This episode of the Pipeliners Podcast captures the importance of meter proving to generate accurate measurements from a pipeline and save companies money.
To help identify key issues in the field, Russel Treat welcomes industry expert Jane Williams to the podcast to discuss meter proving, the frequency of conducting proving measurements, how to correctly conduct a prove, the different types of meters available to conduct measurement, plus more topics.
Download this episode to get a better understanding of how meter proving works and the factors that impact crude oil and natural gas measurement.
Fundamentals of Meter Proving: Show Notes, Links, and Insider Terms
- Jane Williams is the President of the Oil and Gas Training Corporation. Connect with Jane on LinkedIn or email email@example.com.
- Meter proving is a method of physically testing the accuracy of a meter through the proving process of measuring temperature, pressure, flow rate, and density against a known prover.
- A PD meter (Positive Displacement meter) requires fluid to mechanically displace components in the meter in order to measure flow.
- A turbine meter uses the mechanical energy of a fluid to rotate a “pinwheel” (rotor) in the flow stream to measure flow.
- An ultrasonic meter measures the velocity of a fluid using ultrasound technology to calculate volume flow.
- A Coriolis meter measures the mass flow of liquid and natural gas as opposed to just volumetric flow.
- Find the meter proving standards in the American Petroleum Institute (API) Manual of Petroleum Measurement Standards.
- Sediment determination is a method of measuring the percentage of sand, silt, and clay particles found in a liquid.
- Paraffinic is a category to describe crude oil based on its composition, regional sourcing, and sediment found in the liquid. To measure the sediment, a special solvent called water-saturated toluene is used.
- A gravimetric test is used to verify the volume of a measurement area from each size prover. When completing a water draw certification for a displacement prover, the weighted amount is determined by the amount of fluid that is registered between detector switch one and detector switch two.
Fundamentals of Meter Proving: Full Episode Transcript
Russel Treat: Welcome to the “Pipeliners Podcast,” Episode 17.
Announcer: The Pipeliners Podcast, where professionals, Bubba geeks, and industry insiders share their knowledge and experience about technology, projects, and pipeline operations. Now your host, Russel Treat.
Russel: Thanks for listening to the Pipeliners Podcast. We appreciate you taking the time. To show our appreciation, we are giving away a customized YETI tumbler to one listener each episode.
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This week, our guest on the Pipeliners Podcast is Jane Williams. Jane spent 25 years with Sun Exploration and Oryx building up a measurement organization for that group. Since leaving that company, she has been working in measurement training and consulting, and she’s the founder and operator of Oil and Gas Training Corporation.
They specialize in providing customized training to oil and gas pipelines and other operators. One of the unique things about Jane, at least in my experience, is she’s got a wealth of knowledge about the detailed, hands-on practice. Jane is with us today to talk about the fundamentals of meter proving.
Jane, welcome to the Pipeliners Podcast.
Jane Williams: Thank you. I’m glad to be here.
Russel: What I like to do when we first get somebody on, I’d like to ask them to tell myself and the listeners a little bit about your background and what you do. Do you mind taking a couple of moments and giving us a little introduction, if you would, please?
Jane: Sure. I actually have both a bachelor’s and a master’s degree in mechanical engineering. I went to work back in 1974 for Sun Exploration and Production Company as a mechanical engineer. I worked in the mechanical engineering department for the first five years just doing general mechanical engineering work.
After that, they put me in charge of the measurement group, and I started that group from scratch and did measurement for all of our locations throughout the United States. I ultimately had 18 measurement technicians working for me, and 40 meter men working for me around the country. I did all of the training for those people.
Russel: That was primarily in crude oil measurement, is that correct? I’m guessing.
Jane: No, it was both crude oil and natural gas measurement.
Russel: That’s a great background for what we want to talk about today, which is meter proving. For the listeners that don’t know, what is meter proving?
Jane: Meter proving is a methodology to verify what the meter is actually putting through it against a known, which is typically either a pipe prover of either ball of piston type, or a small volume prover as the known.
Russel: Basically, what we’re doing is we’re taking what we’re getting in the field meter, and we’re verifying it against something that can be operated to a known number. Why is that important? Why is it important to prove?
Jane: There are many different reasons that you may have some issues with your measurement with a meter. For example, whether it’s a PD meter, whether it’s a turbine meter, or an ultrasonic meter, or even a Coriolis meter. I’m going to predominantly be talking about PDs and turbines, because they’re the most widely used meters out in the field.
Those meters have something called slippage, especially the PD meters where there is fluid that gets past the measuring chamber and you’re basically counting the number of rotations the measuring chamber goes around to determine the total amount of product, whether it’s crude oil or petroleum products of some sort that went through that meter.
Russel: The analogy is I take a bucket and I hand it to somebody. Every time that positive displacement mover gives me a click, it’s equivalent to a bucket of fluid. Then the slippage, you can think of that as what’s slushing out of the bucket. In other words, it’s not getting registered by the meter.
Russel: That’s one of many things that can go wrong.
Russel: How often should I be proving a meter?
Jane: There’s different ways to look at that. If you’re using the same type of crude oil in relatively similar conditions, it’s very common to prove the meter on a monthly basis. For example, in the field, you only have one source of oil and the temperature and pressure that are stable. If you’re in a pipeline situation, you may be dealing with multiple different products that have very different gravities, viscosities, etc. so that you need to prove much more frequently.
I was involved in an offshore platform project, Offshore California, where the pipe with people like myself helping determine what needed to happen. We ended up proving anytime you had a significant change in pressure, temperature, gravity of product, etc. so that we got really good accuracy.
Russel: I know that there’s all kinds of ways to prove. What are the rules? Where do I go for resources and references to know how I ought to be doing my proving?
Jane: The American Petroleum Institute Manual of Petroleum Measurement Standards has the documents or the chapters that cover both how to operate your meters and select meters, and also how to utilize a prover and obtain a proper meter factor.
That’s covered in chapter five… there’s various chapter fives depending on the type of meter, and then chapter four covers the proving. There’s multiple different chapters in four, as well.
Russel: If I’m not necessarily a measurement technician or a measurement person, what might I need to know about proving?
If I’m in accounting or something like that where I’m taking these numbers that I’m getting from these meters and I’m doing something with them to work them against contracts and turn them into invoices. What might I need to know about proving that might impact me and my job?
Jane: You would want to make sure that the proving has sufficient information, which is you need to know the temperature, the pressure, the time, or the volume of throughput that went through the prover for each of the different runs to establish the meter factor.
Russel: That’s probably something we ought to dive into a little bit more, because basically, the output of a proving process is an adjustment to my meter factor. Is that…
Jane: Yes, that’s exactly right. You’re comparing what went through the meter to a known volume. Let’s say I have a measuring cup and my measuring cup holds a gallon. I put something through a device, meter it through a device, and that fluid went through the meter into my measuring cup.
If the meter says it had 1.1 gallon but my measuring cup only registered 0.9 gallons, then I know there needs to be an adjustment to the meter factor, because the meter factor should match and convert whatever it says to equal what the measuring cup said, ultimately.
Russel: Simply stated, it’s a direct multiplier to what the meter registers to turn it into a true number.
Russel: What I think a lot of people don’t know or might not understand is that you have to be careful about how you use meter factors because there’s some assumptions. The biggest of which is I am developing meter factor under flow conditions that are the same as my operating flow.
Jane: It should be correct.
Russel: What are the things that I need to be mindful of when I’m trying to do a prove and make it representative of actual flow?
Jane: The biggest thing that I’ve encountered is the fact that when you add the extra piping with your prover and the connections between the meter and the prover, you’re adding more friction so you have some pressure loss.
With that, it may actually cause a slight change in the meter factor, so you need to make sure there’s an adjustment that you can make using a back pressure valve to make sure everything stays the same through the tube.
Russel: The tool I’m using to do the prove is actually impacting what would be normal production measurement.
Russel: I’ve certainly seen issues where swings in temperature, if you think about I’m proving a meter in the winter in the northeast, versus I’m proving a meter in the summer, I might get a different meter factor doing those different proves, because the viscosity of the fluid is going to be different because of the temperature change.
Jane: That’s absolutely the case. Also, the temperature itself will affect it, as well. Things that affect it are changes in flow rate, changes in viscosity, changes in temperature, and if you have any foreign matter that gets into your product, whether it’s water, sand, etc. You’re not selling water and sand.
Russel: I think one of the things a lot of people don’t realize about meter proving is, monthly is an accepted industry standard. If you’re in a situation where, for whatever reason, my operating condition is changing more frequently than monthly, I might need to be proving more often than that, particularly if I’m trying to get very tight measurement.
Jane: Exactly. In fact, on that offshore platform, there were three offshore platforms owned by different entities feeding an onshore pipeline facility. We were watching in that situation the type of fluid we have, the flow rate, etc., and the proving frequency because each platform had a prover for each meter.
Then, you could adjust to any change in the situation that was the fluid going through the meter, you could prove on a faster time. In one situation, everything is very, very stable. You might prove weekly or monthly, but you might end up actually proving for maybe 10 times in a day, maybe more based on changing conditions.
Russel: I know of at least one meter site down in Mont Belvieu (Texas) where there’s eight meters and there’s a prover on-site. Each one of those eight meters is getting proved at least once a day.
Jane: That doesn’t surprise me.
Russel: It’s just a matter of how frequently what’s being delivered through those meters, what the quality of that fluid is is changing. Consequently when the fluid changes, they need to reprove. This is also common when I’m moving petroleum products, refined products like gasoline, jet fuel, that sort of thing. Each time I get through a fluid transition, I reprove a meter.
Russel: I think one of the things that’d probably be relevant to ask, we’re talking primarily about things that relate to displacement meters, turbines, and PDs, and so forth.
Obviously, there’s the newer technologies, Coriolis. While there’s still a lot of those older style meters, Coriolis, at least in terms of new installation, seems to be more common. What are the differences for proving a Coriolis, versus proving some of these other types of mechanical meters?
Jane: The overall concept is identical. It’s just the meter itself works differently. In a Coriolis meter, you typically have tubes that the fluid flows through and there are magnetic pickups and they’re watching the movement of the tubes compared to each other. That translates into the amount of fluid that was going through that meter at any point in time.
You still can connect to that and do the comparison very similarly as you would a PD or a turbine. To be truthful, I don’t have a lot of field experience with the Coriolis. I understand them, I’ve been to places they’re using them, but I’ve never actually been there when a proving occurred.
Russel: I have a little bit of experience with that. I certainly wouldn’t put myself out as an expert in that subject. What I would speculate is this. The mechanical meters, they’re directly measuring volume.
The more accurate way to measure the fluids, and most of the standards are written around and the qualities are determined by their densities, which means mass is a better number to measure with. Coriolis meters are direct mass meters. They’re recording a mass. The distinction for people that might not know this is a volume would be a gallon and a mass would be a pound.
Russel: A bit of an oversimplification, but that works. You can think of it, if I’m measuring gold, the volume of a pound is very small compared to a measuring helium where the volume of a pound is very large, but the mass is the same.
What I believe to be true with Coriolis meters is because they operate more reliably across a broader spectrum of product pipes, they don’t need to be proved as frequently, because I’m not verifying volume, I’m verifying mass.
The actual prove is the same and the prove is a volume that gets converted to mass. You don’t have to prove them as frequently because mass is more accurate across a broader range of operating conditions.
Jane: I would agree with that, but I will also point out that when the standards for proving a Coriolis meter was first being worked on by API, it took years to get that accomplished, to get that document written.
Russel: Do you know why that was?
Jane: I would suspect, I don’t really know because I was not involved directly on that committee, but I did attend a few meetings. I suspect there was a lot of misunderstanding from people who were very grounded in the PD meters and turbine meters, and not understanding the difference between the volume and the mass that you just pointed out.
Russel: I think you made a very good point earlier, though, because really, the key takeaways is proving is proving. It’s really the same, regardless of the meter type.
It’s more about, if I’m going to apply a meter factor to a Coriolis, normally, that meter factor is adjusting mass. It’s not adjusting volume. That is an important difference. Beyond that, the actual operation of the prover is the same.
Russel: The issues around what would require a new prove are the same.
Russel: I think this is the first time, Jane, I’ve led a conversation at a place where neither the guest nor myself knows the answer.
Russel: Hopefully, that will stir up some commentary about this episode. [laughs] I know that what you primary do is training. I know you do training in this domain. What do you find is most important when you’re doing training for people about how to do meter proving?
Jane: You have to understand what your audience is, first and foremost. If the people that are going to be doing meter proving, you have to explain the process completely so that they fully understand what they need to do.
The other thing is if they’re not going to be doing the actual meter proving but they’re just going to be witnessing a meter proving, making sure it’s being done correctly, they still need to understand the process. They just don’t have to understand you do this, you do that, you do this, you do that in a sequential order so that you get to the end result you need.
People who do this, it’s a repetitive type thing. It’s second nature to do it. Everything is about doing and looking at the details of a meter proving. You don’t want any leaks. You need to check for leaks because if there’s a leak, what went through the meter didn’t necessarily go through the prover.
It may look like a wonderful meter factor but it’s absolutely wrong, because you didn’t have every single drop going through both devices. Just doing it doesn’t necessarily get you the right answer.
Russel: I also find that what can be very important for people that are doing a repetitive test is to understand the why. Why am I doing it? Why is it so important that this is done just so? It’s one thing to know how to do it. It’s another thing to know why it’s done that way.
Jane: Of course.
Russel: In fact, I think that’s probably a good segue, because before we got on, we were talking a little bit about some training that you had done related to the sediment determination. Why don’t you elaborate on that for our listeners about what we were talking about?
Jane: I was teaching for a client up in Alaska this last year. In that particular instance, I was teaching them all about oil measurement in general and meter proving and the determination of sediment and water.
As part of my training, we actually took some oil from a prover. Then, we took it back to the lab and we actually did hands-on in the determination of sediment and water. It turned out that their crude oil was paraffinic and consequently needs some special solvent to be utilized.
They were not using the special solvent which is water-saturated toluene. Also, because it was paraffinic, paraffin does not necessarily dissolve into the oil. It is oftentimes a solid and looks like sediment even though it’s a very desirable petroleum product.
It turns out that they were getting sediment and water levels of like 0.6, when in reality, if they have done the test at increase temperature with the proper solvent, it reduced the sediment and water for that same oil to 0.1, which was the real answer.
Russel: That’s huge. [laughs] I’m sorry, but that’s huge. That’s like adding a quarter percent to your production simply by changing your measurement practice to the correct practice.
Jane: Exactly. They were selling out of 100,000 barrel tanks. They had very large volumes, as well.
Russel: That’s the thing about measurement that I think…I’ve actually had this conversation. It’s been years, but I had a presentation I build at one time to talk about this. When you’re dealing with a great deal of volume, a very small number on a very large volume means a lot of money.
Russel: If you think about 100,000 barrels times a quarter percent times 65 bucks a barrel, that’s lot of money.
Jane: Yes, it is. That’s just for one transfer. How many transfers are made in a year?
Russel: Exactly. That goes straight to the bottom line, too, because there’s no additional cost for that production. It’s production you already have and you’re just measuring it correctly.
Russel: Big deal. It’s a big deal. One of the things I like to do when I get to this point in a conversation is I try to get to, what are the three key takeaways in this conversation? I’m going to attempt to do that. If I get it wrong or if you have a different take, Jane, maybe you can edit or correct, if you would.
I think the first thing that’s a key takeaway is that proving is a mechanism to get a more accurate number out of the meter. That’s one key takeaway.
The other key takeaway is that good proving is done at the same conditions for which the meter is normally operating, which may mean I might ought to do proving quite frequently, depending on how often what’s going through the meters change.
Then lastly, there’s a lot little details in getting a prove done correctly and getting a good meter factor. It’s important to know all the hands-on practices, why they’re important to get a good number. Did I miss anything? Do you think I got it there?
Jane: Those are the major points, but I would also like to point out that you also need to look at the information about the prover. An example is typically a prover volume is determined by either a water draw or a gravimetric test. You get what that volume is between the switches on the prover.
I have been to provings before where the data for the prover was data for an incorrect prover. You have to make sure that things match up, too. That’s a one-time type thing.
Russel: It’s an extremely good point, because if I’m running a prover, it’s one thing. If I’m witnessing a prove on behalf of a company and I’ve got a third-party prover coming through, I got to be very careful about making sure that all the i’s are dotted and t’s are crossed and that I’m getting good numbers.
Jane: Exactly. There’s things that can affect the volume of the prover, which is why they have to be calibrated on a frequency, as well. I’ve encountered provers that had significant damage to the internal coding, or that it didn’t have coding and had eroded.
I have encountered provings where we were having trouble with repeatability and the sphere had failed. There’s numerous things like that that can also impact the proving, as well.
Russel: I guess that’s the advantage of having done all this for a long time, you get to see a lot of the things that can go wrong.
Russel: [laughs] It shouldn’t be so funny to me, but it is. I tell people frequently, “You know what experience is? Experience is what you get when you didn’t get what you wanted.”
Jane: That’s somewhat true.
Russel: You know what wisdom is? Wisdom is learning the right lesson from the experience. [laughs]
Jane: That’s a good definition, too. I like that.
Russel: Jane, I sure appreciate you taking the time to be with us and to give us some details and education about meter proving and such. If somebody’s interested in getting in touch with you and to talk to you about maybe getting some help with their measurement, either from a training perspective or to get some expert help, how would somebody best get in touch with you?
Jane: There’s two ways. My email is firstname.lastname@example.org or call me at 817-271-9133.
Russel: I would certainly encourage you to. If you feel like you need somebody to visit with that offers some assistance, I think Jane is a great person to reach out to. I certainly encourage you to do that.
Again, Jane, thanks for being a guest. Hopefully, we’ll be able to have you back and we’ll talk about some other domain. Maybe we’ll talk about what are all the things that can go wrong in measurement. That one will take up a lot of time.
Jane: [laughs] That might take a lifetime.
Russel: [laughs] Exactly. Thanks again, Jane.
Jane: Thank you, Russel.
Russel: I hope you enjoyed this week’s episode of the Pipeliners Podcast. I enjoyed the opportunity to talk to Jane and I learned a bit more about meter proving. Hopefully, you did, as well.
Just a reminder before you go, you should register to win our customized Pipeliners Podcast YETI tumbler. Simply visit pipelinerspodcast.com/win to enter yourself in the drawing.
If you have ideas, questions, or topics that you’d be interested in hearing about on this podcast, please let us know on the Contact Us page at pipelinerspodcast.com, or you can reach out directly to me on LinkedIn. My name is Russel Treat, that’s R-U-S-S-E-L, just one “l” in Russel, and my last name is Treat, just like it sounds, T-R-E-A-T.
Russel: Thanks for listening and I’ll talk to you next week.
Transcription by CastingWords