In-Pipe Inspection Technologies Enable High-Resolution Downhole Data Acquisition
Chris Carpenter_
This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 36492, “Innovative On-Site OCTG Data-Acquisition Technologies,” by Sebastien Petit and Jonathan Bibby, SPE, Vallourec. The paper has not been peer-reviewed. Copyright 2026 Offshore Technology Conference.
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This paper introduces in-pipe inspection technologies enabling high-resolution digital measurements of tubular internal diameter (ID) and wall thickness (WT) for critical downhole applications. The resulting data sets support engineering decision-making by reducing reliance on nominal mill data and enabling joint-level selection for specific well functions. Typical applications include optimizing casing-joint placement for packer setting, selecting joints with higher measured WT for sections exposed to collapse or wear risk, and improving cement-volume estimations.
In-Pipe Inspection With Laser Measurements
The inspection system used for ID measurement is a self-propelled, in-pipe laser-based device equipped with rotating triangulation sensors. As the device traverses the joint, the rotating sensors generate a helical scan of the internal surface, resulting in a dense data set (typically on the order of 10⁶ measurement points per joint) (Fig. 1).
Typical operational characteristics include:
- Applicable ID range of approximately 6 to 18 in.
- Inspection time of approximately 2–3 minutes per joint
- Reported average ID accuracy of ± 0.2 mm The resulting data allow extraction of minimum, maximum, and average ID profiles, as well as ovality metrics, over the usable length of the joint.
The device has two sets of three centralizing arms attached with rubber-tired wheels at each end. These arms are adjusted manually to suit the size of the tubular. Two of the rear wheels are drive wheels and propel the device along the ID using a built-in electric motor. One wheel in each set of three is a rotary distance encoder.
To verify the accuracy of the laser ID measurements, the device normally is installed at the box end of a tubular. This means that the laser can be referenced against the machined box ID, known as the counterbore or D1. This machined ID has a tight tolerance of +0/–0.5 mm and can be used to cross-check laser accuracy.
The device also has optical proximity sensors, which detect when it reaches the end of the joint. This triggers the forward motion to cease and a reverse motion to begin, bringing the device back to the starting point at the initial end of the joint.
When the device has returned to the starting point, it can be manually retrieved from the tubular, and the recorded raw laser timing data can be quickly downloaded onto a laptop using Wi-Fi and then processed using dedicated software to provide the diameter data being sought, as well as an “out-of-roundness” evaluation.
The complete paper includes a field case study illustrating the benefits of accurate ID data.