A new wireline tool that creates X-ray backscatter images of objects within a production well has been developed. Using X-rays to produce images instead of the more conventional optical video recordings offers the significant advantage that the measurement is not hindered by the nature of the production fluid. Therefore, X-ray imaging does not require the well to be specially treated in any way, saving the time and costs associated with cleaning or replacing well fluids.
The tool generates hard X-rays (>10 keV) and measures the backscattered radiation from objects and fluids directly in front of the tool using X-ray detector arrays arranged around the tool axis. Measurements of backscattered radiation are converted into three-dimensional renderings or two-dimensional images of the object using a novel fluid-based surface reconstruction technique.
Example images from operating the tool in a laboratory setting demonstrate the ability of the tool and technique to create reconstructions of objects in a variety of normal production fluids including clean water, saline water, oil, and fluids with suspended rust particles. They reveal the maximum practical imaging depth range from the bottom nose to be approximately 10 cm. The images also demonstrate the millimeter-scale resolution and accuracy of the tool.
The images were produced with a tool exhibiting a commercially viable outer diameter. Thus, this new X-ray imaging method and wireline tool can provide improved visualization and diagnostic capabilities for a significant number of offshore production wells while avoiding the expense and inconvenience of conventional imaging techniques.