Not an expert, but love solving new problems (habit of being an engineer)- I did some quick research and on page 4 of
http://www.lancasterpump.com/documents/jetpumps2.pdf under paragraph "Attach suction pipe to well casing adapter" they repeatedly mention "(offset) well casing adapters" I found a variety of these casing adapter fittings just from google search, but they seem to each be proprietary to the particular pump. I can't quite read the text on the side of the case in your pics, but that might provide you further information?
But one piece of professional advice I
can give you is replace the fitting- NO STICK WELDER!
Or at least use a MIG 