Designing a valid geological model of a medium by tailoring its detail degree
Degree of detail and validity are the closely related characteristics of geological models. Either accuracy, or an error of parameters included into a geological model can be used as criteria of validity for a geological model in case they were measured at fixed detail degree of this model (distribution of layer thicknesses in respect to models of layers, and distribution of sizes of the identified areal anomalies in respect to maps).To fulfil particular interpretation tasks successfully (namely: determination of leads for geological prospecting and identification of promising objects, calculation of hydrocarbon reserves, reservoir engineering, etc.) one should find optimal ratio between detail degree and validity of a model. First of all, detail particularity of a model is determined by specific structural features of a studied geological section, density of logging per unit area, design of survey (e.g., size of a bin during 3D seismic measurements), spectrum and resolution of survey data (e.g., high- frequency geophysical well logging, mid-frequency seismic and low-frequency gravity and magnetic surveys), and level of interference violating geological-geophysical data.Using test materials author substantiates necessity to regulate/optimize detail degree of models in order to get valid characteristics of media. He concludes that there is a universal dependency between validity of predicted parameters and a level of approximation of a real medium, i.e. between the detail degree of a model, a level of noises and the density of observations.