Reservoir Evaluation and Development ›› 2022, Vol. 12 ›› Issue (2): 382-390.doi: 10.13809/j.cnki.cn32-1825/te.2022.02.014

• Comprehensive Research • Previous Articles     Next Articles

Numerical simulation of influence of water injection pressure and cave internal pressure on fracture propagation

YE Shen1(),QIAO Jiangmei1,LI Tongchun2   

  1. 1. School of Civil Engineering, Wuhan University, Wuhan, Hubei 430072, China
    2. Huaneng Fujiang Hydropower Co., LTD., Mianyang, Sichuan 622553, China
  • Received:2021-03-03 Online:2022-04-26 Published:2022-05-07


The cave is the main reserve space in fracture-cavity carbonate reservoir. The basic method of fracture-cavity reservoirs exploitation is to generate hydraulic fractures connecting the boreholes and caves through hydraulic fracturing. Based on the TOUGH-AiFrac coupling solver, the influence of different water injection pressures and internal pressure of caves on hydraulic fracture propagation is studied respectively. The results show that with the increase of water injection pressure, the influence of in-situ stress on hydraulic fractures is gradually weakened, and the fractures tend to initiate and propagate along the initial direction. When the water injection pressure is 1.6 times greater than the horizontal maximum principal stress, the rangeability of the fracture initiation directions weaken obviously, and the fracture direction tends to be stable. When the water injection pressure is 2.4 times greater than the horizontal maximum principal stress, the fracture propagation path tends to be stable. The greater internal pressure of the caves, the stronger the cave’s effect on hydraulic fractures. The caves with internal pressure reaching two times of the maximum principal stress exert a kind of “attraction” effect on the hydraulic fractures, which will be gradually strengthened with the increase of cave’s internal pressure while be weakened with the increase of injection pressure. The research results can be used as a guideline to optimize the fracturing work parameters and thereby enhance the oil/gas production rate according to the geological conditions.

Key words: fracture propagation, water injection pressure, cave internal pressure, TOUGH-AiFrac, fracture-cavity reservoir

CLC Number: 

  • TE357