Venezuela is an example of a petrostate, where the government is highly dependent on fossil fuel income.
Petrostates are vulnerable to what economists call Dutch disease, in which a government develops an unhealthy dependence on natural resource exports to the detriment of other sectors.
The oil price plunge from more than $100 per barrel in 2014 to under $30 per barrel in early 2016 sent Venezuela into an economic and political spiral, and despite rising prices since then, conditions remain bleak.
(Source: Council of Foreign Relations)
So yeah, socialism didn’t kill the Venezuelan economy, over-reliance on fossil fuel did.