石油技術協会誌
検索
OR
閲覧
検索
79 巻 , 1 号
選択された号の論文の11件中1~11を表示しています
    • |<
    • <
    • 1
    • >
    • >|
講演
  • 松岡 俊文, 本田 博巳
    79 巻 (2014) 1 号 p. 4-16
    公開日: 2016/07/15
    ジャーナル フリー
    Contributions of applied geophysics to petroleum exploration are discussed. We succinctly look over geophysical prospecting in exploration of structural and stratigraphic plays. Structural prospecting has been the first, main concept for petroleum exploration through seismic imaging of subsurface. Stratigraphic prospecting was eventually successful as a by-product of structural exploration before digital seismics were introduced in 1960's through 1970's. Wireline logging provides us of basic data for our subsurface mapping and formation evaluation, and for calibration and improvement of quality of seismic processing.
    Geophysical prospecting was performed as; (1) gravity profiling in the latest 19th century, (2) single channel refraction and/or reflection profiling in late 1920's through 1930's, (3) multichannel reflection seismic survey to minimize noises by stacking CDP gathers during 1950's, (4) analysis of subsurface seismic velocity data qualitatively defining subsurface lithology and fluid in 1960's through 1970's, (5) analyses of allostratigraphy and sedimentary facies in 1970's, and (6) 3D seismic surveys that lead detailed, regional paleogeology and definition of stratigraphic plays in 1980's through 1990's.
    Seismic stratigraphy is a key in stratigraphic prospecting. We now can perform seismic geomorphology and reconstructive basin analysis based on 3D seismic data-cubes normally and inversely processed. 4D surveys represent changes of physical properties of subsurface formations through time.
    Future progress in the geophysical prospecting is expected in (1) combining of macro- and nano-surveys; that is, clarifying and solving enigmas in petroleum technology, e.g., primary migration of oil and gas, and efficient development of shale resources.
    Human development in technological education and management system of human resources are also the keys for this progress. Multidisciplinary education of geology, applied geophysics is desired for effective performance in petroleum exploration and exploitation. High seismic resolution is required for not only structural imaging but also rock physical one.
    抄録全体を表示
  • 峯岸 政人, 清水 祥四郎, 内藤 信二郎, 白木 秀明, 佐藤 隆一, 辻 喜弘
    79 巻 (2014) 1 号 p. 17-25
    公開日: 2016/07/15
    ジャーナル フリー
    JOGMEC/MOECO carried out an onshore seismic survey with explosive sources in 2012 in Cambodia. The project was executed under the Basic Agreement for the Study and Survey Program in Block XVII onshore Cambodia between JOGMEC and CNPA. This was the first experience of seismic data acquisition with explosives in Cambodia. Therefore, there were a lot of issues to be resolved before the field work was launched. One of most serious issues was the implementation of safe operations in a Mine/UXO contaminated field. Other issues were a lack of regulations in Cambodia, education of non-experienced Cambodian people including both government staffs and local residents, explosive management and so on. Firstly JOGMEC/MOECO hired excellent Cambodian national staffs and further educated on seismic surveys. Then, they seriously and actively worked for communications with both government staffs and local residents. Such efforts resulted in good cooperation with all relevant parties even though unexpected procedures caused delays in the schedule. Finally, the seismic survey was successfully completed and no lost time for injury was recorded. A lot of knowledge on the seismic survey has been accumulated for all relevant parties through this experience. The procedures established by JOGMEC/MOECO through this survey will be one of the standards for onshore seismic data acquisitions in Cambodia.
    抄録全体を表示
  • 義山 智之, リー チー クン
    79 巻 (2014) 1 号 p. 26-33
    公開日: 2016/07/15
    ジャーナル フリー
    Broadband acquisition and multi azimuth acquisition techniques in marine seismic survey are currently drawing considerable attention to improve the imaging for complex geology such as sub-basalt and sub-salt imaging.
    In the Block DWR, offshore Sabah, Malaysia, complex toe-thrust structures are existing and conventional legacy seismic data over these structures is suffering the deterioration of imaging due to complexity of geology and existence of shallow amplitude anomalies.
    JX Nippon Oil & Gas Exploration (Deepwater Sabah) conducted 3D seismic survey with combination of broadband acquisition technique using slant streamer and multi-azimuth (two azimuth) acquisition technique over the Block DWR.
    Broadband acquisition technique enhanced low frequency components in the seismic data and provided with improved imaging in toe-thrust structures and deeper seismic events. Processing for merged multi-azimuth seismic data is in progress, however, the seismic stack of each azimuth show better illumination than the other in different places. This fact indicates that merged azimuth seismic data can show better imaging and better seismic event continuities.
    抄録全体を表示
  • 岡田 信
    79 巻 (2014) 1 号 p. 34-42
    公開日: 2016/07/15
    ジャーナル フリー
    Since farming in to an offshore exploration block of Elf Gabon (presently Total Gabon) in 1974, MPDC Gabon Co., Ltd. (subsidiary of Mitsubishi Corporation) has been acting E&P business in Gabon. The Nguma permit is located in northern offshore Gabon approximately 65 km southwest from Port Gentil city and covers an area of 1,199 km2 (presently reduced to 600 km2).
    The turbidite sandstone in several geological periods is expected as possible reservoir in this area, and the main target is the Batanga sandstones in the Maastricht period. This facies is missing in the some wells and possibly to be distributed unevenly, and grasping Batanga sandstone distribution is one key point of this exploration.
    The distribution of reservoir sandstone was predicted using Extended Elastic Impedance (hereafter referred as EEI). EEI can approximate reflectivity or impedance to several elastic parameters (such as bulk modulus, Lamé parameter, rigidity modulus, and poison ratio) by a projection of acoustic impedance (AI) and gradient impedance (GI) data (AVO attributes). Gamma ray (GR) is the most suitable well log item to indicate sandstone reservoir and this prediction is first target for this study. However it is not tied to elastic modulus directly like as water saturation. Therefore it may not be necessarily derived from AVO attributes, and then the feasibility evaluation for applying EEI in this area was applied by taking empirical correlation.
    In data processing, EEI inversion with its proper (AVO friendly) pre-conditioning was applied on 3D seismic bin gather after pre-stack time migration. This EEI inversion derived pseudo GR and it has fine consistency with real GR at not only control well but also new well. In interpretation, turbidite sandstone distribution was predicted and delineated using EEI data.
    抄録全体を表示
  • 常山 太, 高原 一峰, 長友 晃夫, 谷岡 慧, 榎本 美津郎, 西塚 知久
    79 巻 (2014) 1 号 p. 43-53
    公開日: 2016/07/15
    ジャーナル フリー
    出光では, 重合前震探データの解析によって岩相や飽和流体を直接検知する技術に着目し, 岩石物理学と震探・坑井データの評価の実践的統合により, 発見確率の向上を図ってきた。本稿では, 岩石物性と直接検知技術の関係, およびケーススタディを紹介する。
    炭化水素を胚胎する砂岩は, AVOクロスプロット上で, P-Impedance値とVp/Vs値の減少により, 原点を通る泥岩のトレンドから第3象限側へ大きく変位したトレンドを形成し, 一方で, インヴァージョン解析では, P-Impedance値を横軸, Vp/Vs値を縦軸としたクロスプロット (RPT: Rock Physics Template) にて, より定量的な区分が可能となる (Ødegaard and Avseth, 2004)。RPT上では孔隙率の減少, 泥岩・砂岩, 内部流体の飽和率に応じてプロット領域が異なり (Dvorkin and Nur, 1996), 炭化水素胚胎砂岩は, 特に低P-Impedance値かつ低Vp/Vs値の領域にプロットされ, 泥岩・水飽和砂岩との分離が可能である。
    ケーススタディの坑井Xでは, 砂岩貯留層Aおよび炭酸塩岩貯留層Bが確認され, いずれもガスの集積が認められた。砂岩層Aでは, 坑井X検層データのZoeppritz式による入射角変化に対応した合成地震記録と, 実際の重合前震探データの両者で入射角の増加に伴いインピーダンス低下の振幅応答が強くなるAVOを確認した。この応答は, AVOクロスプロット上では, 泥岩のバックグラウンドトレンド (BGT) からAVO Gradient値が負の方向に乖離する。一方, 炭酸塩岩層Bは, 泥岩BGT上に位置し, 両軸の絶対値が著しく大きい特徴を持つ。この違いに着目し, 異なる傾きを持つ2つのBGTからの乖離を計算し, 砂岩および炭酸塩岩を強調した重合データ (Sand stack, Carbonate stack) を作成した。
    インヴァージョン解析では, 坑井検層データのRPTにて, 砂岩層Aは顕著に低P-Impedance値かつ低Vp/Vs値の領域にプロットされ, さらに, 水飽和への入れ替えにより, ガス飽和砂岩が泥岩や別の水飽和砂岩層と分離可能と確認した。炭酸塩岩層Bは, 約9.5km/sec*g/cc以上の高P-Impedance値が特徴的である。ただし, ガス飽和の炭酸塩貯留岩も他の岩相との重複が大きく, 区別は困難であると判明した。上記の区分を, P-ImpedanceとVp/Vsの三次元データに適用して, 岩相・流体の空間分布を予測した。ただし, この手法では, ガス飽和砂岩と水飽和砂岩の遷移帯等を連続的に表現できない。そこで, RPT上で泥岩あるいは水飽和砂岩を表すトレンドを設定し, そこからの乖離を定量的に表現するアトリビュートの併用も必要となる。両解析により, ガス胚胎砂岩層Aと炭酸塩岩層Bおよび類似した貯留層が, 隣接する断層ブロックや坑井Xの到達深度以深にも堆積している可能性が示唆された。
    抄録全体を表示
  • 新部 貴夫, 青木 直史, 高梨 将
    79 巻 (2014) 1 号 p. 71-78
    公開日: 2016/07/15
    ジャーナル フリー
    Although sub-basalt exploration has been achieved great attention, the progress is very limited due to the difficulty of imaging beneath the basalt. Most of seismic energy are usually scattered and attenuated by thick basalts. Also Basalts usually generate a lot of multiples. As a result, quality of seismic data are usually not enough for interpretation. But recently, seismic techniques are advanced rapidly and some of those new techniques are expected to be effective in sub-basalt imaging. In this article, we review issues relating to sub-basalt imaging and some of the new recently advanced techniques, especially de-ghosting techniques in data acquisition are reviewed because low-frequency is a key factor in sub-basalt imaging.
    抄録全体を表示
  • 青木 直史, 新部 貴夫, 高梨 将
    79 巻 (2014) 1 号 p. 79-87
    公開日: 2016/07/15
    ジャーナル フリー
    As the deep water drilling technology continues to evolve, sub-salt basins has become one of the most prospective targets for hydrocarbon reserves. Even though sub-salt is a difficult target for seismic imaging, various advanced technologies have been developed in the lost decade and difficulties encountered in the new prospect have been reduced. New seismic acquisition technologies such as broadband seismic, full-azimuth and ultra-long offset acquisition mitigate the problems from the presence of salt. Sub-salt imaging techniques has also evolved with the aid of the advanced new acquisition technology, high oil price, and low cost high performance computing (HPC). Anisotropic RTM has became a usual technique in the Gulf of Mexico, and FWI grows in use and popularity nowadays.
    抄録全体を表示
総説
  • 鶴 哲郎, 佐々木 亮, 占部 滋之
    79 巻 (2014) 1 号 p. 54-62
    公開日: 2016/07/15
    ジャーナル フリー
    A new seismic attribute method using seismic attenuation is present. Contrary to conventional seismic attributes providing reflection strength and phase properties, the attenuation attribute method maps relative Q spatially. Although the method has disadvantage in resolution, it potentially bears big advantage in applicability to analyses of physical properties of rocks in less reflective areas such as volcanic and highly-faulted areas where continuous reflections are rarely observed. The present paper reports on its applicability to evaluate fault seal ability, through a case study using 3D seismic data over two oil fields. As the result of the case study, a fault that traps oil is characterized by lower attenuation, whereas a fault that doesn't trap oil is marked by higher attenuation. According to recent laboratory measurements, seismic waves highly attenuate when they pass through a fault with lower coupling, reversely they don't attenuate very much within a fault with higher coupling. Assuming that the strength of fault coupling is proportional to the ability of fault seal based on existing microscopic observations on fault contact surface, we can form a hypothesis that the higher the fault seal is the lower the attenuation becomes. The hypothesis is supported by the present case study.
    抄録全体を表示
論説
  • 亀井 理映, 三善 孝之, プラット ゲルハルト, 高梨 将, 柾谷 将吾
    79 巻 (2014) 1 号 p. 63-70
    公開日: 2016/07/15
    ジャーナル フリー
    We apply full waveform inversion (FWI) to a land seismic dataset acquired along a long crooked survey line in a geologically complex mountainous region in Japan. The conventional reflection processing has been difficult due to the acquisition parameters and weak reflection signals at near-offset traces. However the dataset contains clear wide-angle reflections and refractions. FWI exploits these waveforms, and successfully yields a P-wave velocity model for the survey area. The FWI velocity model images the geological structure for the area including a large thrust structure. We validate the velocity model by comparing with the previously obtained migration image and the sonic logs. In addition, the synthetic waveforms generated from the FWI velocity model agree well with the observed waveforms, further confirming the validity of the FWI velocity model. Our results suggest that FWI is potentially a good velocity imaging technique for a geologically complex area.
    抄録全体を表示
討論
    • |<
    • <
    • 1
    • >
    • >|
feedback
Top