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Abstrak :
Dalam suatu eksplorasi minyak dan gas bumi, pengetahuan dan pembelajaran suatu kerangka regional dari suatu lapangan minyak sangat mutlak diperlukan. Hal ini diperlukan untuk mengetahui struktur dan geometri dari suatu tubuh reservoar agar dapat diketahui daerah-daerah prospek eksplorasi minyak dan gas bumi. Semakin menipisnya cadangan minyak bumi, semakin sempitnya daerah eksplorasi dan semakin meningkatnya harga minyak dunia akhir-akhir ini merupakan tantangan bagi para ekplorasionis untuk terus mencari dan mengembangkan metoda-metoda pencarian minyak dan gas bumi. Metoda gabungan seismik inversi data pre-stack AVO dan geostatistik mencoba memberikan pendekatan lain untuk memetakan properti fisik lµr pada suatu interval reservoar batupasir formasi Talang Akar di lapangan minyak WGR yang terdapat di cekungan Sunda, Sumatra Tenggara. Hasil akhir pemetaan properti lµr dengan gabungan kedua metoda tersebut di atas mampu memberikan informasi yang cukup baik dan berguna dalam penentuan daerah prospektif minyak dan gas bumi di daerah ini. Namun masih ada beberapa kekurangan dan kelemahan sehingga saran dan kritik masih terbuka untuk penyempurnaan selanjutnya. ......In hydrocarbon exploration, knowledge and study of regional framework is completely required to get an understanding the structure and geometry of reservoir, which will lead into hydrocarbon prospective zone. The decrease of hydrocarbon reserve, the narrower exploration area and the rising of oil price have made challenges for explorationist to discover and to develope methods of finding hydrocarbon. Joint methods of pre-stack seismic AVO inversion and geostatistic attempt to give another approach to map physical properties of lµr at reservoar interval of sandstones Talang Akar formation at WGR oil field at Sunda basinal area, Southeast Sumatra. The map of physical property of lµr using combination approach of AVO inversion and geostatistic shows good result and usefull for determining prospect area of hydrocarbon accumulation in this area. There are still liabilities and weaknesses, thus critics and sugestions are all wide opened for future work.

Abstrak :
Telah dilakukan penelitian dalam karakterisasi reservoar karbonat di Lapangan "A" yang terletak di Cekungan Jawa Timur Utara. Inversi Simultan dan parameter Lamda-Mu-Rho (LMR) salah satu metode geofisika yang dipilih untuk mengkarakterisasi zona hidrokarbon, litologi, dan kandungan fluidanya pada reservoar karbonat. Inversi dilakukan dengan menggunakan data angle gather baik itu near angle gather (0°-15°), mid angle gather (15°-30°), dan far angle gather (30°-45°), serta dikontrol dengan menggunakan data sumur A-01. Sebagai hasilnya, dalam Inversi Simultan menghasilkan nilai Impedansi-P sebesar 5253-6882 m/s*gr/cc, sementara hasil dari Impedansi-S sebesar 1134-1783 m/s*gr/cc. Selain menghasilkan parameter Impedansi-P dan Impedansi-S, dari Inversi Simultan juga menghasilkan Densitas sebesar 2.66-2.97 gr/cc dan Rasio VpVs sebesar 2.99-4.92. Dari semua hasil Inversi Simultan ini belum mampu mengkarakterisasi kandungan fluida yang ada di daerah penelitian, maka dari itu dilakukan transformasi Lamda-Mu-Rho (LMR). Berdasarkan analisis parameter Lamda-Mu-Rho (LMR), menyatakan bahwa zona target penelitian pada sumur A-01 memiliki potensi hidrokarbon yang cukup banyak sehingga bisa digunakan untuk produksi. Hasil dua parameter yang berasal dari Lamda-Mu-Rho (LMR) adalah parameter Lamda-Rho sebesar 25.7-27.7 Gpa*gr/cc, sedangkan untuk parameter Mu-Rho sebesar 1.96-2.92 Gpa*gr/cc. Integrasi analisis pada Inversi Simultan dan Lamda-Mu-Rho (LMR) menghasilkan nilai sama pada zona target penelitian. Sehingga dapat diketahui persebaran litologi berupa karbonat, terdapatnya hidrokarbon yang berupa minyak, serta kandungan fluida. ......Carbonate reservoir in the field ?A? has been characterized located on the North East Java Basin. Simultaneous Inversion and parameter Lamda-Mu-Rho (LMR) is the chosen method to characterize hydrocarbon zones, lithology and fluid content of the carbonate reservoir. Inversion is done using data from angle gather both the near angle gather (0°-15°), mid gather angle (15° -30°), and far gather angle (30°-45°) , and controlled using data from well A -01. As a result, the Simultaneous Inversion produce value Impedance-P 5253-6882 m/s*gr/cc, while the results of Impedance-S of 1134-1783 m/s*gr/cc. In addition to producing parameter Impedance-P and Impedance-S, on the Simultaneous Inversion also produce a density of 2.79-2.87 gr/cc, and VpVs ratio of the 2.99-4.92. Of all the results Simultaneous Inversion have not been able to characterize fluid content in the research area, therefore transformation of Lamda-Mu-Rho (LMR). Based on the analysis of parameters of Lamda-Mu-Rho (LMR), stated that the target zone of research at well A - 01 have considerable hydrocarbon potential so that it can be used for production. The results of the two parameters are derived from Lamda-Mu-Rho (LMR) is Lamda-Rho parameter of 25.7-27.7 Gpa*gr/cc, while for Mu-Rho parameter of 1.96-2.92 Gpa*gr/cc. Simultaneous Inversion analysis on the integration and Lamda-Mu-Rho (LMR) produces the same values in the target zone research. So it can be seen spread lithology, the presence of hydrocarbons inte fomr of oil, and fluid content.

Abstrak :
ABSTRACT
Telah berhasil dilakukan karakterisasi pada reservoir karbonat menggunakan simultaneous inversion pada lapangan x untuk mengetahui litologi dan kandungan fluida pada lapangan X. Reservoir tersebut berupa reef karbonat pada formasi Tuban yang terletak di cekungan Jawa Timur bagian Utara. Reservoir karbonat berbeda dengan reservoir lainnya dikarenakan karbonat memilik tingkat heterogenitas yang tinggi serta dapat mengalami diagenesa. Inversi Simultan digunakan pada penelitian kali ini dikarenakan dapat menghasilkan parameter impedansi akustik, impedansi shear, dan densitas secara simultan. 3 output dalam inversi simultan kemudian akan dilakukan transformsi untuk mendapatkan parameter lame yaitu Lambda Rho yang sensitif terhadap fluida serta Mu Rho yang sensitif terhadap litologi. Diharapkan parameter Lame dapat mempertajam Identifikasi litologi maupun fluida yang berada di reservoir. Vp/Vs ratio juga dapat dimunculkan dengan bantuan dari ketiga output inversi simultan tersebut yang berguna juga untuk menganalisis fluida. Inversi Simultan yang dilakukan pada lapangan xdikontrol oleh dua sumur yaitu M01 dan M02 yang masing-masing diantaranya hanya berbeda 1 inline. Input data seismik yang digunakan pada penelitian kali ini adalah data angle gather. Berdasarkan analisis dari Lambda Mu Rho serta Vp/Vs ratio, zona target sumur M01 dan M02 memiliki potensi sebagai reservoir hidrokarbon. Indikasi hidrokarbon ini ditunjukan dari analisis crossplot Vp/Vs vs Lambda Rho dengan nilai Vp/Vs berkisar 1.7-1.8 dan Lambda Rho berkisar 40-60 Gpa g/cc dengan nilai Mu Rho berkisar 40 ndash; 80 Gpa g/cc. Dari nilai tersebut dapat dibuat slicing untuk mengetahui litologi dan arah penyebaran kandungan hidrokarbon dan arah sebarannya mengarah ke arah Barat Laut untuk litologi dan kandungan fluida hidrokarbon.

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ABSTRACT
Carbonate Reservoir have been characterized in X field using Simultaneous Inversion to determine lithology and fluid content. This reservoir located in Nort East Java Basin in the form of big Reef Carbonate on Tuban Formation. Carbonate Reservoir has unique charateristics than the other reservoir because its heterogenities and diagenesis can be occured. Simultaneous Inversion used in this study because it can generate accoustic impedance, shear impedance and density simultaneously. Those 3 outputs then can be transformed to extract Lambda Rho which is sensitive to fluid content and Mu Rho which is sensitive to lithology. Vp Vs also can be generated from those 3 outputs which is usefull to determine fluid content. Hopefully, those parameters can be used to sharpen analysis about lithology and fluid content. Simultaneous inversion which used in X Field controlled by 2 wells, M01 and M02 which respectively only space for 1 inline. Seismic input on this study using angle gather. Based on analysis from Lambda Mu Rho and Vp Vs ratio, this reservoir has potential hidrocarbon inside. Hidrocarbon is indicated from crossplot Vp Vs vs Lambda Rho, Vp Vs is about 1.7 ndash 1.8 and Lambda Rho is about 40 ndash 60 Gpa g cc and Mu rho is about 40 ndash 80 Gpa g cc from Mu Rho vs Densitys Crossplot. Then Slicing can be generated to determine distribution of lithology and fluid content and the spreading delineated to North West for lithology and hidrocarbon fluid itself.

Abstrak :
Studi ini dilakukan untuk memetakan penyebaran zona reservoar batupasir Formasi Menggala Lapangan X4 Cekungan Sumatera Tengah dengan menggunakan metode inversi Lambda Mu Rho (LMR). Parameter Lambda-Rho dapat mengindentifikasikan kandungan suatu fluida di dalam batuan sedangkan parameter Mu-Rho dapat mengidentifikasikan jenis batuan. Dalam studi ini, parameter Lambda Mu Rho menunjukkan bahwa litologi dan hidrokarbon pada Formasi Menggala dapat terpisahkan dengan baik. Daerah Gas-sand terlihat dari nilai Lambda-Rho dan Mu-Rho yang relatif rendah, yaitu Lambda-Rho kurang dari 20 GPa/g*cc dan Mu-Rho antara 20 GPa/g*cc - 30 GPa/g*cc. Analisis dari inversi Lambda Mu Rho, data sumur, dan data geologi terlihat bahwa zona reservoar terkonsentrasi dari bagian barat laut ke tenggara. ......This study is carried out to map the distribution of sandstone reservoir zone Menggala Formation in X4 field Central Sumatra Basin by using Lambda Mu Rho (LMR) inversion. Lambda-Rho parameter indicates the presence of fluid while Mu-Rho parameter indicates the rock type. In this study, Lambda Mu Rho parameter shows that the lithology and hydrocarbon on Menggala Formation can be well separated. Gas-sand zone can be seen at quite low range of Lambda-Rho and Mu-Rho which are Lambda-Rho less than 20 GPa/g*cc and Mu-Rho between 20 GPa/g*cc - 30 GPa/g*cc. Analysis from Lambda Mu Rho inversion, well data, and geological data show that the reservoir distribution zone are concentrate from north-west to south-east.

Abstrak :
[Lapangan “BINTANG” berada di Cekungan Jawa Timur. Formasi target adalah Formasi Ngimbang yang memiliki beberapa zona target dengan ketebalan antara 20-40meter yang berada dibawah ketebalan tuning seismik. Zona-A dan Zona-C merupakan zona target penelitian. Formasi Ngimbang pada daerah penelitian, memiliki lithologi karbonat dan shale, sehingga perlu untuk memisahkan kedua lithologi kedua melalui data seismik. Data sumur test produksi daerah penelitian menunjukkan keberadaan hidrokarbon. Berdasarkan analisa sensitifitas, parameter P-Impedance dan Mu-Rho digunakan untuk memisahkan lithologi daerah penelitian. Daerah reservoar yang merupakan batuan karbonat berada pada nilai P-Impedance dan Mu-Rho kecil diatas cuttoff. Parameter Lambda-Rho*Poisson Ratio digunakan untuk mengidentifikasi sebaran hidrokarbon dimana zona bernilai kecil merupakan daerah yang mengindikasikan sebaran hidrokarbon. Inversi dilakukan dengan metode Extended Elastic Impedance (EEI) dimana metode ini menghasilkan volum reflektifitas langsung dari parameter yang dipilih. Inversi dengan metode EEI yang diaplikasikan dengan parameter Mu-Rho paling baik menggunakan sudut korelasi -45 dan untuk parameter Lambda-Rho*Poisson Ratio menggunakan sudut 33,5. Proses multiatribut digunakan untuk memprediksi sebaran porositas. Hasil multiatribut menunjukkan bagian utara daerah penelitian merupakan daerah yang lebih dangkal sehingga porositas lebih tinggi dibanding daerah selatan arah tenggara. Daerah utara masih berada pada bagian lagoonal sedangkan arah selatan-tenggara merupakan outer margin yang semuanya berada pada lingkungan pengendapan platform carbonate. ......"BINTANG" field is located in the East Java basin. The target formation is Ngimbang Formation which have several target zones with thickness between 20-40 meters which is below seismic tuning thickness. Zone-A and Zone-C is the target zone. Formation Ngimbang in this study area has carbonate and shale lithology, so that needs to seperate this two lithology by seismic data. From the sensitivity analysis, parameter P-Impedance and Mu-Rho used to separate the lithology in the study area. Carbonate rocks reservoir is at value of PImpedance and Mu-Rho small above the cuttoff. Parameter Lambda-Rho*Poisson Ratio used to identify the distribution of hydrocarbons, which small value area indicates the distribution of hydrocarbons. Inversion is performed using the extended elastic impedance (EEI) method which directly produces the reflectivity volume of the parameters has been selected. Inversion with EEI method which applied with Mu-Rho parameter best correlation angle is -45 and for Lambda-Rho*Poisson Ratio parameter is 33,5. Multiatributte process used to predict the porosity. Multiattribute results show that the northern part of study area is shallow area, that porosity is higher than the southern of the southeast regions. Northern areas are still located on the lagoonal while the south-southeast is the outer margin area which all area in platform carbonate depositional environments.;"BINTANG" field is located in the East Java basin. The target formation is Ngimbang Formation which have several target zones with thickness between 20- 40meters which is below seismic tuning thickness. Zone-A and Zone-C is the target zone. Formation Ngimbang in this study area has carbonate and shale lithology, so that needs to seperate this two lithology by seismic data. From the sensitivity analysis, parameter P-Impedance and Mu-Rho used to separate the lithology in the study area. Carbonate rocks reservoir is at value of PImpedance and Mu-Rho small above the cuttoff. Parameter Lambda-Rho*Poisson Ratio used to identify the distribution of hydrocarbons, which small value area indicates the distribution of hydrocarbons. Inversion is performed using the extended elastic impedance (EEI) method which directly produces the reflectivity volume of the parameters has been selected. Inversion with EEI method which applied with Mu-Rho parameter best correlation angle is -45 and for Lambda-Rho*Poisson Ratio parameter is 33,5. Multiatributte process used to predict the porosity. Multiattribute results show that the northern part of study area is shallow area, that porosity is higher than the southern of the southeast regions. Northern areas are still located on the lagoonal while the south-southeast is the outer margin area which all area in platform carbonate depositional environments.;"BINTANG" field is located in the East Java basin. The target formation is Ngimbang Formation which have several target zones with thickness between 20- 40meters which is below seismic tuning thickness. Zone-A and Zone-C is the target zone. Formation Ngimbang in this study area has carbonate and shale lithology, so that needs to seperate this two lithology by seismic data. From the sensitivity analysis, parameter P-Impedance and Mu-Rho used to separate the lithology in the study area. Carbonate rocks reservoir is at value of PImpedance and Mu-Rho small above the cuttoff. Parameter Lambda-Rho*Poisson Ratio used to identify the distribution of hydrocarbons, which small value area indicates the distribution of hydrocarbons. Inversion is performed using the extended elastic impedance (EEI) method which directly produces the reflectivity volume of the parameters has been selected. Inversion with EEI method which applied with Mu-Rho parameter best correlation angle is -45 and for Lambda-Rho*Poisson Ratio parameter is 33,5. Multiatributte process used to predict the porosity. Multiattribute results show that the northern part of study area is shallow area, that porosity is higher than the southern of the southeast regions. Northern areas are still located on the lagoonal while the south-southeast is the outer margin area which all area in platform carbonate depositional environments.;"BINTANG" field is located in the East Java basin. The target formation is Ngimbang Formation which have several target zones with thickness between 20- 40meters which is below seismic tuning thickness. Zone-A and Zone-C is the target zone. Formation Ngimbang in this study area has carbonate and shale lithology, so that needs to seperate this two lithology by seismic data. From the sensitivity analysis, parameter P-Impedance and Mu-Rho used to separate the lithology in the study area. Carbonate rocks reservoir is at value of PImpedance and Mu-Rho small above the cuttoff. Parameter Lambda-Rho*Poisson Ratio used to identify the distribution of hydrocarbons, which small value area indicates the distribution of hydrocarbons. Inversion is performed using the extended elastic impedance (EEI) method which directly produces the reflectivity volume of the parameters has been selected. Inversion with EEI method which applied with Mu-Rho parameter best correlation angle is -45 and for Lambda-Rho*Poisson Ratio parameter is 33,5. Multiatributte process used to predict the porosity. Multiattribute results show that the northern part of study area is shallow area, that porosity is higher than the southern of the southeast regions. Northern areas are still located on the lagoonal while the south-southeast is the outer margin area which all area in platform carbonate depositional environments.;"BINTANG" field is located in the East Java basin. The target formation is Ngimbang Formation which have several target zones with thickness between 20- 40meters which is below seismic tuning thickness. Zone-A and Zone-C is the target zone. Formation Ngimbang in this study area has carbonate and shale lithology, so that needs to seperate this two lithology by seismic data. From the sensitivity analysis, parameter P-Impedance and Mu-Rho used to separate the lithology in the study area. Carbonate rocks reservoir is at value of PImpedance and Mu-Rho small above the cuttoff. Parameter Lambda-Rho*Poisson Ratio used to identify the distribution of hydrocarbons, which small value area indicates the distribution of hydrocarbons. Inversion is performed using the extended elastic impedance (EEI) method which directly produces the reflectivity volume of the parameters has been selected. Inversion with EEI method which applied with Mu-Rho parameter best correlation angle is -45 and for Lambda-Rho*Poisson Ratio parameter is 33,5. Multiatributte process used to predict the porosity. Multiattribute results show that the northern part of study area is shallow area, that porosity is higher than the southern of the southeast regions. Northern areas are still located on the lagoonal while the south-southeast is the outer margin area which all area in platform carbonate depositional environments., "BINTANG" field is located in the East Java basin. The target formation is Ngimbang Formation which have several target zones with thickness between 20- 40meters which is below seismic tuning thickness. Zone-A and Zone-C is the target zone. Formation Ngimbang in this study area has carbonate and shale lithology, so that needs to seperate this two lithology by seismic data. From the sensitivity analysis, parameter P-Impedance and Mu-Rho used to separate the lithology in the study area. Carbonate rocks reservoir is at value of PImpedance and Mu-Rho small above the cuttoff. Parameter Lambda-Rho*Poisson Ratio used to identify the distribution of hydrocarbons, which small value area indicates the distribution of hydrocarbons. Inversion is performed using the extended elastic impedance (EEI) method which directly produces the reflectivity volume of the parameters has been selected. Inversion with EEI method which applied with Mu-Rho parameter best correlation angle is -45 and for Lambda-Rho*Poisson Ratio parameter is 33,5. Multiatributte process used to predict the porosity. Multiattribute results show that the northern part of study area is shallow area, that porosity is higher than the southern of the southeast regions. Northern areas are still located on the lagoonal while the south-southeast is the outer margin area which all area in platform carbonate depositional environments.]

Abstrak :
Cekungan Jawa Timur Utara tersebut merupakan cekungan Tersier yang produktif akan hidrokarbon pada setiap interval stratigrafi (Marianto et al., 2017). Penelitian ini dilakukan pada lapangan B dan  terfokus pada formasi Kujung. Formasi Kujung adalah formasi yang litologinya di dominasi oleh karbonat pada reservoirnya dan memiliki batuan penutup berupa shale. Karakterisasi reservoir karbonat merupakan suatu tantangan sebab batuannya memiliki struktur pori yang kompleks akibat proses diagenesis. Sehingga mempengaruhi kecepatan gelombang seismik yang merambat pada karbonat. Data yang  digunakan dalam penelitian ini adalah data Seismik 3D PSTM dengan kontrol 3 sumur berbeda. Metode yang digunakan untuk mengkarakterisasi reservoir karbonat ini adalah dengan menggunakan metode seismik inversi simultan. Metode Seismic Inversi Simultan tersebut akan menghasilkan model Impedansi-P (AI), Impedansi-S (SI) dan densitas yang kemudian akan di transformasikan menjadi Lambda-Rho dan Mu-Rho. Model dari parameter hasil inversi simultan dan hasil transformasi tersebut akan digunakan untuk mengetahui sebaran litologi, porositas dan konten fluida pada pori batuan. Berdasarkan hasil analisis, daerah prospek pada penelitian ini terletak pada build up karbonat serta memiliki porositas yang tinggi dengan nilai AI sebesar 16000-31000 ((ft/s)(g/cc)) dan Mu-rho sebesar 10-27 (GPA g/cc) dan fluida minyak dengan nilai λÏ? 10-36 (GPA g/cc. ......North East Java Basin is a tertiary basin which prolific of hydrocarbon on almost all stratigraphic intervals (Marianto et al., 2017). The study area is located on B field and focused on Kujung formation. Kujung formation is dominated by carbonate on its reservoir and has shale as its caprock or seal. Reservoir characterization considered as a huge challenge because of its complex structural pore caused by diagenesis processes. Therefore, affect the seismic wave propagation which travels through carbonate body. This study use 3D Seismic PSTM with 3 different wells as a control. The method used in this study is Simultaneous Seismic Inversion. The Seismic Simultaneous Inversion will extract P-Impedance (AI), S-Impedance (SI) and density as output models. Those three models will be transformed into Lambda-Rho dan Mu-Rho. The Output models of inversion and transformation will be used for characterizing distribution of the litology, porosity and fluid content that fills rocks pore. Based on analysis result, the prospect area in this study located on carbonate build up, high porosity indicated by AI value between 16000-31000 ((ft/s)(g/cc)) and Mu-rho value between 10-27 (GPA g/cc) and oil by value between 10-36 (GPA g/cc).

Abstrak :
Cekungan Jawa Timur Utara merupakan salah satu cekungan penghasil minyak dan gas terbesar di Indonesia. Intepretasi seismik secara kuantitatif sangat diperlukan dalam proses eksplorasi keberadaan cadangan hidrokarbon. Atribut seismik inversi simultan dan amplitude vs offset (AVO) adalah metode yang diaplikasikan pada penelitian ini. Seismik inversi adalah metode untuk menghasilkan parameter dari data seismik refleksi dengan pengikatan dengan data sumur. Inversi seismik pada studi ini adalah inversi simultan untuk mengestimasi kecepatan gelombang P (Vp), kecepatan gelombang S (Vs), densitas dan rasio Vp/Vs batuan untuk ditransformasi ke parameter Lambda – Mu – Rho yang dapat dimanfaatkan sebagai parameter untuk memprediksi kandungan fluida dan jenis litologi dibawah permukaan. Nilai rasio Vp/Vs dan densitas dihasilkan dengan baik dari proses inversi simultan dan dapat memisahkan antara karbonat tersaturasi hidrokarbon dengan nilainya yang kecil. Ampllitude vs offset (AVO) adalah metode untuk melihat perubahan amplitude seiring bertambahnya offset atau sudut. Dengan tersaturasinya gas pada suatu batuan, akan menghasilkan respon yang berbeda dengan saturasi minyak atau air. Pada penilitian ini didapatkan dengan keberadaan saturasi gas, nilai intercept akan semakin kecil dibanding dengan minyak atau air. Nilai lambda-rho berhasil mendefinisikan keberadaan karbonat gas dengan nilai kecil. ......The North East Java Basin is one of the largest oil and gas producing basins in Indonesia. Quantitative seismic interpretation is needed in the exploration process for the presence of hydrocarbon reserves. The seismic attribute simultaneous inversion and amplitude vs offset (AVO) is the method applied in this study. Seismic inversion is a method for generating parameters from seismic reflection data by binding to well data. Seismic inversion in this study is a simultaneous inversion to estimate the P wave velocity (Vp), S wave velocity (Vs), rock density, and Vp / Vs ratio to be transformed into Lambda - Mu - Rho parameters which can be used as parameters to predict fluid content and type of subsurface lithology. The value of the Vp / Vs ratio and the density is generated well from the simultaneous inversion process and can separate the hydrocarbon saturated carbonates with small values. Amplitude vs offset (AVO) is a method of seeing the change in amplitude as the offset or angle increases. With the saturation of gas in a rock, it will produce a different response to the saturation of oil or water. In this research, it was found that in the presence of gas saturation, the intercept value will be smaller than that of oil or water. The lambda-rho value defines the presence of gaseous carbonates with small values

Abstrak :
Aplikasi Inversi Seismik Post-Stack dan AVO dalam penyebaran Lapisan Hidrokarbon Gas Pada Lapangan Nauli Formasi Talang Akar Cekungan Sumatera Selatan Lapangan Nauli adalah salah satu lapangan marginal yang berada di wilayah Barat Indonesia dan telah terbukti menghasilkan hidrokarbon minyak dan gas. Lapangan ini berada pada Cekungan Sumatera Selatan dengan target reservoir batupasir pada Formasi Talang Akar. Tujuan dari penelitian ini adalah mengindentifikasi fluida hidrokarbon gas dari data log sumur dan mengintegrasikan dengan data seismik untuk mengetahui kemungkinan penyebarannya di seluruh lapangan. Karakteristik reservoir seperti porositas dan saturasi air dihitung pada masing-masing lapisan di tiap sumur. Metode seismik inversi dipilih untuk memperkirakan attribut P-impedance Zp , S-impedance Zs dan densitas r . Inversi Amplitude Versus Offset diterapkan dengan menggunakan attribut Lambda-Mu-Rho. Perubahan pada hasil inversi Lambda-Mu-Rho dapat memberikan informasi mengenai litologi dan kandungan fluida di dalam pori-pori reservoir. Hasil analisis dan pengolahan mendapatkan nilai porositas efektif pada Lapangan Nauli berkisar antara 10-20 p.u dengan saturasi air 20-70 dengan ketebalan Net pay berkisar antara 2-8 meter. Inversi post-stack menunjukkan adanya anomali impedansi pada skala waktu 1580 ndash; 1590 ms dengan nilai impedansi 22.000 ndash; 25.000 m/s g/cc. Hasil analisis petrofisika menunjukkan posisi ini pada lapisan-X yang merupakan salah satu lapisan pembawa gas gas bearing layer . Attribut inversi AVO Lambda-Mu-Rho LMR mengkonfirmasi adanya kehadiran gas pada anomali impedansi tersebut yang ditandai dengan nilai Lambda-Rho sebesar 11-20 Gpa g/cc relatif bernilai lebih kecil dari nilai Mu-Rho yaitu sebesar 28-32 Gpa g/cc.

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Title Application of Seismic Post Stack Inversion and AVO for Gas Reservoir Delineation in Nauli Field, Talang Akar Formation South Sumatera Basin. Nauli Fields is one of the marginal fields located in the western region of Indonesia and has been proven to produce oil and gas hydrocarbons. This field is located in the South Sumatra Basin with target reservoir is sandstone from Talang Akar Formation. The purpose of this study is to integrate petrophysical interpretation and seismic data analysis.Reservoir characterization such as porosity and water saturation calculated for each layer within the wells. Seismic inversion methods chosen to estimate the attributes of P impedance Zp , S impedance Zs dan densitas r . AVO inversion applied using Lambda Mu Rho attribute can provide information on lithology dan fluids content in the reservoirs. Data processing and analysis shows that the effective porosity for Nauli Field is 10 20 porosity unit p.u with 20 70 water saturation. The thickness of net pay is 2 8 meters. Post stack inversion shows impedance anomaly around 1580 1590 ms with value 22.000 25.000 m s g cc. Petrophysics analysis estimate this anomaly in layer x with gas fluid estimated. Lambda Mu Rho attribute confirm this fluid with lower Lambda Rho values around 11 20 Gpa g cc than Lambda Rho values around 28 32 Gpa g cc.

Abstrak :
Karakterisasi reservoir merupakan salah satu tahap penting dalam eksplorasi hidrokarbon agar dapat menentukan reservoir yang baik berdasarkan karakteristik litologi dan kandungan fluida di reservoir. Penelitian ini dilakukan di Lapangan “R”, Cekungan Jawa Timur Utara dengan menggunakan metode inversi simultan. Berdasarkan hasil inversi simultan diketahui bahwa zona reservoir di area penelitian tersusun atas litologi karbonat dengan nilai impedansi-P 26.000 ft/s*g/cc – 35.000 ft/s*g/cc, impedansi-S 8.000 ft/s*g/cc – 22.000 ft/s*g/cc, dan densitas 2. g/cc – 2.39 g/cc. Hasil tersebut ditransformasikan menjadi parameter elastis batuan, yaitu Parameter Lame yang terdiri atas Lambda-Rho dan Mu-Rho. Transformasi Lambda-Mu-Rho berhasil mengidentifikasi reservoir karbonat yang berpotensi mengandung hidrokarbon dengan nilai rigiditas tinggi sebesar 6 GPa*g/cc – 21 GPa*g/cc dan inkompresibilitas rendah sebesar 6 GPa*g/cc – 11 GPa*g/cc yang diinterpretasikan sebagai gas. Integrasi analisis dari parameter impedansi-P, impedansi-S, densitas, Lambda-Rho, dan Mu-Rho menunjukkan bahwa persebaran batuan karbonat yang tersaturasi gas memiliki orientasi timur laut – barat daya. ......Reservoir characterization is one of the most crucial stages in hydrocarbon exploration to determine good reservoirs based on their lithology and fluid content. This research was conducted at the “R” Field, North East Java Basin using the simultaneous seismic inversion method. The results show that the reservoir zone in the research area consists of carbonate rocks with P-impedance values of 26.000 ft/s*g/cc – 35.000 ft/s*g/cc, S-impedance of 8.000 ft/s*g/cc – 22.000 ft/s*g/cc, and density of 2.25 g/cc – 2.55 g/cc. These results were transformed into rock elastic parameters, namely Lame Parameters consisting of Lambda-Rho and Mu-Rho. Lambda Mu Rho Transformation has successfully identified carbonate reservoirs that potentially contain hydrocarbons with high rigidity values of 6 GPa*g/cc – 21 GPa*g/cc and low incompressibility of 6 GPa*g/cc – 11 GPa*g/cc interpreted as gas. Integration analysis of P-impedance, S-impedance, density, Lambda-Rho, and Mu-Rho parameters shows that the distribution of gas-saturated carbonate rocks has a northeast – southwest orientation.