Shutdown Guidelines for Tanks and Oil & Gas Storage Equipment

Shutdown Requirements for Tanks and Oil & Gas Storage Devices

The guidelines on the storage of materials for the upstream petroleum industry date back to the mid-1990s. It is essential to adhere to the prerequisites when it comes to double-walled tanks, API 12F tanks, oil production tanks, and other process tanks and equipment to ensure operator safety and protection of the environment. We have put together a few requirements that you should know about to ensure your facility is secure.

Directive 055

A Steering Committee was set up during the 1990s to review the storage of oilfield waste in Alberta. The Committee included the Alberta Environment (AENV), Alberta Energy and Utilities Board (EUB), and the Canadian Association of Petroleum Producers (CAPP). During this period, the stipulations were expanded to include the storage of all materials, and Guide 55 was published.

Under the Energy Resources Conservation Board (ERCB), the predecessor to the current Alberta Energy Regulator (AER), the Guide 55 was transformed into Directive 055 in 2001. Several changes were made to it over the years, to keep a check on spill containment and prevent overfilling of production tanks.

High-Level Shutdown Requirements

It is the responsibility of an oil and gas operator to protect the environment by preventing a spill from occurring. When it comes to tank storage, this means detecting when there is a high level in the tank and immediately shutting the flow to it. The construction aspect in section 5.3.1 of the Guide states:

The operator of an oil and gas facility must incorporate the required measures to prevent the overfilling of tanks. A few of the requirements include the following:

  • Installing shutdown valves on the supply line to the tank
  • Automatic overfill shutoff devices
  • Overfill alarm devices of the audible or visual type
  • Vent restriction devices
  • Inventory control

High-Level Shutdown Devices

The high-level shutdown device (HLSD) on a tank is one of the simplest control devices that automatically closes a valve on the inlet supply line in case of emergencies. When using this piece of equipment, one must consider what will happen to the process once this valve shuts off, and what other spill prevention safeguards are required.

HLSD come in different types, ranging from simple floats to radar sensing instruments. Here are a few examples:

  • Pneumatic Level Switch with Test Mechanism
  • Pneumatic Level Switch
  • Guided Radar Level Transmitter or Switch

Factors to Consider When Selecting an HLSD

Before choosing a high-level shutdown device, be sure to ask the following questions:

  • Is the switch or transmitter appropriate for all fluids?
    • Ensure it is compatible with sour liquids.
    • Make sure it works well in foaming conditions.
    • Are composite floats the correct material for proper buoyancy.
  • Is the HLSD susceptible to the buildup of substances such as sludge, wax, asphaltenes, or ice and make the switch inoperable?
  • Can you test the HLSD from outside the tank?
  • Have you considered the following if the HLSD is powered by natural gas:
    • Is the natural gas dry enough not to become frozen in the winter?
    • Is the natural gas clean enough, so the tubing line of the equipment does not plug off?
  • If the HLSD is on a produced water tank, is it protected from freezing in the winter?
  • If the HLSD is an electric switch, is there adequate backup power in the case of power or battery loss?
  • Is there safe access to the HLSD for inspection and maintenance?

BC and Saskatchewan Requirements

The Saskatchewan Ministry of Energy and Resources (SMER) and the British Columbia Oil and Gas Commission (BCOGC) also have similar requirements.

  • Directive S-01
    As per Section 3.2 of Saskatchewan Upstream Petroleum Industry Storage Standards, all tanks should have one or more overfill protection systems, including automatic shutoff devices.
  • BCOGC Requirements
    The Drilling and Production Regulations state that all necessary precautions must be taken to prevent the loss of water or oil from storage tanks.

Get Top-Quality Process Tanks & Equipment with HLSD

The designers at Aspire Energy Resources Inc. understand the guidelines required to ensure the safety of tanks. We make sure that each of our wellsite separator tank combination units has the proper high-level shutdown systems. We will also ensure that you can easily access the HLSD for testing and maintenance.

For more information about how we implement high-level shutdowns on our separator and tank combination units, reach out to us by calling toll-free at 1-800-993-9958.

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