Drilling caused Indonesian mudslide, petroleum geologists say

Petroleum geologists, polled on the cause of the mudslides from Indonesia's Lusi volcano, say they were caused by oil and gas company Lapindo Brantas, which drilled the Banjar-Panji-1 exploration well.

Eric Watkins
Oil Diplomacy Editor

LOS ANGELES, Nov. 1 -- Petroleum geologists, polled on the cause of the mudslides from Indonesia's Lusi volcano, say they were caused by oil and gas company Lapindo Brantas, which drilled the Banjar-Panji-1 exploration well.

The cause of the Lusi mudslides, which started to erupt in East Java on May 29, 2006, was considered in a debate at the American Association of Petroleum Geologists Conference in Cape Town, South Africa.

Seventy-four world-leading petroleum scientists considered the evidence presented by four experts in the field, and 42 of the scientists voted that the Lapindo Brantas drilling project was the cause.

Three scientists voted for the alternative explanation that the Yogyakarta earthquake 2 days before the eruption, whose epicenter was 280 km from the Lusi mud volcano, was the cause.

Some 16 scientists voted that the evidence was inconclusive, while 13 agreed that a combination of earthquake and drilling was the cause.

The vote followed months of scientific investigation and analysis published by some of the world's leading experts in their field.

Key reasons supporting drilling rather than the earthquake as the cause include:

--The earthquake was too small and too far away to have had a role.

--The well was being drilled at the same time and only 150 m from the volcano site.

--The well took a huge influx of fluid the day before the eruption, resulting in pressures that the well could not tolerate.

--The pressure measured in the well after the influx provides strong evidence that the well was leaking and even evidence for the initial eruption at the surface.

"The conference allowed us to present new data on the pressures in the well the day before the eruption,and these provide a compelling tape recording of the well as it started to leak," said Professor Richard Davies of the University of Durham.

"I remain convinced that drilling was the cause of the mud volcano," Davies said. "The opinion of the international scientists at the event in South Africa adds further weight to my conviction and the conclusions of many other leading scientists who have studied Lusi."

"There is no question, the pressures in the well went way beyond what it could tolerate, and it triggered the mud volcano," said Susila Lusiaga, a drilling engineer and one of the individuals interviewed by the Indonesian police as an expert after being provided access to all the drilling data.

"The key observation from an earthquake perspective is that there were many much larger and quite a bit closer earthquakes that did not trigger an eruption," said Michael Manga, Professor of Earth and Planetary Science at the University of California, Berkeley.

"The Yogyakarta earthquake was simply too small and too far away to initiate an eruption," Manga said.

Lusi first erupted in the Porong subdistrict of Sidoarjo in Eastern Java, close to Indonesia's second city of Surabaya. Lusi is still flowing at 100,000 cu m/day.

Some 20,000-30,000 people have lost their homes, and factories have been destroyed. Thirteen people have also died as a result of a rupture in a natural gas pipeline that lay underneath one of the holding dams built to retain the mud.

Contact Eric Watkins at hippalus@yahoo.com.

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