Research on Pisha-sandstone's anti-erodibility based on grey multi-level comprehensive evaluation method

After a comprehensive analysis for the influential factors like anti-erodibility chemical constitutes, mineral components and micro-structure characteristics of the Pisha-sandstone, and by combining AHP and grey correlation analysis, the anti-erodibility quantitative comparison for 5 types of Pisha-sandstones in Ordos is made on the basis of the grey multi-layer comprehensive assessment mode. The result shows that, from the anti-erodibility point of view, the order of those types is: Pink sandstone, celadon sandstone, purple sandstone, grey sandstone and commixed sandstone. For the evaluation process adopts a simple method, a direct, reasonable and practical result is given, which is also identical to the result of the field survey on soil and rock erosion problems. Consequently, the research on the Pisha-sandstone's anti-erodibility issue is turned from the qualitative description process to the quantitative evaluation stage.

Research on the fault controlling mechanism of geothermal water in Zhangzhou Basin

Fault has an important influence on the storage and movement of geothermal water. The Zhangzhou Basin is wholly located in a granodiorite rock mass. Due to the low permeability of granodiorite, faulted structure has an evident control action on the hydrothermal activity of geothermal fields. Hot springs in Zhangzhou Basin crack along Pingtan-Dongshan Fault to the northeastern direction and emerge along Fu'an-Nanjing Fault. Through measurement of the temperature of several hot springs in the Basin, we found the temperature along the northwestern direction of Zhangzhou-Tianbao Fault is high and the temperature gap between the two sides of Yangxi-Yuanshan Fault is huge; the estimation of geothermal reservoir temperature of geothermal water through quartz geothermometer indicates that the geothermal reservoir temperature of the northern area of Nanjing-Xiamen Fault is obviously higher than that of southern area. Such result indicates that Fault obviously obstructs underground heat source. Under the condition that the average geothermal gradient of the Zhangzhou Basin is set, the circulation depth of the geothermal water of the Zhangzhou Basin measured by geothermal reservoir temperature is 3 550-5 200 m and the circulation depth of the geothermal water of the north of Nanjing-Xiamen Fault is deeper than that of the South.

A review of fluid flow and heat transfer in the CO2-EGS

Carbon dioxide enhanced geothermal system（CO2-EGS） now is an emerging research field that is attracting an increasing research interest with broad application prospects based on its low-carbon, economical and renewable features. The fluid flow and heat transfer is the core of CO2-EGS research. In this paper, further research focus is pointed out after summarizing the latest research progress in this field based on the explanation and the advantages of CO2-EGS development process in the hope of providing reference for researchers engaged in this field.

Optimization of geothermal water exploitation in Xinji,Hebei Province,P.R.China

Geothermal with features of large reserves and non-pollution has been one of the most important energy. China has significant geothermal resources. There are rich hydrothermal resources in Xinji, which has been in development for 5 years. However, hot water continues to decrease because of extensive exploitation and utilization. We selected exploration area as study area, build a set of numerical models of Guantao formation on the basis of actual geological conditions. We get the distribution of hydraulic conductivity from 1.7 m/d to 1.9 m/d by parameter inversion using historical water level monitoring data, and simulation effect is good. We calculate the maximum permissible exploitation under the limitation of 200 m in depth in 50 years which is about 2.2 million m3/a. The results will provide theoretic support for plan making of geothermal exploitation.