Research on Productivity of Horizontal Well with a Longitudinal Fracture in Multilayer Oil Reservoirs

Horizontal well with a longitudinal fracture in heavy oil reservoirs is a good method in increasing production. To evaluate the performance of this kind of wells, a rigorous analytical model has been developed to predict the productivity of a multi-layered reservoir drained by a horizontal well with a longitudinal fracture, it rigorously couples flow in a box-shaped drainage volume to flow in the facture, and then to flow in the wellbore. Along with friction, acceleration, and fluid-inflow effect, change in flow regime from laminar to turbulent is also taken into account to describe flow in the wellbore. Calculation results showed that: For a given reservoir size, fluid viscosity and fracture conductivity there exists the only fractured horizontal well specific productivity index. The distribution form of pressure in the fracture is characterized by steop-shaped, pressure loss at the high permeability parts is larger. Fracture conductivity has an insignificant effect on productivity, specific productivity index peak when conductivity is between 15 to 20 Dc·cm. Fluid viscosity has great influence on specific productivity index, lower the viscosity is the key factor for enhancing heavy oil well production.