“The gas pipe exploded because the land has sunk more than 5m in the centre of the mudflow,” the head of the national team overseeing the mud disaster, Basuki Hadimulyono, told online news site detik.com.
“Because the land has sunk, it created pressure and caused 28 inches of pipe to explode."
The explosion is the latest unpleasant turn in a series of events that could cost Australian petroleum major Santos and its joint venture partners dearly. The mudflow is believed to have been caused by careless drilling in May at the Banjar Panjir-1 gas wildcat, in which Santos owns an 18% stake.
The blast, which occurred around 7.30pm on Wednesday, sent a fireball 500m into the air and caused “massive fires”, according to Indonesia’s state news agency, Antara.
Latest reports from Indonesia say at least 13 people were killed with several others injured.
Officials said most of the people killed by the explosion were military, police and government personnel trying to secure a mudflow zone and control the resulting damage. Some were killed by the explosion; others drowned in the mud.
Mud has been flowing in the area for almost six months. On May 29, the Banjar Panjir-1 well was drilling at a depth of 2834m when steam, water, mud and gas were seen venting to the surface about 200m away from the drilling location.
A decision not to insert casing in a shaft as it was being drilled apparently caused a shaft collapse, freeing the high-pressure heated mud.
The mud has engulfed eight villages, displacing more than 12,000 people so far, and is still flowing at a rate of more than 120,000 cubic metres a day.
An extensive civil construction effort has been undertaken to construct a series of levee banks and holding ponds to contain water and mudflow. About 1400 army personnel are also involved in the effort to stabilise the levee walls and to increase the capacity of the mud containment area.
Six weeks ago, Banjar Panjir-1 operator Lapindo Brantas estimated the total costs for drilling relief wells and mud management to be about $US180 million ($A232.4 million).
With the mudflow continuing, the complexity of the event and the dynamic nature of the ongoing work, it was not yet possible to accurately estimate a total rectification cost, the company said.
Based on Santos’ 18% participating interest in the Brantas production sharing contract, and prior to any potential insurance, this higher figure equates to about $A43.7 million, or 7.4c per Santos ordinary share.
Santos yesterday said it was seeking further information on the cause of the accident, its impact and the measures being undertaken by both government authorities and pipeline operator Pertamina.
For now, production from Santos’ Maleo gas project, which uses the pipeline, has been shut-in.
This equates to about 7000 barrels of oil equivalent per day net to Santos.
The well in the Brantas PSC in East Java’s Sidoarjo province, is operated by Lapindo, which has a 50% working interest in the PSC. The other parties are PT Medco E&P Brantas (32%) and Santos (18%).
