The U.S. has more than doubled its crude output over the last decade. Much of the growth is due to the Permian Basin of West Texas and New Mexico. WSJ traces the hotspot of North America’s crude oil boom, with a look at challenges that producers in the region face. As the American shale-drilling industry slowly recovers from a historic crash in oil prices, it is poised to grow in fewer places than before. Even before U.S. benchmark prices fell into negative territory in April, investment in once-booming oil fields in North Dakota and South Texas was waning while producers drilled through many of their sweetest spots. Now,…