Daqing is usually completely missed by travellers to Heilongjiang province. That should be reason enough to visit in my book. I don’t think it is even mentioned in Lonely Planet, which seems to get everywhere and list everything.
I only really knew about it because when I did my TESOL course in Harbin, some people had previously gotten teaching jobs in Daqing after finishing the course.
It is only a couple of hours from Harbin and is totally worth the trip.