Present‐Day Geothermal Characteristics in South China

Abstract

Geothermal energy potential in China is high, and although they currently lead the way in direct heat production, geothermal power generation is still low. Hot spring analysis and surface heat flux data indicate significant potential resources for the major industrial province of Guangdong, South China. This pilot study investigates the Heyuan Fault, Guangdong, as a potential site for a geothermal power plant. Here we line out (i) preferred locations of possible hot spots on fault intersections, (ii) the possible sources of the heat anomalies, (iii) potential pathways for hot fluid circulation in the upper crust, (iv) available hot spring data and (v) the future work plan to investigate the geothermal hot spots. We find that hot springs occur along the NE trending Heyuan Fault, clustering where NNW striking faults crosscut the Heyuan. The increased heat flow can be explained partly by radioactive decay of a large granite pluton beneath the fault, however, additional heat sources may need to be considered to explain the heat flow maxima of above 85 mWm-2. We postulate that advective (topographically driven) and convective (deep fluids ponding at the brittle-ductile transition) processes may be operating to generate these heat anomalies. Expansive quartz reef systems exposed on the Heyuan Fault, are proposed here, to represent uplifted sections of these deep fluid circulation patterns. A detailed systematic analysis of reef structures will reveal (i) the fluid provenance, (ii) precipitation conditions and (iii) deformation mechanisms, which will ultimately help us understand how fault intersection relations control fluid flow; which is of key significance if it can be utilised for targeting geothermal energy.

Palaeogeothermal response and record of the effusing of Emeishan basalts in the Sichuan basin

“…From the distribution of heat flows in 240 Ma in Figure 7, we observed that the heat flow values in most parts of the Sichuan basin range between 55-65 mW/m 2 except the southwestern Sichuan basin where extra-high heat flow values were recorded and can be related to the Emeishan mantle plume. In 220 Ma, the heat flow in the Emeishan area is still relatively higher while the heat flow in the entire Sichuan basin reduced to 55 mW/m 2 which was very close to the present values [58].…”

Geological models of gas in place of the Longmaxi shale in Southeast Chongqing, South China

“…The current geothermal gradient in Southeast Chongqing ranges between 21 and 23 C/km (Yuan et al, 2006). Zhou et al (2014a) reported that the measured temperature of the Longmaxi shale reservoir based on a horizontal well in the Fuling Block is 64 C at a depth of 2300 m, which gives a geothermal gradient of 22 C/km with a surface temperature of 15 C. The fluid pressure coefficient of the Longmaxi shale system varies greatly in the studied area.…”

Distribution and Thermal Maturity of Devonian Carbonate Reservoir Solid Bitumen in Desheng Area of Guizhong Depression, South China

“…Based on the geothermal gradient map and the geothermal flow chart of China [43][44][45], the present geothermal gradient of the Guizhong Depression is about 3.5 ∘ C/100 m and the heat flux is ranging from 45 to 55 mW/ m 2 . According to the regional paleogeographic data, the paleogeothermal gradient in the Guizhong Depression prior to the late Indosinian uplift is estimated to be 2.82 ∘ C/100 m. There are two important uplift erosion movements in the Guizhong Depression.…”