Search

Advanced and effective models for gas saturation interpretation in tight reservoirs are mainly based on electricity and acoustics; however, these methods are not always effective, especially in determining the rationality of some undetermined constant methods. Therefore, the purpose of this study is to achieve high-precision prediction of gas saturation in tight reservoirs by comparing the principles and case analysis results of different typical gas saturation models. In this paper, the Archie formula, the three-phase Biot-type equation, and the effective medium symmetrical conduction model were used to evaluate the gas saturation of tight sandstone reservoirs from the perspective of electricity and acoustics. Through the research of this paper, we determined the Archie constant of the target layer. In the application of the three-phase Biot-type equation, an adaptive method is proposed to obtain the value of the formation consolidation parameter α. In addition, a quantitative relationship between resistivity and α was established. The evaluation accuracy of this method is less affected by the shale content, although it will be affected by the true Sg of the formation. The effective medium symmetrical conductivity model has a good predictive ability for Sg in sandstone reservoirs with high shale content. The research results can provide a wide range of references for the quality evaluation of tight sandstone reservoirs.

The coaxial electrospinning of two kinds of materials is one of the most popular fabrication methods to endow the composites with desirable properties. For the biodegradable and coaxial-electrospun poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) composite membranes, the effects of spinning parameters and the membrane density on the structure and mechanical property were still uncovered. In this work, biodegradable PLA and PBS composites were fabricated by means of coaxial-electrospinning followed by rolling press. The effects of PLA solution flow rate on the porous and crystal structure of the membrane were initially investigated. It was found that the pore size and porosity were independent on the flow rate. The crystallinity of PLA in the membrane increased with the increasing flow rate while that of PBS decreased, which brought about the composite membrane with enlarged tensile strength and reduced elongation. Then the influence of membrane density adjusted by the roller press was explored. Results showed that the porous structure greatly varied with the density. The larger the density was, the smaller the pore size and porosity were. Meanwhile, when the density was over 322 kg/m3, the tensile strength and elongation of the coaxial membrane were both higher than that of pure PLA and PBS, achieving the complementary effect of PBS and PLA on mechanical property. The investigation concentrated on the biodegradable PLA and PBS composites is beneficial to the composite materials with complementary properties for various applications.

Metal-organic frameworks (MOFs) have been recognized as promising adsorbents for carbon capture due to their ultrahigh surface areas and tunable properties. However, a majority of MOFs have strict requirements for preparation and high mass transfer resistance that limits the gas separation time. In order to improve the applicability of MOFs to practical applications, herein, we reported an experimental approach to prepare structured CuBTC/graphene aerogel (GA) composites using ionic liquid (IL) additives (CuBTC/GA-IL) at room temperature for CO2 capture. The material was characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), specific surface area analysis, and CO2 adsorption tests. It was demonstrated that CuBTC/GA-IL exhibited the higher CO2 uptake than CuBTC/GA prepared without IL additives. Besides, the breakthrough experiments have shown that CuBTC/GA-IL exhibited the lower mass transfer resistance compared with CuBTC-IL and good cyclability. The effective approach of fabricating CuBTC into GA using IL additives to improve CO2 adsorption in this study may be extensively applied for other MOF-based composites.