LiquiGel® Delivers Subsea Multi-diameter Solution

A GoM upstream operator engineered a pre-existing 22” gas pipeline and a pre-existing 8” oil pipeline for common use. This re-engineered scope eliminated CAPEX costs on installing a new pipeline and decommissioning costs on removing the in-service assets by utilizing in-place assets to achieve the new production requirements.

Pipeline: 8” x 6,228’ Liquid Pipeline & 22” x 37,000’ Gas Pipeline

Challenge

  1. In-service pipelines required product evacuation and safe pigging solutions that mitigated all risks to internal pipeline integrity or mechanical pig failure.
  2. Dewatering procedure for the new multi-diameter pipeline must not exceed a MAOP of 260 psi.
  3. Water treatment solutions must comply with Department of Interior (DOI) regulatory standards.
  4. Specified flowrate required a minimum 90% efficiency of seawater removal for the commissioning of gas product.
  5. Commission the reconfigured multi-diameter pipeline using nitrogen while mitigating additional costs for mechanical pig launchers and receivers.

Solution

  • Phase 1: High volume/low pressure seawater flush and water treatment solutions to evacuate pipeline product in preparation of subsea reconfiguration.
  • Phase 2: Dewater the reconfigured multi-diameter pipeline with nitrogen and LiquiGel® Pig System for proper commissioning.

Technical Achievements & Benefits

  1. LiquiGel® Pig System transversed a multi-diameter pipeline surface while maintaining a proper seal and 100% dewatering efficiency in a single pass.
  2. Received the 22” LiquiGel®  Pig System through 2” ports, enabling the operator to forego the installation of traditional pig launcher and receiver types.
  3. Successfully mitigated the pipelines structural integrity limitations, never exceeding a system pressure of 160 psi.
  4. LiquiGel®  Pig System maintained a 100% seal during the dewatering phase for a 24-hour unplanned shutdown process.