The Influence of Multiphase Flow on the Interpretation of Pressure Transient Data in Multilayer Reservoirs with Cross Flow

The authors investigated multiphase flow effects on the analysis of pressure responses in layered reservoirs with cross flow. Virtually all studies on the subject of multiphase well test analysis have been carried out in single-layer reservoirs. However, many reservoirs are found to be composed of number of layers whose characteristics are different from each other and the wells in such reservoirs may be completed and produced from more than one layer. In order to examine the behavior of pressure data in multiphase multilayer reservoirs with interlayer communication several cases are considered. The contrast in phase saturations in each layer is the parameter of interest. For each case the applicability of conventional well test analysis is investigated and reservoir parameters such as phase mobilities, skin factor, and average reservoir pressure are compared with actual values. According to the results of this work, conventional multiphase well test analysis in the single layer reservoir can be used in layered reservoirs with cross flow; however, the data should be interpreted with care if horizontal saturation gradient in the layers is significant.