Abstract: The present disclosure describes systems and methods for monitoring and diagnosing reservoirs. At least some illustrative embodiments include a method that includes collecting measured near-wellbore data representative of conditions at or near wells within the reservoir (e.g., oil and gas wells), storing the measured near-wellbore data in one or more databases and graphically presenting to a user simulated interwell data generated by a reservoir simulation based at least in part on the measured near-wellbore data. The method further includes graphically overlaying at least some of the measured near-wellbore data over the simulated interwell data and graphically presenting to the user one or more production indicators calculated based at least in part on the simulated interwell data.