Wells may also be drilled for the purpose of monitoring the reservoir development plan during the productive life of the reservoir. The wells are equipped with pressure monitoring systems, to determine the extent of propagation of the pressure transient from the producing wells into the reservoir. The observation wells may also be used to monitor encroachment of the gas-oil interface or the oil-water contact into the oil zone, as well as progress of injected fluids such as the water front, during enhanced oil recovery by waterflood. These wells may also be converted for functions other than observation, such as production or injection later in the productive life of the reservoir.
