Challengeable Engineering Design of a Deck for Coiled Tubing WellAbandonment on a Dynamic Positioning Barge

摘要

Ship collision with offshore platform is one of the rare events in oil and gas industry and generally associateswith huge physical and financial damage. An oil tanker collided with a jacket in the South Pars gas fieldand caused tough conditions for the operator to restore the jacket and wells to their original state. Thecrucial stages after the accident were killing a perforated well, wreck removal and cutting the wells belowthe section they had been bent or distorted and finally the wells abandonment by cementing coiled tubingoperation on a dynamic positioning barge. This paper focus on engineering design of a platform for coiled tubing injector head and pressure controlequipment on the barge as well as finding a way that coiled tubing string pass through the gap between theplatform and the underwater cut point of wells. For this purpose, a deck was proposed to build on the bargehaving a heavy duty flexible steel pipe extended from the deck to inside the wells cut point. Various measures should be implemented to design this structure in order to have an operational safemethod. The structure had to have sufficient strength to resist the forces applied on it especially duringthe operation in the predominant weather condition of Persian Gulf in the monsoon season. Therefore, acomprehensive study was conducted to determine stresses applied on the structure subjected to differenttypes of wave velocities using finite element method. The engineering design and simulation led to construct the proposed deck extending over the port sideof the barge and elevating between the main deck and mezzanine deck with a long 4" flexible steel pipeat its bottom. In order to verify the engineering design and simulation before the operation, the structureload tested up to 40 metric tons. This paper will peer over the challengeable engineering design of the deck for coiled tubing wellabandonment under the condition of insufficient offshore facility.