E&P players have focused on exploiting maturing basins in recent years, as lower commodity prices favor existing operations and known petroleum systems that may offer lower-cost production and application of innovative practices and new technologies. Maturing basins in many cases offer significant upside in conventional and unconventional resource exploitation and exploration. Such basins can provide a mix of investment opportunities to suit all, with smaller, short-cycle and brownfield investments and traditional greenfield projects. What are the key technical or commercial ingredients for success in developing maturing basins? What parameters drive the attractiveness of maturing basins within the portfolio of a major E&P company or for a new entrant, in a price and carbon-constrained world? How best to innovate to exploit the basins and fields as they start to decline? Does that phase require new ownership and operating practices?