 From a geologic perspective, what is the best depositional setting for shale gas to form? Basins form as catchments for sediments and these sediments can be carbonates, they can be sandstones, they can be shale and shale often consists of a combination of carbonates plus plastic rocks and the important thing about shales is that that most shales are non-organic and so there is a very special set of conditions on the ocean floor that are necessary to preserve organic matter which then can be captured in shale and those conditions require the absence of oxygen and and the absence of oxygen happens occasionally in enclosed basins which means that that water doesn't flow in and out of those basins freely and the basins are deep enough so that windblown circulation of water does not take place down in the deeper portions of the basins while organic matter is being carried into the basin along with sediments and the organic matter and sediments are buried over time in an in an in organic in an in an environment that is is without oxygen and in effect then the organic matter is preserved because without oxygen the bacteria that would otherwise reduce the organic matter Can't attack the organic matter which happens in most ocean basins