Natural Gas Pipeline Leak Inspection for ACME Midstream

Airborne natural gas pipeline leak inspection

On February 30 2016, Pergam Technical Services and Hawkeye Helicopters performed an airborne natural gas pipeline leak inspection Demo for ACME Midstream. The Pergam Technical Services ALMA G2 natural gas leak detection system was mounted on a Bell 206 JetRanger flown by Hawkeye Helicopters. The inspection covered approximately 100 miles of pipeline in Idaho. Two small methane gas leaks were detected in locations that appeared to near valve settings.

Description of ALMA G2 Laser Methane Leak Detector

ALMA G2, Airborne Laser Methane Assessment Generation 2, is an instrument for remote detection from helicopters of an increased methane gas concentration in ambient air (the gas cloud coming from a leak or other sources). The ALMA G2 is based on an infrared laser with radiation wavelength ~ 1650 nm of which Methane absorbs. A laser beam is emitted from the Optical Unit (OU) and hits a topographic object (soil, grass, trees, concrete, asphalt, etc.). The system analyzes the laser light back scatter to determine how much if any of the laser energy was absorbed by the methane in natural gas. A unique detection algorithm allows for real-time measurement of total methane content along the laser light path from the OU to the topographic object. The system compensates for atmospheric methane using a laser rangefinder. The D-Box and operator laptop with C-Box (control panel) are for system control, data and video storage, and data analysis.

The system continually records the inspection data including GPS location information. The on-line software is used for system control and real-time inspection data monitoring from the laptop. The data process software is used for off-line review of inspection data and generation of a report. The system includes a Digital Video Recorder, up to four video cameras, and a monitor to assist the pilot in aiming the laser. The operator monitors the data provided by the system to confirm gas detections, helps the pilot with navigating along the pipeline, and determines if an area needs further inspection.

ALMA G2 Technical Parameters

Pictures of ALMA G2 Installed on JetRanger Helicopter

The ALMA G2 system consists of 4 parts:
Optical Unit (Housing the Laser, Rangefinder, and Cameras)
D-Box (Housing the Digital Video Recorder and Electronics)
Laptop with C-Box (Control Panel) & GPS
Pilot Monitor

Figure 3 - JetRanger with ALMA G2 Optical Unit (grey) Mounted to Belly

Figure 4 – ALMA G2 D-Box Secured to Backseat with Seatbelt

Figure 5 – ALMA G2 Laptop with C-Box. Held by Operator in Either Front or Back Seat.

Figure 6 – ALMA G2 GPS Mounted on Instrument Console.

Figure 7 – ALMA G2 Pilot Monitor Mounted to Side of Instrument Console.

Using ALMA’s Gas Detection Report to Find the Source of Gas

Important Information:

The ALMA equipment detects the gas cloud coming from the leak in the pipeline not the leak itself. See diagram below.
ALMA’s laser must pass downwind of the pipeline to detect the gas cloud.
ALMA can detect methane gas coming from other sources than the pipeline such as animals, farms, cars/trucks, etc…

Information in Report about Each Gas Detection (Potential Gas Leak)

How to Find Gas Leak Source

Step 1: Go to gas detection location per GPS coordinates or map, and picture.

Step 2: Search for the Source of the Gas.

The location from step 1 is where the gas was detected at that particular time. Walk to the pipeline and inspect the area around the pipeline in both directions as illustrated below by the orange oval.