New evidence presented at the Geological Society of London seeks to clear drilling operations as a cause of Java’s 2006 mud volcano.
Article By Tayvis Dunnahoe
Published Nov 7, 2008
On May 29, 2006, the island of Java, the most populated island in the World, experienced a mud volcano that has since displaced an estimated 40,000 residents. It currently vents 5.2 MMcf of hot mud per day. The eruption has been named LUSI, a compendium of “lumpur” (the Indonesian word for mud) and Sidoarjo, the town near where the eruption occurred.
The causes of the eruption have not been unanimously decided although a vocal group of scientists have attributed the event to the drilling of Lapindo Brantas Inc.’s Banjar Panji-1 nearby.
The event has been labeled as one of the world’s most significant natural disasters in recent years. New facts presented at the Geological Society of London is casting doubts on the premise that drilling provided a trigger for the catastrophe.
According http://www.mudvolcano.org, a Web site devoted to the event, Lapindo Brantas began drilling the Banjar Panji-1 well to target gas reserves in the Kunjung formation, which is a deep sedimentary basin located 1.9 miles (3 km) below the surface. The site is in Sidoarjo, East Java, Indonesia.
At 5:54 a.m., on May 27, 2006, an earthquake occurred, which measured 6.3 on the Richter scale. The tremor was felt on the drilling rig and approximately seven minutes later the well experienced a “loss” of 20 bbl of mud. The drilling team controlled the situation to industry standards before continuing operations.
On May 29, 2006, a sudden eruption of hot mud and steam began near the well. The initial event was reported as an intermittent hot water eruption with a maximum height of 25 ft (7.6 m) with an elapsed five minute period between the bursts in a distinct geyser-like cycle of active and passive periods.
Due to time of occurrence and its close proximity – 656 ft (200 m) – from the drillsite, general public opinion speculated that the mud flows were triggered by an underground blowout of the Banjar Panji-1 well.
Presented in London’s Geological Society on October 23, a paper titled, “East Java Mud Volcano (LUSI): Drilling Facts and Analysis” (Control ID 472920), Bambang P. Istadi, Nurrochmant Sawolo, et al, examines the drilling data from the Banjar Panji-1. According to its authors the objective of the paper is to, “clearly and transparently set out the drilling engineering data and analysis to correct the technical record and to provide a platform for further analysis.” The analysis focuses on key drilling pressure measurements and drilling facts to investigate the early speculation that drilling was the trigger of LUSI.
Based on their analysis of the drilling evidence, the annular pressure was too low to fracture the wellbore. There was no sustained pressure to propagate fractures. Most importantly, the wellbore was open and totally dead while mud erupted at a rate of more than 300,000 b/d only 656 ft (200 m) from the well. The paper questions data and facts relied on for other papers citing drilling as the cause.
The paper also points the mud volcanoes are numerous in the area, namely the Porong collapse northeast of LUSI among others. The authors claim that LUSI is a special case that allows observation of the ongoing geological processes from the volcano’s controversial beginning. The paper also points other viable hypotheses including mud volcanism due to remobilization of over pressured shale through a reactivated fault as the conduit and geothermal activities where superheated hydrothermal fluids at high temperature and pressure are through fault zones or fracture networks as the conduit.
An open letter
Bambang Istadi and Nurrochmat ‘Rocky’ Sawolo have published an open letter describing their current effort to dispel the “drilling caused” scenario for LUSI. The letter emphasizes the earlier earthquake, which killed more than 6,000 people and rendered an estimated 1.5 million homeless after striking Yogakarta, Java, approximately 161 miles (260 km) from LUSI only two days before the mud volcano erupted.
The letter asserts that new facts make it clear that drilling could not have triggered LUSI. “We do not know where they got their original data, we only know that their findings are incorrect,” Istadi and Sawolo said in response to the vocal minority of scientists that continue to stand by the view that drilling caused the event.
In an effort to sustain their hypotheses, the authors took out an advert in the New Scientist to ask that facts and the official data should drive findings of the causes of LUSI. They also openly invited interested parties to scrutinize their data adding, “To find the real trigger of LUSI we need good science, not unsubstantiated hypotheses.”
They closed their letter with the hope that LUSI could serve as a watershed moment for the science and geology communities stating, “Either we base our conclusions on the facts and complete official data or we don’t.”
A full description of LUSI and the various research attempts it has inspired can be found at http://www.mudvolcano.org. For the full version of Istadi’s and Sowalo’s paper visit click here.