Topic: Intervention

UNDERSTANDING WELLBORE HOLD-UP ISSUES

Wellbore deformation can occur at any stage in the life of a well. Whether a result of changes in temperature, pressure or tectonic forces, wellbore deformation may result in serious downhole issues such as restricted access for interventions or the loss of well integrity, and could ultimately lead to premature well abandonment.

With no symptoms presented at surface, operators often discover deformation issues the hard way – during interventions. However, proactive diagnosis of well deformation enables operators to understand the cause and severity of the issue, enabling them to adjust their strategy and overcome it before a critical stage is reached.

EV’s 24 arm Integrated Video Caliper was deployed on e-line to help identify the cause of the hold up. The IVC tool combines industry leading Optis camera technology with multi-finger caliper technology to provide measurements of internal tubing and casing diameters.

This combination of video with multi-finger caliper data leads to enhanced interpretation and provides invaluable 360° pipe coverage to compliment the limited radial coverage available from a stand-alone mechanical caliper.

The liner top was inspected and a full 360-degree 3D model was provided. No visible signs of damage were identified and the geometry was confirmed to be normal. However further up the casing, the caliper data processed on MIPSPro indicated that the casing was helically buckled above the liner hanger.

Further RestrictionVA analysis was carried out based on data obtained from the multi-finger caliper. Firstly, a Pipe Deformation Analysis (PDA) was undertaken to define and quantify the 3D geometry of the tubulars that may have been sheared, buckled or deformed by other mechanisms. This process confirmed the presence of helical buckling in the casing and the reason why the original plug and perf string was unable to descend to the target depth. Then, by simulating the passage of multiple BHAs through this 3D geometry, a drift analysis was provided to understand the limits for access and identify the optimal BHA to pass the restriction.

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