Using DPS Measurements for PTA with System Identification

Pressure measurements obtained with distributed pressure sensing (DPS) could be used to estimate circumferentially averaged reservoir parameters with pressure transient analysis (PTA). System identification (SI) for PTA allows us to estimate parameters such as permeability with dynamic bottom hole pressure and flow rates measurements, with the benefit of not having to rely on constant flow rates as input signals as required in traditional well testing. The focus of this research is: (1) flow rate estimation based on DPS data for vertical and deviated wells, (2) introducing a workflow for parameter estimation with SI for PTA with DPS measurements and (3) applying the workflow to numerical simulations of a well test to investigate the scope for using SI as a PTA method. With the friction component of the pressure drop between two sensors, the flow rates over the reservoir section can be estimated. Subsequently, the estimated flow rates and the pressure measurements during well operation are used to estimate a transfer function based on the data and are compared to analytical transfer functions in the frequency domain. Numerical experiments with a simulated vertical well showed that the flow rate can be estimated, and the permeability profile along the well bore can be constructed for homogeneous, layered and heterogeneous reservoirs. Numerical experiments with a simulated deviated well showed that measurements errors have most effect at the bottom of the well.