The ultra-deep reservoir is characterized by huge reserves and high productivity with high temperature and pressure, which has broad exploration and development prospects. In recent years, sand production often occurs in this kind of reservoirs such as Nanyuan oilfield, Dina gas reservoir, and Tarim Basin in China (Figure 1). Sanding onset has caused serious safety
In order to explore the law of groundwater evolution, the water source connection between faults and aquifers and the main sources of mine water inrush in the deep mining area of Yangcheng Coal Mine in Jining City, 40 groups of hydrochemical samples were collected and analyzed by Piper Diagram and Durov Diagram. The results showed that the fluidity of groundwater developing to the deep became weaker, the value of total dissolved solids (TDS) became larger. So, the roof and floor of coal seam were more similar in water quality types due to the conduction of faults. Using principal component analysis (PCA) to the raw data, two principal components were extracted, and the principal component scores were used as clustering variables for hierarchical cluster analysis (HCA), 5 groups of abnormal water samples were eliminated and 3 clustering groups M1, M2 and M3 were obtained from the other water samples on the tree diagram. The results showed that the combination of HCA and hydrochemical analysis was more effective in screening water samples, and the 3 clustering groups could be qualified samples to represent 3 major aquifers (Taiyuan Formation limestone aquifer, Shanxi Formation sandstone aquifer and Ordovician limestone aquifer). Finally, taking M1, M2 and M3 as grouping variables, the discriminant functions
f
1
,
f
2
and
f
3
of the 3 aquifers were obtained, the results of stepwise discrimination analysis (SDA) showed that the discrimination model established by using 25 groups of standard water samples could discriminate the known water samples with the correct rate of 96%, 10 groups of unknown water samples collected at the fault are identified as Taiyuan Formation limestone water samples, which was consistent with the classification results of HCA, proving that the water inrush of fault DF53 was from Taiyuan Formation limestone aquifer, while the fault had little influence on Ordovician limestone aquifer.
The consolidation and conservation of earthen sites is one of the difficult problems at home and abroad. Tianluoshan relic sites is a typical earthen sites located at humid circumstances. For public exhibitions and research purposes, a few chemical grouts were recommended for solidification and conservation of the excavated historical heritage sites. In this paper, the potential application of methyl acrylic acid resin for strengthening Tianluoshan relic soils were evaluated by a series of unconfined compression tests considering the influence of curing condition, curing time, and water content. The results showed that methyl acrylic acid resin can effectively improve the strength of Tianluoshan relic soils.
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