More than 70% of oil production comes from mature fields with more than 30 years old.
Generally, these fields start producing, in some cases, by natural upwelling and otherwise it is necessary to equip the wells with artificial production systems.
After the wells pass the primary production stage that can vary from one to five years, the study of a project is started, to increase the oil recovery factor, which, to a large extent, is defined according to the viscosity of the oil. For light oils, the injection of water is generally used and for heavy oils the injection of steam is used. After the study comes the implementation and monitoring stage.
For these methods to be successful there are at least three factors to take into account:
1- Determine what is the current distribution of fluids in the reservoir per layer
2- Location of the injection wells based on the above
3- Rigorous monitoring of the injection project
In the case of subsaturated oil, we are far from producing gas by lowering the pressure, so that only oil and water are produced.
At the beginning of the primary production stage, oil with a low percentage of water is produced, and then oil production declines, as the pressure (energy) of the reservoir drops.
When implementing the water injection project, for example, water and oil production begins, oil production reaches a peak, while water production continues to increase, from there oil swept by water, begins to decrease, while moving large volumes of water.
The water cut varied from 5% to 90% throughout the process.
The recovery factor went from 25% to 40% according to the effectiveness of analysis and application of the points mentioned above.
It is necessary to consider at least three factors:
1- Human resources
3- Economic resources
It is key that you work as a team, that you use an adequate methodology, which will indicate the technology to be used and thereby optimize the economic resources to be used.
The great advantage of mature fields is that the largest investment is made, the wells, batteries, treatment plants and transport networks, so that with an optimal investment you can recover more oil, making the economy of them profitable.
Human resources in mature fields
According to the number of existing projects, it will be the number of people working in the same in the operating companies and in the service companies.
They have reservoir personnel, production and facilities
Generally, reservoir staff remains constant, more production personnel are needed, as the number of wells increases and the number of personnel of facilities decreases once they are operating.
Drilling: begins a massive drilling stage that lasts according to the number of wells, then they are removed.
Workover: it is a constant activity throughout the life of the site.
Movement of injection valves: it is a constant activity, which begins with the secondary recovery stage and is done during the entire life stage of the deposit.
Injection of chemicals: it increases with the increase of water volumes.
Maintenance of equipment and facilities: it is maintained throughout the life stage of the deposit.
The most required jobs in mature fields are:
- Production Operative Assistant
- Completion Assistant
- Production Operative Assistant with knowledge of Water Injection
- Assistant in Safety, Hygiene and Environment
The role of technology
New technologies are changing in an accelerated manner, the number of people involved, the efficiency and safety of the processes.
Depending on the above, fewer staff will be required, as is the Operators as in the Service Companies, as processes are being automated.
The new fields of work are being developed in the use of data analysis (Data Analytics), Automation, Safety and Environment.
The most required course in this case will be that of Telemetry Assistant