The Atterberg limits are essential information and the first step in soil classification for geotechnical purposes. Established laboratoryprocedures use distilled water in the plasticity and liquid limits determination. However, saline solutions frequently interact with soilsin the construction environment through fluid percolation processes. This work aims to understand the variation of the geotechnicalbehavior of two standard materials with different mineralogical compositions (kaolinitic and smectitic) when affected by NaCl ionicsolutions in different concentrations. The purpose is to simulate different soils in environments with the presence of saline solutions.This paper reports an experimental program in which a kaolinite-rich and a smectite-rich material received NaCl solutions in threedifferent concentrations (0.6 %, 3.5 %, and 15.0 %) and had their Atterberg limits determined under these conditions. Additionally,non-contaminated samples of both materials have had their limits measured using distilled water. Physical characterization testsincluded hygroscopic moisture, grain size distribution, grain density, plastic limit (PL), and liquid limit (LL). These data allowed thedetermination of the Skempton activity index (AI), plasticity index (PI), consistency index (CI), classification of soils in the UnifiedSoil Classification System (USCS), and in the Highway Research Board (HRB) with the group index (GI). Mineralogy was determinedby X-ray diffraction and physical chemistry by measuring pH in H2O and KCl, determining the ΔpH, the point of zero-charge (PZC),and the surface electrical potential (Ψo). The results show that the pH values rise with increasing salinity, while ΔpH, PZC, Ψo, LL,AI, PI, GI decrease with increasing salinity. The PL decreases with the increase in salinity for smectite and increases for kaolinite. TheUSCS and HRB demonstrate that the materials start to behave as fewer plastic materials with increased salinity. It is concluded that thevariations in the physicochemical parameters of the environment control and modify the geotechnical behavior of the fine-grained soils.

Permeability models are very relevant for the characterization of oil systems. However, limitations related to the resolution of seismic data make it difficult to identify subseismic, sedimentary, and tectonic structures, which can significantly impact the flow pattern. This study analyzed the spatial variability of permeability according to stratigraphic and structural geology control to propose a useful model for poorly consolidated, fractured, and faulted siliciclastic reservoirs. In an outcrop analogue to this type of reservoir, air permeability was measured in 3 orthogonal directions at 24 points, spaced 2 m apart.The models were obtained by sequential Gaussian simulation (SGS) after statistical data treatment. The models were validated to ensure the consistency of the generated scenarios. Permeability values showed a positive asymmetric distribution and reduced medians toward tectonic structures. The fitted semivariogram model was exponential, with higher spatial continuity in the horizontal flow direction and lower in the vertical one. The permeability models emphasized the importance of considering subseismic structures in the flow analysis of reservoirs since they have proven to play a significant role in the permeability distribution in the outcrop assessed.

RESUMO: O objetivo deste artigo é analisar de forma integrada as características sedimentológicas, tafonômicas e diagenéticas que interferem na permeabilidade e na definição de Rock Types de coquinas. Para tal, foram utilizados blocos de rocha da Formação Morro do Chaves da Bacia de Sergipe-Alagoas. Essa formação é considerado um análogo para o entendimento dos processos geológicos que afetam a configuração de importantes reservatórios do intervalo pré-sal. Para isso, foi realizada a descrição, de feições faciológicas, tafonômicas e diagenéticas das amostras. Concomitantemente, a permeabilidade ao ar das amostras foi medida, por meio de permeâmetro portátil. Foram elaborados quatro Rock Types(RT): RT "α" -coquina pouco fragmentada, teor de siliciclásticos inferior a 5%, cimentação intensa, dissolução fraca e orientação convexup; RT "β"coquina pouco fragmentada, teor de siliciclásticos menor que 5%, cimentação intensa, dissolução moderada e orientação convex-up; RT "γ"coquina muito fragmentada, teor de siliciclásticos menor que 5%, cimentação dispersa, dissolução intensa e orientação caótica; RT "δ"coquina pouco fragmentada, teor de siliciclásticos inferior a 5%, cimentação dispersa, dissolução fraca e orientação caótica. Em dois destes blocos foram realizadas medidas sistemáticas da permeabilidade que apontam a diagênese como um fator de forte influência na permeabilidade das coquinas da Formação Morro do Chaves.