There's a picture of the lobby
here which appears to be a render so the comment about 'virtual hotels' may not be too wide of the mark!
The hotel is presumably still a 'work in progress', though odd that so few details of it exist online
EDIT: Sheraton Mianyang would seem to be aither a) a refurb and re-brand of the Fulejiuzhou International Hotel (sometimes spelt Fule Jiuzhou) or b) a new build in the Xianhai Leisure Resort zone on the edge of Chengkang Reservoir a few miles further out of town.
The limited sources I've identified give conflicting info. This 'Green building certification' resource
Sheraton Mianyang :: Green Building Information Gateway shows the address as 1 Furong Road, Youxian District, Mianyang which would appear to be the same address as the Fule Jiuzhou Hotel, whereas postings on a a number of job sites, e.g.
https://www.hozpitality.com/marriott...ccounting.html give the address as Lot D Xianhaishuili Scenic Area, Mianyang, which Google Maps says is up by the reservoir.
Elsewhere I've found reference to a Q2/2121 opening, so presumably if still on schedule it will appear on Marriott inventory quite soon.