Abstract
Wells in high permeability reservoirs are frequently constructed with deviated wellbores completed with a high permeability fracture (HPF). If the deviated well is not drilled perpendicular to the minimum horizontal stress, significant misalignment between the wellbore and the fracture plane is likely to occur. In turn this leads to limited communication between the fracture and the wellbore, resulting in a reduced number of flowing perforations and additional pressure drop. In low permeability reservoirs, even for a misaligned fracture the majority of the flow is through the hydraulic fracture. In contrast in deviated HPF wells a significant flow contribution may be through the gravel pack (GP) perforations that are not connected to the fracture, thus bypassing the fracture. The flow fraction bypassing the fracture depends on the formation permeability and the fracture and gravel pack skins. This paper will show that the conventional inflow performance calculations can not be applied for a HPF well with a misaligned fracture. It is generally incorrect to treat the inflow performance for a deviated HPF well in the same manner as for a vertical well.
This paper provides a semi-analytical model for the flow pattern taking into account both flow to the fracture and flow that bypasses the fracture to the GP wellbore region. The model shows that the limited communication between hydraulic fracture and wellbore has a great impact on the entire flow pattern. A field example with a deviated deepwater well (DW) from the Gulf of Mexico (GOM) will be shown. The flux method will be revised taking into account flow contribution from the GP region, resulting in additional flow perforations but adding more risk for fines movement and skin increase.
