New Mechanical Pipe Cutting Capabilities on Electric Line - A Compilation of Case Stories from Norway
Authors: Buch Jørgen , Skeie Terje , Eikeland Tommy 
Published: April 2015

Abstract

Objectives/Scope
This paper will present several case histories on the subject of mechanical pipe cutting on electric line (e-line) as well as the operational steps selected to make the pipe cuts. A description of a new pipe cutting tool together with lessons learned to improve future operations will also be discussed.

Methods, Procedures, Process
A recently introduced mechanical pipe cutter tool has enabled pipe cutting operations to be performed with e-line. Operations can be executed from fixed platforms and mobile drilling units (MODO) and as Riserless Light Well Intervention (RLWI) through a subsea lubricator for wireline work. With expanded Surface Read Out (SRO) capabilities for collected data this has increased the possibility to determine a positive cut of the tubing. The scope of work includes drill pipe, liner, tubing and casing recovery operations.

Results, Observations, Conclusions
The described cutting tool leaves a cut profile in the well ideal for subsequent fishing operations because the cut is performed as a grinding inside the tubing, which creates a smooth beveled surface. This minimizes flaring at the cut and thus the time to prepare the pipe for an overshot or retrieval through restrictions.

Case #1
P&A operation where the objective was to cut a 7″ tubing, which had severe scale deposits from a depth between 5 ,905 – 7, 717 ft. A Multi Finger Caliper (MFC) indicated a consistent 5.5” ID at 6, 565 ft, which also was the required cutting depth. The mechanical cutter tool was used to break through the scale as well as cutting the tubing, all in one operation. The cut was performed flawlessly with increased operational efficiency as additional runs where made redundant.

Case #2
An operator challenged a service company to perform a “double” cut in one run as they were required to pull the tubing in two sections. The well was undergoing a full P&A and cuts were aimed to be performed at depths 15,590 ft and 11,414 ft . There was a restriction in tubing measured to be 3.747” caused by tubing buckling. The mechanical cutter tool was run and cuts completed as planned, yet with unexpected timing with regards to the cutting process itself, but the technical objective was met.

Case #3
Cutting tubing in smart wells and allowing for control lines to be parted at weak point has its challenges. By modifying the cutting pads to ensure cutting in connections, the service company has established best practice for cutting above production packers within the confined length for “exposed” control lines. Multiple operations have successfully been carried out in the North Sea basin.

Novel/Additive Information
The mechanical cutting tool is a novel tool that provides several benefits to the industry. A key benefit to safety and efficiency is that explosives are not required. The transfer of explosives is logistically cumbersome and may incur significant operational delays. Another benefit is the cutting crown design that precludes the tendency for sticking, which is a major concern with other mechanical cutters. The tool further incorporates a fail-safe mechanism that prevents it from remaining anchored. There is also a constant review for re-developments and optimization of this tool as new and complementary technology becomes available.