The invention is related to non-linear, paraffin-soluble olefin/carbon monoxide and olefin/acetylene/carbon monoxide copolymers. The invention is also related to a method for preparing olefin/carbon monoxide copolymers by heating a feed of at least one olefin, carbon monoxide, carbon dioxide, hydrogen, and methane in the presence of a free radical polymerization initiator. More particularly, the feed comprises at least one olefin, the total olefin amount ranging from about 5 to about 40 mole %, carbon monoxide in an amount ranging from about 1 to about 40 mole %, hydrogen in an amount ranging from about 4 to about 55 mole %, carbon dioxide in an amount ranging from about 3 to about 10 mole %, and methane in an amount ranging from about 4 to about 85 mole %. The feed may also include acetylene in an amount ranging up to about mole %.