- [Instructor] So we setup this comparison study between the two vendors, and both vendors are very happy to participate in this. Vendor A, Vendor B again. So we designed this to be, to go through both Dean-Stark and Retort analysis at both vendors, and try and give a simple procedure to follow so that everyone could follow the same procedure and see if you come back with the same results, and then you start getting into is there an analytical difference, is it a procedural difference, what causes that 20 to 30% separation in just total porosity? And that's before we even get into the discussion around separating that porosity into fluid components and fluid saturations. So at Vendor A, we did Dean-Stark, Retort, and we also did a full plug routine core analysis, which I'm gonna touch on briefly towards the end of the presentation, but again, it's not a main focus. I think the main focus of a lot of unconventionals now is crush analysis and that's the bulk of what I'll speak about today. And then in Vendor B, we did not do the routine plug, but again, we did Dean-Stark, the Retort analysis. We also did TOC there so we could get an idea of, again, the other components that I alluded to earlier. So we did TOC there and then we did XRD at a third vendor just to be neutral and share it between the vendors. So that way we kind of have an idea of the mineral makeup of the rock, try and span some mineral variability along with the TOC and then set up these different experiments. This is using fresh, wax-preserved core from the Permian Basin, so this is Bone Spring rock. This is fresh core, it's all been preserved. It's been handled well, and I'll touch on the handling topics a little bit just to pose a few questions. And we also took a single puck here, so we basically took a single puck, homogenized the whole thing and tried to get everything, so that the vendors are ideally starting with the same rock. So sample preparation, as I mentioned, it's all used in preserved rock. We take the waxed section, so this is waxed at the well site, taken to the lab, kept in wax at the lab, removed, slabbed, and you know it's chilled between any of these settings, so ideally minimizing fluid loss. We remove the wax section, cut from the wax, unwrap this preserved core from the, you know, the thermal wrap. We cut a significant puck from this. So puck is maybe not the most professional term, but it's just a significant chunk of rock we're taking, so that we can homogenize everything and get a representative sample to split between the two vendors. We also did the bulk density measurements, so we weighed that puck, bulk density, you know, do an immersion measurement on that puck, so we use a representative bulk density for the entire sample. We then crush the puck, and sieve it, so we sieve it to 12/20 mesh in this case, run it through a sample splitter, we ran it through the sample splitter, you know ten times under shell supervision to make sure, you know, that everything is fair and we're really trying to create as fair a comparison study as you possible can here. Then we send the splits, double-bag each sample. Make sure we weigh everything, so we're tracking the weights the whole way. It's really just trying to apply as much scientific method as you can to something that's not fully scientific all the time, and also chill these samples during shipment. So now I have wait, so what uncertainties have I already introduced here? And this is a topic, you know, people are probably reading through the procedure we've already set up on the handling side and there's probably people that say, hey you're not thinking about this, or did you think about this, et cetera, et cetera, et cetera? So just some things to think about, and I'm not gonna provide necessarily answers here, except for the last question. And maybe that's an opinion more than an answer, but just some things to think about as you consider a core analysis program, core handling and how you set things up before you even get into testing the rocks. So the first thing is the fluid losses from the well site to the lab, so I've already touched on fluid losses fromto the surface, and then the transportation of the core is another uncertainty you're introducing. Do you wax preserve on site? It's a very time-consuming process. Or do you just shim the core and, you know, end cap it and ship it back to the lab that way? And do you chill it? Do you ship it in the back of a pick-up truck? There's just things to think about in how you transport and preserve the core that you've spent a lot of money and time to acquire. Similarly, how long was the core exposed during slabbing? So you get the lab, whether it's waxed or shimmed, and you extrude it and then you're gonna slab for your library slab and you're gonna have your butt section that you can go sample. How long are you exposing it? Are you leaving it overnight? Is there a significant handling error that you're introducing? And then you take this and you take your gloves and then we're crushing them here for unconventional analysis. So we're crushing these and if folks have watched this crushing process happen, it is obviously a very mechanical process, so you're dropping rocks and crushing them, and there's a lot of dust that sprays around, and do you create fluid loss during that process? Or is that just another thing that's just part of the procedure that you cannot avoid? And then transportation between the vendors in this case, so I'm crushing, homogenizing, and then splitting between Vendor A and Vendor B. Do I create a transportation issue? How long does it sit in the truck? Does it chill during shipment? Is it 100 degree outside? It is humid? Just things to think about, and I can pose so many questions, and you can always poke holes in things. It's just important to think about these and how you introduce any uncertainty to your rock analysis. And then finally, and this is a question I've had quite a bit so I wanted to throw this in here, in terms of sieving. So sieving is one of these topics that's pretty debated in crushed core analysis. Do you actually sieve? Do you sieve to a certain mesh size? And do the mesh sizes mean anything? And what I wanted to share here is just an example of some testing we've done, so what you're looking at is this is the core's XRD basically, and this is for four different mesh sizes on a single sample. So we have 12 to 20 mesh, 20 to 35, less than 35 and then greater than 12. You've got four different mesh sizes, and what you can't see on this plot, this is actually four different curves stacked on top of each other, and you don't see any separation between the curves, so it just looks like a single curve. What I'm trying to illustrate here is I don't think that the sieving actually causes any separation in the samples. I think they all stack very nicely, and so it's unlikely that sieving actually effects the results either positively or negatively. You're probably getting a fair distribution of the rock whether you're sieved or unsieved. So just a little bit of background on the two procedures here, both the Dean-Stark and the Retort. The first one is the crushed Dean-Stark extraction. This is obviously work that was paid by Mr. Luffel and the Gas Research Institute. They originally did some of this crush analysis and published the technique, and I have some of their references down here for those who are either not familiar or just want a refresh or would like to go read through this. These are great papers, really great information. Another shout-out here to Pat Lasswell. It's another reference I have down here, and he have a great presentation. This is back in 2011, just a great overview of these procedures and unconventionals, which I think is a great read-through for anybody to really get up to speed for those who are not familiar with unconventional core analysis. To go through the procedure, we weigh the samples in the bags when they're received by the vendor, confirm there was no mass loss during transportation, and just minimize that uncertainty. Then do an as-received grain volume measurement using helium bohr symmetry, then we start the toluene extraction, extract until stability, then do the chloroform/methanol extraction. Dry that to weight stability. Weigh the samples, and perform the post-extraction grain volume bohr symmetry as well. So a typical Dean-Stark procedure using crushed, nothing particularly unusual here. In terms of the Retort, it's similar to the standard and the reference I've used here is this is a great overview from, originally, terra technofrom Handwerger where they go through this Retort procedure, obviously Retort's been around for a very, very, very long time in the industry, but this is just a good summary of how it's been applied to unconventional rocks and it's very similar procedure to what we followed here. So you weigh the samples in the bag again, confirm you still have a representative sample. Do your as-received grain volume measurement, which is where you begin before you start sending your volume back to that. And Retort to 105C and then we let the labs, the labs are very confidential, actually, about how long they, how quickly they ramp the temperature, how long they hold it there so we let them hold that and use that lab's specific protocol. Do the same, and then Retort to 300C, the same thing. Do another post-Retort grain volume measurement using helium, so that's basically you're recording your weights and volumes but you can also check this using bohr symmetry. Then there's another solvent extraction on this, it's similar to the final Dean-Stark extraction, using chloroform/methanol. Dry that to weight stability, and then weigh the samples and perform another post grain volume measurement. In the last three steps here, I'll just mention briefly a design to address the problem of any bitumen that's left in the rock, which we don't think would be extracted from a 300C Retort, so by doing this chloroform extraction, basically, theoretically, getting a direct measurement of the bitumen correction. So if you have any bitumen in your rock, this'll get you a way to measure it. So back to the samples, specifically here we did 10 different plugs as I mentioned, so you take these 10 plugs homogenized, and this is the mineralogy, so I want to highlight this just to show the variability in the samples, and we tried to do this so that you do a trend comparison. You don't just do a sample-to-sample comparison. So you don't just say there's a 10% porosity and this is 10.1. You say, okay does the bulk density and the porosity line up? Or do I see separations and trends similar to the, you know, one of the first slides I showed? So from an XRD perspective, this is Bone Spring, so we did predominately, you know, silicate-based rock, quartz-based rock, typically 60%-ish quartz. In the samples, the majority of these are cleaner sands. We did do three organic-rich samples, and you can see I have these identified as higher TOC on the bottom right-hand of the plot. These are more organic-rich, and then a single sample in the five in the middle of the plot is a single tight piece of rock, so more dolomitic. It's actually, I'm showing carbon attraction there, but it's really a dolomitic piece of rock. So you get a span of porosity, that was the intention. Also just a note, quickly, the TOC ranges, here even though they say higher TOC samples, the TOC numbers are pretty low in general. So this scale is zero to four, these higher TOC samples are around three weight percent.