A geothermal exploration well has been drilled in Dongying Port Economic Development Zone in Shandong Province, China, confirming thermal waters at 162 °C at 4002.17 meters depth. With a wellhead temperature of 138 °C and flowrate of 101.3 cubic meters per hour, the well is being considered for power generation and industrial steam supply.
The discovery of the high-temperature geothermal resource presents a new pathway for energy diversification and decarbonization for Dongying, which is a traditional petrochemical city.
Overcoming geological challenges
Wei Shanming, a senior engineer and project leader at the 801 Geological Team of Shandong Provincial Bureau of Geology and Mineral Resources, explained that the results of the Donggaore 1 well is revelatory as it deviates from the traditional model of high-temperature geothermal resources being found in the tectonically active western regions of China like Tibet, Yunnan, and western Sichuan. It also challenges the long-held belief that sedimentary basins, like those found in northern Shandong, typically host low to medium-temperature geothermal resources.
Based on the geological survey done by the Shandong Provincial Bureau of Geology and Mineral Resources, a hydrothermal-type, sedimentary-hosted buried hill system was proposed for the Shandong geothermal resource. Although having thick and deep karst reservoirs was ideal for high-temperature geothermal resources, the anticipated challenge was that there will be poor connectivity of deep karst fissures and that pores will be blocked by minerals.
Thus, the geological agency utilized high-temperature acid stimulation technology to open fractures and improve the permeability of the reservoir. Injection at 3500 meters depth proved successful, with the conductivity increased 12-fold and the wellhead temperature increased by 18 °C.
Incidentally, Jiangsu Province just to the south of Shandong had also just recently launched a pilot project for geothermal power generation, as ThinkGeoEnergy reported.
An upgrade to an operating geothermal region
The region of Dongying has already had success in geothermal energy utilization, albeit at lower temperatures. The Shuangfu Flower Base in Niuzhuang Town grows orchids in a greenhouse where temperature is maintained at 26 C using geothermal waters. According to the company’s general manager, the use of geothermal has led to energy savings of about 5 million yuan (approx. USD 716,600) per year compared to coal-fired heating.
Currently, the base has become one of the largest flower production bases in northern China, with its Phalaenopsis orchids exported to Vietnam, Russia, Uzbekistan, and other countries.
The flower farm is only one part of a model established by Niuzhuang Town for the cascade use of geothermal waters. Groundwater at around 80°C is extracted from a depth of about 1,950 meters underground, and then used for community heating through heat exchange equipment, with the tailwater temperature dropping to about 40°C. This water is then introduced into the modern agricultural industrial park to heat the flower and fruit and vegetable greenhouses. Finally, the tailwater is injected back into the ground through reinjection wells.
With the discovery of the high-temperature resource, the region can now look into the use of geothermal energy for power generation and industrial steam use. If used for power generation, the well can supply the electricity needs of about 10,000 people and displace approximately 27,000 tons of standard coal annually. Moreover, the economic benefits of developing the resource could reach approximately 450 million yuan and benefit about 180,000 urban and rural residents.
Source: Sina.com.cn
