In this paper, investigation of horizontal well pressure transient behavior in stratified reservoirs is presented.
Although many horizontal wells have been drilled and completed in stratified reservoirs consisting of multiple sublayers devided by interbeds of unknown in-situ permeability, the following three aspects concerning the methodology of horizontal well test analysis have never been touched.
The first one is the influence of permeable interbeds. The second one is the heterogeneity among sublayers. The last one is the applicability of the assumption that the drainholes are perfectly horizontal, whereas the real wells often show complicated traces sometimes penetrating one sublayer to another.
In this paper, the aspects mentioned above are investigated using both analytical and numerical methods in order to know when a horizontal well single layer solution is applicable to a stratified reservoir with crossflow. An example of field data interpretation using the insights obtained in the investigation is shown.