Sidoarjo mud flow
It is the biggest mud volcano in the world; responsibility for the disaster was assigned to the blowout of a natural gas well drilled by Lapindo Brantas,[2] although company officials contend it was caused by a very distant earthquake that occurred in a different province.
This was a significant decline from the previous year, when mud was being discharged at a rate of 100,000 cubic meters (130,000 cu yd) per day with 320 bubbles around its gushing point.
The East Java Basin contains a significant amount of oil and gas reserves, therefore the region is known as a major concession area for mineral exploration.
[14][16] The drilling-induced triggering model proposes that the increase in pressure within the wellbore was sufficiently high to induce a large hydraulic fracture in the formation.
[23] Two days before the mud eruption, an earthquake of moment magnitude 6.3 hit the south coast of Central Java and Yogyakarta provinces killing 6,234 people and leaving 1.5 million homeless.
At a hearing before the parliamentary members, senior executives of PT Lapindo Brantas argued that the earthquake was so powerful that it had reactivated previously inactive faults and also creating deep underground fractures, allowing the mud to breach the surface, and that their company presence was coincidental, which should exempt them from paying compensation damage to the victims.
This argument was also recurrently echoed by Aburizal Bakrie, the Indonesian Minister of Welfare at that time, whose family firm controls the operator company PT Lapindo Brantas.
[1] In June 2008, a report released by British, American, Indonesian, and Australian scientists,[26] concluded that the volcano was not a natural disaster, but the result of oil and gas drilling.
Soon afterwards then-vice president Jusuf Kalla announced that PT Lapindo Brantas and the owner, the Bakrie Group, would have to compensate thousands of victims affected by the mud flows.
[27] Criminal investigations were then initiated against several senior executives of the company because the drilling operation had put the lives of local people at risk.
Afraid of being held liable for the disaster, Bakrie Group announced that they would sell PT Lapindo Brantas to an offshore company for only $2, but Indonesia's Capital Markets Supervisory Agency [Id] blocked the sale.
[29] A further attempt was made to try to sell to a company registered in the Virgin Islands, the Freehold Group, for US$1 million, which was also halted by the government supervisory agency for being an invalid sale.
Their research used GPS and satellite data recorded between June 2006 and September 2007 that showed the area affected by Lusi had subsided by between 0.5 and 14.5 metres (1.6 and 47.6 ft) per year.
The scientists found that if Lusi continued to erupt for three to 10 years at the constant rates measured during 2007 then the central part of the volcano could subside by between 44 and 146 m (144 and 479 ft).
[40] New mudflows spots begun in April 2010, this time on Porong Highway, which is the main road linking Surabaya with Probolinggo and islands to the east including Bali, despite roadway thickening and strengthening.
It is worth mentioning that the owner of the energy company, Aburizal Bakrie was the Coordinating Minister for People's Welfare at the time of the disaster, and is currently the chairman of Golkar, one of the most influential political parties in Indonesia.
[citation needed] The assertion of the geologists and drillers from Energi Mega Persada was that "At a recent Geological Society of London Conference, we provided authoritative new facts that make it absolutely clear that drilling could not have been the trigger of LUSI."
[citation needed] In 2009, this well data was finally released and published in the Journal of Marine and Petroleum Geology for the scientific community uses by the geologists and drillers from Energi Mega Persada.
After hearing the (revised) arguments from both sides for the cause of the mud volcano at the American Association of Petroleum Geologists International Convention in Cape Town in October 2008, the vast majority of the conference session audience present (consisting of AAPG oil and gas professionals) voted in favor of the view that the Lusi (Sidoarjo) mudflow had been induced by drilling.
[46] The article stated that the voting process was a decision by the moderator and only reflected opinions of a group of individuals in the session room at that time and in no way endorsed by the association.
On the possible trigger of Lusi mud volcano, a group of geologists and drilling engineers from the oil company countered the hydro fracturing hypothesis.
[15][47] In February 2010, a group led by experts from Britain's Durham University said the new clues bolstered suspicions the catastrophe was caused by human error.
In journal Marine and Petroleum Geology, Professor Richard Davies, of the Centre for Research into Earth Energy Systems (CeREES), said that drillers, looking for gas nearby, had made a series of mistakes.
[48][49] In the same Marine and Petroleum Geology journal, the group of geologists and drilling engineers refuted the allegation showing that the "kick" maximum pressure were too low to fracture the rock formation.
The 2010 technical paper in this series of debate presents the first balanced overview on the anatomy of the Lusi mud volcanic system with particular emphasis on the critical uncertainties and their influence on the disaster.
More geological field studies and analysis based on factual data need to be done before any conclusion can be deduced on what actually caused Lusi mud volcano.
The new chronology[15] highlights that a number of key claims made by Lapindo Brantas are contradicted by their own daily drilling and well-site reports (that are included as an appendix in[14]).
[14][15] In July 2013, Lupi et al. proposed that the Lusi mud eruption was the result of a natural event, triggered by a distant earthquake at Yogyakarta two days before.
As a result, seismic waves were geometrically focused at the Lusi site leading to mud and CO2 generation and a reactivation of the local Watukosek Fault.
In June 2015, Tingay et al. used geochemical data recorded during the drilling of the Banjar Panji-1 well to test the hypothesis that the Yogyakarta earthquake triggered liquefaction and fault reactivation at the mudflow location.
