1) Static derrick load
Fd = (
𝑛+2
𝑛
) 𝐻𝐿
Fd, Static derrick load
𝐻𝐿 = Hook load
𝑛 = number of lines
Dynamic Derrick Load
Fd = 𝑇𝑓 + 𝑇𝑑𝑙 + 𝐻𝑙
𝑇𝑓 = Tension in fast line load
𝑇𝑑𝑙 = Tension in the dead line load
𝐻𝐿 = Hook load
2) 𝑇𝑓 =
𝐻𝑙
𝑛𝐸
𝑇𝑓 : Fast line load
𝐸: Efficiency
𝑛: number of lines
3) 𝑇𝑑𝑙 =
4) Fd =
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𝐻𝑙
𝑛
𝐻𝑙
𝑛𝐸
+
𝐻𝑙
𝑛
1+𝐸+𝑁𝐸
+ 𝐻𝑙 = (
𝑁𝐸
) 𝐻𝐿
5) Static deadline load:
𝐻𝑙
𝑁
6) Actual derrick load =(
7) Fast line load:
1+𝐸+𝑁𝐸
𝑁𝐸
) 𝐻𝐿
𝐻𝑙
𝑁𝐸
N: number of lines, E: Efficiency, 𝐻𝑙 : hook load
8) 𝐹𝑑𝑒 = (
𝑛+4
𝑛
) 𝐻𝑙
𝐹𝑑𝑒 : maximum equivalent load
9) Derrick efficiency factor =
10)
𝐸 =
𝐹𝑑
𝐹𝑑𝑒
𝑂𝑢𝑡𝑝𝑢𝑡 𝑝𝑜𝑤𝑒𝑟
𝐼𝑛𝑝𝑢𝑡 𝑝𝑜𝑤𝑒𝑟
E: hoisting efficiency factor
11)
P.O = 𝑉𝑡𝑏 𝐻𝑙
P.O, Output power
𝑉𝑡𝑏 ,velocity of the fast line load
𝐻𝑓𝑙 𝑖𝑠 𝑡ℎ𝑒 𝑓𝑎𝑠𝑡 𝑙𝑖𝑛𝑒 𝑙𝑜𝑎𝑑
12)
P.I = 𝐻𝑓𝑙 𝑉𝑓𝑙
P.I, Input power
13)
𝑉𝑓𝑙 = 𝑛𝑉𝑡𝑏
𝑉𝑓𝑙 , velocity of fast line speed
𝑛, the number of lines strung between the travelling block and the crown
block
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14)
T=
90
𝑉𝑡𝑏
T, time to trip a stand (90 ft)
ɳ=
15)
𝑃.𝑂
𝑃.𝐼
ɳ, efficiency
1
𝐹𝑝 = 𝜋𝐿𝑠 (2𝑑𝑙2 − 𝑑𝑟2 )𝐸𝑣
16)
2
𝐷𝑢𝑝𝑙𝑒𝑥 𝑝𝑢𝑚𝑝 𝑓𝑎𝑐𝑡𝑜𝑟
𝐹𝑝 : pump displacement factor (in gal). The total volume displaced per complete pump cycle
𝑑𝑟 : rod diameter
𝐿𝑠 : stroke length
𝑑𝑙 : liner diameter
𝐸𝑣 : volumetric efficiency
17)
3
𝐹𝑝 = 𝜋𝐿𝑠 𝐸𝑣 𝑑𝑙2
4
𝐹𝑝 : pump displacement factor for triplex pump (in gal).
18)
𝑃𝐻 =
∆𝑃𝑞
1,14
𝑃𝐻 , hydraulic power
𝑞, flow rate in gal/min
∆𝑃, 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 𝑖𝑛 𝑝𝑠𝑖
19)
𝜔 = 2𝜋𝑁
𝜔, 𝑎𝑛𝑔𝑢𝑙𝑎𝑟 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦
N, revolution per minute(rpm)
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𝑇𝑟𝑖𝑝𝑙𝑒𝑥 𝑝𝑢𝑚𝑝
20)
Power Output = 2𝜋𝑁𝑇
T, torque in ft-Ibf
N, engine rotary speed, rpm
21)
Q = 𝑤𝑓 H
𝑤𝑓 , consumption rate in Ibm/min
Q, total rate of energy consumed in hp
H, fuel heating value, Btu/Ib
22)
P.I = 𝑄𝑓 𝐻
𝑄𝑓 , rate of fuel consumption Ib/hr
23)
P.O = 𝜔𝑇
T, torque
24)
Pa = 0.9Pt
Pt, tensile strength, Ib
P, hook load (excluding top drive weight), Ib
Pa, maximum allowable tensile strength, Ib
25)
MOP = Pa – P
MOP, margin of over pull
26)
S. F =
𝑃𝑎
𝑃
S.F, safety factor
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𝐿𝑑𝑝 =
27)
0.9𝑃𝑡 −𝑀𝑂𝑃
𝑊𝑑𝑝 𝑥𝐵𝐹
−
(𝐿𝑑𝑐 𝑥𝑊𝑑𝑐 )+(𝐿ℎ𝑤𝑑𝑝 𝑥𝑊ℎ𝑤𝑑𝑝)
𝑊𝑑𝑝
𝐿𝑑𝑝 = length of drill pipe
𝑊𝑑𝑝 = weight of drill pipe
𝐿𝑑𝑐 = length of drill collar
𝑊𝑑𝑐 = weight of drill collar
𝐿ℎ𝑤𝑑𝑝 = length of heavyweight drill pipe
𝑊ℎ𝑤𝑑𝑝 = Weight of heavyweight drill pipe
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