Affiliations: [a] , Beijing 100027, China | [b] Beijing Research Center, | [c] College of Petroleum Engineering,
Correspondence:
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Corresponding author: Wensheng Zhou, State Key Laboratory of Offshore Oil Exploitation, Chaoyang, Beijing 100027, China. E-mail: liqianru00@126.com.
Abstract: Most of commingled production wells have long pay intervals in offshore oilfield. So the problem of interlayer interference is very serious. In order to evaluate interlayer interference correctly, we established a mathematical model, in which dominated factors are taken into account, including number of layers, thickness of layer, permeability, porosity, viscosity, reservoir pressure, drainage area, relative permeability data and working parameters of productivity test. This computational model can simulate main mechanisms of interlayer interference, such as interlayer heterogeneity, threshold pressure gradient, interlayer communication through wellbore and alteration of liquid output rate among layers. Through mathematical simulation, degree of interlayer interference was evaluated. I Degree of interlayer interference is governed by the proportion of thickness of outputting liquid in water free producing period. Therefore in water free producing period, all layers can be developed together and interlayer interference can be inhibited to a certain extent, as long as the producing pressure difference or the liquid output rate is kept as large as possible. Degree of interlayer interference is governed by the proportion of output rate of every layer after water breakthrough. Therefore, in this period, in order to reduce interlayer interference, we can divide all layers into several development zones, or take some stimulation measures such as hydraulic fracturing for thin and lower penetrability layers, water shut-off, profile control and so on. This study is of great importance to offshore oilfield development.
