The Application of Solar Indirect System in Passive House in Cold Region and Severe Cold Region of CHINA

AbstractThis paper, the future developing prospect of application of passive house in China was provided,solar indirect system combined with fresh air ventilation system with heat recovery was used in designing to provide heat to meet fresh air load in the passive house, taking the Xining city as an example. The aperture areas of solar collector in different conditions were calculated by changing the influence factors such as the tilt angle of the collector and the solar fraction. This paper analyzed the relationship of the solar collector aperture area with the tilt angle of the collector and the solar fraction. On the basis of the analysis, it is safe to draw a conclusion that the program of using solar indirect system combined with fresh air ventilation system with heat recovery in passive house in cold region and severe cold region of China is economically feasible

Design of Multifunctional and Efficient Water-Based Annulus Protection Fluid for HTHP Sour Gas Wells

In order to solve the corrosion problem of production string in the process of acidizing for the purpose of production, a new water-based annular protective fluid suitable for HTHP acid gas, including H2S-CO2 wells, was developed. Firstly, an appropriate deoxidizer, bactericide, and corrosion inhibitor shall be selected according to the production string of acid gas. In addition, the synergism between additives is evaluated. Then, by designing the additive ratio, the optimal formulation of the water-based annular protective fluid is determined. Finally, a high-temperature autoclave was used to evaluate the protective performance of the water-based annular protective liquid. The results showed that it is recommended to use water-based annular protective liquids prepared with clear water that comes easily from nature (rivers, etc.), which consist of a corrosion inhibitor, CT2-19C (30,000 ppm), BN-45 bactericide (2 g/L), and anhydrous sodium sulfite (3 g/L). The density of the water-based annulus protection liquid is 1.02 g/cm3, and the freezing point is −2.01 °C. The dissolved oxygen content of water-based annulus protection fluids prepared with clear water in formation water shall be controlled within 0.3 ppm. The corrosion inhibition rate of water-based annular protective fluid in the liquid phase is higher than 90%, and the corrosion rate of P110SS steel in the gas–liquid phase is lower than the oilfield corrosion control index (0.076 mm/y)

Research on Prediction Methods of Wellbore Hydrate Formation of Ultra-Deep Gas Wells in Northwest Sichuan

According to the formation and handling situation of hydrate in ultra-deep high-pressure sulfurcontaining gas wells in northwest Sichuan, the formation conditions of natural gas hydrate was studied based on previous studies on hydrate, the molecular dynamics of natural gas hydrate and the multiphase flow law of high-temperature high-pressure high-sulfur-containing gas wellbore were combined, and the pressure prediction model with high-temperature high-pressure sulfur-containing gas wells as the target was built. The chemical and physical control methods of wellbore hydrate plugging were discussed to provide the scientific theoretical basis for the prediction and control of hydrate in high-temperature high-pressure high-sulfurcontaining gas wells