| 1. |
- Rodrigues, Luiz F, et al.
(författare)
-
Origin and alteration of organic matter in hydrate-bearing sediments of the Rio Grande Cone, Brazil : evidence from biological, physical, and chemical factors.
- 2020
-
Ingår i: Radiocarbon. - : Cambridge University Press. - 0033-8222 .- 1945-5755. ; 62:1, s. 197-206
-
Tidskriftsartikel (refereegranskat)abstract
- The Rio Grande Cone is a major fanlike depositional feature in the continental slope of the Pelotas Basin, Southern Brazil. Two representative sediment cores collected in the Cone area were retrieved using a piston core device. In this work, the organic matter (OM) in the sediments was characterized for a continental vs. marine origin using chemical proxies to help constrain the origin of gas in hydrates. The main contribution of OM was from marine organic carbon based on the stable carbon isotope (δ13C-org) and total organic carbon/total nitrogen ratio (TOC:TN) analyses. In addition, the 14C data showed important information about the origin of the OM and we suggest some factors that could modify the original organic matter and therefore mask the “real” 14C ages: (1) biological activity that could modify the carbon isotopic composition of bulk terrestrial organic matter values, (2) the existence of younger sediments from mass wasting deposits unconformably overlying older sediments, and (3) the deep-sediment-sourced methane contribution due to the input of “old” (>50 ka) organic compounds from migrating fluids.
|
|
| 2. |
- Iglesias, Rodrigo S., et al.
(författare)
-
Characterization and modeling of CO2‐water‐rock interactions in Hygiene Sandstones (Upper Cretaceous), Denver Basin, aimed for carbon dioxide geological storage
- 2018
-
Ingår i: Greenhouse Gases. - : Wiley-Blackwell. - 2152-3878. ; 8:4, s. 781-795
-
Tidskriftsartikel (refereegranskat)abstract
- Carbon capture and geological storage are among the most valuable technologies capable of reducing CO2 emissions. Long‐term interactions between CO2 and a reservoir, and the integrity of geological formations, are key factors in the selection of adequate reservoirs for permanent storage. Numerical models of CO2‐water‐rock geochemical interactions are often employed to predict the fate of CO2 stored in a reservoir over time. The Hygiene Sandstone, in the Denver Basin, Colorado, USA, is a geological formation with potential for CO2 storage, and was therefore studied in this work, in which we collected and characterized outcrop samples in order to supply the input parameters for numerical simulations. Four representative thin sections of Hygiene Sandstone outcrops were quantified in terms of detrital constituents, diagenesis, and porosity on the basis of conventional petrography. Sandstone mineralogy included, in decreasing order, quartz, K‐feldspar, muscovite, albite, illite, smectite, kaolinite, poikilotopic calcite, and siderite. Porosity ranged from 4% to 13%. A geochemical modeling study of CO2‐water‐rock interactions performed with two characterized samples and brine data from the Hygiene Sandstones, simulating reservoir conditions, suggested that the mineralogy of the sandstone is quite stable under the conditions that were tested and only minor mineralogical and porosity alterations would occur within a thousand years of storage.
|
|
