Patent ID: 6389361
Filing Date: 2002-05-14
Classification: G01V

Abstract:
A method for measuring and enhancing the ambient permeability fields of a fluid reservoir without appreciably altering the ambient permeability field, comprising the steps of:establishing a network of earthquake recording devices for acquiring, resolving, analyzing and monitoring earthquake waves, said network being of a predetermined size and location in and around said reservoir; causing a fluid pressure wave to be generated by operation of at least one fluid injection site in said reservoir, said fluid pressure wave causing failure to occur on ambient fractures that form an ambient permeability field associated with said at least one injection site, with said failure enhancing permeability on said ambient fractures, and with said failure generating earthquake seismic waves acquired by said network; using said network to image at least one conidial volume of ambient fractures generating said earthquake seismic waves for said at least one injection site, with said at least one conidial volume having an acute apical angle and a cone axis that passes through said at least one injection site, said conidial volume showing a temporal migration of earthquakes away from said at least one injection site, said cone axis being a maximum compressive stress direction of an ambient stress field in the vicinity of said at least one injection site; and using said at least one conidial volume and said showing of said temporal migration of said earthquakes away from said at least one injection site to identify said ambient fractures as those that comprise said ambient permeability field to which said at least one injection site is connected; whereby said ambient permeability field of a said fluid reservoir is both measured and enhanced in time and space.