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"AFI (AVO Fluid Inversion) menganalisa respon dari anomali AVO, kemudian membandingkannya dengan respon yang didapat secara teori dan memprediksi sifatsifat fluida. AFI dalam prosesnya terbagi dalam 2 tahap. Tahap pertama didapatkan peta atribut AVO. Pada peta ini akan ditentukan zona-zona berdasarkan intensitas warna. Tahap selanjutnya melakukan analisa tren dari data sumur. Dari analisa tersebut didapat model parameter stochastic. Hasil penggabungan model parameter stochastic dengan ekstraksi wavelet dari data seismik akan didapat simulasi crosplot antara perpotongan (Intercept) dan kemiringan (Gradient) yang terdiri dari 3 fluida yaitu minyak, gas dan brine. Dari simulasi crosplot tersebut dimasukkan sayatansayatan data dari peta atribut AVO yang akan menentukan penyebaran kandungan reservoar hidrokarbon. Penentuan karakteristik hidrokarbon diperkuat lagi dengan peta indikasi dan peta probabilitas. Dari penggunaan analisa AFI dapat diketahui bahwa karakteristik reservoar hidrokarbon pada daerah TPS merupakan gas dan didominasi oleh minyak.

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AFI (AVO Fluid Inversion) analyze AVO response, compare them without theoretically derived response and predict fluid properties. There are two steps in AFI process. First, using AVO attribute maps. In this map will be decided zones based on color intensity. The next step is doing trend analysis from well database. From that analyze will obtain stochastic models parameters. The result from gathering stochastic models parameters and wavelet extraction from seismic data are crossplot simulation between intercept and gradient which consist of oil, gas and brine. Then input data slices from AVO attribute maps to crossplot simulation which will determine hydrocarbon reservoar distribution. The determine of hydrocarbon characteristic will be more certain with indication and probability maps. By using AFI analysis can be determine that hydrocarbon reservoar characteristic at TPS is gas and dominated by oil."

"[Lapangan “X” merupakan lapangan gas terbesar di delta mahakam dengan luas area permukaan yang mancapai 1350km2 dan total akumulasi gas terproduksi mencapai 8 tcf sejak tahun 1990 hingga saat ini. Penurunan produksi yang cukup tajam melatarbelakangipengembangan gas di zona dangkal (shallow gas). Sedimen pada zona dangkal ini tersusun oleh endapan deltaik berumur Miosen Atas – Pliosen dengan batupasir sebagai batuan reservoar utama. Keberadaan fluida gas pada batupasir akan berdampak pada penurunan kecepatan gelombangP dan densitas batuan sehingga memberikan kontras impendansi akustik yang kuat terhadaplapisan shale. Kontras impedansi akustik ini terlihat sebagai anomali amplitudo (brightspot)pada seismik. Adanya kenaikan nilai amplitudo seiring dengan bertambah besarnya sudutdatang menjadi hal yang menarik dalam interpretasi shallow gas ini.Tujuan dari penelitian ini adalah untuk mendeteksi keberadaan shallow gas di lapangan “X”menggunakan atribut AVO Sismofacies dengan 2 sumur yang dijadikan referensi untukpemodelan synthetic AVO. Penulis menggunakan 2 sumur lainnya sebagai kalibrasi terhadapanomali AVO dari Sismofacies cube yang dihasilkan.Metode AVO sismofacies ini tidak menggunakan parameter intercept (A) dan gradient (B)untuk kalkulasi AVO melainkan menggunakan dua data substack yaitu Near dan Far stack.Crossplot antara Near dan Far pada zona water bearing sand dan shale diambil untukmendapatkan background trend sehingga anomali yang berada diluar trend tersebut dapatdiinterpretasikan sebagai gas sand.Hasil dari analisis AVO Sismofacies ini cukup baik dan menunjukkan kesesuaian denganinterpretasi gas di beberapa sumur dan efek Coal berkurang jika dibandingkan Far stack.Meskipun demikian interpretasi AVO ini sebaiknya diintergrasikan dengan analisis dariatribut seismik lainnya untuk memperkuat interpretasi;Field “X” is a giant gas field in mahakam delta which cover 1350km2 of the area with totalcummulative gas production has reached 8 tcf since 1990 to recently. A significantdecreasing of gas production has led to produce gas accumulation in shallow zone as aneffort to fight againts this decline. Shallow zone is a deltaic sediments which depositedduring Upper Miocen to Pliocene with dominant reservoir is sandstone.The presence of gas in sandstone has an impact on decreasing of velocity P as well as densitywhich giving a contrast of acoustic impedance to the overlaying shale. Contrast ofimpedance can be observes in seismic as an amplitude anomaly or so called a brightspot. Anincrease of amplitude along the offset become more interesting in shallow gas interpretation.The aim of this study is to detect shallow gas accumulation di field “X” by using AVOSismofacies attribute with 2 wells as references to model respons of AVO. The result ofAVO sismofacies will be a cube and the interpreation will be calibrated with 2 existing wellscontaining proven gas bearing sands.AVO Sismofacies method will introduce Near and Far substack to be used in the calculationinstead of using common AVO paramter intecepth (A) and gradient (B). A crossplot betweensubstacks will create a background trend from water bearing zone and shale hence anyoutliers can, then,be interpreted as gas anomaly.AVO Sismofacies result is encouraging and some of AVO anomaly has been well calibratedwith existing wells. Coal effect which led to misintepretaion in shallow gas sand isdiminished compared to Far stack. Despite of this result, this anomaly interpretation need tobe intergrated with anothers seismic attribute to gain the level of confidence for shallow gasinterpretation., Field “X” is a giant gas field in mahakam delta which cover 1350km2 of the area with totalcummulative gas production has reached 8 tcf since 1990 to recently. A significantdecreasing of gas production has led to produce gas accumulation in shallow zone as aneffort to fight againts this decline. Shallow zone is a deltaic sediments which depositedduring Upper Miocen to Pliocene with dominant reservoir is sandstone.The presence of gas in sandstone has an impact on decreasing of velocity P as well as densitywhich giving a contrast of acoustic impedance to the overlaying shale. Contrast ofimpedance can be observes in seismic as an amplitude anomaly or so called a brightspot. Anincrease of amplitude along the offset become more interesting in shallow gas interpretation.The aim of this study is to detect shallow gas accumulation di field “X” by using AVOSismofacies attribute with 2 wells as references to model respons of AVO. The result ofAVO sismofacies will be a cube and the interpreation will be calibrated with 2 existing wellscontaining proven gas bearing sands.AVO Sismofacies method will introduce Near and Far substack to be used in the calculationinstead of using common AVO paramter intecepth (A) and gradient (B). A crossplot betweensubstacks will create a background trend from water bearing zone and shale hence anyoutliers can, then,be interpreted as gas anomaly.AVO Sismofacies result is encouraging and some of AVO anomaly has been well calibratedwith existing wells. Coal effect which led to misintepretaion in shallow gas sand isdiminished compared to Far stack. Despite of this result, this anomaly interpretation need tobe intergrated with anothers seismic attribute to gain the level of confidence for shallow gasinterpretation.]"

"A new thermodynamic property model for propane is expressed in form of the helholtz free energy function....."

"Penggunaan refrigeran HFC dan HCFC yang mempunyai dampak terhadap ozon lebih kecil dibandingkan CFC, ternyata dari masyarakat pemerhati lingkungan mengajukan keberatan atas penggunaan jenis refrigeran ini. Karena senyawa ini masih memiliki potensi pemanasan global atau GWP (Global Warming Potensial) yang cukup tinggi. Walaupun pelarangan resmi secara internasional senyawa ini belum ada, pada beberapa negara main seperti negara-negara di Eropa mengkategorikan refrigeran HFC dan HCFC sebagai refrigeran yang harus dikontrol penggunaannya dan mengusulkan agar jadwal pengurangannya harus diatur secara internasional.Refrigeran alternative hidrokarbon dengan komposisi utama propana, yang tidak memiliki dampak terhadap pengurangan ozon dan tidak memiliki dampak terhadap pemanasan global saat ini di tawarkan sebagai pengganti HCFC-22- Dari hasil pengujian unjuk kerja refrigeran hidrokarbon H dapat menggantikan refrigeran HCFC-22, dan juga mempunyai beberapa kelebihan diantaranya tekanan kondensasi, temperatur buang, dan daya listrik yang rendah dibandingkan refrigeran HCFC-22."

"New thermodynamic property model for n-butane exprasesed in form of the Helmholtz free energy equation is presented....."

"Proses prediksi litologi sekaligus kandungan fluidanya merupakan bagian terpenting dalam karakterisasi reservoar. Salah satu metode yang digunakan dalam proses ini adalah metode inversi seismik simultan. Pada Lapangan Poseidon, Cekungan Browse, Australia, parameter-parameter yang dihasilkan melalui inversi seismik simultan kurang dapat mengkarakterisasi reservoar dengan baik karena saling tumpang tindihnya nilai impedansi antara hydrocarbon sand, water sand, dan shale yang menyebabkan tingkat ambiguitas yang tinggi dalam interpretasi. Inversi Poisson Impedance memberikan solusi terhadap permasalahan tersebut dengan cara merotasi impedansi beberapa derajat yang didapatkan melalui koefisien c. Hasilnya menunjukkan bahwa PI memberikan hasil yang lebih baik dalam memisahkan zona reservoar tersaturasi hidrokarbon. Berdasarkan hasil crossplot LI-GR, crossplot ¼- effecitive porosity, dan crossplot FI-Sw dengan nilai c masing-masing 2.04, 2.28, dan 1.05 didapatkan nilai korelasi optimum masing-masing 0.74, 0.91, dan 0.82 menunjukkan bahwa litologi porous sand tersaturasi hidrokarbon berada berada pada nilai LI ≤2800(m/s)(g*cc), 𝜙𝐼 ≤-5500(m/s)(g*cc), dan FI ≤3750(m/s)(g*cc). Keberadaan nilai LI, ϕI, dan FI yang rendah ini berkorelasi baik dengan keberadaan hidrokarbon pada sumur. Masing-masing nilai c tersebut kemudian diaplikasikan pada data seismik. Hasilnya menunjukkan bahwa distribusi persebaran porous sand tersaturasi Hidrokarbon pada penampang inversi seismik terlihat pada arah timur laut-barat daya yang diperkirakan sebagai arah persebaran gas.

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The prediction process of lithology and fluid are the most important parts of reservoir characterization. One of the methods used in this process is the simultaneous seismic inversion method. In the Poseidon field, Browse Basin, Australia, the parameters generated through simultaneous seismic inversion are not able to characterize the reservoir accurately because of the overlapping impedance values between hydrocarbon sand and shale which causes a high level of ambiguity in the interpretation. The Poisson Impedance inversion provides a solution to this problem by rotating the impedance through the coefficient c. Based on the results of the LI-GR crossplot, the 𝜙I-effective porosity crossplot, and the FI-SW crossplot with c values of 2.04, 2.28, and 1.05 respectively, obtained the optimum correlations of 0.74, 0.91,and 0.82 respectively, indicating that hidrocarbon-saturated porous sand is at the value of LI ≤ 2800 (m/s)(g *cc), 𝜙I ≤ 5500 (m/s)(g*cc), and FI ≤ 4000 (m/s)(g*cc). The presence of low values of LI, 𝜙I, and FI correlates accurately with the presence of hydrocarbons in the well. The results show that the distribution of hydrocarbon saturated porous sand on the seismic inversion section is seen in the northeast-southwest direction which is estimated as the direction of gas distribution."

"[Lapangan X merupakan lapangan mature yang berada di Cekungan Sumatera Tengah. Lapangan ini memiliki struktur antiklin produk dari reverse oblique-slip fault yang membentuk zona patahan di sisi Barat Lapangan X. Zona ini terbukti menghasilkan hidrokarbon ditunjukan oleh sumur produksi X-027, X-153 dan X 154. Sehingga zona patahan ini memiliki potensi untuk di eksplorasi lebih lanjut. Namun, kondisi seismik di zona ini chaotic sehingga sulit untuk menginterpretasikan zona patahan. Penelitian ini akan menggunakan metode geoelectric IVEL dan continuous wavelet transform (CWT) untuk mendapatkan informasi keberadaan hidrokarbon dizona patahan Lapangan X. Geoelectric IVEL (Inversion Vertical Electrical Logging) menggunakan metode vertical sounding schlumberger yang diolah untuk menghasilkan penampang resistivitas medium. Hasil penampang resistivitas medium pada penelitian ini menunjukkan adanya kemiripan nilai resitivitas dengan nilai log resistivitas sumur untuk zona reservoar 350sd dan 550sd (10-20 ohmm). Nilai resistivitas ini terlihat juga di zona patahan yang dijadikan indikator hidrokarbon. Hasil dalam domain kedalaman membantu dalam interpretasi kedalaman reservoar di zona patahan. Analisis continuous wavelet transform (CWT) pada penelitian ini menunjukan amplitudo tinggi pada frekuensi rendah 5-20 Hz dan merupakan indikasi adanya hidrokarbon. Amplitudo tinggi pada frekuensi rendah telihat juga di zona patahan, pada posisi dimana IVEL menunjukan nilai resistivitas sebagai indikator.

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Hidrocarbon X field is a mature field in Central Sumatera Basin. It has anticline structure as a result of reverse oblique-slip fault that produces fault zone in the North side of X Field. It is proved hydrocarbon with the production well X-027, X-153 and X-154. However, it is very difficult to interpret the fault zone with the available seismic data because of the chaotic seismic condition in fault zone. This study uses Ivel Geoelectric method and Continuous Wavelet Transform (CWT) to get hydrocarbon indicator in fault zone. Geoelectric IVEL (Inversion Vertical Electrical Logging) using vertical sounding schlumberger is processed to get medium resistivity section. Medium resistivity section from geoelectrical IVEL at reservoir zone showes similar resistivity value with resistivity log (10-20ohm) for reservoar 350sd and 550sd. This value is showed in fault zone as hydrocarbon indicator. Medium resistivity geoelectrical IVEL is depth domain. It is helpful for interpretation of reservoir depth at fault zone, that is not able to be done by seismic. Continuous wavelet transform (CWT) showes high amplitude at low frequency (5-20Hz) as hydrocarbon indicator. High amplitude at low frequency is showed in fault zone where IVEL showes the hydrocarbon indicator;X field is a mature field in Central Sumatera Basin. It has anticline structure as a

result of reverse oblique-slip fault that produces fault zone in the North side of X Field. It is proved hydrocarbon with the production well X-027, X-153 and X-154. However, it is very difficult to interpret the fault zone with the available seismic data because of the chaotic seismic condition in fault zone. This study uses Ivel Geoelectric method and Continuous Wavelet Transform (CWT) to get hydrocarbon indicator in fault zone. Geoelectric IVEL (Inversion Vertical Electrical Logging) using vertical sounding schlumberger is processed to get medium resistivity section. Medium resistivity section from geoelectrical IVEL at reservoir zone showes similar resistivity value with resistivity log (10-20ohm) for reservoar 350sd and 550sd. This value is showed in fault zone as hydrocarbon indicator. Medium resistivity geoelectrical IVEL is depth domain. It is helpful for interpretation of reservoir depth at fault zone, that is not able to be done by seismic. Continuous wavelet transform (CWT) showes high amplitude at low frequency (5-20Hz) as hydrocarbon indicator. High amplitude at low frequency is showed in fault zone where IVEL showes the hydrocarbon indicator;X field is a mature field in Central Sumatera Basin. It has anticline structure as a result of reverse oblique-slip fault that produces fault zone in the North side of X Field. It is proved hydrocarbon with the production well X-027, X-153 and X-154. However, it is very difficult to interpret the fault zone with the available seismic data because of the chaotic seismic condition in fault zone. This study uses Ivel Geoelectric method and Continuous Wavelet Transform (CWT) to get hydrocarbon indicator in fault zone. Geoelectric IVEL (Inversion Vertical Electrical Logging) using vertical sounding schlumberger is processed to get medium resistivity section. Medium resistivity section from geoelectrical IVEL at reservoir zone showes similar resistivity value with resistivity log (10-20ohm) for reservoar 350sd and 550sd. This value is showed in fault zone as hydrocarbon indicator. Medium resistivity geoelectrical IVEL is depth domain. It is helpful for interpretation of reservoir depth at fault zone, that is not able to be done by seismic. Continuous wavelet transform (CWT) showes high amplitude at low frequency (5-20Hz) as hydrocarbon indicator. High amplitude at low frequency is showed in fault zone where IVEL showes the hydrocarbon indicator.;X field is a mature field in Central Sumatera Basin. It has anticline structure as a

result of reverse oblique-slip fault that produces fault zone in the North side of X Field. It is proved hydrocarbon with the production well X-027, X-153 and X-154. However, it is very difficult to interpret the fault zone with the available seismic because of the chaotic seismic condition in fault zone. This study uses IVEL Geoelectric method and Continuous Wavelet Transform (CWT) to get hydrocarbon indicator in fault zone. Geoelectric IVEL (Inversion Vertical Electrical Logging) using vertical sounding schlumberger is processed to get medium resistivity section. Medium resistivity section from geoelectrical IVEL at reservoir zone showes similar resistivity value with resistivity log (10-20ohm) for reservoar 350sd and 550sd. This value is showed in fault zone as hydrocarbon indicator. Medium resistivity geoelectrical IVEL is depth domain. It is helpful for interpretation of reservoir depth at fault zone, that is not able to be done by seismic. Continuous wavelet transform (CWT) showes high amplitude at low frequency (5-20Hz) as hydrocarbon indicator. High amplitude at low frequency is showed in fault zone where IVEL showes the hydrocarbon indicator, X field is a mature field in Central Sumatera Basin. It has anticline structure as a

result of reverse oblique-slip fault that produces fault zone in the North side of X

Field. It is proved hydrocarbon with the production well X-027, X-153 and X-154.

However, it is very difficult to interpret the fault zone with the available seismic data

because of the chaotic seismic condition in fault zone. This study uses Ivel

Geoelectric method and Continuous Wavelet Transform (CWT) to get hydrocarbon

indicator in fault zone.

Geoelectric IVEL (Inversion Vertical Electrical Logging) using vertical sounding

schlumberger is processed to get medium resistivity section. Medium resistivity

section from geoelectrical IVEL at reservoir zone showes similar resistivity value

with resistivity log (10-20ohm) for reservoar 350sd and 550sd. This value is showed

in fault zone as hydrocarbon indicator. Medium resistivity geoelectrical IVEL is

depth domain. It is helpful for interpretation of reservoir depth at fault zone, that is

not able to be done by seismic. Continuous wavelet transform (CWT) showes high

amplitude at low frequency (5-20Hz) as hydrocarbon indicator. High amplitude at

low frequency is showed in fault zone where IVEL showes the hydrocarbon indicator]"

"ABSTRAKProses pemisahan litologi dan fluida reservoir merupakan bagian penting dalam mengkarakterisasi reservoir. Hal ini akan menjelaskan sifat fisis litologi batuan reservoir serta kandungan fluidanya dengan mengintegrasikan data geofisika dan data petrofisika. Proses ini sulit dilakukan di lapangan ldquo;B rdquo; apabila menggunakan parameter impedansi akustik dan LMR, karena masih memiliki tingkat ambiguitas yang cukup tinggi. Impedansi Poisson PI telah di implementasikan sebagai solusi untuk menjawab masalah tersebut. Pada crossplot antara Impedansi Akustik AI dan Impedansi Shear SI dilakukan rotasi kedua sumbunya dengan mengikuti tren litologi-fluida hingga memenuhi persamaan PI c = AI ndash; cSI. Untuk meningkatkan akurasi perhitungan PI, nilai c faktor optimalisasi rotasi dihitung melalui metode TCCA Target Correlation Coefficient Analysis . Mirip seperti EEI fungsi sudut, kemudian dilakukan korelasi dengan data sumur yang akan diprediksi. Analisis parameter sensitivitas dilakukan pada 2 sumur yang ada di lapangan ldquo;B rdquo;. Dari simultaneous inversion didapat parameter-parameter Zp, Zs dan densitas yang kemudian ditranformasi menjadi PI. Model PI kami menunjukan dengan jelas pemisahan litologi batuan reservoir hidrokarbon. Lithology Impedance LI hasil dari korelasi PI dengan GR mampu memisahkan sand dan shale dengan baik. Begitu pula dengan Fluid Impedance FI sebagai hasil korelasi PI dengan SW juga mampu memisahkan kandungan air di dalam reservoir dengan nilai Sw tinggi relatif terhadap gas dengan nilai Sw yang rendah. Zona Hidrokarbon diperkirakan berada pada kedalaman antara 2360-2400m. Hasil slicing pada volume Poisson Impedance inversion telah memberikan gambaran distribusi dan interpretasi litologi dan kandungan fluida yang jelas pada reservoir di lapangan ldquo;B rdquo;, Sumatera Selatan.

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ABSTRACTThe separation process of lithology and fluid reservoir is an important part in the characterization of reservoir. This would explain the physical properties of reservoir rock lithology and fluid content by integrating the geophysics and petrophysical data. This process is difficult to do in the field B when using parameters of acoustic impedance and LMR, because it still has a fairly high degree of ambiguity. Poisson impedance PI has been implemented as a solution to address the problem. In crossplot between Acoustic Impedance AI and Shear Impedance SI conducted a rotation of both axis according to the trend of lithology fluid to satisfy the equation of PI c AI ndash c SI. To improve the accuracy of PI calculation, the value of c optimization factor of rotation is calculated through the method of TCCA Target Correlation Coefficient Analysis . Much like EEI, then do the correlation with to be predicted wells data. Analysis of sensitivity parameter performed on two wells in the field B . Parameters Zp, Zs and density which obtained from the simultaneous inversion then transformed into PI. Our PI models clearly show the separation of rock lithology of hydrocarbon reservoir. Lithology impedance LI as a result of the PI GR correlation is able to separate sand and shale very well. Similarly, the impedance Fluid FI as a result of PI SW correlation is also able to separate the water content in the reservoir with high Sw value relative to gas with a low value of Sw. Hydrocarbon zone proven at 2360 2400 m. The slicing result of the volumes of Poisson impedance inversion has provided a clearly distribution and interpretation of lithology and fluid content reservoir at the field B of South Sumatera."

"Lapangan G yang berlokasi pada Cekungan Sumatera Selatan, merupakan salah satu lapangan reservoar hidrokarbon. Untuk mengetahui karakter dari reservoar Lapangan G, dalam penelitian ini, dilakukan pendekatan petrofisika serta penggunaan multi atribut seismik dengan metode Probabilistic Neural Network yang berfokus pada Formasi Gumai. Atribut seismik yang digunakan adalah atribut sesaat, yaitu amplitudo sesaat, fase sesaat, dan frekuensi sesaat serta parameter nilai petrofisika yang dicari adalah nilai porositas, saturasi air, dan volume shale. Anomali seismik Lapangan berupa dim spot diantara kedua patahan utama yang berorientasi NorthWest-SouthEast dan patahan berorientasi NorthEast-SouthWest, diperkirakan sebagai tempat akumulasi hidrokarbon. Output utama penelitian ini adalah hasil lumping untuk melihat zona suatu sumur yang memiliki prospek hidrokarbon dan hasil volume seismik prediksi dari ketiga nilai parameter petrofisika serta output sampingan dari interpretasi penampang seismik. Baik hasil lumping dan volume seismik prediksi, menampilkan bahwa Formasi Gumai memiliki prospek hidrokarbon yang juga ditampilkan pada data sumur, didapatkan bahwa Zona 5 pada Sumur G1 dan Zona 4 pada Sumur G3 memiliki prospek cadangan hidrokarbon dengan nilai volume shale sebesari 0.500, nilaii saturasii airi sebesari 0.406, dan nilai porositas sebesar 0.131.

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Field G, which is located in the South Sumatera Basin, isi onei ofi thei hydrocarboni reservoir fields. To determine thei character ofi thei G Field reservoir, in this study, a petrophysical approach was used and the use of multiple seismic attributes using the Probabilistic Neural Network method which focused on the Gumai Formation. Seismic attributes used are instantaneous attributes, namely instantaneous amplitude, instantaneous phase, and instantaneous frequency and the parameters of the petrophysical value sought are the value of porosity, water saturation, and shale volume. Seismic anomaly in the field in the form of a dim spot between the two main faults oriented NorthWest-SouthEast and fault oriented NorthEast- SouthWest, is estimated as a place of accumulation of hydrocarbons. The main output of this research is the lumping results to see the zone of a well that has hydrocarbon prospects and the predicted seismic volume results from the three petrophysical parameter values as well as the side output from the interpretation of the seismic cross-section. Both the lumping results and the predicted seismic volume, showing that the Gumai Formation has a hydrocarbon prospect which is also shown in the well data, it is found that Zone 5 in Well G1 and Zone 4 in Well G3 have prospects for hydrocarbon reserves with a shale volume value of 0.500, a water saturation value of 0.406, and a porosity value of 0.131."

"Cekungan Jawa Timur Utara membentang sepanjang lebih dari 600 km dari barat ke timur, dan memanjang sekitar 250 km dari arah utara ke selatan, serta telah menjadi tempat eksplorasi dan eksploitasi minyak sejak seratus tahun lamanya (Lunt, 2013). Pada batas antara Eosen dan Oligosen, Central Deep mulai mengalami pemekaran (rifting), kemudian terjadi subsidensi secara cepat ke kondisi laut sangat dalam dan menangkap sebagian besar sedimen yang sebelumnya tertransport jauh ke arah timur. Daerah penelitian berada di area struktur Central Deep, tepatnya pada formasi Kujung. Formasi tersebut didominasi oleh litologi claystone dengan banyak sisipan tipis karbonat dan batupasir. Penelitian ini bertujuan untuk mengarakterisasi reservoir yang ada pada formasi Kujung (middle Kujung hingga lower Kujung) menggunakan inversi seismik simultan dan transformasi LMR. Metode tersebut akan menghasilkan model properti batuan berupa Zp, Zs, densitas, rigiditas, dan inkompresibilitas, yang dapat digunakan untuk mengetahui sebaran litologi dan kandungan fluida di dalam batuan. Berdasarkan hasil analisis, dapat disimpulkan bahwa hasil inversi simultan mampu mendelineasi zona reservoir karbonat dan batupasir dengan masing-masing nilai parameter sebagai berikut. Reservoir karbonat memiliki nilai impedansi P sebesar 8823 – 11788 (m/s)*(gr/cc), impedansi S 5338 – 6636 (m/s)*(gr/cc), densitas 2.47 – 2.7 gr/cc, dan rasio VpVs paling rendah yaitu 1.63 – 1.8. Sedangkan reservoir batupasir memiliki nilai impedansi P sebesar 7764 – 8823 (m/s)*(gr/cc), impedansi S 4597 – 5338 (m/s)*(gr/cc), densitas 2.33 – 2.47 gr/cc, dan rasio VpVs sebesar 1.75 – 1.99. Hasil transformasi LMR menunjukkan bahwa reservoir yang mengandung hidrokarbon memiliki nilai parameter sebagai berikut. Zona hidrokarbon pada karbonat memiliki nilai inkompresibilitas 31.9 – 34.2 GPA*gr/cc dan riditas 22.7 – 32.1 GPA*gr/cc. Sedangkan zona hidrokarbon pada batupasir memiliki nilai inkompresibilitas 27.9 – 31.9 GPA*gr/cc dan rigiditas 17.4 – 22.7 GPA*gr/cc.

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The North East Java Basin extends more than 600 km from west to east, and about 250 km from north to south, has been a place of oil exploration and exploitation for hundred years (Lunt, 2013). At the boundary between the Eocene and the Oligocene, the Central Deep begins to rifted, then subsided rapidly to very deep sea conditions and captures most of the sediment that was previously transported far to the east. The research area is in the Central Deep structure, precisely in the Kujung formation. The formation is dominated by lithology of claystones with many thin interbeds of carbonates and sandstones. This study aims to characterize the reservoir in the Kujung formation (middle Kujung to lower Kujung) using simultaneous seismic inversion and LMR transformation. This method will produce a rock property model in the form of Zp, Zs, density, rigidity, and incompressibility, which can be used to determine the lithological distribution and fluid content of the rocks. Based on the results of the analysis, it can be concluded that the simultaneous inversion result can delineate the carbonate and sandstone reservoir zones with each of the following parameter values. The carbonate reservoir has a P-impedance value of 8823 - 11788 (m/s)*(gr/cc), S-impedance value of 5338 - 6636 (m/s)*(gr/cc), density of 2.47 - 2.7 gr/cc, and the lowest value of Vp/Vs is 1.63 - 1.8. While the sandstone reservoir has a P-impedance value of 7764 - 8823 (m/s)*(gr/cc), S-impedance value of 4597 - 5338 (m/s)*(gr/cc), density of 2.33 - 2.47 gr/cc, and the Vp/Vs of 1.75 - 1.99. The results of the LMR transformation show that the reservoir containing hydrocarbons has the following parameter values. The hydrocarbon zone in the carbonate has an incompressibility value of 31.9 - 34.2 GPA*(gr/cc) and rigidity of 22.7 - 32.1 GPA*(gr/cc). Meanwhile, the hydrocarbon zone in the sandstones has an incompressibility value of 27.9 - 31.9 GPA*(gr/cc) and rigidity of 17.4 - 22.7 GPA*(gr/cc)."