Um fluxo de trabalho de estimativa de falhas sutis de alta resolução: um estudo de caso no campo petrolífero de Marlim, Brasil

Abstract

The study of deep parts of the Earth, usually inaccessible to direct analysis, can be accomplished through geophysical observations. Fault and fracture mapping is a topic of enormous relevance in reservoir characterization. The identification of subtle faults and fractures, those with small displacements near or below seismic adjustment thicknesses, plays an important role in predicting hydrocarbon migration and accumulation paths. The aim of the present study is to present a high-resolution enhancement workflow to map the fault and subtle fault system in the Marlim oil field in the offshore portion of the Campos Basin. For this purpose, the database provided by the National Petroleum Agency (ANP) was used. The seismic data and well data from the Marlim Field were processed and interpreted using the Opendtect Pro software. Through relative acoustic impedance inversion and application of fault enhancement attributes, we obtained high-resolution images of the distribution of faults along a region characterized by large accumulation of hydrocarbons marked by an important temporal region and the top of the Oligocene, a horizon that traditionally houses turbidite reservoirs, separating it into two main regions with distinct fault densities and directions, Outside the reservoir, large zones of high-grade faults were observed with a north-south trend varying slightly to the northwest (NNW-SSE) and northeast (NNE-SSW), inside the reservoir, fractures and smaller faults were observed in an east-west direction with trend towards WNW-ESE. It was also possible to correlate the top and bottom of the reservoir, in order to obtain different characteristics between the structures, faults external and internal to the reservoir and the regions subject to greater accumulations of hydrocarbons.