Gigantic gas stride for the environment: NAGPD eliminates routine flaring
Aramco is committed to achieving zero routine flaring, and the Northern Area Gas Producing Department has innovated high integrity protection systems to safely stop routine flaring at three high-pressure nonassociated gas reservoirs, saving an annual 210 million scf of valuable gas.
In Saudi Arabia’s northern corner, Aramco has ended routine flaring for the mammoth 5.1 billion standard cubic feet (scf) of high-pressure natural gas produced each day from three of the company’s nonassociated gas reservoirs.
Until late last year, to safely control excessive pressure buildups, about 210 million scf of the gas captured each year from the offshore Hasbah and Arabiyah and onshore Khursaniyah fields was flared — enough gas to produce approximately 22,000 megawatt hours of electricity for a year.
Production from the three reservoirs — spread over more than 20,000 km2 and in offshore water depths ranging from 40 to 70 meters — is managed by the Northern Area Gas Producing Department (NAGPD), and manager AbdulRahman M. Al-Qahtani says the progressive conversion up to October 2021 from continuous flaring to maintenance flaring was a considered decision.
“Flaring gas is a waste of a precious natural resource that could potentially be put to good use,” said Al-Qahtani.
“There is seldom a precedence for change, and I am very proud of how our people safely stopped our routine flaring.
“They systematically worked through the risks, consulted with experts, and the impressive result they achieved has reduced our environmental footprint, added a robust layer of safety protection, and saved valuable gas,” he added.
Achieving lower carbon by stopping routine flaring
Nature’s pure pressure from natural gas is both a gift, and a challenge. Aramco primarily uses natural underground pressure of gas to lift oil and gas to the surface, and the company uses the gift of pressure for production from these reservoirs.
However, oil and gas reservoirs require vigilant control over excessive natural pressure, which can be dangerous for industrial facilities, the people working there, and the environment.
Burning the gas (flaring) is a safe control mechanism to depressurize equipment and manage pressure variations, but is also wasteful, and emits greenhouse gases.
Stopping routine flaring — a waste of valuable energy causing both carbon dioxide and methane emissions — supports Aramco’s commitment to the World Bank’s Zero Routine Flaring by 2030 initiative.
High integrity protection systems
With gas from the NAGPD fields reaching an exceptional pressure level, up to 9,000 pounds per square inch, successfully stopping flaring for Khursaniyah’s two manifolds, and Hasbah and Arabiyah’s four tie-in platform flares, required engineering to investigate the best engineering technology for dealing with the hazard of overpressure.
The team looked to high integrity protection systems (HIPS), and outlining the concept, engineering superintendent Ali M. Alkhalidy said the automated safety system uses 9-inch valves to safety shut off the source of the pressure within two seconds.
Instead of relieving the pressure by flaring the gas, HIPS automatically seals off the pressure, which is then held within the wellhead’s fully rated production piping systems.
— Ali M. Alkhalidy
“Critical to HIPS is infrastructure construction integrity to manage with the withheld pressure, and Aramco invests in quality infrastructure,” Alkhalidy added.
Thanks to HIPS, flaring is now only required for maintenance activities.
New safety layer
Gas production — traveling through flow lines from the wellhead platforms to tie-in platforms and onward through trunk lines to a gas plant — has safety and operational challenges requiring continuous monitoring and control.
Digitization helps to deal with these operating conditions that are neither simple nor easy, and emergency shutdown systems for the Khursaniyah, Hasbah and Arabiyah fields are controlled by onshore central rooms in the Wasit and Fadhili gas plants.
After gas reaches a wellhead, it passes through a choke valve for correction to normal operating pressure, and control of its flow rate.
Operation superintendent Marree M. Qahtani explained that HIPS, the next step after the choke valve, was chosen to reduce gas flaring and venting, “It is not only protecting the environment, it adds a safety barrier to protect the people.”
Flaring during periodic maintenance
Aramco, achieving 99.9% reliability during 2021, has a formidable reputation as a reliable supplier of energy to the world, and key to reliability is maintenance.
Each NAGPD offshore field has floating accommodation boats, which are serviced by helicopters from Tanajib or Ras Tanura, and a fleet of up to 15 service boats.
Meticulous planning, and extensive team coordination, goes into regularly maintaining the offshore fields’ extensive subsurface, subsea and above surface equipment, and for safety reasons, during periodic maintenance flaring has to be reactivated.
“When the continuous flaring system is stopped, to remain safe, a minimal amount of flaring is required during maintenance activities, such as during pipeline cleaning,” said Qahtani.
Converting to maintenance flaring offers a contributing solution to air pollution, and an opportunity to create a more productive energy system. For instance, it has also saved 13% of the three fields’ energy consumption.
— Marree M. Qahtani
Impact at scale
Aramco reduced its flaring intensity from 5.97 scf per barrels of oil equivalent in 2020 to 5.51 in 2021.
HIPS is also installed in the North and South Ghawar Producing Departments’ wellheads to relieve pressure on both flow and trunk lines, and reduce flaring.
Caption for top photo: Flaring, a source of greenhouse gas emissions, is used to deal with the hazard of gas pressure buildups in oil and gas facilities, and without compromising safety standards, NAGPD has switched from continuous to maintenance flaring in three nonassociated gas fields. Pictured is a nonassociated gas field Hasbah III tie-in platform.
At the heart of HIPS: Hydraulics
The heart of HIPS’s ability to prevent over pressurization of a piping system, and a processing facility, is its accompanying hydraulic system.
Maintenance technician Wael A. Alharbi graduated from Aramco’s Industrial Training Center in 2013, and his regular duties include looking after the wellhead, modular skid and scraper compartment for NAGPD wellhead facilities. Alharbi explains that hydraulics power the HIPS, “If an overpressure event occurs, pressure supplied by a hydraulic system keeping the HIPS valve in an open position is released to close the HIPS valve, which protects the pipes and the facility.”
“It feels good when I finish my work, as it is my part in helping the environment,” said Alharbi. “We are avoiding a lot of gas emissions to the atmosphere.”
Committed to the environment and safety
A flameless 46 meter elevated flare towers silently above gentle sand dunes rolling alongside Khursaniyah’s onshore gas gathering infrastructure.
Field operator Amer H. Alshamari, walking to the East manifold’s flare stack, says, “Gas is no longer continually burnt to the atmosphere.” Also idle beside the quiet hum of the manifold’s neat assembly of pipes, scraping equipment and corrosion inhibitor tanks, is the flare knock out drum.
Alshamari, who trained for 18 months with Aramco’s own Industrial Training Center, says flaring is now only required during routine maintenance. “We only open the purge line for safety during maintenance activities, and this is better protection for the environment.”