Liquids, like water, are great examples of uncountable nouns that can also be counted when you quantify them. 'Water' can mean all the water in the world, or it can just mean the water in your glass.
Consider the following:
- I didn't know you drank a beer.
- I didn't know you drank beer.
The first refers to a specific beer, so it must also be a specific occasion where someone drank a beer. The second just means beer in general, so it must be an expression of surprise that the other person drinks beer at all.
It's really no different with 'analysis'. Used as a non-countable noun, it means analysis in general - that is the process of analysis. But when you use it with an article then it must be a specific analysis.
Interestingly, your example uses the word 'consulting', which can also be countable or non-countable. 'Consultation' refers to the act of speaking in general, whereas a consultation is a specific instance of it. You are speaking about specific consulting projects, so it makes sense that any analysis attached to them would be countable, too.
- Consultation projects do not require a painstaking analysis.
If you were speaking more generally, you might say:
- Consultation does not require painstaking analysis.