An expert in logging and reservoir monitoring technology has launched a new, multi-purpose inspection tool that provides quantitative measurements of well casing thickness and inner diameter (ID), as well as a comprehensive analysis of casing material properties. It operates in high-pressure wellbores, including those in highly deviated and horizontal wells, up to 20,000psi, in temperatures as high as 175°C.
The iQ was developed in direct response to demand for a quantifiable, reliable and cost-effective intelligent well integrity evaluation solution by independent wireline companies in North America. Highly deviated and horizontal wells require a consistent, easier way to comprehensively evaluate cement and well integrity in a single run. The challenge was to help wireline companies evaluate these wells, which are becoming increasingly complex, particularly in terms of trajectory and tortuosity of the well path. It is critical that potential weak points are accurately identified to avoid well integrity problems, especially in completions that must withstand the extreme pressures required for hydraulic fracturing.
Raising the bar
The iQ provides an economic, reliable and simple method of gathering accurate quantitative casing thickness measurements with azimuthal sensitivity, and carrying out comprehensive casing material property analysis.
Its ruggedised mandrel tool design means that it is more reliable and cost-effective some other casing thickness tools. It also delivers highly accurate quantitative measurements. For example, quantitative electromagnetic (EM) casing ID and properties are assessed through multi-frequency measurements and inversion, and quantitative quadrant casing thickness is assessed and corrected by measured casing properties. The iQ’s calibration procedures are simple, ensuring that measurements are always accurate, and may be relied upon as a consistent source of data.
During the past 18 months, the iQ was put through a series of rigorous tests at Probe’s technology centre in Fort Worth, Texas. It is currently being qualified for use by a major wireline service company, as well as several other independents in North America.
How it works
The Probe iQ provides precise casing measurements such as ID, thickness and material properties, including magnetic permeability and electrical conductivity with quadrant circumferential sensitivity. The four-segment receiver incorporated within the tool mandrel measures casing thickness in 90° sections (quadrants) based on remote-field eddy current (RFEC) principles. The measured electromagnetic (EM) field attenuations and phase shifts from transmitter to receivers are quantitatively translated to single-layer casing thicknesses following corrections made based on EM property variations. In addition, the axial differential measurements, which are also measured in quadrants, deliver enhanced axial resolutions of small defects on the casing wall.
Meanwhile, the precise casing ID, magnetic permeability and electrical conductivity are derived from multi-frequency measurement and inversion, while the EM caliper sensor arrangement satisfies the near-field eddy current (NFEC) conditions. As a result, both internal and external casing wall defects can be identified by combining casing ID with quadrant thicknesses when interpreting the data.
When used in conjunction with Probe’s MAC tools, the EM caliper can further determine the non-metallic deposition on the casing. The intelligent measurement algorithm simplifies the calibration procedures, consistently delivering reliable results. To provide a relative tool orientation and monitor shock and vibration, iQ features a tri-axial accelerometer. In addition, an auxiliary temperature sensor in the electronics sub enables complementary monitoring of the tool’s overall operating condition.