Project Management in the Oil and Gas Industry

3.4 Calculate the Activity Time Period 
The calculation of the activity period requires taking data from different 
disciplines, but its accuracy depends on the skill and strong experience of 
the planner. On the other hand, there is a performance rate for each activ-
ity and, in international contractor companies, usually have a standard 
guide for the performance rate for each activity.
There are many factors that affect labor productivity:
• Job size and complexity
• Job site accessibility
• Labor 
availability
• Equipment 
utilization
• Contractual 
agreements
• Local 
climate
• Local cultural characteristics, particularly in foreign 
operations.
There is a method for calculating the time of an activity through the use 
of performance rates. Below shows the method of calculating the period of 
time to excavate 15000 m
3
, and this requires, first, determining the method 
of excavation. In this example, it has been identified by the equipment.
Assume you need to excavate 15000 m
3
of soil. Using two bulldozers and 
loaders and trucks to transport the disposal will be the method of excava-
tion. The equipment used will be two bulldozers, two loaders, and four 
trucks. The performance rate for one bulldozer is 120 m
3
/hour and the 
performance rate for one loader and two trucks is 75m
3
/hour.
The rate of excavation is 2 × 120 = 240 m
3
/hour.
The required time for excavation is 15000/240 = 62.5 hours = 9 days.
The rate for removing disposal is 2 × 75 = 150 m
3
/hour.
The time period for removing disposal is 15000/150 = 100 hours = 
15 days.
Therefore, the excavation time equals about nine days and the trans-
fer of residue is approximately fifteen days, taking into consideration that 
the number of working hours in the day equals only seven hours in the 

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Project Management in the Oil and Gas Industry
preparation of the timetable. For the excavation activity, take the largest 
time period which is fifteen days. It may be after finishing the excavation 
to start pouring the plain concrete, so it will start after nine days, as there 
is no need to wait pouring the concrete until the transfer of all waste from 
the site is completed.