Metodologia para geração de modelo 3D fotorrealista de testemunhos de sondagem utilizando fotogrametria SFM/MVS

Abstract

In the last two decades, the Geoscience field is currently undergoing a digital revolution thanks to technological improvements on processing hardware and remote sensing equipment. One of the techniques that propelled this revolution is SfM/MVS photogrammetry, capable of creating digital 3D model of real world objects and surfaces based on the capture of highly overlapping photographs and the assistance of computer vision algorithms. These technological boosts helped to promote the generation of Digital Outcrop Models (DOM) in geological studies, that being 3D realistic digital representations of rocky structures on the surface of the Earth, which are essential for studies like reservoir characterization and geological modelling, very common activities in the Oil & Gas industry. This type of data allows geological studies to be also conducted in a digital environment, a task that were so far only possible in loco. Besides that, it also brings the possibility of integration between several multidisciplinary and multiscale data sources. Associated to the study of outcrops, it is also common the study of drill cores, i.e. cylindrical rock samples recovered by well-drilling techniques, being capable of sampling an extensive vertical profile of the subsurface. Just like the 3D modelling of outcrops, the digitization of drill cores could bring similar benefits, allowing data analyses and interpretation on a digital environment. When it comes to rock sample documentation, the 3D digitization of drill cores can also brings the advantage of preserving its integrity, since destructive laboratorial analyses are common. However, no published work so far has been found that aims for the 3D documentation of an entire drill core, having a shortage of accessible and portable alternatives in the market for this type of activity. Having all that in mind, the current work developed a workflow that uses SfM/MVS photogrammetry for the generation of a realistic digital model of an entire drill core. The methodology focuses on the optimization of steps of the acquisition and processing workflow to make this task feasible, since drill cores are extensive rock samples, with dozens or even hundreds of meters. The technique validation was conducted using a questionnaire answered by geologists, where 78% of the 18 participants agreed that the Drill Core 3D Model is capable of well represent relevant geologic characteristics of the physical drill core, with a more efficient and realistic product when compared to traditional techniques that are currently used. With that, it is expected to be able to promote digital drill core sharing at worldwide level and enrich geological studies through virtual integration with other sources of digital models, like DOM for example, working also as structure for multidisciplinary dataset union.