Drilling Processes for Oil and Gas
Oil and gas industry relies on the drilling process for the construction of oil fields. Natural gas and oil are found in the earth’s crust, and they have to be drilled out. Natural gas remains stored within sandstones, carbonates, coal and shale. Wells are constructed on oil beds and generally take two to three months to become functional. The productive life of a single well is 20-30 years on an average. A number of resources are used for drilling vertical, horizontal and multi-layered wells for target formation.
The step by step overview of drilling process is given below:
1. The drill site is prepared for drilling. This would need proper surveys and licensing.
2. Steel pipes and other equipments are inserted to bore the area
3. Fresh water aquifer is protected by cement pipes
4. Drilling process is continued to the earth’s crust till its maximum point.
5. Drill fluid is inserted in the hole to crack the shale. The drill fluid consists of water, some chemicals and mud additives.
6. Fracturing process completes in 2-5 days. Till then, other processes continue on the area.
7. Once the well is dug, necessary facilities are installed and the well is prepared to function.
As discussed earlier, the oil well keeps working for about 20-30 years.3 million to 5 million gallons of water is used to create the right hydraulic pressure during the drilling process. This same amount of water can be consumed on a golf course in around 15 to 20 days. Drilling site is studied by certified geologists to develop a strategy to minimize challenges. Climatic conditions are also studied to be prepared for future risk management. Social and local issues are also taken in consideration. Land permit is sought from the government. This involves paying certain taxes.
Geologists work with environmentalists, engineers, and regulatory staff to collect information about the drill area. Initially a short length drill is done which is later extended to the water table. The depth is specified by the geologists working on the area. After drilling, some drilling mud is pumped in to make clear surface and boundary of the hole. After the steel pipes are removed, cement castings are filled on the boundaries. A plug is also inserted in the casting to check the section of the wall. Once the well is constructed, then it is taken further by the upstream processing and the downstream processing from here.