VERTICAL FLOW AND EARLY ALERT IN LOW HYDRAULIC CONDUCTIVITY MEDIA

Deep oil and gas recovery by means of water-based fluid injection into traditional low hydraulic conductivity shale strata provides unique economic opportunities. Low hydraulic conductivity proposes natural groundwater flow conditions related to water movement in tens of thousands years along the strata. This movement might speed up within this strata in several orders of magnitude under human intervention, ie. Hydraulic fracturing. Therefore, access to good quality water in the northern-eastern semiarid region of Mexico and south-eastern USA requires involving groundwater protection measures, directing the concerns of residents and developers. Experience on fractured hydrogeology in Mexico has increased recently under the basis of the Tóthian flow systems theory. The response of groundwater flow from kilometers distance below the ground may be traced at surface within minutes after pumping started in an abstraction well. This response usually termed up-conning, might deteriorate obtained water quality by ascending deep flow to the extraction level; thus, the concept of Early Alert needs to be developed according to the Hydrogeological nature of the geological media. Due to the nature of the flow to be involved geochemical tools could prove adequate for a sound Early Alert definition, from which other readily and simple tools for well users could be formulated.