Pak Rovicky, Data yang berhubungan dengan masalah Lemat-granite wash dari sumur penelitian itu saya publikasi secara terbatas pada pertemuan Sumatra Stratigraphy Workshop (SSW) di Duri pada September 2005. Presentasi2 dalam pertemuan ini kemudian dimintakan makalah lengkapnya dan dibukukan di bawah komando Pak Yarmanto (Chevron) dan dilepas ke publik pada PIT IAGI yang lalu (2008) di Bandung -ini adalah tradisi workshop stratigrafi, seperti juga workshop stratigrafi Jawa sebelumnya. Sayang, saya tak sempat membuat makalah lengkapnya untuk publikasi SSW -meskipun telah ditagih beberapa kali oleh Pak Yarmanto - maaf Pak Yarmanto, di buku itu saya hanya memberikan abstraknya dan di ex Panitia Workshop ada bahan presentasinya. Sumur tersebut sampai sekarang masih berada di blok aktif. Datanya (raw data & interpretation) bila sudah terbuka kalau mengikuti aturan data terbuka sejak data diperoleh, bisa diakses. Hanya untuk mendapatkannya mesti menghubungi Operator terkait (karena blok aktif) secara business to business di bawah fasilitasi dan pengawasan BPMIGAS. Di bawah ada abstrak makalah tersebut. Salam, awang INDONESIAN ASSOCIATION OF GEOLOGISTS – RIAU CHAPTER SUMATRA STRATIGRAPHY WORKSHOP DURI, RIAU 12 – 13 SEPTEMBER 2005 “GRANITE WASH” OF LEMAT FORMATION OR IN-SITU GRANITE OF BASEMENT ? : THE PROBLEM OF SOUTH SUMATRA STRATIGRAPHY AND NEW APPROACHES FOR ITS SOLUTION Awang Harun Satyana (BPMIGAS - Badan Pelaksana Kegiatan Usaha Hulu Minyak dan Gas Bumi) Basement of the South Sumatra Basin is a complex of Mesozoic igneous rocks and of Paleozoic and Mesozoic metamorphics and carbonates intruded by Mesozoic igneous rocks. Structural relationships of rocks composing of the basement are complex as can be seen at outcrops in the Barisan Mountains. This complexity extends into the subcrops of the South Sumatra Basin. In some places, strata of Late Cretaceous to Early Eocene are also grouped as the basement. This has caused a problem of identifying the basement. The problem is more complicated when the strata composed of “granite wash” – a unit of re-deposited granite in the lower part Lemat Formation (Early Eocene-mid Oligocene) overlie the basement which also composed of in-situ granite. ”Granite wash” can be difficult to distinguish from in-situ granite, even in outcrop, let alone down hole. Additional complication by alteration may obscure original fabric of the rock. Several approaches have been used to determine whether or not the upper parts of several granite plutons have been eroded and re-deposited as “granite wash”. The approaches include : petrography of granite, absolute dating of granite and its veins, and paleomagnetics of granite. Petrographic analysis can reveal sedimentary origin of “granite wash” like the presence of fine grained matrix material or showing hydrothermal origin of in-situ granite. Absolute dating of veins is done to constraint the age of fabric present at the time of veining. If the rock is considered to be re-deposited, the re-deposition would have to be older than the vein formation. The vein age would provide a minimum age for granite/”granite wash” fabric. As for paleomagnetics, it is hypothesized that in-situ granite should give a relatively strong uni-directional signal of paleomagnetics whereas granite broken into constituent sand grains and then randomly rearranged in a sedimentary rock is less likely to give a uni-directional signal. Some wells in South Sumatra Basin penetrated either “granite wash” of Lemat Formation or in-situ granite of the Basement, and/or both of them. Identification of top Basement is problematic when it is not known precisely which granite constitutes the lithology. This study shows how the above approaches were applied to solve the problem.
--- On Tue, 1/20/09, Rovicky Dwi Putrohari <[email protected]> wrote: From: Rovicky Dwi Putrohari <[email protected]> Subject: Re: [iagi-net-l] Re: [Forum-HAGI] [iagi-net-l] Talangakar dan Lemat To: [email protected] Date: Tuesday, January 20, 2009, 1:13 PM On Tue, Jan 20, 2009 at 1:55 PM, Awang Satyana <[email protected]> wrote: > > Saya punya data sebuah sumur yang menembus baik Talang Akar-Lemat-granite wash-dan insitu granite (fresh granite) Basement - dan dengan jelas bisa didefinisikan batas-batas batuan itu, kebetulan sumur ini adalah sumur penelitian untuk memahami masalah granite wash dan endapan pre-TAF, sehingga punya analisis yang lengkap baik petrografinya, umur absolutnya, bahkan geomagnetismenya. > > salam, > awang Pak Awang, Apakah ada public data (publikasi) sehubungan dengan sumur "penelitian" diatas ? Sangat menarik tentunya. Bisa menjadi kunci untuk membuka pintu2 gudang minyak di sumatra selatan. RDP "masih mimpi open file data policy" -------------------------------------------------------------------------------- serah-terima pp-iagi: senin sore, 13 oktober 2008 ketua umum: LAMBOK HUTASOIT sekjen: MOHAMMAD SYAIFUL pasukan sedang disusun, hanya satu IAGI... -------------------------------------------------------------------------------- ayo, segera pula siapkan utk PIT IAGI ke-38 dg tuan-rumah adalah PENGDA JATENG * mungkin di semarang * mungkin pula di solo * mungkin juga join dg HAGI dll. ----------------------------------------------------------------------------- To unsubscribe, send email to: iagi-net-unsubscribe[at]iagi.or.id To subscribe, send email to: iagi-net-subscribe[at]iagi.or.id Visit IAGI Website: http://iagi.or.id Pembayaran iuran anggota ditujukan ke: Bank Mandiri Cab. Wisma Alia Jakarta No. Rek: 123 0085005314 Atas nama: Ikatan Ahli Geologi Indonesia (IAGI) Bank BCA KCP. Manara Mulia No. Rekening: 255-1088580 A/n: Shinta Damayanti IAGI-net Archive 1: http://www.mail-archive.com/iagi-net%40iagi.or.id/ IAGI-net Archive 2: http://groups.yahoo.com/group/iagi --------------------------------------------------------------------- DISCLAIMER: IAGI disclaims all warranties with regard to information posted on its mailing lists, whether posted by IAGI or others. In no event shall IAGI and its members be liable for any, including but not limited to direct or indirect damages, or damages of any kind whatsoever, resulting from loss of use, data or profits, arising out of or in connection with the use of any information posted on IAGI mailing list. ---------------------------------------------------------------------
