Upvote:-2
Here's a pretty good scholarly article detailing exactly the answers you are looking for including not just how much they exported but whom they traded with and what they received in return.
Upvote:4
A big picture is summarized in this table. More detailed data are here; the relevant data are at pages 129 for the years 1930-1934 and 163 for the years 1935-1939; items 21 (Нефть сырая, crude oil) and 22 (Нефтепродукты, refined products), among them (numbers below refer to table rows):
The first column is Units (metric tons). Two columns for each year are Amount and Total Price in thousands of roubles.
The (international trade) rouble in thirties was bound to US dollar. See here for the exchange rates. I still don't know how the payments were arranged.
(Edited to include a screen shot)