INVESTIGATING USE OF PRESSURE PULSES TO ASSESS NEAR WELLBORE RESERVOIR PARAMETERS

Pressure surge in a pipe due to sudden flow rate change or full-stop of fluid flow is a pressure wave propagating in fluid along the pipe. This phenomenon has been used to determine the flow rate and to detect and monitor changes in effective flow diameter. It turns out that the pressure surge, also known as pressure pulse, can be used to estimate the formation transmissivity and storativity in the near wellbore region. In this study, propagation of pressure pulse generated by sudden valve closure is simulated with a transient pipe flow model, and it is coupled with a transient analytical reservoir model. The coupled model is used to estimate the reservoir parameters by history matching approach, which is to iterate the transmissivity and the storativity values until an acceptable match is obtained between the measured and simulated pressure history at the upstream of valve. The developed modeling and estimation scheme is applied with two data sets from a field well test to estimate reservoir parameters. The reservoir parameters transmissivity and storativity in the near wellbore region were obtained from the history matching analysis. Matching analysis with the coupled model on the recorded wellhead pressure during two tests showing obvious different flowing conditions points out very similar reservoir parameter values