Drysdale moves into contention in the Masters.
Drysdale carded a second consecutive 67 at Jaypee Greens Golf Club for a halfway total of 10 under par that left him just two shots behind clubhouse leaders Chapchai Nirat of Thailand and China's Liang Wenchong.
Overnight leader Chinnarat Phadungsil, who had been five clear of the field after a stunning 61, fared 13 shots worse with a 74 that left him one behind Drysdale on nine under.
"The golf course gives you a lot of opportunities for birdies, the par fives are all in reach so it's been a steady two days," said Drysdale, who had five birdies and no bogeys.
"I got through the turn at nine under and expected to be four or five behind at that point after the lad shooting 11 under, but saw he had come back to the field so that was a pleasant surprise.
"In the pro-am on Wednesday I was thinking it would be somewhere in the 20s under par that would win this week, especially if the weather stays like this and the wind doesn't get up. After someone shoots 11 under you are just trying to shoot as many birdies as you can.
"When I first saw the course I thought it was a bit of a bomber's paradise, it looks wide from the tee but actually it's not that wide and it's quite a good design, quite narrow which suits me a little bit."
As for the trouble sleeping - hardly ideal before a tee-time of 7.10am local time yesterday morning - Drysdale added: "I only got a couple of hours sleep, which is strange because I was in Dubai for a couple of days so I should be more than used to the time change."