Holistic Subsea Chemical Delivery Design and Management

Subsea development projects face significant flow assurance and production chemistry challenges that require the application of chemicals subsea or downhole. The application of these chemicals via umbilical/downhole capillary string requires stringent qualifications prior to deployment to avoid system failure due to blockage or corrosion resulting in loss of integrity. It also requires properly designed chemical delivery system to ensure proper dosages and uptime can be steadily/reliably delivered for the chemicals to be effective, including proper storage volume, pump size/turndown, metering, chemical injection valves, etc. The paper is to share the best practice of having an end-to-end view on properly managing subsea chemical delivery, including what can and have gone wrong if not followed. For example, chemical/material compatibility is a key qualification requirement for subsea chemical delivery. However, when requested for demonstrating compatibility with the chemical injection system, each chemical vendor typically have their own internal "list of materials". It hasn't been fully recognized that the actual list of materials that the chemical can encounter throughout the entire chemical injection flow path from transportation to tanks, pumps, injection lines, and mandrels/valves, can be way more extensive. Getting one compatibility wrong, it will become the Achilles’ heel and compromise the entire injection system and render the chemical treatment ineffective. Therefore, designing the chemical delivery system and qualifying subsea chemicals with an end-to-end view is crucial to the success of chemical treatment programs and oil/gas production.