In order to make effective decisions for oil field management, well and reservoir surveillance data needs to be utilized to better understand how the subsurface and surface systems in a field interact. This can be done at the reservoir, well and surface facility level, but is most effective when considering the entire production or injection system. IPM (Integrated Production Modeling) is now being used more often and, has demonstrated its usefulness in many oil and gas field applications. The use of integrated production modeling methodologies for improving production, identifying and eliminating bottlenecks and improving production allocation for wells from multiple reservoirs from both onshore and offshore oil fields are presented. Methods for coupling the surface and subsurface are reviewed and its usefulness for identifying bottlenecks at both the well and surface facility level are demonstrated. Field examples are presented where issues were identified and overcome by operational means and, found to increase production. Prioritization of wells and production intervals can also be incorporated to improve production/system uptime and field life. The use of artificial lift for oil wells and additional compression for gas wells can be effectively modeled by reasonably calibrated IPM models. Without proper calibration, these models can yield results that lead to inadequate decisions that have a significant impact on project economics. The use of IPM models as a tool to better allocate field production data has proved to be very reliable and has resulted in better field management. This approach requires both reservoir and surface facility information gathered on a regular basis in order to be reliable and accurate. Reservoir, well and surface models require occasional calibration or updates of inflow type curves. Application of these methods are discussed and presented for some field cases for oil reservoirs some under waterflood and others with active water drive.