Hogan's goals underlined the home side's superiority and moved Keith Hill's men five points clear of the League Two play-off places.
The U's missed the first clear chance in the 21st minute. John Mullins met Danny Rose's back-post cross and saw his initial effort blocked by Josh Lillis' legs and when the ball rebounded back to him, he screwed a shot wide of the unguarded goal from four yards.
The visitors paid for that wasted chance when Jamie Allen lifted a cross to the back post for Peter Vincenti and his header was forced over the line by Hogan on the stroke of half-time.
Four minutes into the second half Hogan netted his second when he collected the ball 40 yards from goal and drifted past three defenders to go one-on-one with Oxford goalkeeper Ryan Clarke. Hogan saw his first effort blocked but seized on the rebound to double his tally.
Hogan's hat-trick came in the 62nd minute when he scuffed Michael Rose's free-kick into the corner of the net to take his tally to the season to 19 goals.