A new method for rapid productivity estimation of 5-spot well pattern

Under the requirement of well pattern estimation for low-permeability reservoirs, horizontal wells and fracturing wells, this paper presents a new method for 5-spot well pattern productivity estimation by introducing shape factor of the drainage area, equivalence radius of fracture/horizontal well and threshold pressure gradient. By applying mirror image and principle of pressure superposition, steady-state flow for an infinite well net can be transformed into pseudo steady-state flow for a producer or an injector in a closed drainage area. This new productivity estimation method for 5-spot well pattern can be unified with a general formula considering the type of well pattern, type of injection-production, type of well completion and type of reservoir. Application in the Yushulin Oilfield showed that the new method presented in this paper is easy to derive, to calculate and to extend. It can be used to estimate the productivity rapidly in oilfields.