A summary of the points raised by Derek Blagg in the November Tank Talk webinar
The November Tank Talk webinar looked at three important factors in the safe, efficient operation of bulk liquid storage tanks, which oil and gas solutions company Varec calls the ‘3 Ms’ – measure, monitor and manage.
The webinar was presented by Derek Blagg, the commercial director of Varec, who has been at the company for more than 20 years. Varec offers software, hardware, and services to the oil and gas industry, including commercial and defence. Its solutions include tank gauging, inventory management, supervisory control and data acquisition (SCADA), automation and back office tools. The company has been in business for more than 90 years, and pioneered inventory tank gauging instrumentation, including the Varec float and tape gauge. Similar gauges are now commonly known as Varec gauges, even when made by other companies. Varec has sold more than 750,000 gauges.
‘The first question that we deal with today is how to select the right technology to measure your inventory,’ Blagg began.
There are a number of options for measurement, which can be simple, like a float and tape gauge with a local display, or complex, like a radar gauge with a real-time view in a centralised control centre. Many variables can impact the decision, including the budget, the type of tank (e.g. below ground, above ground, floating roof, small), and the type of product that is being stored.
‘What level of accuracy do you need? Are you performing custody transfer, or do you just need to know if the tank is roughly full or empty?’ Blagg said. ‘For example, in our arsenal of products we have everything from a float that sits on top of the product that measures out onto a gauge board on the outside of the tank that measures in feet or inches, vs the more advanced gauges that can get down to fractions of inches and centimetres.’
Other things to think about include measuring temperature, density, whether there is power at the tank, whether there is wired or wireless connections, and whether the data is needed in real time.
A float and tape gauge is the cheapest option, but is not suitable where high levels of accuracy are needed. The construction of the tank is important as some gauges require stilling wells, such as servo gauges. Some types of products are not suitable for certain types of gauge, or require certain types of software. Blagg said that it is very important to work with the provider to make sure that the solution meets all the requirements.
Figure 1: Features and benefits of different gauge technologies
‘Tank farms, load racks, storage and distribution facilities are complicated. No two are alike, many have similar operations and equipment, however. The back office, or the control room, where the HMI or the computer system is located, allows for monitoring and control of the automated system of those components that you’ve selected out in the field at your tank gauges and other places. Storage tanks can benefit from automatic tank gauges, density measurement, temperature measurement, and level alarming. Valves and pumps can benefit from the ability to open and close those valves from a remote location,’ said Blagg.
It might be beneficial to include presets with temperature measurement and blending, as well as grounding and overfill protection systems, which can be monitored from the control room or remotely. Weight scales can help with product receipt and delivery, and ensuring tankers aren’t overfilled. Gate controls can also be included in automated systems to keep operations going during unmanned hours.
Effective monitoring of facility operations through an integrated system has many benefits. Transaction and physical inventory data can be stored in one database, increasing data accessibility and visibility. Information technology, security and maintenance, including preventative maintenance, is simplified, reducing overall costs. One such example is the ability to review pump run times.
‘Adam [Wishall, Blagg’s colleague at Varec] designed logic into some pump rotation programmes to ensure the best use of pumps in a rotation, eliminating uneven use. We’ve had installations at sites where multiple pumps would come on to keep pressure or flow at a constant rate, but what would happen is that those pumps would come on, 1, 2, 3, 4, and turn off four, three, two, one, leaving pumps one and two to run most of the time. His logic provided a more even run of those pumps,’ said Blagg
When multiple field devices are integrated into one system, users can view pump and valve status, flow rates, product levels, personnel status, and tank status, amongst other things, on one system. Unnecessary paperwork, missing paperwork and errors are greatly reduced, and often eliminated. Additionally, secure operations can be maintained during unmanned hours, such as gate access, preload validations, offloading and remote troubleshooting.
Figure 2: An example of the tank overview in Varec FuelsManager software
In Varec’s FuelsManager software, an overview screen for a tank can show product levels, water levels, density, net available volumes, alarm limits and transfer status, as an example. Software can be configured depending on each customer’s specific needs and the data they have available, including automated data and the input of manually collected data. A load rack screen can show whether a truck is in a bay, what is being loaded, the company which owns the truck and the driver, a real-time view of volume requested, volume loaded, and remaining loading time, for example.
When purchasing and installing software systems, it is vital to consider your specific needs.
Once you have all the data, what do you do with it?
‘Inventory management is the culmination of the data collection that we’ve talked about so far. All of the level measurement and transaction data that we’ve collected so far end up on the desk of a fuel inventory accountant at some point. It’s their responsibility to reconcile the account and ensure all the product is accounted for, and they must investigate any discrepancies they find,’ says Blagg.
Very few sites still use paper ledgers. Most use some sort of electronic format, be it unspecialised, such as Microsoft Excel, or specialist software like FuelsManager. Data can come in from automated systems, in electronic spreadsheets, on paper tickets, or increasingly, from handheld devices such as tablets. Reconciliation of the data is essential and ensures that accurate reports go to customers or financial systems.
Inventory accounting must consider a number of important factors, including accounting standards, proper training for staff so that they understand how the data is collected, how to spot errors, and the frequency of reconciliation. Daily inventory accounting allows errors to be spotted much more quickly and corrected more easily. There are also some key questions organisations should ask. Are the gain-loss reports being properly audited by management? Are tank strap charts current? Is the data secure?
Essential inventory data must be accurate, whether automated or from manual processes, which Blagg believes can be just as, consistent, reconciled, and repeatable if executed correctly. Systems must be simple. Managers are busy and a simple system allows for rapid oversight. It is also important to have a quality recurring training program for staff with opportunities to ask questions.
There are multiple types of reconciliation to carry out. When done daily, it can help spot any problems more quickly. Comparing sales transactions to a 24 hour reading on a meter, where sales are metered out, is a quick way to spot missing transactions or meter problems. Receipts should be reconciled to make sure that what was stated on delivery documentation was actually what was received, and trends monitored over time, again helping to spot meter or other problems. On a daily basis it is critical to check that the physical inventory is the same as the book inventory. Customer feedback, such as issues they spot is also very important, as they might be looking at their numbers or a situation in a different way and see things a tank farm did not.
‘Proper reconciliation and management completes that circle of the three Ms of bulk liquid storage. It is as important as selecting the proper measurement devices and automation system for monitoring. Those things all go together and once you’ve made the selection up front for which device, or devices, you’re going to use, and once you’ve selected the automation system that you have between that, completing the reconciliation completes that circle. It will provide you with oversight and management of that product, save you money, save you time and solves a lot of problems,’ says Blagg.
Blagg concluded the webinar with a look at the trends Varec is seeing in industry.
One of the major trends they are seeing at the moment is that traditional on-site installations are increasingly moving to the cloud. Cyber security and connectivity become hugely important with cloud operations, but as connectivity improves, cloud operations are becoming more attractive. Cloud operations can offer cost savings, making automation affordable for users where it previously was not. Many companies simply see the benefits of not having to manage on-site servers or maintain cyber security requirements, allowing them to focus on other operational needs. Leveraging the cloud, scaling up is simpler, and allows companies with multiple locations, some smaller and possibly more remote, to run similar systems everywhere, with centrally accessible data.
Blagg also mentioned ‘device agnostic accessibility’. Many operators carry around mobile phones or tablets and it is increasingly expected that all such devices are able to access site systems. Varec is considering control and cyber security for such systems, which Blagg thinks is not far off.
‘Another area that is very near and dear to my heart and I think one of the areas that will see the biggest movement in the near future, is dashboards and data analytics,’ said Blagg. ‘Think about the dashboard in your car, giving you immediate access to very important information about your system. Companies want more data in real time and dashboards can supply that.’
Data analytics can then take that further, to help with planning and predictive analysis. By analysing trends in the data, it is possible to get insights that would not be possible from a hard copy report.
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