| Zhangzhou is located in the southeast coastal geothermal zone which belong to the four geothermal zones in China, meanwhile many experts consider that the potential of hot dry rock resources is great in the background of emerging hot dry rock resources development research.The geothermal system of hydrothermal type had researched systematically by the predecessors, but the comprehensive evaluation of the hot dry rock geothermal system is because of the beginning of the hot dry rock geothermal resources survey. This article carry out the research of the radioactive heat generation rate characteristics and the hot dry rock resource potential which provide the data support for the hot dry rock geothemal resource development through the hot dry rock geothermal system research.Density of rocks, the contents of the radioactive heat generation element, like U, Th, K and the heat conductivity are test in this research. And the radioactive heat generation characteristics, total amount, radioactive heat flow, governing factor and level of the typical granitic pluton are get by the study of the radioactive heat generation rate. Meanwhile the research results get the hot dry rock resource base and upper limit, mid-value, lower limit of exploitation among the four typical granite plutons, and evaluate preliminarily the potential.The average density of rock of the granite and overlying strata is 2.60g/cm3 and 2.57g/cm3 respectively in the Zhangzhou area. The content of U, Th, K of granite is 6.7ppm, 25 ppm and 3.55%, while the overlying strata is 5.0ppm, 15.5ppm, 2.52%. And the heat conductivity of the granite and overlying strata among the four plutons showed as follows: Zhangzhou pluton is 3.00W/m K and 2.74 W /m K, Chengxi pluton is 3.13W/m K and 2.84W/m K, Maping pluton is 3.37W/m K and 2.23W/m K, Lingtongshan pluton is 3.07W/m K and 2.51W/m K. The typical Zhangzhou pluton is controled by the fault structure, intrusion stage, lithologic character, magmatism and metamorphism. And the characteristics of the radioactive heat generation are as follows, the radioactive heat generation rate is in the medium level, meanwhile the Early Yanshanian pluton is higher than the Late Yanshanian pluton. Also the radioactive heat generation rate increase from the southeast to the northwest of Zhangzhou, and fluctuate in the form of zigzag vertically. The radioactive heat generation rate, radioactive heat generation amount and the radioactive heat flow contribution rate are as follows, Zhangzhou pluton is 4.33μW/m3, 38.97 MW and 45.57%, Chengxi pluton is 4.53μW/m3,38.51 MW and 47.68%, Maping pluton is 3.12μW/m3, 34.32 MW and 34.67%, Lingtongshan pluton is 2.85μW/m3, 7.98 MW and 38.93%。The amounts of the hot dry rock resources of the Zhangzhou typical granite pluton among the 10 km depth is 1.76~1.99×103EJ, that convert into the 6005 ~ 679 billion tons of coal. The amounts of the hot dry rock resources that temperature below 75℃, 75 ~150 ℃and over 150℃is occupy the 23%、30%、47% of the gross. And the recoverable upper limit, mid-value and lower limit of the hot dry rock resources among the four typical granites plutons are as follows, Maping pluton 81.89~92.12, 40.95 ~46.06, 4.01~4.6 billion tons of coal, Zhangzhou pluton 70.97~80.52, 35.49 ~40.26, 3.55~4.01 billion tons of coal, Chengxi pluton 62.78~70.97, 31.39~35.49, 3.14~3.55 billion tons of coal, and Lingtongshan pluton 21.84~25.93, 10.92~12.97, 1.09~1.3 billion tons of coal.The characteristic of radioactive heat generation and the research of dry hot rock resource among the granites plutons that most located around the Zhangzhou geothermal field in this article show that the radioactive heat generation rate, radioactive heat flow, the radioactive heat flow contribution rate and of the Late Yanshanian granites pluton is 4.43μW/m3 44.3 m W /m2 and 45%, respectively. And the hot dry rock resource potential of the Late Yanshanian granites pluton is higher than the Early Yanshanian granites pluton. Therefore, the research value and potential of the hot dry rock development of the Late Yanshanian intruded granites pluton is greater than other plutons. |
PDF Full Text Request