LIU Yexuan, LIU Xiangjun, DING Yi, et al. Evaluation method of fracability of shale oil reservoir considering influence of interlayer[J]. Petroleum Reservoir Evaluation and Development, 2023, (1): 74-82. DOI: 10.13809/j.cnki.cn32-1825/te.2023.01.008.
The physical properties of shale oil reservoir are extremely poor
so it is necessary to form a network fracture system through volume fracturing to realize economic and effective development. However
there are lower permeability interlayers both in the top and bottom of shale oil reservoirs
so to master the fracture propagation law of reservoir with interlayers is the key for the successful fracturing of shale oil. With the help of the numerical simulation software
RFPA
of the rock fracture damage analysis system
the influencing factors of fracture propagation in the reservoir interlayers are studied. On the premise of considering the heterogeneity of strata
and by the comprehensively consideration of the elastic modulus
Poisson's ratio
uniaxial compressive strength
tensile strength
horizontal stress difference and interlayer stress difference of the reservoir
the fracability of shale oil reservoir is evaluated by the analytic hierarchy process. The results show that the elastic modulus of the reservoir interlayer
the difference of horizontal in-situ stress and the uniaxial compressive strength of the reservoir are negatively correlated with the degree of crack propagation. As these parameters increase
the cracks are more difficult to expand. However
there is a positive correlation between the ratio of tension and compression of reservoir and the stress difference between layers of reservoir and the degree of fracture propagation
that is
the increase of tensile strength and interlayer stress difference will help to increase the scale of fracture propagation
and the larger interlayer stress difference will make the fractures pass through the interlayers and continue to develop in the interlayer. Meanwhile
the mathematical model of the fracability is established by the analytic hierarchy process in fuzzy mathematics
and applied to the fractured wells in the work area. The predicted results are consistent with the experimental microseismic monitoring results
and the research results can provide reference for shale oil fracturing reform.