Introduction

In today’s world, from the transmission of natural gas to homes (domestic), jet fuel to airports (commercial), and crude oil to refineries (industrial) to even transportation of solid when converted into slurry, the pipeline network is one of the most sought out methods of transportation used. Pipeline inspection is a part of the integrity management for keeping the pipeline in good condition. Their upkeep is vital not only for smooth day-to-day operations but also to ensure safety and regulatory compliance. The pipeline inspection includes external inspection and internal inspection.

Why is Pipeline Inspection crucial?

Due to prolonged usage pipelines can lose their internal coating and are easily prone to damages, leaks, etc. To meet safety regulations, the internal inspection of pipelines is mandatory, as defects can lead to cracks, which could result in complete pipe failure or, in the worst case, personal injury/death. Pipeline damages have an impact on the environment also.

Unfortunately, the inside condition of these pipelines cannot be easily determined as it may require emptying the entire pipeline which itself is a very tedious and long process. These structures, though static,  need timely inspections to determine their long-term viability and condition and to reduce any mishaps.

Flooded Pipeline Inspection using ROV

Underwater Remotely Operated Vehicles(ROV) or Underwater Drones gradually replaced divers in many inspection scenarios. They evolved out to be the supreme inspection device that allowed access to dangerous environments. They have proven to be an invaluable tool to inspect flooded/submerged pipelines, collect key data on structural health conditions, and thus help make timely decisions and corrective actions. An ROV helps to do routine inspections without emptying the pipeline and with not much hindrance to the daily activity in limited time as compared to the traditional methods. An ROV-based inspection provides the user with the following:

• Real-time Visual Inspection

• The fast and efficient method in areas where divers cannot operate 

• AI/ML power defect detection and tagging

• Image and Video Enhancement software

• Corrosion mapping and payload integration

• Predictive analysis- historical data comparison

• Low light HD camera

• Overlay in videos

• Hybrid power option 

• Payload integration possibilities

ROV Innovations were contracted to complete an internal inspection of the auxiliary cooling water discharge pipeline for a major thermal power plant, carrying seawater for cooling purposes. For the project, we utilized our flagship product EyeROV TUNA.

Inspection Methodology and Results

Conventionally, ROV enters the flooded pipeline by efficiently utilizing the openings at both ends as well as the shafts/ intermediate entry points along the length of the pipeline. ROV follows a “LAWN MOWER” pattern along parallel surveying lines appropriately spaced for maximum coverage and overlap of images. Measurements and Dimensions of anomalies are done using Laser measuring systems onboard ROV. 

All the data is live streamed by ROV onto the control station. EyeROV TUNA ROV along with profiling sonar attached to the ROV  as a payload was used to accurately measure the buildup of debris and the sizes of corrosion within the pipelines. Also, HD videos were taken covering 360 degrees of the pipe to get a clear image of the internal condition. Generally, an expert team consisting of an ROV Pilot, Field Supervisor, Data Manager, and supporting crew is recommended to execute such time-bound jobs where pipeline shutdown time is very critical. All data was post-processed with depth and structural position tagging​ using EyeROV Visualization and Analytics (EVAP) software platform. This kind of advanced inspection methodologies could be effectively employable in flooded lines without dewatering, map areas of blister formation in PU coating, map cracked blisters, and map blisters along with corrosion. This survey helped asset owners to get an idea of the internal condition of their assets and take up maintenance actions at the earliest.