Portal:Indonesia/AOTW/22, 2007

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The Sidoarjo mud flow is an ongoing eruption of gas and mud from the earth in the subdistrict of Porong, Sidoarjo in East Java, Indonesia (20 kilometer south of Surabaya). It is considered to be a mud volcano. It appears that the flow will continue for an undetermined amount of time. So far, all efforts to stop the flow have failed.

On 28 May 2006, PT Lapindo Brantas targeted gas in the Kujung Formation carbonates in the Brantas PSC area by drilling a borehole named the Banjar-Panji 1 exploration well. The drill string went into a thick clay seam (500–1,300 m deep), and then sands, shells, volcanic debris and into permeable carbonate rocks. From a model developed by a geologist, the drilling pipe penetrated the overpressured limestone, causing entrainment of mud by water. The most likely cause of these hydraulic fractures in the shallowest strata is by the unprotected drill string with a steel casing.

As of February 2007, the erupted mud pool had an estimated total volume of 0.012 km³ (12 million liter), covered an area of 360 ha (1.4 miles²), was up to 10 m (32.8 feet) thick, buried four villages and 25 factories, displaced at least 11,000 people. It is expected the mud eruption will last for years, even centuries, and the area will experience a significant depression to form a caldera. Infrastructure has been damaged extensively, including roads, railway lines, power transmission systems, and gas pipelines.(Read more...)