Productivity Analysis of Commingling Production of a Multiple-Channel Reservoir with Closed Boundary by a Horizontal Well

Based on the characteristics of the closed channel reservoirs, a new method, commingling production of the multiple-channel reservoirs by using a horizontal well, was proposed to develop these kinds of reservoirs. The productivity of the horizontal well in this case was analyzed and evaluated by establishing and solving a mathematical model corresponding to this case. Firstly, according to the Green functions at different directions and boundary conditions, a set of control equations for a horizontal well in a single-channel reservoir were derived through Newmann product. Then, both the pressure distribution under constant rate and the production behavior under constant wellbore pressure were obtained by taking Laplace transform and Duhamel convolution. Thirdly, the model for the single-channel reservoir was extended to the multiple-channel reservoir. Finally, we analyzed and evaluated the horizontal well’s productivity in a multiple-channel reservoir. Results show that this new method can efficiently develop the multiple-channel reservoirs and reduce the number of production wells through the comingling production by a horizontal well. Each channel’s productivity is closely related to initial channel reservoir pressure, formation coefficient and storage capacity, and the influence of formation coefficient will decrease in the middle-time development. The initial channel reservoir pressure is the key factor to determine the development effect of the commingling production in the multiple-channel reservoirs. The intrusive flow may be observed when the initial pressure difference among the channels is great. The volume and duration of the intrusive flow depend on the initial channel reservoir pressure difference, reservoir petrophysics and production system. It’s reasonable for the multiple-channel reservoirs with the similar initial channel pressure to conduct the commingling production. This work proposed a model for efficiently developing the multiple-channel closed reservoirs, also provided a method to evaluate the horizontal well’s adaptability and productivity in these reservoirs, which can guide the development of these oilfields.