I started playing with this mod recently and noticed something odd. The Mineral Liquid and Oil Sludge fluids don't show up in the Fluids menu. Instead, they show up in the Intermediaries menu, where ores raw materials live. I believe that - by the game's own structure and nomenclature - anything that's a Fluid should be under Fluids, the same as Crude Oil, Petroleum and others such. Additionally, this causes an odd issue with Helmod, which attempts to measure Mineral Liquid by belt capacity, rather than pipe capacity.

I was curious as to why this is, so I had a look at the Lua class files. Now, I'm not a mod-maker or a Lua programmer so I'm not really sure what I'm talking about here, but... There's an odd definition for both fluid types - subgroup = "science-pack". I believe this may be responsible for filing the Fluids under Intermediary, since that's where the various Science Packs live. What is this setting for, and could that be the culprit?

1. Mineral Liquid and Oil Sludge are Intermediate Products ( Intermediaries menu is not exclusive for Ores. The Vanilla Game has no Fluid tab, Gas and Liquids are in the Intermediaries Tab.
2. Helmod works correct for me. ( I play on 1.1.3 )

My initial post was confusing, so please let me explain. There are two issues that I'm having, but yes, you are correct: your mod adds intermediary fluids which show up in the "Intermediate products" in recipe inventories (my inventory, assembler inventory, chemical plant inventory, etc). This is as it should be and is the case for Vanilla fluids. However:

1. When looking at a Signal inventory, Fluids show up in their own separate Fluids tab. Say I want to compare the amount of fluid in a tank with a number. For Vanilla Fluids (Water, Crude/Light/Heavy Oil, Steam, Petroleum, Acid, Lube), I need to go to the Fluids tab to set them as a signal. For Mineral Liquid and Oil Sludge, I need to go to the Intermediate products tab, which is not where the rest of the fluids are. This freaked me out initially, because I couldn't find either of the fluids and thought I was facing a technical issue.

2. The recipe for Crude Oil creation ("buy-oil" I believe) shows up in the Fluids tab in my inventory (and in the Chemical Plant inventory), and is in fact the only item in that entire tab. That seems like something which should show up under Intermediate products in recipe inventories.

In short: Mineral Liquid and Oil Sludge recipes show up under Intermediate products properly, but the the actual Mineral Liquid and Oil Sludge fluid signals should show up under Fluids. Inversely, the "buy-oil" recipe should show up under Intermediate. I don't know if you have any fine control over this. Just waned to clarify what I meant.

As a follow-up, I played around with your mod files a bit, to see if I could reclassify some of the items myself. So far, I've successfully reclassified your "buy-oil" recipe and caused it to show up in Intermediate Products with the rest of the fluids. To do this, I added a subgroup definition to it:

subgroup = "fluid-recipes",

I'm not sure what the engine classes recipes by (possibly results), but it was classing your Oil recipe as a Fluid. Doing the above reclassified it as an intermediate recipe. I'm still working on reclassifying the fluids themselves, and will update this post if I have more information.

edit
Well, that's as far as I go. I can see why you tagged your Fluids with the the science pack subcategory. Without that, the recipes show up in the Fluids tab for reasons I can't fully understand. I tried tagging them with subgroup = "intermediate-product" but that didn't seem to accomplish anything. Despite the recipe being tagged as an intermediate product, it doesn't show up in the Intermediate Products tab as long as it's a category = "crafting-with-fluid", which it has to be in order to be crafter in Fabricators. For whatever reason, the game insists on classing recipes which take only fluid and produce only solid as Fluid. Or some such, anyway.

Apologies for making a big deal out of it.