Integrated Geophysical and Hydrogeological Investigations for Geothermal Resources

Haoran Li ； Chenggong Liu ； Jie Mao

《World Scientific Research Journal》 7卷1期 (2021/01) Pp. 183-188

https://doi.org/10.6911/WSRJ.202101_7(1).0027

摘要

In order to survey the geothermal resources in Linfen County, Shanxi Province, hydrogeological surveys, hydrological drilling, and geophysical surveys were carried out in the Yongle Palace‐Dayudu area of Linfen County. The hydrogeological survey of 51.88km2 and two controllable source audio‐magnetotelluric (CSAMT) profiles were obtained. The hydrogeological survey results show that the exploration area is located at the edge of the Yuncheng Basin. The tectonic movements of each phase are superimposed on each other, and a series of small faults are derived. The geological structure is intricate; the strata are mainly mud sandstones of the Quaternary and Tertiary strata, which dissipate heat It is small in nature and strong in water conductivity; the exploration area has abundant groundwater resources, which provides a material basis for the formation of underground hot water. According to the two‐dimensional inversion results of the controlled source audio‐frequency magnetotelluric method, it is speculated that the formation in the southeast of Linfen County (section 1‐2 of line VI) is relatively stable, and the depth of the Cambrian bedrock roof is below 2600m; the northwest of Linfen county (section of line VII) ) The basement Cambrian roof burial depth varies greatly, controlled by a fault developed near the location of 1600‐1800 m. The basement burial depth on the south side of the fault is larger, more than 2200 meters, and the basement burial depth on the north side of the fault is shallow, only a few hundred In the field survey, the fault trend is northwest‐southeast, leaning southwest, the dip angle is large, the fault distance is about 1700 meters, and the length of the fault is unknown. The analysis is a secondary fault zone caused by the large fault in the southern foot of Zhongtiao Mountain, and the fault affects the bandwidth About 260‐350 meters, the fault development scale is relatively large. According to drilling data, the temperature at 2100 m is 67°C, and the temperature at the depth of 3500 m is more than 100°C. Based on this, it is judged that the Yongle Palace‐Dayudu geothermal field in Linfen County is a medium‐temperature geothermal field. The electrical section and drilling results in the exploration area show that the thickness of the Quaternary and Tertiary sediments is above 2000 m, and the mudstone and gravel with very low thermal conductivity are used as thermal insulation layers for thermal storage and as thick deposit caps. Provides good capping conditions for deep heat storage.

關鍵字

Three‐potential electrode system ； Forward modeling ； Least square inversion

參考文獻

Li J M,Luo Y Z.New progress in electrical exploration[M].Beijing: Geological publishing house,1996.

Lei W,Xiao H Y.Geoelectric field and electric method exploration [M].Beijing: Geological publishing house,2008.

Yan J Y,Meng G X,Lu Q T.The progress and prospect of the electrical resistivity imaging survey[J].Geophysical and Geochemical Exploration,2012,36( 4) : 576-584.

Dong H B,Wang C L.Development and application of high density electrical method[J][J]. Geoscience Frontiers,2003,10( 1) : 171-176.

Gan P,Xue J Q,Hou L P,et al. Application of high density electrical method in hydrogeology and engineering geological exploration [J]. Journal of Qinghai University,2017,35( 3) : 46-51.