Petroleum Experts (Petex) develop the Integrated Production Modelling software (IPM). IPM 12.5 models the complete oil or gas production system including reservoir, wells and the surface network. The IPM suite of tools: GAP, GAP TRANSIENT, PROSPER, MBAL, PVTP, REVEAL, MOVE and RESOLVE can be run together seamlessly, allowing the engineer to design complete field models. The models can include the reservoir tanks, all the wells and the surface gathering system. IPM can model and optimise the production and the water or gas injection system simultaneously. With the Reservoir, Wells and Complete Surface Systems model completed and the production history matched, the production system can be optimised and production forecasts run.