In situ calculation of average effective shale permeability



Journal Title

Journal ISSN

Volume Title



For the past several years attention has been drawn to a newly recognized factor in petroleum reservoir mechanics-- shale water influx. Numerous cases have been noted by recent observers which strongly indicate significant invasion of volumetric reservoirs by what is thought to be shale water. It is assumed that shale water influx is Darcian flow, hence dependent on shale permeability. Search of the literature revealed very little shale permeability data. A method to estimate shale permeability in situ for volumetric reservoirs was devised by utilizing a computer solution of the unsteadystate fluid flow equation (hydraulic diffusivity equation) for one dimension. Two computer programs were written and provide for: 1) computation of shale water influx given a pressure-production history and a constant shale permeability; and for 2) calculation of a variable average effective shale permeability from pressure-production history and independently determined shale water influx. [...]