LiquiGel® Pig Offers Safe DeWatering Method For Multi-Diameter Subsea Application
A Gulf of Mexico operator required a safe method to dewater a subsea pipeline upon a recent integrity test. Previous attempts to dewater the pipeline of the hydrotest medium with a foam pig proved unsuccessful. Importantly, the said pipeline was documented to contain heavy paraffin accumulation. Furthermore, the pipeline asset required an application that could mitigate the multi-diameter profile while assuring the client of a complete dewatering task. BlueFin’s casted SoliGel pig was designed to travel throughout the different pipeline diameters while mitigating flow assurance challenges and using production gas as the propelling medium.
LOCATION
Gulf of Mexico
SPECIFICATIONS
Operator Type: Upstream
Facility: Subsea Pipeline
Hydrocarbon Type: Liquids
Diameter: 6” x 8” x 6” (Multi)
Length: 9 miles
Geography: Offshore
SCOPE OF WORK
Hydrostatic Test Water Dewatering
CHALLENGES
Dewatering using production gas
Mulit-diameter subsea pipeline
Paraffin build-up around the inner pipe wall suspected
Previous attempts to dewater the pipeline with a foam pig proved unsuccessful
Short notice of mobilization
PLAN OF EXECUTION
Project Pre-planning
a. Engineering modeling to determine the most efficient and effective method
b. Proper attention to risk exposure and mitigation for client through HAZID process
c. Assessment and evaluation of previous work performed on the PL
Project Preparation and Mobilization
a. Modeling and case histories concluded that a pig train consisting of AquaGel and SoliGel would efficiently sweep and de-inventory the test medium while transporting any loose solid debris out of the pipeline
b. Mechanical sea fastening on marine vessel
Project Execution
a. Effective use of back pressure valve system with choke manifold enabled controlled pigging operations
b. Safe hydrocarbon receiving methods required a fluid handling and water treatment spread at the pipeline termination point
TECHNICAL ACHIEVEMENTS & BENEFITS
Executed 24-Hour SIMOPS schedule
Jobs completed with zero incidents and no environmental impact.
Successfully removed paraffin deposition throughout the entire pipeline with AquaGel and SoliGel
Displaced a total of 24 bbls of paraffin and 1,120 bbls of dirty water
Received foam pig that was unaccounted for during previous dewatering attempts
Restored pipeline to full internal volume capacity
Overboard water treatment reduced disposal fluid volume
Launched LiquiGel® pig train through a short radius 90
Extruded Gel pig through 2” port
