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  • Geolog Internasional Bahas Lumpur Lapindo di London

    Jakarta (ANTARA News) – Lebih 100 pakar geologi dari berbagai universitas ternama di dunia, termasuk Indonesia, mengadakan pertemuan dua-hari mulai Selasa di London untuk membahas fenomena semburan Lumpur Sidoarjo, Jawa Timur.

    Hal tersebut disampaikan pakar dari Universitas Durham, Dr. Richard Davies, dalam jumpa pers di London, Senin, terkait konferensi internasional para ahli kebumian internasional dengan tema “Subsurface Sediment Remobilization and Fluid Flow in Sedimentary Basins”, kata Sunaryo Suradi, salah seorang peserta dari Indonesia kepada ANTARA di Jakarta, Selasa.

    Menurut Sunaryo, Dr. Davies yang berinisiatif menyelenggarakan jumpa pers itu mengatakan lumpur Sidoarjo akan dibahas secara professional keteknikan dengan data-data hasil penelitian terkini.

    Sebanyak 40 pakar berkesempatan bicara dalam dua hari tersebut. Pada hari pertama 22 pakar kebumian akan mempresentasikan makalah yang fokusnya mempertanyakan mengapa sedimentasi di cekungan bawah tanah menjelma reaktif dan menyembur.

    Konferensi itu yang disponsori perusahaan minyak BP, Chevron, ConocoPhilips, DONG Energy, Oilexco, Shell dan StatoilHydro juga dihadiri Prof. Dr. Michael Manga dari Universitas California, Berkeley, Richard Swarbrick Geopressure Technology dan Dr. Bambang Istadi, pakar geologi yang bekerja pada PT Energy Mega Persada sebagai pembicara selain Dr. Richard Davies. Profesor Svensen dari Universitas Oslo sebagai pembicara kunci dalam acara itu.

    Sunaryo mengatakan semburan lumpur Sidoarjo sangat menarik perhatian pakar dunia dan hingga sekarang belum ada penjelasan tentang penyebab dan asal air, tekanan, volume dan material lumpurnya.

    “Acara pertemuan pakar geologi dunia ini sangat menarik dan penting bagi masa depan Porong, Jawa Timur,” katanya.

    Dalam konferensi pers itu suasana sempat memanas dan saling pamer analisa. Dr. Davies, misalnya, menyatakan bahwa temuannya menggunakan data asal Lapindo sendiri.

    Namun pernyataannya itu langsung disanggah dan dipertanyakan oleh Dr. Sawolo, kepala Drilling Sumur Banjar Panji (BJP I). “Data mana dan dari mana otorisasi untuk mendapat data itu, karena Lapindo merasa tidak pernah memberi data,” bantahnya.

    Yuniwati Teryana, wakil Presiden PR Lapindo Brantas Inc. juga mengatakan ia tidak pernah dimintai konfirmasi oleh Davies tentang masalah data tersebut.

    Fokus diskusi hari ini adalah menyangkut pemicu semburan lumpur Sidoarjo, bukan penyebab semburannya. Analisa pakar Internasional seperti Prof Dr. Michael Manga dari (University of California, Berkeley) , Dr. Richard Davies (university of Durham), Mark Tingay (university of Adelaide), Richard Swarbrick (Geopressure Technology)), dan Prof. Dr. Adriano Mazzini (University of Oslo) benar-benar akan menjadi tumpuan warga Porong dan landasan upaya penutupan semburan, kata Sunaryo.

    Terungkap dalam konperensi pers bahwa fenomena lumpur Sidoarjo akan sangat signifikan bagi geolog dunia karena setelah semburan besar 29 Mei 2006, ternyata muncul 99 semburan baru dan gerakan-gerakan tektonik lain. (*)

    © Antara

  • Temuan Baru tentang Lumpur Lapindo

    Luapan lumpur itu hampir dipastikan diakibatkan oleh kesalahan pengeboran yang dilakukan oleh Lapindo Brantas Inc dan bukan akibat efek dari gempa bumi.

    oleh Rusdi Mathari

    SEBUAH tim peneliti independen yang terdiri dari para ahli geologi dari Universitas Durham, Inggris dan Universitas California, Amerika Serikat, kemarin mengungkapkan temuan penting sehubungan semburan lumpur panas Lapindo di Porong, Sidoarjo. Menurut laporan mereka yang dikutip oleh kantor berita AP, luapan lumpur itu hampir dipastikan diakibatkan oleh kesalahan pengeboran yang dilakukan oleh Lapindo Brantas Inc. Mereka bahkan menyebut dengan istilah “99 persen” untuk tidak menyebut 100 persen sebagai kesalahan teknis pengeboran yang dilakukan oleh Lapindo. Gempa bumi memang bisa menyebabkan luapan lumpur, tapi menurut mereka kemungkinan itu sangat kecil, mengingat titik gempa yang cukup jauh dari sumur pengeboran Banjar-Panji 1 Lapindo.

    Laporan para peneliti itu merupakan laporan resmi pertama dari hasil penelitian independen yang dilakukan oleh para geologi internasional tentang luapan lumpur panas Lapindo. Hingga munculnya laporan tersebut, laporan-laporan yang ada tentang lumpur Lapindo tak pernah secara khusus menyebutkan kesalahan pengeboran sebagai satu-satunya penyebab.

    Misalnya sebuah laporan yang pernah dikutip oleh Kompas, hanya menyebutkan bahwa 11 hari sebelum semburan gas, Lapindo sudah diingatkan soal pemasangan casing atau pipa selubung oleh rekanan proyek. Pipa itu seharusnya sudah harus dipasang sebelum pengeboran hingga di formasi kujung atau lapisan tanah yang diduga mengandung gas atau minyak di kedalaman 2.804 meter. Namun Lapindo tidak memasang casing berdiameter 5/8 inci itu pada kedalaman 2.590 meter. Padahal pemasangan casing adalah salah satu rambu keselamatan dalam pengeboran. Namun laporan itu tak pernah menyebutkan secara tegas, apakah hal itu sebagai kelalaian itu yang dilakukan oleh Lapindo atau tidak.

    Laporan dari para peneliti internasional itu, sekaligus juga memutarbalikkan anggapan yang sejauh ini telanjur dipercaya bahwa bencana luapan lumpur yang menenggelamkan 12 desa dan menyebabkan 30 ribu orang kehilangan tempat tinggal itu— diakibatkan oleh gesekan lempeng bumi pasca gempa bumi di Yogyakarta, beberapa hari sebelum lumpur meluap pada 29 Mei 2006. Pihak Lapindo termasuk yang paling berkepentingan dengan dalil bencana alam itu.

    Selama dua hari pada 20-21 Februari 2007, Ikatan Ahli Geologi Indonesia pernah menyelenggarakan lokakarya internasional tentang luapan lumpur panas Lapindo di Jakarta. Lokakarya itu menggandeng Badan Pengkajian dan Penerapan Teknologi dan Lembaga Ilmu Pengetahuan Indonesia dan mengangkat tema diskusi bertajuk “International Geological Workshop on Sidoarjo Mud Volcano.” Hasilnya mengejutkan: peserta lokakarya yang katanya juga menghadirkan ilmuwan dari luar negeri itu berkesimpulan, semburan lumpur panas Lapindo diakibatkan oleh gempa bumi.

    Bertolak Belakang dan Manipulatif

    Kesimpulan dari lokakarya dari para ahli geologi itu lalu menjadi pegangan Lapindo. Dalam kasus luapan lumpur itu dan antara lain karena “rekomendasi” IAGI berdasarkan kesimpulan lokakarya itu, pihak Lapindo bersikeras bahwa penyebab semburan lumpur adalah efek dari gempa bumi yang terjadi di Yogyakarta pada awal Mei 2006. Beberapa pihak yang sependapat dengan alasan itu, menyebutnya sebagai bencana yang sulit tidak diperhitungkan sehingga karena itu, pemerintahlah yang harus bertanggung jawab dan mengambil alih persoalan.

    Namun beberapa kalangan yang lain justru menganggap kesimpulan semacam itu terlalu prematur. Sony Keraaf Ketua komisi II DPR-RI yang juga mantan Menteri Lingkungan Hidup bahkan mengatakan adalah manipulasi fakta jika semburan lumpur Sidoarjo adalah akibat gempa bumi. Dikutip oleh situs Tempointeraktif, Ketua IAGI periode 1973-1975, Koesoemadinata, juga tak kalah sengit memberikan komentar terhadap kesimpulan lokakarya IAGI. Koesoemadinata menilai kesimpulan lokakarya itu tidak mencerminkan IAGI yang independen, tidak relevan dengan materi, bahkan cenderung bertolak belakang. Tak lupa Koesoemadinata mengatakan, dirinya sangat prihatin dengan hasil lokakarya yang disebutkan bertaraf internasional itu.

    Menurut Koesoemadinata, sebagai lembaga ilmuwan yang independen IAGI seharusnya juga memberi ruang mengenai adanya pendapat bahwa semburan lumpur panas itu terjadi karena kelalaian pengeboran. Koesoemadinata mengkhawatirkan IAGI telah digunakan untuk kepentingan-kepentingan tertentu. Padahal menurut dia, kebenaran ilmiah sebagai ilmuwan harus dipertahankan.

    Masih Berpotensi

    Beberapa laporan menyebutkan lumpur panas Lapindo yang menyembur dapat mencapai 125 ribu meter kubik per hari dengan bau menyengat. Untuk mengetahui volume lumpur yang sudah merendam 600 hektare sawah, dan menenggelamkan 10 ribuan rumah penduduk Porong, tinggal mengalikan jumlah hari selama dua tahun terakhir dengan debit lumpur yang dikeluarkan setiap hari.

    Tak jauh dari lokasi eksplorasi sumur Banjar Panji 1 dulunya berdiri 24 pabrik yang memproduksi berbagai komoditas dan menyerap puluhan ribu tenaga kerja. Sejak lumpur meluap, semua pabrik itu terkubur oleh lumpur termasuk perekonomian kecil yang diusahakan oleh penduduk setempat. Hingga setahun bencana, Kamar Dagang dan Industri Jatim mencatat, jumlah kerugian akibat kasus lumpur Lapindo yang diderita pelaku industri mencapai Rp 2 triliun. Badan Perencanaan dan Pembangunan Nasional atau Bappenas memperkirakan, kerugian langsung maupun tak langsung yang ditimbulkan oleh bocornya sumur gas Lapindo sudah mencapai Rp 27,4 triliun.

    Menteri Pekerjaan Umum Djoko Kirmanto pernah menaksir luas kawasan bencana akibat semburan lumpur panas Lapindo mencapai sekitar 400 hektare. Itu taksiran Pak Menteri pada beberapa bulan pertama bencana lumpur Lapindo. Sekarang, luas areal itu tentu saja telah bertambah dan semuanya menjadi hak Lapindo, karena mereka telah mengklaim membayarkan ganti rugi kepada penduduk yang ikut menjadi korban.

    Rennier A.R. Latief yang pernah menjabat Direktur Utama Lapindo mengatakan, dalam dua tahun mendatang Grup Bakrie akan mendapatkan untung besar dari luasnya areal bencana itu. Terutama jika areal itu kelak benar-benar kering. Seorang pakar dan pelaku bisnis perminyakan mengatakan, di areal itu masih tersimpan cadangan gas dan minyak yang cukup besar. Grup Bakrie, kata dia, hanya menunggu waktu sembari mengulur-ulur waktu pembayaran ganti rugi kepada sebagian penduduk yang kini masih belum menerima ganti rugi dari Lapindo.

    Laporan terbaru dari para ahli geologi Inggris dan Amerika Serikat yang dipublikasikan Selasa kemarin, tentu akan menimbulkan perdebatan. Namun temuan itu seharusnya mulai juga menjadi salah satu pertimbangan pemerintah untuk menyelesaikan berbagai persoalan akibat luapan lumpur Lapindo di luar pertimbangan IAGI yang menyebutkan luapan lumpur itu akibat efek gempa bumi. Antara lain untuk meminta pertanggungjawaban Grup Bakrie secara ekonomi dan sosial dan tidak lagi membebankan sebagian atau semua akibat luapan lumpur itu kepada keuangan negara.

  • New report says Indonesia mud disaster man-made

    JAKARTA, June 10 AAP – Indonesia’s devastating mud volcano is a man-made disaster caused by exploratory drilling for gas, a new report has found.

    Researchers say the finding disproves the theory, long-argued by the exploration well’s operator, that an earthquake 250km away was to blame.

    The mud volcano burst through the earth two years ago during deep drilling at the exploratory gas well, linked to Indonesia’s richest man and also part-owned by Australian company Santos.

    It has spewed millions of cubic metres of hot, stinking sludge in heavily populated East Java over the past two years.

    “We are more certain than ever that the Lusi mud volcano is an unnatural disaster and was triggered by drilling the Banjar-Panji-1 well,” Professor Richard Davies, of Durham University in the United Kingdom, said in a statement.

    The mud now covers seven square kilometres, and has displaced 30,000 people and swallowed 11 villages, thousands of homes, businesses, paddy fields and mosques. It continues to spurt 100,000 cubic metres of mud each day.

    The study – described as the most detailed scientific analysis to date – was published in the academic journal Earth and Planetary Science Letters this week.

    It follows a study by Durham University last year which found the mud eruption was “almost certainly man-made”, and caused by the exploratory drilling.

    But the well’s operator Lapindo – linked to the powerful family of Indonesia’s Public Welfare Minister Aburizal Bakrie – has long argued it was a natural disaster caused by a 6.3 magnitude earthquake in Yogyakarta two days earlier, a claim backed by a Jakarta court ruling last year.

    In the latest study, University of California researchers tested claims that the eruption was caused by the Yogyakarta tremor and found it did not play a role.

    “We have known for hundreds of years that earthquakes can trigger eruptions – in this case, the earthquake was simply too small and too far away,” said the university’s Professor Michael Manga.

    The report found the effect of the earthquake was minimal, with only a “tiny” resulting change to underground pressure. It said scientists were 99 per cent certain drilling operations were to blame.

    The research comes just weeks after another study by Durham University, which found the mud volcano was in danger of collapsing on itself. It warned the bleak, sodden landscape is sinking – and could subside by as much as 146 metres over the coming years.

    Comment was being sought from Lapindo.

    © AAP News Wire

  • Indonesian Firms Denied Drilling Caused Mud Volcano

    JAKARTA (Reuters) – A volcano that started spewing hot mud in Indonesia two years ago displacing more than 50,000 people was triggered by tectonic activity, experts working for the energy firm blamed by some for the disaster said on Thursday.

    The comments contrast with the view of an international team of experts who said on Monday that drilling for a gas exploration well, and not an earthquake, set off the volcano in East Java.

    A geologist and drilling expert working for oil and gas firm Lapindo Brantas said that the international team, led by Richard Davies of Britain’s Durham University, had based their findings on the wrong data and assumptions.

    “Experts opinion, Davies and others, that concluded that the burst came from the drilling well is based on a study that used the wrong data and assumption,” Edy Sutriono, drilling expert at Lapindo, told a news conference.

    The international team had said records kept by Lapindo during the drilling of the gas exploration well called Banjar-Panji-1 showed an underground blowout that could have triggered the disaster.

    But Bambang Istadi, a geologist at Lapindo, said tectonic activity had caused an old escarpment to crack and become the channel for the mud to flow.

    The company and some experts have argued that the mud flow was caused by a 6.3 magnitude earthquake in Yogyakarta and its aftershocks that happened two days before the eruption. That quake, centred 160 miles from the mud volcano, killed 6,000 people and left 1.5 million homeless.

    Richard Davies told Reuters on Thursday that the well was being drilled next to a mud volcano at the same time it erupted.

    The hot noxious mud began spewing near the gas exploration site in Sidoarjo, in East Java, on May 29. “I mean, it’s just I’m sorry, there’s just too much evidence now to propose that this isn’t due to the well,” he added, noting there would be a public debate with Lapindo experts on the issue in late October this year in Cape Town, South Africa.

    The mud, which is flo wing at a rate of more than 100,000 cubic metres a day, has displaced more than 50,000 people and covered more than 2.5 square miles.

    A mud volcano is usually a naturally occurring phenomenon created when a mix of mud, water and gas forms underground and is forced to the surface. There are a few thousand on earth.

    PT Energi Mega Persada indirectly controls Lapindo, which holds a 50 percent stake in the Brantas block where the mud originated. PT Medco Energi International Tbk holds a 32 percent stake and Australia-based Santos Ltd the rest.

    The situation has also become a major embarrassment for the government since Energi is owned by the Bakrie Group, controlled by the family of chief social welfare minister, Aburizal Bakrie.

    Indonesia’s government has ordered Lapindo to pay 3.8 trillion rupiah ($408.1 million) in compensation to the victims and to cover the damage ($1=9311 Rupiah).

    Olivia Rondonuwu | © Reuters

  • Two Years On, a Mud Volcano Still Rages and Bewilders

    As a disastrous mud eruption on Indonesia’s Java Island marks its second anniversary, the unprecedented event continues to stir debate about whether it resulted from an exploratory gas well drilling accident or a distant earthquake and how long it will last. The mud volcano, nicknamed Lusi, has been disgorging mud at a rate of up to 150,000 cubic meters per day. Officials are struggling to contain the effluent within dikes that are regularly breached and built anew farther out.

    In November 2006, ground deformation near the volcano ruptured a natural gas pipeline, killing 13 people. Lusi’s mud has engulfed 750 hectares, destroying the homes of more than 30,000 people as well as factories and farms. “Sadly, it’s not about simple technical problems anymore. It’s more [about] economic and social and political problems,” says Satria Bijaksana, a geophysicist at Institut Teknologi Bandung.

    Lapindo Brantas, the oil and gas exploration company that operated the ill-starred gas well, and the government have promised compensation to landowners, but it has been slow in coming. Hundreds of families are still living in temporary shelters. In two separate cases, Indonesian courts have ruled the eruption a natural disaster, absolving Lapindo Brantas of liability.

    Ivan Valentina Agung, a lawyer for Walhi, an Indonesian environmental group that filed one of the suits, says the group is appealing to a higher court in hopes of getting Lapindo Brantas to take responsibility for environmental rehabilitation.

    For scientists, Lusi is an intriguing specimen. A flurry of papers refines previous work on the eruption’s dynamics and offers insights into the evolution of mud volcanoes. “This is a great opportunity. Nobody knows how other mud volcanoes looked when they were first appearing,” says Adriano Mazzini, a geologist at the University of Oslo.

    There is general agreement on the sequence of events. On 27 May 2006 at 5:54 a.m. local time, a magnitude-6.3 earthquake struck near Yogyakarta, in central Java. Between 5 and 8 a.m. the following day, Lapindo Brantas’s gas well, which was being drilled 250 kilometers to the east near the town of Sidoarjo, began to flood. Workers shut the well’s blowout preventer to keep the fluid from gushing out the top. They noted that pressure inside the well rose rapidly before gradually subsiding. Early in the morning of 29 May, mud began burbling out of the ground about 150 meters away.

    In a February 2007 article in GSA Today, Richard Davies, a geologist at the University of Durham, U.K., and colleagues claimed that the drillers penetrated a porous limestone formation about 2800 meters below the surface, inadvertently tapping into a highly pressurized aquifer. The borehole’s casing didn’t extend deep enough to protect rock from cracking under the pressure when the blowout preventer was shut, he concluded. Water then channeled its way to the surface, bringing mud with it (Science, 2 February 2007, p. 586).

    That’s not how Mazzini and his colleagues see it. In the 30 September 2007 issue of Earth and Planetary Science Letters, they argued that the region’s geological structures, pressurized hydrocarbon deposits, common in the region, and a seismic fault created conditions “perfect for a mud volcano.” The only thing missing was a trigger, Mazzini says. The drilling might have contributed, he says, but he believes a more important factor was that the Yogyakarta earthquake reactivated the fault. At roughly the same time Lusi broke, mud also erupted from eight fissures along a 100-kilometer stretch of the fault line. “I don’t think this is a coincidence,” he says.

    Global Positioning System (GPS) data and an obvious kink in a rail line show that ground along the fault has shifted up to half a meter since the Yogyakarta earthquake. But Michael Manga, a geologist at the University of California, Berkeley, who has studied how earthquakes trigger distant volcanic eruptions, contends that the quake was too small and too far away from the fault to influence it. In recent decades, he says, “there were many earthquakes that were both closer and bigger and by any measure more likely to have triggered an eruption.”

    In a paper published online on 5 June in Earth and Planetary Science Letters, Manga, Davies, and colleagues suggest that the fault is likely to be shifting in response to the movement of vast amounts of material to the surface. The mechanism is not clear. Co-author Rudi Rubiandini, a petroleum engineer at the Institut Teknologi Bandung, says the analysis “makes every other reason [for the eruption] impossible.” Most earth scientists agree that the well must have had some effect, says James Mori, a seismologist at Kyoto University in Japan. But he says researchers can’t determine whether the volcano would have formed without the drilling.

    While sympathizing with Lusi’s victims, geologists say they relish the rare opportunity to study a mud volcano’s birth and evolution. GPS and satellite-based interferometric synthetic aperture radar data indicate that the surface near the volcano’s vent is collapsing into a funnel shape, characteristic of sand draining from the top bulb of an hourglass. Davies and colleagues concluded in a paper published online on 21 May in Environmental Geology that between June 2006 and September 2007, the funnel’s center sank at about 4 centimeters per day, which in 3 years would produce a sag of 44 meters. They also report that areas outside the funnel are rising, probably due to movement of the fault.

    Scientists are puzzling over other phenomena as well. Since March 2007, the flow has periodically stopped for hours or days only to resume with its previous vigor. The likely explanation, Davies says, is that the weight of mud at the surface is collapsing the vent deep underground. Pressure backs up until it breaks through the blockage. In addition, there have been 88 minieruptions of water and methane where the ground is subsiding. Rubiandini believes the subsidence is cracking open pressurized gas pockets. And along the fault, geysers of water have suddenly shot up in the middle of yards, rice paddies, and even within factories, probably due to the rearrangement of subsurface plumbing.

    “The volcano is taking on a life of its own,” Davies says. How long this will go on, he says, is anybody’s guess.

    Unstoppable

    The mud volcano Lusi is unique in its longevity and the volume of material ejected. It may also be setting records for the number or failed attempts to plug it. Immediately after the 29 May 2006 eruption, Lapindo Brantas., the company whose exploratory drilling, some claim, triggered the eruption, pumped concrete into the well to try to stop the gush of hot, salty water from a subsurface aquifer. When that failed, the company brought in a consultant from Houston, Texas, who directed the drilling of two relief wells intended to intercept the original borehole and pump in high density drilling mud to plug the leak. This effort was abandoned when the wells were short of their target, also, reportedly, because Lapindo ran out of money.

    In February 2007, following a proposal from geophysicist Satria Bijaksana and two colleagues from Institut Teknologi Bandung, Lapindo Brantas started dropping into the vent clusters of concrete balls, 20 centimeters and 40 centimeters in diameter, roped together with steel cables. The objective, Bijaksana says, was “to reduce the sheer volume of mud coming out of the vent to a manageable level.” This effort was abandoned after 398 of a planned 1000 clusters had been dropped; a government agency that took over management of the disaster concluded that the balls were having little effect.

    The only hope of plugging Lusi is to drill another relief well to plug the original well at a point below where it was breached, says Rudi Rubiandini, a petroleum engineer at Institut Teknologi Bandung. He estimates that the well would cost $70 t0 $100 million. But that is unlikely to happen, he says: “Our government now thinks this is a natural disaster and impossible to kill.”

    Dennis Normile

  • Confronting evidence questions cause of mud eruption disaster

    Devastation from a mud erupting volcano on the Indonesian island of Java is not caused by an earthquake as previously thought, claims a Curtin University of Technology geologist in a paper published in the current issue of Geology.

    The Lusi mud volcano has erupted unabated for over two years, flooding 11 villages and displacing over 40,000 people in East Java.   Curtin researcher Mark Tingay, whilst working for the University of Adelaide, uncovered evidence of unsafe drilling practices prior to the eruption.  As a result he questions the theory that the 2006 earthquake which triggered the flow is the direct cause of this large scale disaster.

    In his paper titled “Triggering of the Lusi mud eruption: Earthquake versus drilling initiation” Post Doctoral Fellow and lead author, Tingay explains the magnitude of the disaster and addresses the questions it provokes.

    “The May 2006 mud flow from the Lusi volcano caused unprecedented damage by flooding an area of seven square kilometres to depths of 20 metres over a two year period.  Although some scientists and the Indonesian government believe the mud flow was triggered by the Yogyakarta earthquake that occurred 250 km away and two days before the eruption, this earthquake is calculated to be too small in magnitude to have caused such devastation,” Dr Tingay said.

    “Earthquakes have triggered events like this before, however the Yogyakarta earthquake was at least ten times too small to have triggered such a disaster, whilst the well that was drilled only 200 metres away from the volcano is the more likely cause.”

    Tingay claims that the skipping of two planned casing points during drilling of the Banjar Panji-1 (BJP-1) gas well meant that the borehole was not properly reinforced and thus vulnerable to a drilling accident known as a ‘kick’.

    “The BJP-1 gas exploration well, located 200 metres from the eruption suffered several drilling problems, including a large ‘kick’, during which we calculate pressures in the well were sufficient to fracture the rocks and create fluid flow pathways to the surface,” Dr Tingay said.

    “The hazardously narrow drilling window in the BJP-1 well, together with the significant deviation from planned protective casing design, are widely regarded as unsafe drilling practices. Indeed, it is possible that this disaster could have been avoided had protective casing been set as planned.”

    Tingay and his co-authors provide a quantitative discussion of the long-running debate on whether the mud eruption was triggered by natural or anthropological events, with the owner of the BJP-1 well potentially facing damage costs estimated to be in the vicinity of US$420 million dollars if found to be negligent.

    “Seventeen people have died as a result of the eruption and around 40,000 are now permanently displaced as mud rises at rates of 100,000 cubic metres a day.  That’s the equivalent of over 50 Olympic swimming pools a day,” Dr Tingay said.

    The Lusi mud flow could continue flowing for over 10 years with the strong possibility that further problems will arise as a result of the area around the disaster area rapidly sinking.

    The study was conducted in collaboration with Dr Oliver Heidbach of Karlsruhe University, Germany, Professor Richard Davies of Durham University, UK and Dr Richard Swarbrick of GeoPressure Technology, UK.

    Tingay’s paper can be viewed on the Geological Society of America site: http://www.gsajournals.org/perlserv/?request=get-toc&issn=0091-7613&volume=36&issue=8

    Contact:  Mark Tingay, Department of Applied Geology, Curtin, 08 9266 7097, [email protected]

  • Mud volcano ‘on brink of collapse’

    The world’s largest mud volcano that has been erupting continuously since 2006 is beginning to show signs of “catastrophic collapse”, according to geologists who have been monitoring it and the surrounding area.

    The volcano – named Lusi – has already devastated homes and businesses in Sidoarjo, East Java, Indonesia, displacing around 10,000 people and killing 14.

    Now scientists say that the land near the central vent could sag by up to 146 metres in the next decade. In March, the scientists observed drops of up to 3 metres in one night. Most of the subsidence in the area around the volcano is more gradual, at around 0.1cm per day.

    “It is starting to show signs that the central part is undergoing a more catastrophic collapse,” said Prof Richard Davies, a geologist at Durham University.

    “The fact that the whole area is collapsing means there are probably new faults forming. These faults are new pathways for fluids to seep up to the surface. We’ve never really seen a mud volcano develop so quickly.”

    The team have monitored the subsidence using fixed GPS stations which are able to record very accurate ground movements by communicating with satellites. They reported their results in the journal Environmental Geology.

    Last year, the Indonesian authorities began a desperate plan to drop 2,000 concrete balls into Lusi’s central vent in an effort to stem the flow. Davies watched the operation, which went on for 2 months.

    “What happened was they dropped them and never saw them again,” he said. “It just gobbled them up.”

    Since it began spewing noxious mud and gasses on May 29 2006, Lusi has blanketed an area of around 7 cubic kilometres, covering 10,426 houses, 35 schools, 65 mosques and one orphanage. The advancing mud is now contained behind human-engineered dykes.

    The central collapse may be good news because it will make room for more mud at the surface and so take the pressure off the dykes. But subsidence around the submerged zone will have more impact on the local community.

    A bridge that developed cracks has already had to be dismantled, railway tracks have been moved out of line and in November 2006, 13 people were killed in a gas blast caused by an underground pipe rupturing.

    Davies does not believe there is any way to stop Lusi now. “I think now the system has become so big … the plumbing system is so complex you couldn’t hope to stop it.”

    James Randerson

    Sumber: The Guardian

  • Lusi sinking into its own caldera

    Two years after it first erupted, Lusi is back in the news again, this time because the area around the vent is starting to show signs of subsidence. The world’s fastest-growing mud volcano is collapsing by up to three metres overnight, suggests new research.

    As the second anniversary (May 29) of the eruption on the Indonesian island of Java approaches, scientists have found that the volcano – named Lusi – could subside to depths of more than 140 metres with consequences for the surrounding environment.

    The sudden overnight three metre collapses could be the beginning of a caldera – a large basin-shaped volcanic depression – according to the research team, from Durham University UK, and the Institute of Technology Bandung, in Indonesia.

    Their findings, based on Global Positioning System (GPS) and satellite measurements, are due to be published in the journal Environmental Geology.

    The fact that subsidence is occuring is actually no surprise; it’s a natural consequence of the eruption itself. Lusi was the result of the breaching of a subsurface aquifer – a porous, water-bearing rock horizon, which was being squeezed by the weight of all the overlying rocks. Because the cap rocks were impermeable mudstones, the water couldn’t move anywhere in response to this squeezing, meaning that the water within the aquifer was being held under extremely high pressure.

    As soon as the breach occurred, all that pressure had an outlet, causing high pressure water to burst upwards, mixing with the overlying mudstones on the way to create the lovely ooze that is currently engulfing Sidoarjo province. For those who remember Super Soakers, they work along a similar principle – you increase the water pressure by pumping air into a sealed water reservoir, resulting in a much stronger water jet when you finally pull the trigger and create a ‘breach’.

    Obviously this is going to lead to a decrease in water pressure within the aquifer; since this pressure was resisting the weight of the overlying rock – now augmented by the weight of the mud that has erupted onto the surface – a decrease will lead to compression of the aquifer, and subsidence, in the area where the eruption is occuring.

    The Environmental Geology paper by Abidin et al. observes exactly this. The GPS data presented was collected between June 2006 and September 2007, and indicates fast subsidence of 2-4 centimetres a day in the first four or five months after the eruption, and slower (and apparently slowing) subsidence of 0.1-0.3 cm a day thereafter. Even after it slowed down, that’s getting on for a metre of displacement every year, which is very fast by geological standards.

    The paper also refers to more recent measurements where large vertical displacements – 10s of cm or even metres – appear to have occurred literally overnight, which might indicate that some of the subsidence is now being taken up by extensional faulting around the vent.

    The formation of such a caldera may restrict the lateral extent of the mud flow, by creating a natural hole for it to fill (although human intervention though the building of dams is also a control here).

    Radar interferometry, which compares altimetry data collected after the eruption to altimetry collected before to highlight changes in topography, has also been used to examine elevation changes over a wider area, and confirms that subsidence has occurred up to 10 km from the central vent. Interestingly, it also shows that a sizeable area to the northeast has been uplifted since the eruption:

    The boundary between the uplifted region and the subsiding vent follows the trend of a fault which runs through the area, indicating that it has been active since Lusi first erupted. This is very interesting, because it is this fault – the Watukosek Fault – that has been cited in the argument that Lusi was a natural response to an earthquake, rather than shoddy drilling practices.

    Does this new data support that interpretation, and let PT Lapindo Brantas (or whatever they’re called now) off the hook? No, actually – the deformation associated with motion on this fault only begins after July 2006, two or three months after the eruption first started, so it in fact fairly conclusively proves that it was not involved in the initial breakthrough. Somehow, though, I doubt this will be the final word on this particular subject.

    Chris Rowan

    Sumber: Science Blogs

  • Volcano of mud makes 50,000 homeless

    Campaigners say drilling by energy firm caused huge eruption, which has already killed 13 in Indonesia.

    The people of Sidoarjo gathered to say prayers this week. Beside a noxious sea of shifting grey mud they asked for help to rebuild their lives and for deliverance from further encroachment by the methane-spitting sludge.

    Already 13 people from this district in the east of the Indonesian island of Java have lost their lives to the world’s largest mud volcano, and a further 50,000 have been made homeless. Every day as the volcano continues to spew forth hot mud, more people and their villages are threatened. Schools and factories have had to be moved.

    An Indonesian court says this is a natural disaster. Yet human rights campaigners, as well as a team of scientists from Durham University, say the mud volcano that has been named Lusi was triggered by a gas-drilling operation two years ago. What gives this story an added twist is that the company is owned by the family of the country’s richest man, who also happens to be Indonesia’s Welfare Minister.

    The images of Lusi are nothing short of remarkable. The area at the very centre of the volcano has been surrounded by 20m-high concrete walls erected by the authorities to try to stem the flow. But already, the area now covered by the splurging mess totals more than 1,500 acres.

    Worse still, there are signs that the entire area is sinking and forming a huge crater. “The centre is falling by 4cm a day, which amounts to around 14m a year,” said Professor Richard Davies, head of a team from Durham University which has studied the volcano. “Sidoarjo is a populated region and is collapsing as a result of the birth and growth of Lusi. This could continue to have a significant environmental impact on the surrounding area for years to come.” He said the plunging volcano could cause other fractures and faults within the landscape and even begin to start shifting the course of rivers.

    Professor Davies said his team was 99 per cent certain that the volcano had been triggered by gas drilling in the region two years ago. He said it appeared workers from the Lapindo Brantas company had drilled to more than 3,000 metres and tapped into a water-bearing aquifer that was located beneath a seam of mudstone. The effect had been to release the pressure in the aquifer, causing the water to push out through the mudstone, creating a volcano of mud.

    That initial eruption two years ago this week killed 13 people and inundated 12 villages with a flood of mud. Every day since the volcano has continued to produce between 50,000 and 150,000 cubic metres of mud – enough to fill 60 Olympic-sized swimming pools.

    Yet the people of Sidoarjo say they have received barely any help or compensation from the government or Lapindo Brantas, which is owned by the family of the billionaire government minister Aburizal Bakrie. While thousands live in makeshift shanties waiting for help and refusing to move, the company this week took out advertisements in newspapers proclaiming its “social commitment” to the area but insisting experts believe the volcano was a natural phenomenon.

    Last month, the company stopped giving out food rations to displaced villages and said they should accept the compensation that had been offered. The homeless insist instead that they be given a lump sum to build new homes. “They can’t live there for ever. They should immediately submit documents and accept the compensation,” said a company spokeswoman, Yuniwati Teryana.

    Last year the authorities ordered the company to pay more than £220m in compensation and for work to halt the spread of the mud. But campaigners say only residents in four of the villages affected by the mud were eligible for compensation and that, of those people, only 20 per cent have so far received any money from the oil and gas giant.

    Campaigners say the government is unwilling to challenge the company to do more. No one has been charged with any crime in relation to the volcano. Chalid Muhammad, who heads a campaign group, the Movement to Promote Justice for the Lapindo Victims, said: “The government only needs to have the political will and the political courage to push the company to pay compensation.”

    All the while, as the people of Sidoarjo pray for help and as Lapindo Brantas continues to deny responsibility for what happened, the world’s largest mud volcano continues to spew mud and grow. Every single day.

    Andrew Buncombe, Asia Correspondent

    Sumber: The Independent

  • Lusi: not man-made after all?

    Regular readers of this blog should be aware of the mud volcano currently erupting in the Sidoarjo district in East Java, Indonesia, and the unsuccessful attempts to stem the flow by dropping concrete balls into the vent. Meanwhile, more and more villages, railways and factories are being engulfed, and tens of thousands of people displaced, by the encroaching mud.

    Obviously someone has to pay for the attempts at mitigation, no matter how hare-brained, and compensate those who have found their homes and livelihoods suddenly below ground level. Precisely who that someone should be has been the subject of a fair amount of legal wrangling between the Indonesian government and PT Lapindo Brantas, an exploration company who were drilling a gas well in the area at the time of the eruption.

    At first glance, it doesn’t look good for Lapindo Brantas: not only is the main vent of Lusi is a mere 200 m from their well, but it also turns out that the lower section of the borehole had not been ‘cased’, or sealed off from the surrounding rock with steel jacketing. In the paper which provided the background to my original post on Lusi, Richard Davies and his co-authors suggested that this lack of protection was directly responsible for the eruption: when the borehole penetrated a sealed limestone aquifer, it released a surge of high pressure water back up the drill hole, fracturing and mixing with the overlying mudstones and sending the a torrent of hot mud racing up to surface.

    But there is a complication. Two days before Lusi erupted, a magnitude 6.3 earthquake hit central Java. Could this have had something to do with the eruption of Lusi? Davies et al. say no, but a paper in press in Earth and Planetary Science Letters argues otherwise – and thanks to the obvious legal ramifications, this little spat is getting a little bit of media attention. In this second paper, Adriano Mazzini, of the University of Oslo, and his colleagues* propose that shaking due to the earthquake weakened a fault which runs close to the Lusi vent, and it was this structure, not the borehole, that initially provided an escape route for the overpressured water. Their Figure 4 shows the location of the fault (dashed line) in relation to the borehole (BJP1) and all the mud eruptions in the area in the first week of activity.

    This is interesting, and I can certainly see how the presence of this fault might have exacerbated matters. But it’s difficult to ignore the fact that even if teleseismic stresses acting on a buried fault did have a hand in triggering the eruption, of all the places Lusi could have erupted along that fault, it erupted at the closest possible point to a borehole which was not properly sealed, and therefore at high risk of blow-out. Could this be a coincidence? Mazzini et al. would have us believe so: they claim that the borehole had not penetrated down to the limestone aquifer at the time of the eruption (directly contradicting Davies et al.), and that, almost miraculously, the eruption has not registered in the borehole in any way at all:

    no kicks [pressure fluctuations]. were recorded at the bottomhole of BJP1 [at the time of the eruption], and no fluids erupted through the well… Borehole tests showed that there was no connection between the fluids circulating in the well and mud erupted on surface.

    Neither of these claims is supported by hard data in the paper, so where the two papers disagree on vital and important facts (particularly the depth attained and the timing and nature of pressure changes in the borehole), it is rather difficult to assess who is right. I have to say that regardless of the root cause of the eruption, the subsurface around the vent is probably now so pervasively fractured, and the borehole is such an obvious weak point, that it seems rather unlikely that you see no sign of the eruption in the borehole fluids.

    You’d also think that the eight experts consulted by the Indonesian police, who must surely have had access to the borehole records, would have been a bit less confident in implicating the drilling if this was the case. But then, when there are bills and blame to be assigned, the science is always going to be stretched to breaking point – especially since a law-suit demands a black-and-white answer to what may turn out to be a complicated question: ‘would Lusi have erupted, and erupted so spectacularly, if the Lapindo Brantas borehole been properly sealed?’.

    The answer to that may well be yes, even if the May 27th earthquake does prove to be a factor.

    Chris Rowan 

    Sumber: http://scienceblogs.com/highlyallochthonous/2007/08/lusi_not_manmade_after_all.php

  • Happy Birthday, Lusi (the Drilling Totally Did It)

    It’s been two years since the ground opened near Sidoarjo, Indonesia, spewing mud over the homes, farms, and businesses of tens of thousands of people. The disaster quickly acquired the rather endearing name of “Lusi”, which is short for “lumpur” (Indonesian for mud) and “Sidoarjo”. The two-year anniversary media bonanza has focused on the continuing plight of the refugees and the publication of a new paper analyzing GPS data around the mud volcano to determine that there is, indeed, going to be a big hole in the ground where the mud used to be. Chris Rowan has already blogged about that study, so I’ll not summarize it again here.

    However, there’s another paper due out, this time in Earth and Planetary Science Letters, discussing the cause of the eruption. The initial eruption was suspiciously near to a gas exploration borehole … but it was also just three days after a magnitude 6.3 earthquake. “Could the earthquake have caused the eruption?” Hah. No. It was totally the exploration well.

    We – and by “we” I mean Richard Davies (also an author on the study documenting the big hole in the ground), myself, Michael Manga, Rudi Rubiandini, and Richard Swarbrick – came to this conclusion through two main lines of argument. The first is something Michael pointed out in short a 2007 article in EOS: the earthquake in question was smaller and farther away than past earthquakes in that part of Indonesia. Compared to other earthquakes that have made mud do interesting things, it’s rinky-dink.

    In the paper, we go on at length about the various ways in which the earthquake was utterly wimpy and unexceptional. I spent a good chunk of last summer estimating the amount of shaking it probably produced and the amount of stress it put on the crust near Lusi. No matter how you slice it, the “trigger” was smaller than anything you might expect to cause an eruption, and also smaller than a bunch of previous earthquakes that didn’t do anything.

    Of course, you could still invoke weird, exotic, or handwavy mechanisms by which a run-of-the-mill earthquake could have triggered an eruption. But we found a much simpler explanation: Drilling mud.

    Boreholes – especially deep boreholes – are almost always filled with mud. This helps keep the hole from caving in, and prevents other bad things from happening when the drill encounters highly pressurized water or oil. Drillers must constantly monitor and adjust the consistency of the mud to ensure that the mud doesn’t escape into the surrounding rock, and conversely, that the fluid in the surrounding rock doesn’t get into the hole.

    The day before the eruption, water from the surrounding rock started flowing into the borehole. In the course of trying to control this, the drillers sealed the top of the hole – but they put a pressure meter inside. We calculated that the weight of the drilling mud, in addition to the pressure recorded at the top of the hole while it was sealed, was enough to muscle into the surrounding rock and force open fractures leading to an eruption.

    We don’t say that PT Lapindo Brantas (the company operating the exploration well) should be blamed for the eruption. In order to throw around concepts of blame or liability, we would need to establish not only that the drilling caused the eruption, but that the drilling practices used – the decisions about whether or not to install steel casing in the borehole, or the actions taken to control the well during the days before the eruption – were somehow deficient.

    Gentle readers, I ain’t touching that question with a ten-foot stand pipe.

    Maria Brumm

    Sumber: http://scienceblogs.com/greengabbro/2008/06/happy_birthday_lusi_the_drilli.php

  • Lapindo vs Rakyat vs Negara

    Kini lumpur Lapindo memasuki babakan baru. Nasib rakyat dipertaruhkan. Juga uang negara. Jika kasus itu dikategorikan bencana alam, triliunan rupiah uang rakyat yang dikutip negara akan dikorbankan. Nuansa itu yang semakin kental dalam penanganan perkara ‘Kota Neraka’ Sidoarjo. Benarkah begitu?

    Hari-hari ini rakyat korban lumpur Lapindo keleleran di berbagai tempat di Jakarta. Mereka menderita dan terus berjuang menuntut haknya. Sisi lain, kasus pidananya masih menggantung. Berita Acara Pemeriksaan (BAP) kasus ini bolak-balik dari Polda Jatim ke Kejaksaan Tinggi dan kembali lagi ke Polda. Itu, katanya, karena kurang alat bukti.

    Dua tahun sudah kasus ini mengambang. Musibah itu terjadi semula diindikasikan karena efisiensi yang dilakukan Lapindo Brantas Inc. Pengeboran yang dilakukan tanpa cassing. Lapisan bumi penutup lumpur terkuak, tekanannya merekahkan tanah, menyemburkan lumpur yang belum diketahui berapa juta atau miliar meter kubik kandungannya.

    Namun indikator itu akhir-akhir ini dimentahkan. 12 pakar yang dilibatkan pendapatnya terpecah. Tiga pakar menyebut lumpur itu akibat human error. Sedang sisanya mengatakan meluapnya lumpur itu adalah bencana alam. Alam yang salah. Mengirim lumpur mencelakakan manusia.

    Itu yang menjadi alasan pihak Kejaksaan akan mempelajari ‘Black Box’. Kesaksian warga yang terkena musibah, serta ahli pengeboran. Namun yang perlu dikritisi, pendapat warga yang mana. Dan juga para ahli pengeboran yang berafiliasi kemana. Sebab perkara ini dalam proses waktu sudah ‘terkonversikan’ dengan uang. Nuansa kasusnya menjadi sangat ekonomis dan politis. Jika pihak Kejaksaan tidak jeli, maka kasus Lapindo ini bisa kian memperburuk citra institusi ini.

    Mengapa musibah dipertalikan dengan uang? Itu tak terhindarkan dalam perkara lumpur Lapindo ini. Contoh sederhana yang sudah bisa dirasakan semuanya, lihatlah media yang memberitakan miring kasus ini selalu happy ending dengan iklan. Simak musibah bulan kemarin ketika tiga orang terbakar gara-gara merokok di daerah yang udaranya sudah dipenuhi gas itu, tidak satu pun media memberitakan. Masuklah Pilkada Jawa Timur, maka ada aroma Lapindo di sana. Serta tanyalah dinding resto Shangrilla Hotel di Jl Mayjen Soengkono, mereka akan banyak cerita nego soal-soal yang berbau lumpur. Jadi jangan kaget jika kecurigaan sejenis juga ditujukan pada polisi dan kejaksaan.

    Mengapa lumpur Lapindo dicurigai kental dengan aliran uang? Itu tidak sulit diraba. Musibah ini bagi sebuah perusahaan ibarat pembuatan water treatment. Wajib dibangun dengan dana besar, tapi kurang produktif bagi pandangan dunia usaha. Akibatnya banyak yang mensiasati dengan menyuap pejabat korup. Itu pula kenapa pencemaran akut tidak terelakkan.

    Dalam kasus lumpur Lapindo hampir sama. Di dalamnya ‘teronggok’ uang bertriliun-triliunan rupiah. Celakanya uang itu masuk kategori tidak produktif, karena untuk dibayarkan pada korban lumpur. Baik untuk ganti rugi lahan persawahan, pemukiman penduduk, serta berbagai pabrik yang terendam lumpur.

    Uang itu darimana? Bisa dari kocek Lapindo Brantas Inc atau dari pemerintah. Lapindo harus mengeluarkan uang itu jika kelak divonis salah dalam pengeboran. Atau pemerintah yang harus mengkafer itu kalau kasus lumpur ini dinyatakan sebagai bencana alam. Tidak mengherankan kalau berbagai aksi dan mungkin juga kesaksian yang mengarahkan kasus itu sebagai bencana alam selalu dituding sebagai langkah menuju ‘pengalihan’ tanggungjawab Lapindo.

    Jika kondisinya seperti itu, bisa dimaklumi jika berbagai pihak sekarang asyik ‘bermain’. Perkara yang semula terang itu jadi mentah. Itu karena skenario besar sedang menggelinding. Padahal pengeboran tanpa dicassing jelas-jelas sebuah kesalahan. Penahan lapisan lumpur itu terkuak, dan tekanannya melesak kemana-mana. Kendati semburan itu tidak persis di pengeboran yang dilakukan Lapindo.

    Namun sebelum semuanya terjadi, yakinlah, rakyat dan negara akan ‘dikorbankan’. Lumpur yang sudah menyembur dua tahun itu bakal divonis sebagai bencana alam. Dengan begitu rakyat yang terkena musibah akan ditangani negara. Uang negara yang dipungut dari rakyat itu akan dijadikan ‘pampasan perang’  untuk mengatasi itu.

    Tanda-tanda menuju ke sana sudah semakin benderang. Tiga gelintir pakar yang tidak kompromi itu naga-naganya ke depan bakal ikut mengamini suara mayoritas. Adakah Kejaksaan dan polisi bisa dijadikan pegangan untuk secara adil menangani kasus ini? Harapan rakyat dan negara memang tinggal itu.

    Djoko Su’ud Sukahar, pemerhati budaya, tinggal di Jakarta.

    © DetikNews

  • Lapindo, Davies, dan Tingay

    Kasus semburan lumpur Lapindo kini menghangat lagi. Polisi akan meminta keterangan para ahli untuk membaca laporan pengeboran sumur Banjar Panji I milik PT Lapindo Brantas yang menyemburkan lumpur panas tersebut. Direktur Reserse Kriminal Kepolisian Daerah Jawa Timur Komisaris Besar Rusli Nasution menyatakan dua ahli baru dimintai keterangan bulan depan (Koran Tempo, 28 Juli 2008). Siapa dua ahli itu? Kita tunggu saja.

    Yang jelas, perkembangan kasus Lapindo makin hangat lagi setelah sekian lama redup. Pekan lalu, misalnya, masyarakat Indonesia seakan kembali tersedak ketika Dr Mark Tingay dari Curtin University, Australia, menyatakan bahwa semburan lumpur Sidoarjo terjadi karena kesalahan manusia.

    Kesimpulan dari berbagai kajian ilmiah yang dilakukan tim Curtin University, menurut Tingay, menunjukkan bahwa semburan lumpur itu bukan akibat gempa bumi Yogya. Alasannya, gempa Yogya yang berkekuatan 6,3 skala Richter ketika sampai di Sidoarjo getarannya hanya tinggal 2 skala Richter. Kekuatan getaran 2 skala Richter sama dengan gelombang kecil di pinggir kolam. Tak akan bisa memicu perubahan struktur geologis yang menyebabkan munculnya semburan lumpur dari perut bumi Sidoarjo (Koran Jakarta, 24, 25, dan 26 Juli 2008).

    Sebelumnya, Richard J. Davies, pakar geologi Inggris, juga mengumumkan hasil penelitiannya tentang penyebab munculnya semburan lumpur panas tersebut. Dengan dedikasi ilmiahnya yang meyakinkan, Davies, ahli geologi dari Department of Earth Science, University of Durham, Inggris, menyatakan bahwa munculnya semburan lumpur panas Sidoarjo bukanlah peristiwa alami, melainkan lebih diakibatkan oleh kesalahan manusia dalam melakukan pengeboran migas.

    Davies dalam makalahnya yang dimuat dalam jurnal Earth Planetary Science and Letters edisi terbaru berjudul “Birth of Mud Volcano: East Java”, 29 Mei 2006, mengungkapkan kesimpulannya yang diterjemahkan secara bebas sebagai berikut: Lusi (lumpur Sidoarjo) muncul karena adanya tekanan tinggi pada kedalaman 2,5-2,8 kilometer pengeboran migas terbuka, sehingga menimbulkan pecahan pada batu-batuan (lapisan bumi). Lusi menunjukkan bahwa gunung lumpur itu muncul akibat adanya retakan-retakan pada lapisan-lapisan tanah di kedalaman berkilo-kilometer, sehingga menyebabkan air dari lapisan yang amat dalam keluar dan bercampur lumpur pada lapisan-lapisan bumi di atasnya.

    Dengan melihat aktivitas semburan lumpur yang telah berlangsung 173 hari (kini 660 hari–Red), kami yakin semburan tersebut akan terus aktif dalam beberapa bulan, bahkan beberapa tahun ke depan. Permukaan tanah di daerah yang terletak beberapa kilometer dari semburan lumpur akan mengalami penurunan (subsidence) dalam beberapa bulan ke depan, dan penurunannya makin parah di daerah yang berdekatan dengan pusat semburan. Dengan membuat model dan pengukuran amblesnya permukaan tanah, akan bisa diprediksi sejauh mana dampak gunung lumpur tersebut terhadap penduduk lokal.

    Sebetulnya, apa yang disimpulkan Mark Tingay dan Davies hampir sama dengan apa yang disimpulkan Prof Dr Rudi Rubiandini, Guru Besar Geologi ITB, dan Dr Andang Bachtiar, mantan Ketua Ikatan Ahli Geologi Indonesia (IAGI). Davies dan Tingay, dengan tradisi ilmiahnya yang ketat, baru menyimpulkan setelah melakukan serangkaian studi dan analisis yang panjang dan teliti, baik di lapangan maupun literatur. Makalah Davies bisa dimuat di jurnal geologi terkemuka dunia tersebut setelah tim redaksi jurnal yang terdiri atas para pakar geologi Universitas Durham melakukan kajian mendalam.

    Tentu saja, kesimpulan Tingay, Davies, dan sejumlah pakar ITB tidak akan bisa diterima oleh pihak Lapindo Brantas. “Siapa pun bisa membuat interpretasi atau pendapat atas terjadinya semburan lumpur tersebut,” kata Kepala Divisi Hubungan Masyarakat PT Lapindo Yuniwati Teryana saat dimintai tanggapan atas kesimpulan Davies. Yuniwati menjelaskan bahwa Lapindo telah melakukan kajian dengan para ahli.

    Kesimpulannya menyebutkan: pengeboran yang dilakukan sudah sesuai dengan standar pengeboran yang berlaku secara nasional maupun internasional. Bahkan Wakil Presiden Jusuf Kalla, yang dikenal dekat dengan Aburizal Bakrie, pemilik Lapindo Brantas, menyatakan bahwa laporan hasil penelitian pihak asing tidak bisa mempengaruhi keputusan pemerintah. Pemerintah telah menetapkan semburan lumpur Sidoarjo sebagai bencana nasional, dan karena itu ganti rugi masyarakat yang terkena dampak diambil dari APBN.

    Sungguh mengherankan bila cara berpikir wakil presiden negeri sebesar Indonesia sama dengan Kepala Divisi Humas Lapindo. Padahal, faktanya, bila pengeboran sudah sesuai dengan standard operasi, kenapa ada operator pengeboran yang disalahkan dan dijadikan tersangka oleh kepolisian? Dan publik sejak awal sudah mengetahui dari pendapat para ahli perminyakan bahwa blow out (semburan lumpur tersebut) terjadi karena pada pengeboran di sumur Banjar Panji-1, khususnya pada kedalaman 4.000 feet ke atas, Lapindo “sengaja” tidak digunakan casing (selubung). Akibatnya, ketika ada tekanan tinggi dari dalam yang menimbulkan semburan tersebut, operator Lapindo tidak bisa mengatasinya. Dan akibatnya terjadilah semburan lumpur yang hingga kini sudah berlangsung dua tahun lebih itu. Bagaimana mekanisme munculnya semburan lumpur akibat tiadanya casing tersebut, Tingay, Davies, Rudi, dan Andang mempunyai penjelasan yang nyaris sama.

    Memang benar, pihak Lapindo berkukuh pada pendapat bahwa semburan lumpur itu muncul akibat pengaruh gempa bumi di Yogyakarta, dua hari sebelumnya. BPPT dan LIPI secara institusi agaknya pro terhadap pendapat terakhir ini. Meski demikian, sejumlah ilmuwan independen, termasuk para pakar geologi dari ITB dan BPPT sendiri, menolak pendapat tersebut. Bahkan seorang pakar geologi dari IAGI menuduh ilmuwan BPPT dan LIPI yang berpendapat bahwa semburan lumpur itu akibat pengaruh gempa bumi di Yogya sudah terkooptasi oleh pemilik Lapindo, yang notabene Menteri Koordinator Kesra Aburizal Bakrie.

    Lantas, mana yang benar? Sampai saat ini pengadilan belum memutuskan siapa yang salah, Lapindo atau gempa bumi. Namun, meski belum ada keputusan pasti siapa yang salah, peraturan presiden yang terkait dengan Lapindo sejak awal menyiratkan bahwa semburan lumpur itu akibat gempa bumi. Dan pemerintah sudah memutuskan bahwa kasus semburan lumpur Sidoarjo adalah bencana alam, sama dengan gempa bumi Yogya. Karena bencana alam, pemerintah yang menanggung segala kerugian akibat semburan lumpur itu dengan dana APBN. Tragis memang, uang rakyat dipakai untuk menanggung kerugian yang amat besar akibat ulah Lapindo. Padahal sebagian besar rakyat Indonesia sangat miskin dan hidupnya sangat menderita.

    Wahyudin Munawir, alumnus Geofisika ITB, anggota Komisi VII DPR RI Fraksi PKS, penulis buku Lapindo Gate

  • Experts set for Cape Town, Vexing Mud Flow Cause Disputed

    On May 29, 2006, on the eastern tip of the island of Java in Indonesia, a giant mud volcano erupted, filling the region with a noxious mix of mud, chemicals and, some would say, mendacity. Even before the mud started swallowing up homes and farms and railroad tracks, the questions were being asked.

    Not “why” so much, but “how” and “who.

    John Snedden, an AAPG member who’s a reservoir connectivity prediction supervisor with ExxonMobil, wants to begin to answer those questions; so during the October AAPG International Conference and Exhibition in Cape Town, South Africa, he is putting together a symposium on what caused the disaster – natural or otherwise – now known as Lusi (from lumpur, the Indonesian word for mud).

    ““Mud Volcano: Earthquake or Drilling Trigger?”” will be offered in Cape Town as part of the conference’s technical program.

    Five speakers representing all sides of the debate will give presentations – reportedly the first time advocates from various positions have been in the same room at the same time – followed by questions, discussions amongst panelists and audience participation.

    It will be moderated by a neutral party, AAPG member Jon Gluyas, with Fairfield Energy in Middlesex, England, who will strive to ensure that all views are heard.

    Included in the forum will be:

    • Richard Davies, department of earth sciences, Durham University, Durham, England.
    • Adriano Mazzini, University of Oslo, Norway.
    • Bambang Istadi, with Lapindo Brantas, Indonesia.
    • AAPG member Mark Tingay, with the School of Earth and Environmental Sciences in Perth, Australia.
    • Hasan Abidin, Institute of Technology Bandung, Indonesia.

    A Contentious Debate

    As to the mud volcano’s origins there are two prevalent theories: It was caused by an earthquake, or it was caused by irresponsible drilling by one of the country’s most prestigious oil and gas operators.

    According to Cape Town technical co-chair Snedden, the forum’s purpose is to “draw a line under the scientific controversy” as to whether the mud volcano was caused by PT Lapindo Brantas, a subsidiary of PT Energy Mega Persada Tbk in Indonesia, which was drilling for gas in the Porong, Sidoarjo region, east of Java, or whether Lusi was caused by natural forces, like an earthquake.

    This debate is more than an academic exercise – thousands of homes, millions of people and perhaps billions of dollars are at stake, plus usability and habitability of the land for years to come.

    Lapindo Brantas geologist Bambang Istadi, perhaps not surprisingly, claims the volcano was caused by natural tectonic forces that occurred two days before Lusi in May 2006. On that day an earthquake hit the Yogyakarta region that killed around 6,000 people and some, including Adriano Mazzini from the University of Oslo, point to that event.

    On the other side of the debate, Richard Davies and AAPG member Mark Tingay propose that Lusi was caused by the drilling of the Banjar Panji 1 gas exploration well.

    Whatever happened, the what of what happened is clear. After the mud erupted, 30,000-50,000 residents lost their homes and, at present, the region shows signs of irreversible collapse and devastation. Snedden says before action can be taken on clean up, “We need to agree first on the cause, so we expect an active debate.”

    Complicating the issue even further is the fact the man at the center of the storm, Aburizal Bakrie, is not only Indonesia’s minister for social welfare but also part of the family that controls Lapindo Brantas. Bakrie has called the volcano a “natural disaster” unrelated to the drilling activities.

    Science vs. Politics?

    Snedden may be after the science, but so far certainly from Davies’ perspective it is politics and money that has been mostly contested. In fact, a court in Java has already agreed with Bakrie that Lusi was caused by natural forces, a claim Davies rejects.

    On National Public Radio recently, Davies said the research on the Yogyakarta earthquake proves it was too small and too far away to have caused the chain of events, concluding that Lusi was “almost certainly” caused by drilling in the area. Specifically, Davies believes that a series of operational events led to a subsurface blowout, which meant the fluids within the well and leaked out on to the surface, which caused the explosion.

    As bad as Lusi is, according to Davies, it is not the largest mud volcano (that happened in Azerbaijan), but is the fastest growing. The debate, almost from the beginning, has been contentious one environmentalist in Indonesia called Lusi “the worst environmental crime of the century” – and that is why Snedden believes the time is right to bring the sides together. There are facts that need to be heard and discussed, he believes, and information that needs to be harnessed.

    Snedden said the idea of holding this symposium at an AAPG international conference in South Africa grew out of an assembled collection of data gathered by an AAPG technical program committee. ““We decided to elevate these papers to a special technical forum, given the considerable attention in the popular press but also the importance and impact of this event,”” he said.

    ““Geology really does matter here,”” he added, ““as thousands in Java can attest.””

  • Mining company ‘likely to blame’ for deadly volcano

    A devastating Indonesian mud volcano could not have been caused by a remote earthquake, researchers have said. Instead, they say, the Lusi eruption that began more than two years ago was most likely caused by the mining company failing to properly reinforce a problematic gas well.

    Petroleum geologist Mark Tingay of Curtin University in Western Australia says the volcano was definitely not caused by an earthquake.

    “None of the known methods by which an earthquake could have triggered this are plausible,” he said.

    Since May 2006 the Lusi mud volcano has been burying villages around the east Javanese city of Surabaya. Seventeen people have died as a result of the eruption and around 40,000 are permanently displaced.

    Some scientists, including UK geologist Richard Davies of the University of Durham and colleagues, believe that drilling for gas by the company Lapindo Brantas caused the explosion. Others, including the company, claim it was triggered by an earthquake that occurred two days before, 250 kilometres away near Yogyakarta, which killed 6,000 people.

    Dr Tingay teamed up with Professor Davies and his colleagues to crunch some numbers, including available company data, to see which theory is best supported. The findings are published in the current issue of the journal Geology.

    Not adding up

    Dr Tingay says while remote earthquakes have triggered such events before, the numbers do not add up in this case.

    “The magnitude of the Yogyakarta earthquake was at least 10 times too small to have triggered off any mud volcanic eruption at the Lusi site,” he said. On the other hand, the analysis did support drilling as a cause.

    “All of the key ingredients necessary for a drilling to have caused the mud volcano were there,” Dr Tingay said. “There are critical safety issues that you have to maintain when you drill a well and we feel that a lot of those were breached.”

    Dr Tingay says all wells should be reinforced using a steel and concrete “casing” or reinforcement at regular intervals to help stop fluids flowing into the well. He believes the company failed to properly reinforce a 2,800-metre deep well they were drilling.

    “Setting casing takes up a lot of time and time is money,” he said. “They skipped two planned casing points.”

    Dangerous situation

    Dr Tingay says the company continued drilling and walls of the well eventually gave way. “They got into this dangerous situation. It’s a bit like driving at night in the wet with bad tyres and no lights,” he said.

    The research says 40 to 60 cubic metres of fluid and hydrogen sulphide gas forced its way into the well and up to the surface. The company responded to this by closing off the surface of the well. “It’s effectively like putting a cork in the well,” Dr Tingay said.

    He says the pressure in the well continued to build up enough to fracture the surrounding rock, resulting in an eruption of mud 200 metres away from the well.

    The mud started erupting at about 5,000 – 20,000 cubic metres a day, but is now spewing forth at 100,000 cubic metres a day, and this could continue for over a decade.

    Dr Tingay says dams are being used to hold back the mud, but he is worried is that these dams will break – made more likely as a 22-square kilometre area around the eruption is starting to sink. He says the Indonesian Government has recently decided to evacuate four more villages from the area.

    The ABC’s attempts to obtain a response from Lapindo Brantas were unsuccessful.

    By Anna Salleh for ABC Science Online