I'm not sure specifically as there could be many graphic novels related to Eugene Porter. It might be about his adventures, his character development, or the world he exists in within the story's context.
The Time Porter of Tang was a fantasy web novel by Xiang Hai. The story was about Xue Xiang, a top graduate from the United States in 2057, who attempted suicide due to a failed investment and traveled to the Tang Dynasty. In the Great Tang, he had discovered that he had the ability to travel back and forth through time and space, and he had become sworn brothers with Werewolf Liang Tian. He had even developed feelings for the princess because of the Joust For A Spouse. The novel was full of ups and downs and thrilling plots, allowing the readers to appreciate the fantasy world of the Tang Dynasty.
It's hard to say for sure. Sometimes stories are a blend of truth and imagination. You'd have to look into the background and author's statements to determine if The Porter has any basis in reality.