Patent ID: 7409858

Claim:
A method for monitoring fluid properties in a wellbore having an inner surface, a top and a bottom, the method comprising: providing a distributed sensor device comprising an upstream sensor, a downstream sensor, and a heating element bundled together in a protective member; causing the distributed sensor to assume a helical shape; pulling the distributed sensor towards the bottom of the wellbore, while retaining the helical shape of the distributed sensor; feeding the distributed sensor into the wellbore so that the distributed sensor is in contact with the inner surface; and measuring fluid flow into the well at a plurality of points along the distributed sensor, the flow measuring method at each point comprising: providing heat to the fluid flow by heating the heater element; measuring the temperature of the fluid at the upstream sensor to obtain a first value; measuring the temperature of the fluid at the downstream sensor to obtain a second value: subtracting the first value from the second value to obtain a third value corresponding to the temperature rise in proportion to heat by the flowing fluid at that point; and deriving a fluid flow rate from the third value.