Pictures shot in fractured wells show how a high-pressure slurry of water and sand carves up the perforations. The technical challenges imposed by tight well spacing and fracture interactions have become a focal point of recent earnings calls between investors and the leaders of several shale producers. The picture of the future is becoming clearer, and there are fewer oil wells in it. Another reminder that it costs more to coax the same amount of oil from new wells as for older wells nearby, with a closer look at the big plays and how the wells are completed. Noble’s first row of wells in its massive Mustang project is helping increase the operator’s DJ Basin output, and similar results are soon expected in the Delaware Basin.