Analysis of the characteristics of pressure stabilization and recovery curves in multibranched horizontal wells

Background. The article presents the results of analyzing pressure stabilization and recovery curves in multibranched horizontal wells. It has been noted that the diagnostic graphs of bottomhole pressure derivatives in such wells are complicated by sections of V-shaped form. Such specific features of actual measurements require mandatory consideration during their subsequent interpretation. Objective. To identify the circumstances that cause the presence of V-shaped sections in the diagnostic graphs of bottomhole pressure derivatives. Materials and methods. The primary tools for analyzing the initial data included methods of systematization and generalization, as well as processing techniques using mathematical statistics and numerical modeling, including with the use of KAPPA Workstation software version 5.40. Results. It was determined that the number of ranges with V-shaped behavior of the derivative corresponds to the number of drainage outlets from the main horizontal borehole, and the distance between them is controlled by the length between lateral branch connections. The possibility of mathematically describing these sections using available analytical models “Fishbone” and “Multi-branch” was assessed. Conclusions. The calculations show that these models, given the current set of active functional options, do not provide an acceptable match between calculated and actual stabilization and recovery pressure curves, as they do not fully reflect the features of real measurements. As an alternative, a numerical model reproducing the dynamics of bottomhole pressure in stopped and closed multibranched horizontal wells is presented. Comparison between recorded data from deep instruments and model curves demonstrated the adequacy of the created digital analogs of pressure response, which can be used for developing algorithms to assess reservoir properties.