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THROUGH-TUBING CASING DEFORMATION AND TUBING ECCENTRICITY IM

Casing deformation and tubing eccentricity is a concern in the oil and gas industry for safety and operational reasons. Casing deformation or tubing eccentricity originates from various sources such as well completion, corrosion, formation swelling, collapse, salt dome creep, etc. It is important to instigate a well integrity surveillance program covering all of the casing and tubing strings for the full well life cycle from initial completion to abandonment. However, there has been no effective logging method to evaluate though tubing the condition of the casing string for deformation and eccentricity. This paper describes a new deformation-and-eccentricity (DEC) tool, which is based on electromagnetic technology and designed to measure casing deformation and tubing eccentricity while logging inside completion tubing. The DEC tool generates a unique compressed-and-focused magnetic field, which provides an increased signal-to-noise ratio (SNR) and employs an array of magnetic sensors to measure the magnetic flux density distributions azimuthally around the tool. The tool’s compressed-and-focused magnetic field is designed to (1) saturate the magnetic flux of the tubing and (2) inject more magnetic flux into the first casing behind the tubing, and therefore, (3) increase signal measurement sensitivity and SNR. The sensor matrix measures flux density changes, which correspond to variations in distance between tubing and casing. The high-resolution azimuthal magnetic sensor matrix delivers high-accuracy measurements, which are used to image the flux density changes. A finite-element-based forward modeling and optimized Gaussian processes regression method has been developed to process the raw logging data. DEC has a built-in orientation measurement based on gyro and accelerometers that are used to align the deformation and eccentricity images and index curves, as well as the tubing thickness image. The tool specifications as 1% of eccentricity ratio and 5% of deformation ratio accuracy in the range of casing OD up to 13.375 in. DEC technology provides an advanced answer product for through-tubing casing deformation and eccentricity measurements in downhole well integrity and plug and abandonment applications. When combined with other well integrity measurements, such as multifinger caliper and multipipe thickness log tool, a complete well integrity evaluation can be achieved throughout the life cycle of a well. For example, significant casing deformation can often indicate the potentially damaged cement behind the casing. Other applications for the technology include tubing clamp location for fiber-optics cables and control lines, the orientation of multistring tubing completions, etc. Performances of the tool have been validated through research simulations, lab tests, and field trials. The paper includes a field case study of a deviated gas production well with tubing buckling and casing microdogleg.
Standard price: 10.00
Discounted price: 1.00
10.00
You could save: 90%
Year: 2021
Author(s): Qinshan Yang, Kuang Qin, Jeff Olson, Marvin Rourke
Company(s): GOWell International
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