Offshore Pipeline Operation Leak Mitigation – A Case Study on Single Point Mooring Operation
Authors: Susanto Tedy , Sharma Rajesh , Finol Renato , Ladd James 
Published: October 2023

This paper aims to demonstrate an effective solution for detecting leaks in a subsea pipeline that connects a Single Point Mooring (SPM) to an Onshore Receiving Facility (ORF) within a Refinery Unit (RU). The proposed solution includes a comprehensive Leak Detection System (LDS) comprising hardware, software, installation, commissioning, and related services. By leveraging a combination of field transmitters, data collection through a controller, telecommunication media connectivity, and real-time visualization in a control room, the pipeline integrity can be continuously monitored during critical operations like loading, unloading, and flushing.

The Oil Movement (OM) Control Room utilizes a Supervisory Control and Data Acquisition (SCADA) system to effectively monitor the operation of the SPM and subsea pipeline over long distances. This system enables operators to configure and manage oil transportation via the pipeline, allowing for adjustable operation settings tailored to different types of oil products based on their American Petroleum Institute (API) degree. All relevant information is displayed on a Human Machine Interface (HMI) screen, providing operators with a centralized view of the pipeline operations. The primary objective of this system is to optimize remote assets and the pipeline infrastructure by transforming field data into valuable business information.

The accuracy of the LDS primarily relies on the precise calculation of line pack using a Real-Time Transient Model (RTTM) and a mass balance method that provides high fidelity. These calculations adhere to the API Recommended Practice (API RP)-1130 for Computational Pipeline Monitoring (CPM) system and API-1149 for Pipeline Variable Uncertainties, which serve as general standards for pipeline operations.

In the event of a leak, the SCADA system enables prompt mitigation actions. By utilizing Global Positioning System (GPS) technology, the leak's location can be accurately identified, allowing for immediate shutdown of the operation. This proactive response minimizes the release of oil or gas into the environment, which can have detrimental effects on ocean habitats, human safety, and asset integrity (e.g., explosion and fire incidents) while safeguarding the company's reputation.

The project faces several challenges during the design, commissioning, and start-up phases. These challenges include, but are not limited to, considerations regarding the total weight of the SPM, limited availability of renewable power resources, space constraints for installing field transmitters, and schedule delays caused by the Corona Virus Disease 2019 (COVID-19) pandemic.

Implementing the LDS offers the advantage of remote monitoring for the SPM and subsea pipeline, eliminating the need for frequent boat visits by operators and engineers. This reduction in travel requirements not only contributes to a decrease in CO2 emissions but also minimizes fuel consumption. Ultimately, this implementation aims to reduce the carbon impact associated with brownfield sites.