MICROSEISMIC MONITORING WITH FIBER-OPTIC NOISE MAPPING

摘要

The combination of one or more 3-component microseismic sensors deployed into a wellbore adjacent a microseismic event and a linear array of distributed fiber optic acoustic sensors deployed uphole thereof provides two sets of data for establishing noise-free signals for locating the microseismic event in the formation about the wellbore. The distributed fiber optic signals monitor noise transmitted along coiled tubing used to pump a completion operation or as a result of the fluid flowing through the casing or coiled tubing, or along wireline used to deploy the microseismic sensors. The noise is mapped and extrapolated for estimating noise at the 3-component sensors. The estimated noise is removed from the 3-component sensor data for producing clean signals representing the location of the microseismic events.

主权项

1. A system deployed within a wellbore for detecting microseismic events in a formation adjacent the wellbore, comprising:
at least one 3-component microseismic sensor deployed in the wellbore adjacent the microseismic events for detecting compressional and shear waves for establishing a first set of data resulting from at least the microseismic events in the formation; and a linear array of distributed fiber optic sensors extending along at least a portion of the wellbore, uphole of the at least one 3-component microseismic sensor, for detecting compressional waves within or adjacent the wellbore for establishing a second set of data for mapping at least noise within the wellbore, wherein the mapping of the second set of data permits extrapolation of noise at the at least one 3-component microseismic sensor, the extrapolated noise being subtracted from the first set of data for producing signals for locating the microseismic event in the formation.