Property parameter determination in individual layers for separately fractured wells with commingled production in multi-layered reservoirs

At present, without any separate rate test for each layer, there is no way to determinate the properties of individual layers for separately fractured wells with commingled production in multi-layered reservoirs. In order to address this issue, much research work was performed and elucidated in this article. To begin with, we illustrated a basic physical model for a separately fractured well in a multi-layered reservoir. Next, we stated the common determination method that can only be used to gain the average properties of multi-layered reservoirs. Then, according to the physical model, we newly established a mathematical model and plotted standard well-test type curves; additionally, we also discussed why we cannot determinate the properties of individual layers by using the new well-test model. What’s more, we presented a new method to determinate the properties of individual layers. Moreover, we compared the advantages and disadvantages among the three methods. In addition, by using the new determination method, we particularly took two field wells as examples to demonstrate how to determine the properties of individual layers. The proposed new method was validated by use of the common method, the new well-test model and the microseismic monitoring results. At the end, we summarized the research conclusions and indicated that the new method was a good tool to determinate the properties of individual layers in multi-layered reservoirs.