Production capacity and mining plan optimization of fault/fracture‐controlled EGS model in Gonghe Basin

Abstract

Taking full advantage of geological conditions is beneficial to reduce the development cost and enhance the exploit of geothermal energy in the Gonghe Basin. In this paper, a thermal-hydraulic coupled model is put forward to study the heat extraction for Gonghe Basin based on local thermal nonequilibrium theory considering the natural fault. An excellent heat recovery system and reasonable combination of parameters are the premise of sustainable geothermal development. Two doublet systems are introduced to investigate the efficiency of the fault/fracture-controlled EGS model.A comparative analysis is performed from the aspect of production temperature, heat extraction ratio, flow impedance, injection pressure, thermal power, and electric power. Key parameters (injection rate, injection temperature, production pressure, number of fractures, vertical interval between the two storages, and the storage permeability) are discussed. The results show that the fault-fracture-controlled doublet model is more suitable for EGS to heat transfer than the common doublet model. The doublet model at a depth of 3300-3800 m has a temperature gradient of 0.04°C/m.For fault-fracture-controlled EGS model, the optimal values are 50 kg/s, 15 MPa, 60°C, 310 m, 4 × 10 −14 m 2 , and two for injection rate, production pressure and injection temperature, vertical interval, storage permeability, and fracture number, respectively. The best well pattern layout method for the Gonghe Basin is one injection well and two production wells. The production temperature varies from 196.8°C to 192.7°C when the heat extraction ratio is 0.13 at the end of the operation. Thus, the fault-fracture-controlled EGS model can provide a mining method and advance the development of geothermal energy for the Gonghe Basin in the future. K E Y W O R D Senhanced geothermal system, fault/fracture-controlled model, local thermal nonequilibrium, parameter optimization | 2967 ZHANG et Al.

Hydraulic Fracturing‐induced Seismicity at the Hot Dry Rock Site of the Gonghe Basin in China

“…The study area is located on the southeastern edge of the Gonghe Basin. Due to the complexity of the geological structure in the Gonghe-Guide Basin, the study area is surrounded by several strike-slip faults, e.g., the Qinghai South Mountain fault, Heka South Mountain fault, Ela Mountain fault and Zhama Mountain fault (Zhang et al, 2019). The faults have a stronger permeability and aperture than common fractures.…”

Efficient evaluation model of beam pumping unit based on principal component regression analysis

“…The contribution rate of the principal component reflects the ability of the principal component to synthesize the original variable information, and can also be understood as the ability to interpret the original variable. 12,13 The sum l i = P P j = 1 l j of the contribution rates of the first m (m p) principal components is called the cumulative contribution rate of the first m principal components, which reflects the ability of the first m principal components to synthesize the original variable information (or explain the original variables). 14,15 The calculation process of the principal component is implemented in SPSS software, and results are shown in Table 5.…”

“…The contribution rate of the principal component reflects the ability of the principal component to synthesize the original variable information, and can also be understood as the ability to interpret the original variable. 12 , 13 …”

Design and Experimental Research on Sealing Structure for a Retrievable Packer

“…With the increase of energy demand, the exploitation and storage technology of oil and gas have been developed rapidly [1,2]. Packer is an important product used in oil and gas production.…”