Analysis of geophysical logs and petrophysical properties of the peak ring sequence of Chicxulub crater

Abstract

In this study we propose a petrophysical model of well M0077A based on the geophysical well logs. The following logs analyzed are: resistivity and electrical conductivity, magnetic susceptibility, density, natural radioactivity and mechanical factors of the well. The M0077A well was drilled on Expedition 364 of the Chicxulub Crater offshore drilling project, with the purpose of investigating the crater's peak ring. Information from the geophysical well logs reveals physical properties of the rocks, such as high porosity, low densities and seismic velocities. Such combination of specific characteristics is associated with microfracturing and alterations, which record the deformation due to the impact and crater formation. These results are consistent with the model predictions for the formation of a peak ring, established which lithologies represent the impacted and deformed rocks, composed mainly of impact breccias and fractured basement granitoids. The interpretation of well logs defines three main lithostratigraphic units in well M0077A: (a) post-impact sediments (0–616.58 m), (b) impactites (617.33–747.02 m), and (c) granitic basement (747.2–1334.27 m). The petrophysical characterization was prepared from the analysis of the M0077A well, and is based on information from other wells and geological-geophysical models of the Chicxulub crater.