Journal: Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering

Abbreviation

Publisher

Academia Sinica

Journal Volumes

ISSN

Description

Filters

20221
Reset filters

Search Results

Publications 1 - 1 of 1
  • Fault slip potential induced by water injection in the Rongcheng deep-seated geothermal reservoir, Xiong'an New Area
    Item type: Journal Article
    Zhu, Siyu; Feng, Chengjun; Tan, Chengxuan; et al. (2022)
    Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering
    Xiong'an New Area is rich in geothermal resources. In the future, large-scale exploitation and utilization of the deep geothermal storage will have important strategic significance for making green Xiong'an, reducing the environmental pollution in Capital Circle region and improve the energy structure of Beijing, Tianjin, and Hebei. There are several buried Quaternary faults in the Xiong'an New Area, such as Rongcheng, Niudong and Xushui-Dacheng faults. For the upcoming exploitation of the Jixian-Changcheng geothermal system, whether water injection will affect the stability of the main buried faults near the reservoir is of critical importance. At present, there has been no report correlations. In this paper, taking the Rongcheng geothermal reservoir as a case study, we firstly investigated the regional in-situ stress field, and then evaluated the initial stability of the main buried faults using the Mohr-Coulomb fracture criteria. Secondly, we calculated the excess pore pressure caused by water rejection at representative deep geothermal wellbores by the Hsieh and Bredehoeft hydrological model. Subsequently, with the modeled excess pore pressure, we estimated the fault slip potential on the main buried faults associated with water injection, based on a probabilistic approach. Finally, we discussed the influence of injection rate, injection time and fluid with drawalon the mapped fault slip potential. Our results suggest that: (1) The excess pore pressure generated by water injection at the rate of 171 m3/h for 40 years is less than 12 MPa at representative deep geothermal wellbores, within a distance of 3 km near the Rongcheng boundary faults. The excess pore pressure decay shows power law-like behavior to distances of less than 9 km.(2) The stability of the middle segment of the western Rongcheng boundary fault (namely F9-2) is significantly affected by water injection, while this influence on other buried faults is not significant.(3) The fault slip potential on the mapped fault F9-2 increases exponentially with water injection rate as well as with injection time. Projected in 2070, the fault slip potential on the mapped fault F9-2 is 33.16%, indicating a high risk.(4)The continuous pumping in deep geothermal wellbores near the boundary fault of Rongcheng uplift can lead to the decrease of the minimum principal stress and the increase of the maximum differential stress; as a result, the stress accumulation on the mapped fault F9-2 gradually approaches the critical state. Therefore, the effect of upcoming geothermal extraction on the stability of faults nearby warrants great attention.
Publications 1 - 1 of 1