A composite model of hydraulic fractured horizontal well with stimulated reservoir volume in tight oil & gas reservoir

• We model a composite model with considering the stimulated reservoir volume.
• We use the explicit discrete fracture model for hydraulic fractures.
• A new flow regime of the pseudo-steady flow is obtained between SRV and unstimulated area.
• SRV size can be determined by the arrival time of pseudo-steady flow.

Due to the low porosity and permeability, multiple hydraulic fracturing is applied in tight oil & gas reservoir. A composite model of multiple fractured horizontal well is built with considering the stimulated reservoir volume (SRV), where the reservoir is divided into three main areas including fractures, stimulated reservoir volume and unstimulated reservoir. The dimension of fracture is reduced based on the discrete fracture model (DFM) to improve the computational efficiency, the stimulated reservoir volume follows the dual permeability model, and the unstimulated reservoir obeys to the single porosity model. The composite model is solved using the finite element method and verified by the classic analytical solution in dual porosity reservoir. The result shows that there are five main flow regimes for the multi-fractured horizontal well (MFHW) in the composite model including linear flow around the hydraulic fractures, pseudo-steady flow of transition area, inter-porosity flow period, radial flow of unstimulated reservoir and the outer boundary pseudo-steady flow. The bigger the size of SRV is, the later the pseudo-steady flow of transition area arrived, so according to the arrival time of pressure wave to the SRV outer boundary, namely the pseudo-steady flow of transition area appeared, the size of SRV can be determined; and the smaller main hydraulic fracture permeability is, the later the time of pseudo-steady flow of transition area arrived.