Outcrop data-base for the geological characterization of fluvial reservoirs: an example from distal fluvial fan deposits in the Loranca Basin, Spain

Abstract

Abstract Sedimentological data for stochastic modelling purposes consist both of qualitative and of ‘hard’ numerical data from reservoir-equivalent outcrops. Data requirements are defined prior to collection of the actual field data-base, and standard procedures for the collection and classification of these data are established. Required data are on individual sandbodies, such as genetic type, geometry, palaeoflow and size; and on the 2D and 3D sedimentary architecture (spatial distribution, interconnectedness). Validity of the data-requirement definition, and feasibility of data acquisition for specific stochastic modelling purposes, were tested in reservoir-equivalent outcrops of distal fluvial fan deposits of Tertiary age in the Loranca Basin in central Spain. Several sandbody genetic types were recognized: meander-loop deposits, channel-fill deposits, crevasse-channel and crevasse-splay deposits and deltaic deposits. Statistical processing of the numerical outcrop data showed that meander-loop deposits are thicker, wider and present higher linearinterconnectedness values than channel-fill deposits.