By Junior Johnson
When I first stepped on an Offshore Oil & Gas Production Facility over 30 years ago I was in awe at the multitude of vessels and piping I observed. This equipment was utilized in the production of oil and gas from a well completed by the Drilling Department.
Although complex in appearance this equipment basically served only one purpose. It was to separate the oil, water, and gas from the well. Separation was the main function of all these vessels and piping.
I will attempt to describe the process in which the Production Facility is utilized to prepare the product for the refinery. I will use a typical well to simplify what the Production Operator is responsible for.
The Drilling Rig will drill into a formation located around 3,000 feet below the ocean floor.
Once the formation is penetrated the well will have about 5,000 psi that will come up the drill pipe to the surface. A safety valve is placed in the pipe below the mud line to open and close the well from the wellhead. The Drilling Rig will move off location and turn the well over to the Production Facility.
At the wellhead there is a choking device to control the flow. As the product reaches the Production Facility the pressure is regulated to about 1,000 psi. From the wellhead the product flows into a large Production Vessel, which separates the gas, water and oil that comes from the formation. Gas is the lightest and exits the vessel from the top, the oil from piping in the middle and water, being the heaviest, from the bottom.
We will follow the gas first as it makes its way through the facility. From the Production Separator the gas travels to a dehydration system called a Reboiler. This vessel is filled with glycol, which is heated to about 400 degrees and circulated through enclosed piping. The gas passes through this vessel and is heated to dehydrate it. Remaining oil is dumped into piping and sent to oil processing vessels. The water and oil free gas goes to the gas sales line and is transported to land.
As the oil is dumped from the Production Separator it’s moved to a Coalescer where any remaining water is removed. The water is carried back to the water processing vessels. The clean oil is moved to a sales pipeline carrying it to land. In some cases the oil is mixed with the gas and transported in the same line and separated again at a facility on land.
From the Production Separator the water is dumped into a line carrying it to a Skimmer where any remaining oil is skimmed and dumped back to the oil processing vessels. The clean water is then dumped overboard back into the ocean.
There is a Safety System set up on each vessel to insure the safety of the employee, environment and equipment.
Each vessel has a high and low level sensor, a high and low pressure sensor and a vessel pressure relief valve, which can shut down the process of the well. There are also Emergency Shutdown Devices located throughout the facility.
The Federal Government has an agency called the Bureau of Safety and Environmental Enforcement that inspects facilities operating in the Gulf of Mexico. They can make unannounced visits to conduct an inspection. Heavy fines are levied if a component isn’t working properly.
As with any Industry, there are risks and dangers but Operators spend over 80 percent of their time working with these Safety Devices, making the Oil & Gas Industry one of the safest.
I proudly served 32 years helping provide the energy needs of our Country.