Geophone Array Production Survey Tool

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Enables interpretation of fluid movement behind casing 

Applications 

  • Planning intervention activities on wells with surface-casing vent-flow (SCVF) or sustained-casing-pressure (SCP) issues
  • Wells with suspected crossflow between zones
  • Wells with casing leaks

Features and Benefits 

  • Three-component geophones create a three-dimensional map of the acoustic environment, which aids in locating gas sources in wells with surface-casing vent flows.
  • The tool can distinguish horizontal flow from vertical flow, which enables the operator to detect low-flow-rate events and reduces cost.
  • The array configuration can collect more samples per depth in less time than a single geophone and therefore improves the speed of data collection and the chances of source detection while reducing rig time and associated costs.

Tool Description 

The Weatherford geophone array production survey (GAPS®) tool is deployed in a cased borehole to profile the background noise levels throughout the length of the well. The background noise profile is analyzed to pinpoint areas with significant gas or water movement occurring behind the casing. This analysis can be instrumental in locating surface-casing vent-flow issues (leaks) and can also help in identifying production issues, specifically behind-casing crossflow between zones in the well. With three-component geophones, the tool can render the recorded acoustic energy into vector components (three-dimensional space) and determine the ratio of vertical-to-horizontal energy arriving at each geophone. This ratio is indicative of the nature of the flow regime behind the casing. Audio files representing the acoustic activity at each recorded depth are produced as part of the final product that Weatherford delivers and are also instrumental in casing leak detection.