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Abstrak :
Keberadaan minyak dan gas bumi di daerah penelitian yang terletak di cekungan Jawa Timur Utara, di sebelah utara Pulau Madura, Indonesia, telah dibuktikan oleh empat (4) sumur yang dibor pada Karbonat CD Formasi Ngimbang berumur Oligosen Awal. Karbonat Formasi ini diendapkan dalam lingkungan paparan. Rata-rata ketebalan karbonat berkisar antara 70 - 143 meter dengan kemampuan aliran sumur terbukti sangat bagus, dicerminkan dengan hasil tes sumuran (DST) berkisar antara 450 - 4,449 BOPD. Reservoar terdiri dari enam (6) zona dengan ketebalan tiap tiap zona berkisar antara 4 - 40 meter. Tiap tiap zona dipisahkan oleh shale yang tipis ataupun karbonat yang ketat. Identifikasi rock type merupakan komponen yang esensial dalam proses karakterisasi reservoar. Dalam studi ini, rock typing bersama dengan analisa impedansi akustik dari data seismik 3D post stack telah dilakukan pada reservoar karbonat. Hasil kedua analisa tersebut dijadikan sebagai masukan untuk pemodelan geologi. Analisa detil core meliputi porositas, permeabilitas dan fasies dilakukan pada dua sumur yaitu sumur Salemba-B dan Salemba-C. Selanjutnya data dari kedua sumur tersebut digunakan untuk kalibrasi rock typing pada sumur yang tidak memiliki data core yaitu sumur Cibubur-A dan Sumur Salemba-A. Dari hasil analisa core, menunjukan tidak terdapat hubungan yang jelas antara lithofasies dengan porositas dan permeabilitas. Sehingga pemodelan geologi berdasarkan pengelompokan lithofasies dari data core sulit untuk dilakukan. Identifikasi rock type secara petrofisika dilakukan menggunakan persamaan Windland R35 yang di kalibrasi dengan data core. Karena ketebalan zonasi reservoar berada di bawah resolusi seismik maka analisa impedansi akustik tidak dapat membedakan zona-zona produktif. Sehingga analisa seismik hanya digunakan untuk pemetaan struktur dan pola karakter gross reservoar secara kualitatif. Untuk mendistribusikan zona produktive yang diperoleh dari analisa petrofisika secara lateral digunakan metoda geostatistik yang dipandu oleh hasil impedansi akustik. Hasil dari pemodelan geologi dapat digunakan untuk mendelineasi distribusi zona-zona produktive yang digunakan untuk pengembangan lapangan. ...... The presences of oil and gas in the North East Java Sea Basin, North of Madura Island, Indonesia, have been proven by four (4) wells drilled into the Early Oligocene CD Carbonate of the Ngimbang Formation. This formation was deposited within carbonate platform setting. The average gross thickness of carbonate ranges between 60 - 143 meters with very good deliverability of 450 ? 4,449 BOPD recorded from DST's. The reservoir comprises of six (6) zones with thickness of each zone ranges between 4 - 40 meters. Each zone is separated by either thin shale or tight carbonate. Reservoir rock types identification is an essential component in the reservoir characterization process. Rock typing together with acoustic impedance analysis from post stack 3D seismic data was carried out on carbonate reservoir. The results of the analysis were used as input for the geological model. Detailed core analysis data covering core porosity, core permeability, and core lithofacies were done on Salemba-B and Salemba-C wells. The data from both wells then used for rock typing calibration for other wells which do not have any conventional core data i.e. Cibubur-A and Salemba-A wells. Facies analysis from the core showed that no clear relation between core lithfacies with the poro-perm. Therefore the lithofacies based geological model from core was dificult to be performed. Rock type identification was calculated using Windland R35 equation which has been calibrated with core data. The productive zones were dificult to differentiate using accoustic impedance analysis due to the thickness of reservoar zonation is less than seismic resolution. Seismic data was only used to map the structure and qualitative gross reservoir charateristic. The geostatistical method was used to distribute the productive zone laterally identified from petrophysical analysis. The geological model produced was used to delineate the productive zones for field development.

Abstrak :
Penelitian ini akan membahas mengenai pemodelan penyebaran fasies sedimen laut dalam di salah satu lapangan yang mengandung gas di Cekungan Kutai. Fasies pengendapan di lapangan Y dibagi menjadi 5 yakni Channel Axis, Channel Margin, Levee Overbank, Mass Transport dan Mud. Fasies pengendapan tersebut dibedakan satu dengan yang lain dalam penelitian ini melalui perbedaan cut-off vshale dan pola log GR. Korelasi antar sumur menggunakan ketentuan stratigrafi sikuen dibantu dengan data plot gradien tekanan dan data seismik. Interpretasi data seismik 3D pada interval pemodelan yaitu interval A bertujuan untuk membentuk kerangka pemodelan penyebaran fasies. Pemodelan penyebaran fasies pada penelitian kali ini menggunakan metode Multi Point Statistic Simulation (MPS). Modul pemodelan MPS dalam software Petrel menyediakan sarana untuk menyertakan berbagai macam input data geologi dan geofisika dalam pemodelan fasies. Data input tersebut antara lain training image, seismik vshale dan data peta medan azimuth. Penelitian ini juga mencoba membandingkan proses pemodelan fasies menggunakan metode MPS dengan salah satu metode stochastic lainnya yakni SIS (Sequential Indicator Simulation). ......This study describes about fasies distribution modeling of deepwater deposit in one of gas field at Kutai Basin.The deepwater depositional fasies in Y field can be divided into 5 fasies such as Channel Axis, Channel Margin, Levee Overbank, Mass Transport and Mud. Vshale cut-off and GR log pattern are used for dividing one depositional fasies to other depositional facies. Sequence stratigraphy concept is applied on well to well correlation supported with other data like pressure gradien plot and seismic section. 3D seismic horizon interpretation at A interval aim to build model framework for fasies distribution. This research utilizes Multi Point Statistic Simulation (MPS) method to distribute the fasies. The MPS modeling modul in Petrel provides some options to use geology and geophysics data as modeling input. Thoose input data are training image, vshale seismic cube and azimuth field map. The study also tried to compare the facies modeling process using the MPS method with one of the other stochastic methods namely SIS ( Sequential Indicator Simulation ).

Abstrak :
[ABSTRAK
Model kecepatan lapisan bawah permukaan yang diestimasi pada proses pengolahan data seismik yang masih memiliki ketidakpastian posisi sebenarnya dari reflektor seismik atau kedalaman lapisan geologi. Penelitian ini melakukan analisis ketidakpastian dari kedalaman posisi lapisan reservoar pada Lapangan X. Hasil penelitian digunakan untuk membantu pemprediksi area target pengeboran sumur penilaian sebelum dilakukan pengembangan pada Lapangan X. Analisis dilakukan dengan menggabungkan dua metode yaitu analisis statistika dari proses koreksi peta kedalaman reservoar dan proses kalibrasi model kecepatan data seismik. Dari kedua analisis ini diketahui nilai maksimum ketidakpastian kedalaman pada batas atas reservoar sebesar 125ft. Distribusi nilai ketidakpastian kedalaman dilakukan dengan menggunakan acuan dari bentuk geologi lipatan Lapangan X untuk menghasilkan peta ketidakpastian kedalaman. Peta ketidakpastian kedalaman digunakan untuk mendapatkan peta lapisan reservoar dengan kasus dangkal, dasar dan dalam. Dari ketiga peta tersebut dikombinasikan dengan data sekunder kontak gas dan air (Gas Water Contact) dan asumsi akuisisi data pada sumur penilaian sehingga diperoleh prediksi area target pengeboran sumur penilaian dengan jarak terdekat 400 m dari sumur eksplorasi pada Lapangan X.

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ABSTRACT
Subsurface velocity model that estimated from seismic data processing still has uncertainty in term of real position of seismic reflector or depth geological layer. The research has been carried out for analyzing depth uncertainty of reservoir layer at X-Field. The result will be used to determine the target area of appraisal well which should be done before field development stage. This research used two methods to analyze the depth uncertainty, there are statistic analysis of reservoir depth map correction process and seismic velocity model calibration. From these analysis was known that maximum depth uncertainty number for top reservoar layer is 125 ft. The distribution of depth uncertainty value use X Field shape as geological model reference for generating depth uncertainty map. The depth uncertainty map was applied to get reservoir map with three alternative model, shallow case, base case and deep case. Combination of these three maps with the gas water contact infomation and data acquisition asumption generated the prediction of the target area for appraisal well at X-Field that the shortest distance is 400m from exploration well.;Subsurface velocity model that estimated from seismic data processing still has uncertainty in term of real position of seismic reflector or depth geological layer. The research has been carried out for analyzing depth uncertainty of reservoir layer at X-Field. The result will be used to determine the target area of appraisal well which should be done before field development stage. This research used two methods to analyze the depth uncertainty, there are statistic analysis of reservoir depth map correction process and seismic velocity model calibration. From these analysis was known that maximum depth uncertainty number for top reservoar layer is 125 ft. The distribution of depth uncertainty value use X Field shape as geological model reference for generating depth uncertainty map. The depth uncertainty map was applied to get reservoir map with three alternative model, shallow case, base case and deep case. Combination of these three maps with the gas water contact infomation and data acquisition asumption generated the prediction of the target area for appraisal well at X-Field that the shortest distance is 400m from exploration well., Subsurface velocity model that estimated from seismic data processing still has uncertainty in term of real position of seismic reflector or depth geological layer. The research has been carried out for analyzing depth uncertainty of reservoir layer at X-Field. The result will be used to determine the target area of appraisal well which should be done before field development stage. This research used two methods to analyze the depth uncertainty, there are statistic analysis of reservoir depth map correction process and seismic velocity model calibration. From these analysis was known that maximum depth uncertainty number for top reservoar layer is 125 ft. The distribution of depth uncertainty value use X Field shape as geological model reference for generating depth uncertainty map. The depth uncertainty map was applied to get reservoir map with three alternative model, shallow case, base case and deep case. Combination of these three maps with the gas water contact infomation and data acquisition asumption generated the prediction of the target area for appraisal well at X-Field that the shortest distance is 400m from exploration well.]

Abstrak :
[ABSTRAK
Uranium merupakan salah satu bahan bakar PLTN. Eksplorasi uranium akan terus meningkat seiring dengan kebutuhan yang meningkat. Metode geomagnet, tahanan jenis dan polarisasi terinduksi dapat diterapkan dalam eksplorasi deposit uranium yang mineralisasinya berasosiasi dengan mineral sulfida. Pengolahan, analisis, dan interpretasi data geomagnet, tahanan jenis, dan polarisasi terinduksi dilakukan untuk dapat mengidentifikasi sebaran deposit uranium, litologi batuan, model geometri dalam 3 dimensi, serta memperkirakan sumber daya terunjuk di daerah Rabau Hulu, Kalan, Kalimantan Barat. Deposit uranium di daerah Rabau Hulu pada umumnya berasosiasi dengan sulfida, turmalin dan terdapat dalam batuan favourable. Gejala mineralisasi uranium dijumpai dalam bentuk-bentuk tidak teratur dan tidak merata terdiri atas mineral uraninit, pirit, kalkopirit, pirhotit, molibdenit, dan ilmenit. Pengolahan data menghasilkan nilai anomali medan magnet total, tahanan jenis, dan faktor logam yang selanjutnya dibuat penampang 2 dimensi. Penentuan nilai tahanan jenis dan polarisasi terinduksi dilakukan dengan mengkorelasi data sumur bor dengan hasil pengolahan data. Tahanan jenis pada zona deposit uranium bernilai kurang dari 2.000 Ωm dan nilai faktor logamnya lebih besar dari 90 mho/m. Zona deposit uranium ini semakin meluas seiring dengan kedalaman. Model 3 dimensi menunjukkan bahwa distribusinya berarah Barat Daya?Timur Laut dan berbentuk lensa. Kadar rata-rata uranium pada zona deposit di daerah Rabau Hulu adalah 0,0085 %. Massa jenis deposit uranium yang digunakan untuk menghitung sumber daya terunjuk adalah 2,83 gr/cm3.

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ABSTRACT Uranium is one of the nuclear fuel. Uranium exploration will continue to increase along with the increased of demand. Geomagnetic, resistivity and induced polarization methods can be applied in the uranium deposits exploration that mineralization is associated with sulphide minerals. Processing, analysis, and interpretation of geomagnetic, resistivity, and induced polarization data conducted in order to identify the distribution of uranium deposits, lithology, model geometry in 3 dimensions and indicated resource estimates in the area Rabau Hulu, Kalan, West Kalimantan. Uranium deposits in the area Rabau Hulu is generally associated with sulphides, tourmaline and contained in favorable rocks. Symptoms of uranium mineralization encountered in other forms of irregular and uneven consists minerals of uraninite, pyrite, chalcopyrite, pyrrhotite, molybdenite, and ilmenite. Data processing generates a magnetic field total anomalous values, resistivity, and metal factor which further created two-dimensional cross-section. Determination of resistivity and induced polarization conducted by boreholes to correlate the data with the results of data processing. Resistivity in the uranium deposits zone worth less than 2,000 Ωm and the value of metal factor greater than 90 mho/m. Uranium deposit zone is expanding along with the depth. Three dimensional modeling show that the distribution of deposits trending South West-North East and form lens. The average concentration of uranium in the deposit zone in the area Rabau Hulu is 0.0085%. The density of uranium deposits which are used to calculate the indicated resource is 2.83 g/cm3., Uranium is one of the nuclear fuel. Uranium exploration will continue to increase along with the increased of demand. Geomagnetic, resistivity and induced polarization methods can be applied in the uranium deposits exploration that mineralization is associated with sulphide minerals. Processing, analysis, and interpretation of geomagnetic, resistivity, and induced polarization data conducted in order to identify the distribution of uranium deposits, lithology, model geometry in 3 dimensions and indicated resource estimates in the area Rabau Hulu, Kalan, West Kalimantan. Uranium deposits in the area Rabau Hulu is generally associated with sulphides, tourmaline and contained in favorable rocks. Symptoms of uranium mineralization encountered in other forms of irregular and uneven consists minerals of uraninite, pyrite, chalcopyrite, pyrrhotite, molybdenite, and ilmenite. Data processing generates a magnetic field total anomalous values, resistivity, and metal factor which further created two-dimensional cross-section. Determination of resistivity and induced polarization conducted by boreholes to correlate the data with the results of data processing. Resistivity in the uranium deposits zone worth less than 2,000 Ωm and the value of metal factor greater than 90 mho/m. Uranium deposit zone is expanding along with the depth. Three dimensional modeling show that the distribution of deposits trending South West-North East and form lens. The average concentration of uranium in the deposit zone in the area Rabau Hulu is 0.0085%. The density of uranium deposits which are used to calculate the indicated resource is 2.83 g/cm3.]