By Adam Wilmoth Energy Editor awilmoth@oklahoman.comExtra attention paid to the link between saltwater disposal wells and the state's earthquakes has driven up costs and created headaches for oil and natural gas producers throughout much of the state, but it also has created opportunities for other companies. Earthquake research and regulations have focused on saltwater disposal wells that take high volumes of water produced along with oil and pump them into the Arbuckle formation, which is the deepest sedimentary rock layer underlying much of Oklahoma. The layer had been a favorite for both industry and regulators for more than 60 years because it was well below freshwater aquifers and oil-producing rock and because it absorbed water easily. Now, however, the rock layer has fallen out of favor. Researchers and regulators say the problem over the past few years appears to be the high volumes and pressures at which the water has been pumped underground. Oklahoma Corporation Commission regulations have shut in or reduced volumes on hundreds of disposal wells throughout the state.Read more on NewsOK.com