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"ABSTRACTUG Massive formation is the main reservoir of Javaz field, oil and gasproducing field, situated in West Natuna Basin. The use of acoustic impedance (PImpedance)only to characterize reservoir hydrocarbon in this field will lead us intolarge uncertainty. Therefore, to overcome that issue, Seismic Simultaneous Inversionmethod is used at Javaz field within UG Massive formation interval. This method isapplied as an alternative method to predict the pore gas (Lambda-Rho) and porositydistribution, using partial post stack 3D seismic data which are invertedsimultaneously; then Javaz-4 well data which will be used as a reference well forpredicting reservoir properties in other wells at Javaz field.Seismic Simultaneous Inversion method resulted Javaz-3 well has similarreservoir properties as studied in Javaz-4 well. However, Javaz-1A and Javaz-2showed different result caused by large uncertainty in seismic resolution (poor qualityseismic data). Porosity and pore gas prediction suggested around 20 to 30 percent and13 to 18 GPa*g/cc respectively, throughout the field. Hence, this method could beused as an alternative to predict UG Massive reservoir properties in Javaz field awayfrom the wells, and it could be applied to the same field with large uncertainty.

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ABSTRAKFormasi UG Massive merupakan reservoar utama pada lapangan Javaz,lapangan ini memproduksi minyak dan gas dan berada pada cekungan Natuna Barat.Study yang dilakukan untuk mengkarakterisasi reservoir hydrocarbon pada lapanganini jika hanya menggunakan akustik impedance (P-Impedance) saja akanmenimbulkan ketidakpastian, untuk mengatasi hal ini maka metode Seismicsimultaneous inversion digunakan pada lapangan Javaz dengan target formasi UGMassive. Metode ini digunakan sebagai alternative untuk memprediksi sebaran poregas (Lambd-Rho) dan porositas, dengan menggunakan partial post stack 3D seismicdata yang di inversikan secara bersamaan dan satu sumur (Javaz-4) data yangdigunakan sebagai kontrol untuk kemudian dijadikan acuan dalam memprediksikarakter reservoir para area sumur lainnya.Dengan menggunakan metode Seismic simultaneous inversion ini, makadidapatkan hasil prediksi karakter reservoir pada sumur Javaz-3 yang memilikikarakter mendekati sumur Javaz-4 pada formasi utama, namun tidak demikian untuksumur Javaz-2 dan Javaz-1A. Untuk perkiraan sebaran porositas maupun pore gasdidapatkan hasil yang cukup baik, dengan nilai porositas berkisar antara 20% hingga30% dan pore gas (Lambda-Rho) yang berkisar antara 13 (GPa*g/cc) hingga 18(GPa*g/cc). Dari hasil study ini maka dapat disimpulkan bahwa metode ini dapatdigunakan sebagai alternative untuk memprediksi karakter reservoar pada formasiUG Massive."

"[ABSTRAKLapangan XXX merupakan lapangan minyak di cekungan Natuna Baratdengan reservoir utama berupa reservoir batu pasir. Ketebalan reservoir padalapangan ini sangat bervariasi sehingga hasil inversi hanya dapat memetakanketebalan reservoir yang mendekati ketebalan tuning.Berdasarkan uji sensitifitas, parameter AI di setiap sumur tidak dapatmembedakan hidrokarbon, sehingga parameter akustik saja tidak dapat diaplikasikandalam karakterisasi reservoir lapangan ini. Namun ketika parameter densitas terpisahdengan parameter kecepatan P, sebaran hidrokarbon dapat dibedakan dengan baik.Kecepatan S tidak tersedia di semua sumur padahal data ini sangat diperlukanuntuk melakukan pengolahan data dengan metode inversi simultan. Oleh karena ituakan dilakukan beberapa estimasi untuk mendapatkan data kecepatan S antara laindengan metode castagna, metode gassmann, metode parsial, metode Xu-White danmetode Lee. Data kecepatan S yang dipakai adalah kecepatan S terbaik yangdiperoleh dari metode Xu White dikarenakan hasil log poisson’s rationya palingmendekati tren kurva saturasi air. Selain itu aspek rasio batuan yangmempertimbangkan nilai porositas dan volume clay, serta kontrol kualitas Vp modeldari metode Xu-White memiliki rasio error minimum jika dibandingkan dengan nilaiVp dari data log.Metode inversi simultan dengan data pre-stack atau partial stackmemungkinkan dilakukannya prediksi parameter Impedansi P, Impedansi S, dandensitas dari data seismik. Selain itu meode inversi simultan dapat dipergunakanmulti wavelet dalam pengolahan datanya. Hasil penampang inversi yang diperolehmenunjukkan bahwa inverse densitas dapat menjelaskan letak sebaran batuanreservoir dan fluida berdasarkan cut off sensitifitas yakni nilai dibawah 2,26 gr/cc.

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ABSTRACTfield is an oil field in West Natuna Basin with sandstone reservoir asprimary target. There was varying reservoir thickness, so the inversion method thatcould only be applied to map reservoir thickness, which close to tuning thickness.Based on sensitivity analysis, Acoustic Impedance parameters couldn’tindicate hydrocarbon appearance for each well, so Acoustic Impedance cannot beapplied for reservoir characterization in this field. Density versus AcousticImpedance could map hydrocarbon appearance.Shear velocity weren’t available where those data was needed for runningsimultaneous inversion method. Predicting velocity shear would be carried out byusing several method such as Castagna, Gassmann, Parsial, Xu-White, and Lee. Thebest estimated velocity shear would be used for inversion, The best estimated shearvelocity from Xu-White method because Xu-White’s poisson ratio log presentssimilar trend with water saturation log (Sw). Moreover, Xu-White’s ratio aspect isalso considering porosity and clay volume value. Based on quality control result, Vpmodel of Xu-White had minimum error ratio compared to Vp from log.Simultaneous inversion with pre-stack and parsial stack data what can be usedfor predicting P-Impedance, S-Impedance, and density from seismic data. Otherwise,this method is also used not only for single wavelet but also multi wavelet. Theinversion result from this study can mapping out the hydrocarbon appearance forreservoir target based on cut off value from sensitivity test of less than 2,26 gr/cc.;X field is an oil field in West Natuna Basin with sandstone reservoir asprimary target. There was varying reservoir thickness, so the inversion method thatcould only be applied to map reservoir thickness, which close to tuning thickness.Based on sensitivity analysis, Acoustic Impedance parameters couldn’tindicate hydrocarbon appearance for each well, so Acoustic Impedance cannot beapplied for reservoir characterization in this field. Density versus AcousticImpedance could map hydrocarbon appearance.Shear velocity weren’t available where those data was needed for runningsimultaneous inversion method. Predicting velocity shear would be carried out byusing several method such as Castagna, Gassmann, Parsial, Xu-White, and Lee. Thebest estimated velocity shear would be used for inversion, The best estimated shearvelocity from Xu-White method because Xu-White’s poisson ratio log presentssimilar trend with water saturation log (Sw). Moreover, Xu-White’s ratio aspect isalso considering porosity and clay volume value. Based on quality control result, Vpmodel of Xu-White had minimum error ratio compared to Vp from log.Simultaneous inversion with pre-stack and parsial stack data what can be usedfor predicting P-Impedance, S-Impedance, and density from seismic data. Otherwise,this method is also used not only for single wavelet but also multi wavelet. Theinversion result from this study can mapping out the hydrocarbon appearance forreservoir target based on cut off value from sensitivity test of less than 2,26 gr/cc., X field is an oil field in West Natuna Basin with sandstone reservoir asprimary target. There was varying reservoir thickness, so the inversion method thatcould only be applied to map reservoir thickness, which close to tuning thickness.Based on sensitivity analysis, Acoustic Impedance parameters couldn’tindicate hydrocarbon appearance for each well, so Acoustic Impedance cannot beapplied for reservoir characterization in this field. Density versus AcousticImpedance could map hydrocarbon appearance.Shear velocity weren’t available where those data was needed for runningsimultaneous inversion method. Predicting velocity shear would be carried out byusing several method such as Castagna, Gassmann, Parsial, Xu-White, and Lee. Thebest estimated velocity shear would be used for inversion, The best estimated shearvelocity from Xu-White method because Xu-White’s poisson ratio log presentssimilar trend with water saturation log (Sw). Moreover, Xu-White’s ratio aspect isalso considering porosity and clay volume value. Based on quality control result, Vpmodel of Xu-White had minimum error ratio compared to Vp from log.Simultaneous inversion with pre-stack and parsial stack data what can be usedfor predicting P-Impedance, S-Impedance, and density from seismic data. Otherwise,this method is also used not only for single wavelet but also multi wavelet. Theinversion result from this study can mapping out the hydrocarbon appearance forreservoir target based on cut off value from sensitivity test of less than 2,26 gr/cc.]"

"Lapangan "Z" merupakan salah satu lapangan hidrokarbon yang sedang dikembangkan dan berada di Cekungan Sumatra Selatan yang terkenal sebagai salah satu cekungan penghasil hidrokarbon terbesar di Indonesia. Pada awalnya inversi seismik dilakukan dengan hanya menghasilkan penampang impedansi akustik yang memiliki keterbatasan dalam mengidentifikasi litologi batuan serta kandungan fluidanya. Untuk mengatasi permasalahan tersebut, dilakukan inversi simultan yang dilakukan pada data pre-stack yang menghasilkan tiga parameter sekaligus, yaitu parameter impedansi akustik, impedansi shear, dan densitas. Ketiga parameter tersebut ditransformasi sehingga memperoleh parameter lame berupa nilai lambda-rho dan mu-rho yang lebih sensitif dalam mengidentifikasi litologi batuan maupun kandungan fluida di dalam reservoir. Skripsi ini bertujuan untuk mengkarakterisasi reservoir batupasir dengan menggunakan metode Simultaneous Inversion. Inversi ini dilakukan pada data pre-stack yang telah dikondisikan terlebih dahulu dengan kontrol dari data sumur dan horison. Hasil inversi yang diperoleh adalah reservoir batupasir berisi gas pada penelitian ini dicirikan dengan nilai lambda-rho yang rendah yaitu bernilai 5700-7000 (m/s)*(g/cc), impedansi-S yang tinggi yaitu bernilai 3200-4700 (m/s)*(g/cc), dan nilai mu-rho yang tinggi bernilai 11-14,3 GPa*g/cc. Sedangkan pada reservoir batupasir berisi minyak memiliki nilai lambda-rho yang tinggi sekitar 7000-9000 (m/s)*(g/cc). Reservoir batupasir pada penelitian ini relatif sangat tipis sehingga diperlukan ketelitian dalam menganalisisnya.

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The 'Z' field is a hydrocarbon field that still on developement and located in the South Sumatra Basin that is known as one of the largest hydrocarbon-producing basins in Indonesia. At first, the seismic inversion is performed by simply generating acoustic impedance cross section that has limitations in identifying rock lithology and fluid content. To solve this problem, simultaneous inversion performed on the pre-stack data which generates three parameters simultaneously, namely acoustic impedance, shear impedance and density parameters. These parameters can be transformed to obtain lame parameter called lambda-rho and mu-rho which are more sensitive in identifying rock lithology and fluid content in the reservoir.

This thesis aims to characterize the sandstones reservoir using Simultaneous Inversion method. This inversion is done on the pre-stack data which previously been conditioned with the control of wells and horizons. Inversion results obtained are gas-containing sandstone reservoir, which in this research identified with the small lambda-rho value about 5700-7000 (m/s)*(g/cc), high impedance-S value about 3200-4700 (m/s)*(g/cc), and high mu-rho value about 11-14.3 GPa*g/cc. In other side the oil-containing sandstone reservoir has a high lambda-rho value about 7000-9000 (m/s)*(g/cc). Sandstones reservoir in this study are relatively very thin, that means it is required a huge accuracy in analyzing it."

"Much recent research has concentrated on the efficient solution of large sparse or structured linear systems using iterative methods. A language loaded with acronyms for a thousand different algorithms has developed, and it is often difficult even for specialists to identify the basic principles involved. Here is a book that focuses on the analysis of iterative methods. The author includes the most useful algorithms from a practical point of view and discusses the mathematical principles behind their derivation and analysis. Several questions are emphasized throughout: Does the method converge? If so, how fast? Is it optimal, among a certain class? If not, can it be shown to be near-optimal? The answers are presented clearly, when they are known, and remaining important open questions are laid out for further study. Greenbaum includes important material on the effect of rounding errors on iterative methods that has not appeared in other books on this subject. Additional important topics include a discussion of the open problem of finding a provably near-optimal short recurrence for non-Hermitian linear systems; the relation of matrix properties such as the field of values and the pseudospectrum to the convergence rate of iterative methods; comparison theorems for preconditioners and discussion of optimal preconditioners of specified forms; introductory material on the analysis of incomplete Cholesky, multigrid, and domain decomposition preconditioners, using the diffusion equation and the neutron transport equation as example problems. A small set of recommended algorithms and implementations is included."

"ABSTRACTProblematic manual recapitulation led to the development of the use of e recapitulation technology. This study aims to determine the feasibility of using e recapitulation of vote counting in the upcoming 2019 general election. The location of this study was in Pekalongan, Central Java Province (pilot project using e recapitulation). The method used is the descriptive qualitative method, the sources KPUD officers, Bawaslu officers, the DPRD, and the political unit of the Kesbangpol of Pekalongan. Data collection techniques used were the interview techniques. The technique of data analysis is the inductive basis, i.e., the data collected are discussed, interpreted, and collected in an inductive manner, and draw conclusions from the specific data. Field results show that technology basically e vote election results recap (in particular USSD and DMR) is feasible to be used on the 2019 concurrent election, based on its ability to maintain the integrity of the vote counting results from the polling stations. Although in the technology itself, the e-recapitulation technology is feasible to be used, it is expected that various problems as identified in this study would occur in the field during the implementation of the technology. Therefore, there needs to be a policy to anticipates the problems that might arise in the use of e recapitulation technology in the 2019 elections. Such as early communication between the Ministry of Home Affairs and the Central Election Commission to require the use of e recapitulation in 2019 election, to improve the quality of democracy in Indonesia, as well as to prepare the internet network throughout Indonesia."

"Lapangan “X” merupakan salah satu lapangan yang memproduksikan minyak yang terletak pada Blok Selat Malaka, Cekungan Sumatra Tengah. Lapangan tersebut memiliki beberapa sumur yang telah proven yang tercakup kedalam data 3D seismik yang kemudian dilakukan eksplorasi untuk area sekitar sumur proven. Penelitian ini menggunakan 3 sumur yang telah dilakukan analisis petrofisika dan data seismik yang berupa partial angle stack yang terdiri dari near angle, mid angle dan far angle. Penelitian ini menggunakan metode inversi simultan dan klasifikasi litologi menggunakan aturan bayesian. Hasil crossplot menunjukkan bahwa impedansi akustik dan rasio Vp/Vs merupakan parameter yang paling sensitif dalam memisahkan litologi dan fluida. Hasil inversi simultan berupa impedansi akustik bernilai 12000 (ft/s*gr/cc) hingga 19000 (ft/s*gr/cc) dan persebaran nilai Vp/Vs bernilai 2.0 hingga 2.5 Area target pengembangan terletak pada barat laut dari Sumur X-1 yang memiliki nilai impedansi akustik dan Vp/Vs yang rendah. Klasifikasi litologi yang dilakukan metode zonasi langsung dan aturan bayesian. Hasil klasifikasi dua metode tersebut menunjukkan bahwa daerah yang proven termasuk kedalam klasifikasi oil sand dan area target pengembangan yang terletak di barat laut Sumur X-1 juga termasuk ke dalam klasifikasi oil sand.

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The "X" Field is one of the oil-producing fields located in the Malacca Strait Block, Central Sumatra Basin. This field has several proven wells included in the 3D seismic data, which were then explored for areas around the proven wells. This study uses 3 wells that have undergone petrophysical analysis and seismic data in the form of partial angle stacks consisting of near angle, mid angle, and far angle. This Study uses simultaneous inversion methods and lithology classification using Bayesian rules. The crossplot results indicate that acoustic impedance and the Vp/Vs ratio are the most sensitive parameters for distinguishing lithology and fluids. The simultaneous inversion results show acoustic impedance values ranging from 12,000 (ft/s*gr/cc) to 19,000 (ft/s*gr/cc) and Vp/Vs values ranging from 2.0 to 2.5. The target development area is located northwest of well X-1, which has low acoustic impedance and Vp/Vs values. Lithology classification was conducted using direct zonation methods and Bayesian rules. The classification results from both methods indicate that the proven area is classified as oil sand, and the target development area northwest of well X-1 is also classified as oil sand."

"ABSTRACTBatumerah area is located in the Aru Basin, offshore South Papua. One well hasalready been drilled in this area and gave inconclusive gas discovery. The wellindicates that there may have good potential reservoir zone, but no definiteinformation was gathered from the well to confirm the statement. Acomprehensive evaluation like reservoir characterization study by integrating welldata, seismic data and geological interpretation is required to resolve thisuncertainty and predict the hydrocarbon potential of the Batumerah area. Due tolimited well data, the most applicable reservoir characterization study inBatumerah Area is Seismic Simultaneous Inversion. Simultaneous inversion is arelatively new and extremely powerful form of inversion. The detailed techniqueessentially takes several seismic angle stacks and inverts them simultaneously.The result is two primary volumes of absolute rock properties tightly calibrated tothe well log data: P-Impedance and S-Impedance. Additional outputs include:Vp/Vs, porosity and Lambda Rho volumes. Having these extra datasets take theexplorationist into a new world of possibilities. The application of a simultaneousinversion algorithm to the seismic angle stacks in Batumerah area hasdemonstrated the ability to minimize uncertainty and addressing some issuesregarding the lithology and reservoir properties due to data limitation.Even though most of well log data are derived from model and only one wellexists on the inversion area, nevertheless, the simultaneous inversion results thatare interpretative results provide best estimation and prediction for reservoircharacterization on the Batumerah area."

"Reservoar gas batu pasir pada formasi Arang telah berhasil di karakterisasi dengan mengintegrasikan ketiga metode dari inversi simultan, analisis LMR dan analisis AVO. Karakterisasi difokuskan dalam dua hal yaitu identifikasi litologi dan kandungan fluidanya. Pada studi ini masing-masing metode akan menghasilkan parameter fisis yang sensitif terhadap karakter dari reservoar.Inversi simultan menghasilkan tiga parameter fisis berupa impedansi P (Zp), impednasi S (Zs), dan rasio Vp/Vs. Sementara transformasi LMR akan menghasilkan dua parameter fisis yaitu Mu-rho dan Lamda-rho. Identifikasi litologi dilakukan melalui analisis parameter fisis Mu-rho dan impedansi S sedangkan identifikasi kandungan fluida melalui analisis parameter Lamda-rho, impedansi P, dan rasio Vp/Vs. Analisis AVO dilakukan untuk mengetahui tipe kelas anomali dari gas yang mengisi reservoar melalui analisis gradien. Hasil studi menunjukan parameter Mu-rho dan lamda rho berhasil menggambarkan persebaran reservoar gas batu pasir secara 3D. Hasil impedansi S, impedansi P, dan Vp/Vs juga menujukan indikasi dari reservoar batu pasir di daerah yang sama. Terakhir berdasarkan analisis AVO tipe gas dalam reservoar adalah kelas IIp.

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Gas sand resrvoir at Arang formation has been characterized by integrating three method from simultaneous inversion, LMR analysis, and AVO analysis.Characterization is focused on two things, litologi identification and fluid content. Each method in this study will produce parameter which sensitive to reservoar character. Simultaneous inversion results three physical parameters P-impedance, S-impedance, and ratio Vp/Vs. Whereas LMR transformation results two parameters, Lamda-rho and Mu-rho. Litology identification is done with Mu-rho and S-impedance analysis while fluid content identification is done with Lamda-rho, P-impedance, and ratio Vp/Vs. AVO analysis has purpose to know anomaly type from gas in reservoar through gradient analysis. This study shows that Mu-rho and Lamda-rho analysis can deliniate Gas Sand Reservoar in 3D form. While S-impdance, P-impedance, and Vp/Vs also indicate gas sand reservoar in the same spot. Finally based on AVO analysis, gas type in reservoar is class IIp."

"Lapangan Phy berada di lingkungan pengendapan delta plain dengan beberapa kualifikasi; batupasir yang berasal dari sungai adalah sungai - sungai yang memiliki sejarah geologi berbeda dengan ketebalan 20 - 40 meter, beberapa sungai - sungai kecil dengan ketebalan 10 - 15 meter, dan endapan sungai lainnya ketebalannya sekitar 2 meter. Berdasar kondisi geologi, lapangan Phy memiliki beberapa paket batupasir pada masing - masing log. Litologi pada lapangan ini juga bervariasi; batupasir, batulempung, batubara, dan gamping. Lapangan ini juga memiliki beberapa tantangan yaitu : a. Klasifikasi litologi dan fluida pada zona sangat dangkal (di atas 700m) dan sangat dalam (di bawah 3000 m) sulit diidentifikasi karena isu amplitude seismic b. Delineasi litologi spasial dan distribusi fluida sulit dipetakan karena anisotropi data seismic c. Resolusi vertikal untuk karakterisasi reservoir kurang baik karena paket batupasir yang tipis.Untuk menyelesaikan tantangan - tantangan tersebut, inversi simultan dan inversi geostatistik dilakukan pada lapangan ini. Separasi litologi dapat dilakukan dengan baik pada zona 2 (lebih kurang 2000 - 5000 m. Namun terdapat beberapa pertimbangan untuk menggunakan hasil inversi simultan dan geostatistik pada lapangan Phy. Kedua hasil inversi simultan dan geostatistik tidak dapat memetakan distribusi hidrokarbon baik secara vertikal maupun horizontal. Hal ini disebabkan karena hasil analisis petrofisika dan fisika batuan tidak memberikan hasil yang dapat merepresentasikan separasi litologi dan fluida. Beberapa perbaikan untuk klasifikasi fluida pada lapangan ini perlu dipelajari lebih lanjut. Melalui korelasi litologi, inversi simultan dan geostatistik dapat memetakan distribusi batupasir dengan baik meskipun beberapa keterbatasan muncul. Distribusi lateral dari prediksi batupasir berkorelasi dengan baik terhadap informasi net sand dari data sumur tetapi resolusi vertikal kurang baik. Secara kontras, inversi geostatistik memberikan hasil yang lebih detail dalam resolusi vertikal tetapi tidak berkorelasi cukup baik dengan data net sand dari sumur karena efek pemodelan variogram.

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Phy field is located on delta plain depositional environment with several qualifications; channel sand bodies are either multi - story channels with a thickness of 20 to 40 meters, many single channels with a thickness of 10 to 15 meters, and distributary channels deposits gave mouth bars with a thickness of around 2 meters.

Due to this geological condition, Phy field has several sand packages on each log. The lithology of this field is also varied; sandstone, shale, coal, and limestone. This field also has several challenges:

d. Lithology and fluid classification at Very Shallow (above 700 m) and Very Deep (below 3000 m) zones, caused by seismic amplitude issue

e. Spatial lithology and fluid distribution delineation, caused by seismic anisotropy

f. Vertical resolution resolving of reservoir characterization, caused by thin sand packages.

To solve those challenges on Phy field, simultaneous inversion (SI) and geostatistical inversion (GI) have been conducted on this field. Lithology separation could be conducted well from Zone 2 (more or less 2000 - 2500 m). Nevertheless, there are several considerations to use GI and SI in Phy field.

Both simultaneous and geostatistical inversion results could not characterize hydrocarbon distribution vertically and horizontally. It is because of the petrophysics and rock physics result of elastic properties which have been used as the inputs for lithology and fluid classification.

Several enhancements for the classification for this field are needed to be studied deeper. Through lithology correlation, simultaneous and geostatistical inversion could delineate sand distribution well even though some limitations also overcome. Simultaneous inversion lateral distribution of sand prediction correlates well to net sand information from wells but lack of vertical resolution. Besides, geostatistical inversion gives more detail in vertical resolution of capturing thin sands but lack of lateral prediction of sands because of variogram effect."