Phase Behavior of Aqueous Na-K-Mg-Ca-CI-NO3 Mixtures: Isopiestic Measurements and Thermodynamic Modeling

A comprehensive model has been established for calculating thermodynamic properties of multicomponent aqueous systems containing the Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cl{sup -}, and NO{sub 3}{sup -} ions. The thermodynamic framework is based on a previously developed model for mixed-solvent electrolyte solutions. The framework has been designed to reproduce the properties of salt solutions at temperatures ranging from the freezing point to 300 C and concentrations ranging from infinite dilution to the fused salt limit. The model has been parameterized using a combination of an extensive literature database and new isopiestic measurements for thirteen salt mixtures at 140 C. The measurements have been performed using Oak Ridge National Laboratory's (ORNL) previously designed gravimetric isopiestic apparatus, which makes it possible to detect solid phase precipitation. Water activities are reported for mixtures with a fixed ratio of salts as a function of the total apparent salt mole fraction. The isopiestic measurements reported here simultaneously reflect two fundamental properties of the system, i.e., the activity of water as a function of solution concentration and the occurrence of solid-liquid transitions. The thermodynamic model accurately reproduces the new isopiestic data as well as literature data for binary, ternary and higher-order subsystems. Because of its high accuracy in calculating vapor-liquid and solid-liquid equilibria, the model is suitable for studying deliquescence behavior of multicomponent salt systems

Sedimentological Analysis of Well Data by the Example of the Dagi Horizon of the Northeastern Shelf of Sakhalin Island

Well logging methods provide important data on data on sedimentary structures, genesis of sedi-ments, and relations of the facies in sedimentary basins. This paper demonstrates the potential of sedimen-tological interpretation when applied to data from the formation microimagers (FMI). The study is based on the results of the joint project on integrated analysis of wellbore images and core samples of the Neo-gene deposits of the northeastern shelf of Sakhalin Island between “Gazprom”, “Gazprom geologora-zvedka”, and Schlumberger Company. The image log represents 300 m of the well section, when 95 m are characterized by the core. The study included detailed matching of the core data with open hole logs as adjusted for core recovery, lithological description of the well section, structural and textural interpreta-tion of the images, facies analysis, orientation of the paleocurrent direction, and reconstruction of the depositional environments