is quenched with the heating of High Frequency Currents and tool joints besides the basic function, simultaneously they serve as protectors. Resources for these variants are received by converting of these acceptance tests with taking into account the rotational currents difference of drill columns.
4. Drill rod’s resource of variant III depends, mainly, on wear resistance of tool joint’s thread Z-50, made together with rod of steel of group of durability T. It was accepted equal 1550 hours. Such resource was accepted on the acceptance tests of tool joints of the same experimental steel with the hardness 36-40 HRC.
5. Resource of the drill rod SUDR (variant IV) depends only on wear resistance of the surface. It is similar for the tool joint and the rod because their area is reinforced with heating of High Frequency Currents and the drill rod is smooth on the whole length. The resource of the thread significantly higher of the resource of the drill rod’s surface and the tool joint owing to the hardening with carbonitration, which completely excludes it’s troubles because of wear and jamming.
Lachinjan L.A., Honoured person in the Science of the Russian Federation. Doctor of the Technical Sciences, Professor
