Erda C1D

Overview

Rigless conductor recovery on Amethyst C1D utilizing the novel Erda Jack-up rig.

The 7 well project on Amethyst C1D was the first of its kind utilizing the Erda Jack-up-rig and its Huisman crane to pull the multistring conductors while having a custom built frame with the DecomCutter and DecomDart installed on the wellhead platform executing the conductor sectioning.

The custom built frame includes a false rotary table to set down the conductor and ensures proper weight distribution of the multistring and the Control Cutter tool package across the wellhead platform beams.

In a single lift the custom frame, DecomCutter and DecomDart is moved from slot to slot ensuring effective progress of operation and eliminating need for rigging for each well.

The 7 well project was executed in 7 days which include rigging up and down the frame and tool package for the first time offshore. Over the 7 wells a total of 21 cuts and 25 pins were completed with an average cutting time below 5minutes and pinning time below 2 minutes.

Background

The Erda Jack-up has been converted from a Drilling rig to a purpose built decommisioning Jack-up rig with capabilities to completed downhole operations, Conductor recovery and Topside skidding.

This unique functionality enables Petrodec to undertake complete decommissioning scope and leave the site with the topside secured on the Erda deck.

To enable efficient conductor recovery operations Control Cutter and Petrodec have collaborated on the custom built frame and handling methods to ensure a safe and efficient recovery utilizing the novel rigless approach.

Challenges

Rigging up the equipment was completed with three simple lifts where the initial lift was the custom built frame that required alignment to the weight bearing structure on the C1D wellhead. The subsequent two lifts were the DecomCutter and DecomDart that were quickly secured to the frame.

A complete system test was completed prior to picking up the conductor from the below wellhead deck and securing in the false rotary with slips. Lifting equipment manufactured to handle the distance from lifting rod to cut point ensure limited handling of conductor string for repositioning between cutting and pinning operation. The system is remotely operated and eliminate the need for any manual handling in between the different operations.

A spreader bar for efficient single lift relocation from slot to slot of the entire frame including Control Cutter tools was manufactured and utilized.

Due to the operational efficiency and limited deck space some waiting time was accrued due to limited vessel availability for backload of cut sections