Project Management in the Oil and Gas Industry

Table 3.2 Example for foundation.
Item Activity
Time (days) Precedence Activity
100
Mobilization
3
–
200
Excavation
8
100
300
Pouring concrete foundation and 
piping support
10
200,100
400
Install the piping
4
300,100
500
Install the mechanical package
1
300
600
Put the grouting 
1
300, 500
700
Connect the piping
5
400,500
800
Commissioning and start-up
2
700

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100 
Project Management in the Oil and Gas Industry
Figure 3.9 shows the latest start and finish for each activity by applying 
the following equation:
LS = LF–D.
In the last activity, calculate back because the latest early finish will be 25 
days by applying the above equation.
From Figure 3.9, by subtracting the latest start (LS) from latest finish 
(LF) and subtracting the early start (ES) from early finish (EF), it gives the 
value of zero, so it means that this activity is on the critical path. But, if the 
difference of the subtraction has a value, it means that this activity can be 
delayed by this time period without affecting the total project time.
100
600
200
400
3
7
7
12
0
3
3
11
11
21
21
22
22
23
23
25
300
500
700
800
Pouring concrete
Excavate
Install piping
Mech. package
Put grouting
Conn. piping
3
1
8
4
10
1
5
Comm. & start up