HOUSTON, May 20 (Reuters) - Crude oil tanker Dubai Angel on Monday moored at the Westridge Marine Terminal in Vancouver, preparing to load the first cargo of crude oil from the recently expanded Trans Mountain pipeline (TMX), ship tracking data showed.

Chartered by Canadian oil producer Suncor Energy, the Marshall Islands-flagged vessel was expected to load about 550,000 barrels of Access Western Blend (AWB) for delivery to China, ship tracking data on Kpler showed.

Trans Mountain said it expects to load the first vessel with oil from the expanded pipeline later this month.

TMX, which will ship an additional 590,000 barrels per day (bpd) to Canada's Pacific coast from Alberta, began commercial operations this month after years of regulatory delays and construction setbacks.

Flows on the pipeline and loadings from the Westridge Marine Terminal are being closely monitored by traders and shippers as the expansion gives Canadian producers more access to U.S. West Coast and Asian markets. Tightening supply of heavy crude has made Canadian oil more attractive to buyers around the world.

However, logistical constraints at the Port of Vancouver could limit the number of shipments, traders and shipping sources have said.

The Port of Vancouver and Suncor did not immediately reply to a requests for comments.

Suncor said this month that it was leasing Aframax vessels in the Pacific and selling direct to customers, seeking to maximize profits on oil being shipped on TMX. (Reporting by Arathy Somasekhar in Houston, Florence Tan in Singapore Editing by Marguerita Choy)