As part of its commitment to full lifecycle asset integrity management and associated overall asset decommissioning program, earlier this year MEPAU decommissioned three wells in the Woodada and the Dongara gas fields areas of the Mid West that were no longer being used.
MEPAU Petroleum Engineer Aaron Anthony says this campaign took about five weeks and included some interesting technical challenges.
“These wells were drilled by other companies. As the permit holder it’s now our responsibility to decommission these historic wells however the record keeping wasn’t always great in those days so we don’t always know exactly what we’re going to find.
Aaron says the decommissioning project, known technically within the industry as “P&A” (plug and abandon) involves pumping cement into the well to isolate the hydrocarbon reservoir from the surface and any groundwater aquifers.
The first part of the project involves pulling out tubing and other equipment and fluids remaining in the well and preparing the well bore.
Cement is then pumped into the well, effectively sealing off the reservoir from the surface.
The well is then monitored for three months before the well head is finally removed and the site returned to the pre-well condition.
Aaron agrees the process, which involves about twelve people working with work strings, wire lines, bridge plugs, cement retainers, cement stingers, perforations and more, is a complex one.
“It’s not easy,” he says, “but it’s important we do the right thing and plug the holes responsibly, complying with all the legislative requirements.”
Aaron says there are many other wells in the Perth Basin no longer being used which are being assessed for future decommissioning activity.
“We have been actively engaged in P&A activities in the Perth Basin since 2014 and we’re progressively working through the list of wells. The ongoing decommissioning program means that we are removing wells at a faster rate than they are being drilled. This means our overall footprint is getting smaller,” he says.
Aaron graduated from Curtin University in July 2015 and worked part-time for MEPAU’s predecessor AWE for about two years while still studying. In the office he works on reporting, planning and budgeting, among other things.
He says, “I enjoy coming out to site. The working environment is great – everyone gets on well. They’re hardworking but they enjoy a bit of a laugh.”
“This time, we stayed at Banksia Village, which is a mining camp. We had breakfast and dinner at the camp but received a container to pack ourselves lunch to take out to the site.”
He adds, “The food was pretty good!”
Cementing supervisor having a chat with the rig manager
Just after the crew had finished rigging up the rig
Rig crew running in hole with the tubing