BISMARCK, N.D. — The denial of the Keystone XL pipeline affected how the company building the Dakota Access pipeline executed its strategy, one of its engineering executives said this week at an oil conference.Joey Mahmoud, senior vice president of engineering for parent company Energy Transfer Partners, said the $3.78 billion interstate pipeline project now in the early stages of construction emphasized using labor unions and avoiding federal lands as the company watched the Keystone XL fail to get built.Mahmoud said 96 percent of the 1,168-mile, 450,000-barrel-a-day crude oil pipeline’s route from Stanley, N.D., to Patoka, Ill., is set and the project should be completed by the end of the year.