Kinda, if you're the oil industry you are allowed to invest in Venezuela. But in a deep irony it seems like the oil industry is mostly uninterested.
I kinda wonder if the White House has just forgotten about Venezuela - there's not any clear reason they are still under general sanctions.
The reason for the reticence by the oil industry may well relate to the nature of the deposits. Although Venezuela has huge reserves they are tar sands[1] which are extremely expensive, industrially intensive and environmentally destructive to extract. Most oil companies don't have that much experience in extracting tar sands also. And that's not to mention the optics and political backdrop. Oil companies are used to having their pipelines and equipment sabotaged (eg in Nigeria oil theft from pipelines is endemic) and having to fluff up despots etc to get access to natural resourses but I could see why they might be much more keen on working on projects in conventional oil fields that are more in their wheelhouse, are easier and have better marginal returns.
[1] as I understand it, tar sands are literally what they sound like - the oil has seeped up to the surface, which is essentially a sandy, oily quagmire. https://www.alamy.com/a-hand-full-of-tar-sand-the-tar-sands-...