Multi-Fracture Synchronous Propagation Mechanism of Multi-Clustered Fracturing in Interlayered Tight Sandstone Reservoir

Abstract

A numerical model was established by using the 3D lattice method to investigate the synchronous propagation mechanism of multiple clusters of hydraulic fractures in interlayered tight sandstone reservoirs in the Songliao Basin in China. The multi-fracture synchronous propagation model under different geological factors and fracturing engineering factors was simulated. The results show that the vertical stress difference, interlayer Young’s modulus, and lithologic interface strength are positively correlated with the longitudinal propagation ability of multiple hydraulic fractures. The three clusters of hydraulic fractures can have adequate longitudinal extension capacity and transverse propagation range with 15 m cluster spacing and a 12 m3/min pumping rate. The viscosity of the fracturing fluid is positively correlated with the ability of hydraulic fracture to penetrate the interlayer longitudinally but negatively correlated with the transverse propagation length. It is recommended that high viscosity fracturing fluid is used in the early stage of multi-clustered fracturing in interlayered tight sandstone reservoirs to promote hydraulic fractures to penetrate more interlayers and communicate more pay layers in the longitudinal direction, and low viscosity fracturing fluid in the later stage to make multiple clusters of fractures propagate to the far end where possible and obtain a more ideal SRV.

Study on the Hydraulic Fracturing Failure Behaviour of Granite and Its Comparison with Gas Fracturing

“…When the fracturing cluster spacing was reduced to 6 m (Figure 13d), the maximum fracture widths generated by HF and GF were increased to 2.232 cm and 2.881 cm, respectively. Although the inter-cluster fractures of HF were denser, the undersized cluster spacing limits its production area; this is fundamentally consistent with previous research [55]. However, compared with HF, GF can generate fractures that gradually extend to the far position from the horizontal well to expand the stimulation range effectively.…”

Multiwell Fracturing Characteristic in Layered Heterogeneous Formation and the Optimization of Stimulated Reservoir Volume

“…The total fluid leakage part contains the seepage into the upper and lower surface along the fracture in any section, and its behavior is determined by where p t and p b are the pore pressure, and c t and c b are the corresponding leak-off coefficients. Substituting eqs and into eq , the Reynolds’ lubrication is written as And the mass conservation equation of fluid flow in the porous matrix is given by where ϕ is the porosity of the matrix, ρ m is the fluid density, κ is the permeability, and μ is the fluid dynamic viscosity.…”