before everyone gets all depressed, please understand that...

before everyone gets all depressed, please understand that it's not uncommon for oil/mud emulsions when flow testing wells. it absolutely happens. I haven't heard any mention of formation water so assume it's not part of the emulsion mix.

the drilling mud itself would be a complex mixture of barite, caustic Soda, defoamers, potassium chloride, bentonite, polyacrylamides, etc and the chemical mix selected is based on the understanding and ASSUMPTIONS of the geological formation, pressure, temperature, etc

So it's not uncommon to happen, there is a degree of inaccuracy in terms of ideal drilling mud chemistry and should it happen... there are remedies/solutions which the industry has developed using chemical agent demulsifiers.

please DYOR... I encourage all to learn about the sector you've invested in. lots of resources available. don't rely on HC only. there are a bunch of knowledgeable posters - Trust but Verify.