Applied torque & safety margins
Designed for high performance
Tested for safety
ERA TorQ rings provide API BTC connections with greater torsional strength across the full 4 1/2 - 20 inch BTC range and provide the following benefits:
Our calculations for applied field torques begin at the theoretical stage and ensure that your applied field torques are maximised for your operation whilst ensuring a significant safety margin for tools going into your well.
We ensure you have all of the information you need before you use our products.
ERA TorQ - Components of field make up calculations
Field make up consists of 2 torque components.
Firstly we have the standard make up of a BTC connection where torque is applied to achieve the "Triangle" positional torque. This is the standard BTC make up component.
Secondly we have the Delta Torque. This is the torque applied into the torque ring once the faces of the casing pin end and the torque ring meet. The delta torque is what we calculate, control and test for your benefit.
ERA TorQ - Calculate the Delta Yield Torque
Delta torque is applied into the ring itself once the BTC connection has been made up to triangle down position.
We calculate the theoretical yield torque for the given ring face cross section area and steel grade.
This is identified as T (yield max).
For this calculation we use the nominal manufacturing dimensions and the lower of the yield pressures for the given steel.
For example, L80 grade steel has a yield point between 80,000 - 95,000 psi (as per API 5CT) across the cross sectional area of the ring.
We always use the lower value. In this instance it would be 80,000 psi.
ERA TorQ - T (yield max)
T (yield max) = 100% possible applied delta torque at which point the ring face may collapse, failures in the metallurgy may occur.
ERA TorQ - Maximum applied field delta torque
Maximum field delta torque as recommended per data sheets = 50% x T (yield max)
ERA TorQ - Safety Margin
The safety margin on recommended field applied delta torque is therefore 100% beyond the advised maximum field delta torque.
From above, you can see that we build into our products a safety margin in both materials strength calculations and in practical field applied torques.
Lets take a worked example...................
ERA TorQ - 9 5/8 BTC 47ppf L80 T (yield max) calculation
Nominal ring OD = 9.32 inches
Nominal Ring ID = 8.681 inches
Steel grade = L80 = 80,000 psi
Nominal ring cross sectional area = 9.034 sq. inches
Yield in pounds inches = 722,720
Yield in Ftlbs = 60,226
ERA TorQ - 9 5/8 BTC 47ppf L80 Field Max Delta calculation (with TT computer in use)
Max Field Dalta (with computer in use) = T (yield max) x 50% = 60,226 x 50% = 30,116 ftlbs
ERA TorQ - 9 5/8 BTC 47ppf L80 Safety Margin (with TT computer in use)
The safety margin for applied delta torque in this example is therefore 30,116 ftlbs or 100% of the maximum recommended applied delta torque.
ERA TorQ - 9 5/8 BTC 47ppf L80 Total torque applied (with TT computer in use)
The total torque applied in this example would be the sum of the 2 torque components explained above.
Contact Triangle Torque + Maximum Recommended Delta Torque = 9630 ftlbs + 30,116 ftlbs = 39, 746 ftlbs
On top of this 39,746 ftlbs maximum field torque figure you also have the safety margin of 30,116 ftlbs.