This paper will present a case study that illustrates wide-ranging capabilities of the latest improvements to visual logging technology. The well studied was identified as having a wellbore obstruction during a routine wireline survey. Conventional well accessibility diagnostics were run that include multi-size drifting tools and lead impression blocks. This assessment was inconclusive, which was attributed to wellbore geometry (deviation). A downhole bailer sample was taken at the wellbore obstruction depth. Extensive composition identification laboratory analysis was conducted on the sample. Physical examination of the sample using magnet attraction and acid solubility was performed along with a solvent extraction test to identify hydrocarbon content in the sample. Additionally, the sample crystalline structure was identified using X-ray diffraction and X-ray fluorescence to determine elemental composition. Laboratory analysis has indicated that the sample is mainly iron sulfides containing iron oxide and calcium carbonate as minor components.

In light of the above findings, two possible sources of the downhole obstruction were conceived:

  1. Severe casing collapse induced by galvanic corrosion.

  2. Scale funneling along the casing wall due to high iron and sulfate contents in the injected water leading to iron sulfide precipitation.

To ascertain the source of obstruction, the latest visual logging technology was deployed in this well. This technology provides extreme wide-angel (185/360°) images along the entire wellbore length through its lens and image capturing design. An advanced operating system inside the tool adds flexibility for image enhancements and real-time data transmission. Specially designed software was used to view the recorded data and align images with time, depth, and tags for log interpretation. The software uses advanced image logarithms to add pan, tilt, and zoom capabilities during live inspection and views of stored images. Visual logging has revealed scale build-up inside the wellbore and ruled out casing collapse.

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