AIMS Geosciences最新文献

Municipal solid waste landfills leachate can cause serious environmental issues for groundwater quality. Therefore, the application of environmental tracing methods to identify groundwater contamination by municipal solid waste landfills leachate is significant. Hydrogeochemical evaluations to trace municipal solid waste landfills leachate are usually carried out. The study was carried out at a landfill in central Italy (Umbria). Samples of leachate and groundwater have been analyzed to evaluate the impact of leachates on groundwater through the comparison of their hydrogeochemical nature. Parameters like pH, Temperature (T), Electrical Conductivity (EC), redox potential (Eh) and Chemical Oxygen Demand (COD) were also measured in situ using digital instruments. Hydrogeochemical data (Na⁺, K⁺, Mg²⁺, Ca²⁺, SO₄²⁻, HCO₃⁻, Cl⁻, NO₃⁻), ionic ratios and geochemical correlations were used to confirm the processes that govern the chemistry of the spring water and to identify leachate contamination phenomena. In fact, the main geochemical diagrams (Langelier-Ludwig, Piper, Schoeller) confirm the leachate contamination in a groundwater sample. In particular, the Piper diagram shows that a sample is in Na⁺ – Cl^- – HCO₃^- mixing zone, indicating a possible influence of the leachate on groundwater chemistry. As a matter of fact, some correlations between major elements, such as Cl^- versus Na⁺ and Cl^- versus HCO₃^-, confirm that the leachate in this study area is highly enriched in Cl^- and HCO₃^- due to wastes dissolution and degradation processes. Further, the assessment of K⁺/Mg²⁺ ratio also confirms the presence of a sample heavily impacted from leachate contamination. These results indicate that also one basic hydrogeochemical study can be useful for fingerprinting the leachate pollution for groundwater samples.

Hydrocarbon exploration is a high-risk venture; therefore, it calls for pre-determining the reservoirs' capacities, forming the bedrock of actualising oil and gas production events. This study delineates hydrocarbon-bearing sands, determines the reservoir area extent, computes the associated petrophysical parameters and presents the reserve volume estimation based on wireline logs with integrated 3-D seismic surveys. It evaluates and indicates three (3) hydrocarbon-bearing reservoirs sands (N_Z(R1), N_Z(R2) and N_Z(R3)) of varying thicknesses (h) across three (3) wells reservoirs N_Z(R1), N_Z(R2) and N_Z(R3). The reservoir properties, including porosity (Ф), free fluid index (FFI), permeability (K), fluid saturations and reservoir thickness (h), represent potentially viable hydrocarbon reservoir units across the field. It presents the estimation of the recovery factor based on the FFI values. Across the reservoirs, Ф is 0.28 in N_Z(R1), 0.27 in N_Z(R2) and 0.26 in N_Z(R3). FFI is 0.26 in N_Z(R1), 0.25 in N_Z(R2) and 0.26 in N_Z(R3). K is 10388 mD in NZ_(R1), 8304mD in N_Z(R2), and 6580 mD in N_Z(R3). Water saturation (S_w) is up to 0.4, 0.36 and 0.20 with the associated hydrocarbon saturation (S_h) of 0.60, 0.64 and 0.80 corresponding to N_Z(R1), N_Z(R2) and N_Z(R3). Considering the delineated reservoir areas based on the prevailing fault assisted structural style, the total volume of recoverable oil is 11.3×10⁶, while the gas capacity is 1.8 ×10⁹ cuft. These findings will aid the field's oil and gas reservoir developmental activities and serve as reference points to related studies involving similar objectives.