Scientists show link between exploration well and Indonesia's Lusi mud volcano

Feb 11, 2010 By Carl Stiansen
Aeriel view of the Lusi mud volcano crater and the dikes and dams constructed to contain the still-oozing mud.(Courtesy of Channel 9 Australia)

(PhysOrg.com) -- New data provides the strongest evidence to date that the world's biggest mud volcano, which killed 13 people in 2006 and displaced thirty thousand people in East Java, Indonesia, was not caused by an earthquake, according to an international scientific team that includes researchers from Durham University and the University of California, Berkeley.

Drilling firm Lapindo Brantas has denied that a nearby gas exploration well was the trigger for the volcano, instead blaming an earthquake that occurred 280 kilometers (174 miles) away. They backed up their claims in an article accepted this week for publication in the journal Marine and Petroleum Geology, by lead author Nurrochmat Sawolo, senior drilling adviser for Lapindo Brantas, and colleagues.

In response, a group of scientists from the United Kingdom, United States, Australia and led by Richard Davies, director of the Durham Energy Institute, have written a discussion paper in which they refute the main arguments made by Nurrochmat Sawolo and document new data that provides the strongest evidence to date of a link between the well and the volcano. That paper has been accepted for publication in the same journal.

"The disaster was caused by pulling the drill string and drill bit out of the hole while the hole was unstable," Davies said. "This triggered a very large 'kick' in the well, where there is a large influx of water and gas from surrounding rock formations that could not be controlled.

"We found that one of the on-site daily drilling reports states that Lapindo Brantas pumped heavy drilling mud into the well to try to stop the mud volcano. This was partially successful and the eruption of the mud volcano slowed down. The fact that the eruption slowed provides the first conclusive evidence that the bore hole was connected to the volcano at the time of eruption."

The Lusi volcano, which first erupted on May 29, 2006, in the Porong sub-district of Sidoarjo, close to Indonesia's second city of Surabaya, East Java, now covers seven square kilometers - nearly three square miles and is 20 meters (65 feet) thick. The mud flow has razed four villages and 25 factories. Thirteen people have died as a result of a rupture in a natural gas pipeline underneath one of the holding dams. The Lusi crater has been oozing enough mud to fill 50 Olympic size swimming pools every day. All efforts to stem the mud flow have failed, including the construction of dams, levees, drainage channels, and even plugging the crater with concrete balls. Lusi may continue to erupt for decades, scientists believe.

Aerial view of the mud gushing out of a Lapindo Brantas Inc. gas exploration well in Sidoarjo, East Java. Greenpeace has called on Indonesian President Susilo Bambang Yudhoyono to hold Lapindo and its shareholders, Bakrie Group, Santos of Australia and Medco Group, fully accountable for one of the country's worst industrial disasters (Courtesy of Greenpeace)

Arguments over the causes of the Lusi volcano have stalled the establishment of liability for the disaster and delayed compensation to thousands of people affected by the mud. The Yogyakarta earthquake that occurred at the time of the volcano was cited by some as a possible cause of the eruption, but the research team rejected this explanation.

The Durham University-led group of scientists believe that their analysis resolves the cause beyond all reasonable doubt. According to their discussion paper, 'The pumping of heavy mud caused a reduction in the rate of flow to the surface. The reason for pumping the mud was to stop the flow by increasing the pressure exerted by the mud column in the well and slowing the rate of flux of fluid from surrounding formations.'

"An earthquake trigger can be ruled out because the earthquake was too small given its distance, and the stresses produced by the earthquake were minute smaller than those created by tides and weather," said co-author Michael Manga, professor of earth and planetary science at the University of California, Berkeley.

The group of scientists has identified five critical drilling errors as the causes of the Lusi mud volcano eruption:

  • having a significant open hole section with no protective casing
  • overestimating the pressure the well could tolerate
  • after complete loss of returns, the decision to pull the drill string out of an extremely unstable hole
  • pulling the bit out of the hole while losses were occurring
  • not identifying the kick more rapidly
"This is the clearest evidence uncovered so far that the Lusi mud volcano was triggered by ," Davies said. "We have detailed data collected over two years that show the events that led to the creation of the Lusi volcano."

"The observation that pumping mud into the hole caused a reduction in eruption rate indicates a direct link between the wellbore and the eruption," he added. "The decision was made to pull the drill bit out of the hole without verifying that a stable mud column was in place and it was done while severe circulating mud losses were in progress. This procedure caused the kick."

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User comments : 9

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dan42day
4 / 5 (4) Feb 12, 2010
What were they thinking? We all know the dangers of pulling out of a hole while the hole is unstable.
Husky
5 / 5 (3) Feb 12, 2010
i think it has to do with bussiness ethics in countries like indonesia where money comes on place 1,2,3 and 4 and safety takes a backseat, just remember the accidents with garuda airlines caused by lack of maintenance and the unprecedented scale of lumbering wood without any regard for the environment.
Shootist
1 / 5 (2) Feb 12, 2010
A ~.3 meter hole, dug 280 km away, causes an eruption?

Nonsense.
yyz
5 / 5 (1) Feb 12, 2010
Obviously both the company and Indonesia want to portray this as a natural disaster (triggered by an earthquake) in order to avoid liability in the matter. Many of those affected are still waiting for compensation, 4 years after the fact. Looks like they'll be waiting a while longer. Business as usual.
Quantum_Conundrum
1 / 5 (1) Feb 12, 2010
A ~.3 meter hole, dug 280 km away, causes an eruption?

Nonsense.


I thought the same thing. I don't see how one drill hole could cause this. The amount of energy here is like a nuclear bomb in slow motion..."seven square kilometers" and "20 meters thick" is 140 MILLION cubic METERS of "mud". The density of this mud is like 3 or 4 grams/ cubic centimeter, so we are talking about a mass of about 560 MILLION metric tons, or 560 BILLION kilograms...

To put this in perspective, this mud volcano is spewing about 35 times the material per year as the U.S. uses in oil and natural gas per year...

This means that it is extremely unlikely that anyone is "at fault" in this. It must have been a highly pressurized and possibly geothermal pocket under ground which went undetected, and nobody would have successfully drilled there...

Still, the article says the EARTHQUAKE occured 280km away, the drilling must have happened either on-site, or within a few kilometers.
Quantum_Conundrum
1 / 5 (1) Feb 12, 2010
So basicly, this is a legitimate volcanic/hydrothermal vent, just like you would find in Yellowstone or iceland.

Anyway, 7km square at 20m deep is an absolutely huge amount of material, or about "0.14 cubic kilometers. That's something like 226 times the volume of the Great Pyramid...
superhuman
5 / 5 (3) Feb 12, 2010
A ~.3 meter hole, dug 280 km away, causes an eruption?

Nonsense.


Earthquake was 280km away, volcano erupted 200m from the drilling well.

http://en.wikiped...ronology
TegiriNenashi
Feb 12, 2010
This comment has been removed by a moderator.
Caliban
3 / 5 (2) Feb 12, 2010
I 've read some other news about this in the past, and if_ I'm not mistaken, this mud vocano is erupting from the bore hole itself- or at least very near by. In any case- I think the point that they are trying to make is that the collapse of the bore hole(after the fall-through, first, of all that drilling mud) created, in effect, a big bullet, which impacted the hydrothermal strata they were either drilling into or very near to. Apparently, there was enough rebound force to either fracture the overburden and open a fissure to the surface, or possibly to partially blow out the bore hole itself some distance along it's length, and follow a fissure from there to the surface.
yyz
not rated yet Feb 12, 2010
@Caliban, Follow the link given by superhuman. That spells out the geology & controversy adequately. Indonesia *says* it sides by those affected by this disaster.