Drilling curbs by oil producers in the largest U.S. shale field will continue until transport bottlenecks ease and investors stop punishing companies for increasing capital spending, executives at an energy conference said on Thursday.  The price of crude in the Permian Basin of West Texas and New Mexico fell sharply last year, selling as much as $18 below U.S. benchmark prices, as a lack of pipeline capacity landlocked some oil output and as investors pushed producers to reduce spending and boost shareholder returns. On Thursday, the regional price of crude was at a $1.10 a barrel premium to U.S. crude futures, the strongest in more than a year as companies including Parsley Energy, Pioneer Natural Resources, Goodrich Petroleum Corp have pared their exploration budgets, […]