GEOMETRICAL CHARACTERISTICS OF A TURBIDITE SYSTEM: A GEOSTATISTICAL APPROACH

A key aspect of evaluating turbidite reservoirs is the 3D geometry and distribution of sedimentary facies and the corresponding reservoir properties such as porosity and permeability. Many different factors are under consideration in the building of an initial conceptual geometry such as slope and bathymetric features, hierarchical stacking of elements, facies distribution, and sedimentary loading of the system. This study utilizes data collected from a literature review of turbidite systems to populate conceptual geometrical and facies models. The geometries of turbidite units (e.g., lobes) are constructed in Petrel and the distribution of units are stochastically varied based on the depositional area (e.g., confined and unconfined depositional areas). The degree of turbidite compensational stacking (e.g., lateral stacking) and the degree of lobe progradation is governed by the confinement of the depositional area. Facies models are created in Petrel to reflect the hierarchy of turbidite systems and are governed by the sand / shale content. The properties of the facies are varied deterministically and stochastically using literature-sourced data and populated based on model facies distribution. The distribution of porosity and permeability is closely examined to determine their effect on the pore pressure distribution within the turbidite reservoir, and can show how areas of overpressure can result in a turbidite system based on property variation.