Publisher's Synopsis
A system of and method for determining whether a liquid moving in an oil-bearing reservoir rock formation is water or oil is provided. The oil-bearing rock formation includes at production well(s) and source(s) of injected water during normal oil production. A fluid pathway is identified, baseline number of passive microseismic events is established, passive microseismic events in the fluid pathway are monitored during oil production to sense microseismic events, the sensed microseismic events are compared to a baseline number of passive microseismic events. The fluid causing the microseismic events is determined to be water if the sensed number of microseismic events approaches the baseline number of passive microseismic events per the predetermined unit, and if the baseline number of passive microseismic is measured during a time period when the water injection is greater than the rate of water injection during normal oil production.
