Abstract

A downhole force recorder is presented that uses onboard strain gauges along with temperature and pressure sensors to measure and record the forces experienced by a downhole assembly at the end of a coiled-tubing string. Field trials are discussed in order to demonstrate the benefits of the downhole force recorder during a typical fracturing operation.

The downhole recorder measures force, pressure and temperature. The recorder utilizes a system of onboard strain gauges, pressure transducers and temperature sensors in order to determine the force applied to the gauge. The pressure and temperature sensors are used to filter the pressure and temperature effects out of the force measurement, as well as to record standard treatment data. All data is stored onboard the tool and recovered postjob at surface. The data obtained is then downloaded and compared to a static tubing forces model to validate the results captured in dynamic well conditions.

Field trials were completed over the course of two and a half years, with design improvements to refine data capture capabilities. Initial downhole recorder trials showed that pressure had a large effect on the force measurement. This was offset by calculating the piston areas of the gauge and writing algorithms to remove the pressure-induced force. The latest field trials verify the data collected by the downhole force recorder represents actual force measurements in dynamic well conditions and in varied reservoir types. This data provides more precise downhole information than the general data found in static models. The downhole force recorder has been successfully used in over a hundred deployments.

Four significant uses for accurate downhole force measurments have been identified:

  • validating third-party force models and better calibrating downhole force recorders used under similar fracturing operations

  • completing an informed rootcause analysis when troubleshooting job performance issues

  • providing operators with more information on force, pressure, and temperature to support job planning for typical completions

  • influencing future product development driven by force and depth requirements captured under specific well conditions.

Novel/Additive Information: The novelty of the new downhole force recorder is its ability to accurately determine the force experienced by a bottomholeassembly (BHA) at the end of the string when used during typical fracturing operations. Capturing this new downhole force information will transform how operators approach job planning and troubleshooting on well completions, and how tool designers approach future product development for fracturing operations.

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