CHAPTER 1 — PART 3 Flashcards
The ___ must have sufficient height and strength to effectively and safely perform its functions.
It is rated based on its capacity to withstand compressive loads and wind loads.
derrick
The compressive load of a derrick is calculated as ___
the sum of its four legs’ strength
___ is calculated in two ways: with OR without pipe setback based on API derricks.
Wind load
The wind load can be calculated as:
Ww = 0.004V²
___ can be calculated using the block and tackle arrangement.
Total compressive load
The load imposed on the derrick i.e. the total compressive load on the derrick is ___ than the hook load due to the arrangement of lines on the block and tackle.
greater
Using the fastline and deadline tension, the derrick load can be calculated as:
Derrick load = hook load + fast line load + deadline load
In practical applications, the total derrick load is NOT distributed equally over all four legs due to the ___
placement of the drawworks
If one leg fails, then ___
the entire derrick fails
used to evaluate various drilling line arrangements
Derrick efficiency
___ allows the driller to handle large amounts of load easily; the load supported by the travelling block to the load imposed on the drawworks
Mechanical advantage
Ideal Mechanical Advantage assumes ___ in the block and tackle
no friction
Tension in the drilling line remains the same all throughout the ___
block-pulley-drawworks
• defined as work done per unit time
• The input power of the block and tackle is measured as the drawworks load (i.e., fast line tension times the fast line velocity)
Power of the Block and Tackle
the ___ can be measured as the travelling
block load (i.e. hookload) times the velocity of
the travelling block
output power or hook load power
