The process of oil production from an oil field produces a fluid, known as an emulsion, consisting of a combination of oil, gas, water, and solids. This is why we need a separate oil treater or an oil treating facility to produce clean oil that meets the specifications of a buyer. A significant portion of the system deals with the by-products.
The main by-products of oil production are:
- Gas – also known as solution gas when produced with the oil, has value and can be sold separately or used as fuel gas in the oil facility.
- Water – can be purified and used in an enhanced oil recovery scheme, such as waterflood.
- Sludge or Solids – are the unwanted incidental products of the oil production process, which must be removed.
Read on to learn more about sludge and how it is removed in an oil treater or a horizontal separator.
What is Sludge?
The solids produced with the emulsion oil often consist of fine particles of the reservoir rocks. As the oil flows through these openings in the rocks, it carries the minute fragments with it. Depending on the age of the formation of the rocks, the particles can be sandstone, carbonates (shells), clay, shales and silts. In addition to reservoir solids, the oil also picks up other particles such as corrosion contaminants, wax, and asphaltenes. When the water, gas, and lighter oil are removed, the solids mix with the heavier oil and form a sludge.
Where is the Sludge Found?
Sludges are dense and sticky and settle in any low spot of the pipeline, inlet separator, free water knockout, oil treater, or tank carrying it. They tend to get collected in the equipment, especially where the flow rates are low, such as against baffles and weirs in a horizontal separator or treater. If sludge builds up in a pipeline, it will restrict the flow of emulsion oil and may also cause corrosion on the inside of the pipe.
Removing Sludge from an Oil Treater
Pressure vessels, such as a horizontal 3 phase separator or tank, have desanding or desludging spray nozzles to help remove sludges regularly. A nozzle system is often installed at the bottom of the equipment. It sprays high-pressure water, chemicals, or a combination of both to clean the sludge. The spray nozzles are activated manually or automatically to wash it from the vessel walls into the drain. The drain nozzles help remove the solid residue from the vessel. If the separator does not have a desludging system, it helps to clean the equipment manually with a high-pressure steam cleaner and vacuum trucks.
Safety Precautions for Removing Sludge
Sludges may contain naturally occurring radioactive material or NORM. It primarily consists of radium, uranium, potassium, and thorium. It helps to take necessary precautions to avoid any hazard when cleaning sludge from oil and gas equipment.
It helps to keep the following in mind when removing sludge:
- Do not eat, drink, or smoke in the presence of NORM.
- Be sure to store NORM and other waste and contaminated materials in a separate area with limited access.
- Reduce operations such as cutting and grinding that may generate dust containing NORM.
- Minimize the time spent in NORM-contaminated areas.
- Use appropriate shielding tools and equipment when handling sludge that may contain NORM.
- Use proper disposal measures to avoid stockpiling the materials.
Contact Us for Oil Treaters & Separators with a Desludging System
The design and installation of desludging systems is a combination of fluid hydraulics, identifying the components of the sludge, and choosing the best practices to clean it. At Crimtech, we have the experience and expertise when it comes to designing oil treaters and horizontal separators. Reach out to us by calling 403-342-7579 or toll-free at 1-800-993-9958 to find the best techniques for your sludge build-up problem.