Final manuscript post peer review, without publisher's formatting or copy editing (postprint)
There exists a fair degree of geological similarity between the internal structure of Mars, its orbital cycle, and axis tilt with that of Earth. The early plate tectonics along with subaerial volcanism have emitted oxygen as evident in the geological history of Earth during the Archaean–Proterozoic transition. The ancient Valles Marineris equatorial rift basin of Mars could have resulted because of lithospheric dynamics. The associated large-scale transtensional strike-slip during the Late Amazonian Period further implies manifestation of possible plate tectonics on Mars. The presence of the earliest organic species, 3.7 billion years ago, had been established on Earth. The presence of lake and ocean and evidence of glaciation infer probable evolution of life in early Mars. The depositional morphology like alluvial fans, debris flow fans, deltas, and lacustrine fans implies possible sedimentation processes active on early Mars. Organic matters on Mars could be in situ or could have been delivered by meteorites. The presence of organic molecules of benzene and propane in 3-billion-year-old rock samples has been evidenced in Gale crater. Deposition of source rock and subsequent decomposition of organic matter could have generated hydrocarbons in early Mars. A comparative geological phenomenon between Meso-Neoproterozoic petroleum geology of Earth and the equivalent Amazonian and older periods has been analyzed in the light of the envisaged hydrocarbon generation and entrapment on early Mars. Possible martian petroleum systems of the ancient Valles Marineris rift basin and crater-induced basins including prevalence of gas hydrate and abiotic origin of methane have been studied.
Recent studies indicate vast storage capacity exists in Cretaceous and Paleocene–Miocene sandstones in the eastern Gulf of Mexico. Understanding the geomechanical integrity of reservoirs and associated seals is useful for reducing the risk of migration of injected CO2 out of the storage complex. In this study, we investigated the rock mechanical properties and reservoir-seal integrity of three potential reservoir units in the DeSoto Canyon Salt Basin using geophysical well logs. Geomechanical analysis shows the Cretaceous reservoir units contain competent carbonate cap rocks that arrest possible fracture propagation from injection. Results of reservoir and seal integrity analyses indicate all three potential reservoirs and associated seals are geomechanically stable. The injection pressure of CO2 should stay below the minimum horizontal stress to prevent the occurrence of tensile hydraulic fractures. The three candidate reservoir units are ranked according to reservoir geomechanics for long-term commercial carbon storage. Future work should focus on geomechanical simulation of the reservoir units and additional assessment of leakage risk to further ensure safe carbon storage during and after CO2 injection. Laboratory core tests are recommended to confirm the accuracy of the empirical geomechanical analysis of the candidate reservoir and seal rocks.
