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"Indonesia has received its share of attention from the worldwide mineral exploration community. A number of articles have commented on the country's attractiveness as a target as regards foreign investment in mineral sector. While these articles no doubt are well intentioned, they often fail to satisfactorily highlight the strong mineral procpectivity throughout much of Indonesia. This factor should not be overlooked when one considers the level of mineral exploration directed towards Indonesia by mining companies. This paper will consider 13 of the more significant greenfield mineral prospects within the country primarily by considering the in-ground value of each. This value is quite substantial and very relevant in the choice of Indonesia as an investment destination."

"Laporan Praktik Keinsinyuran ini menggambarkan desain sumur eksplorasi migas di Lapangan "A" di Indonesia. Fokus utama adalah pada eksplorasi sumber daya migas yang terdapat dalam formasi batuan. Karena target eksplorasi berada dalam kondisi High Pressure & High Temperature (HPHT) dan pada kedalaman yang signifikan, desain sumur menjadi krusial untuk menjamin keberhasilan dan keselamatan operasi pengeboran. Proses desain dimulai dengan penetapan well trajectory dimana metode Minimum Curvature digunakan untuk menentukan lintasan pengeboran berbentuk 'S' dari permukaan ke target. Desain ini memungkinkan pencapaian target vertikal meski terdapat keterbatasan koordinat permukaan, mengakomodasi isu pembebasan lahan. Selanjutnya, ukuran lubang dan casing sumur ditetapkan. Desain ini didasarkan pada kebutuhan akuisisi data, metode coring, dan wireline logging. Diagram hole and casing size selector membantu menentukan ukuran yang paling sesuai untuk setiap trayek sumur. Pertimbangan efisiensi biaya mengarah pada pemilihan liner daripada casing penuh untuk tahap tertentu, terutama di trayek terakhir yang memerlukan hydraulic fracturing. Penentuan casing setting depth dilakukan dengan menggunakan data gradien tekanan pori dan tekanan rekah formasi batuan, dengan mempertimbangkan safety factor dan hasil analisis sumur offset di lapangan. Proses ini menetapkan kedalaman kaki casing yang optimal untuk setiap trayek sumur, dengan mempertimbangkan aspek perlindungan sumber air bawah tanah dan pengaturan peralatan pengeboran. Desain casing dan pemilihan spesifikasi casing dilakukan berdasarkan standar internasional API. Aspek teknis seperti burst, collapse, axial, dan triaxial stress diperhitungkan untuk memastikan integritas struktural sumur. Secara keseluruhan, laporan ini menyajikan metodologi desain sumur eksplorasi migas di Lapangan "A", menyoroti tantangan dan solusi dalam eksplorasi migas di lingkungan HPHT. Pendekatan ini diarahkan untuk mencapai pengeboran yang efisien dan aman, esensial dalam industri migas.

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This Engineering Practice Report describes the design of oil and gas exploration wells in "A" Field in Indonesia. The primary focus is on the exploration of hydrocarbon resources found in rock formations. Given that the exploration target is in a High Pressure & High Temperature (HPHT) environment and at significant depth, the well design is crucial for ensuring the success and safety of drilling operations. The design process begins with the determination of the well trajectory, using the Minimum Curvature method to define an 'S'-shaped drilling path from the surface to the target. This design allows for the achievement of vertical targets despite limitations in surface coordinates, accommodating land acquisition issues. Next, the sizes of the wellbore and casing are established. This design is based on data acquisition needs, coring methods, and wireline logging. The hole and casing size selector diagram aids in determining the most suitable sizes for each well trajectory. Cost efficiency considerations lead to the selection of liners over full casing for certain stages, particularly in the final trajectory requiring hydraulic fracturing.

The determination of casing setting depth is conducted using data on pore pressure gradients and formation fracture pressures, considering a safety factor and results from the analysis of offset wells in the field. This process sets the optimal casing shoe depth for each well trajectory, considering aspects such as protection of underground water sources and the arrangement of drilling equipment. The design and selection of casing specifications are based on international API standards. Technical aspects such as burst, collapse, axial, and triaxial stress are considered to ensure the structural integrity of the well. Overall, this report presents a methodology for designing hydrocarbon exploration wells in "A" Field, highlighting the challenges and solutions in hydrocarbon exploration in HPHT environments. This approach is aimed at achieving efficient and safe drilling, essential in the oil and gas industry."

"Material polikristalin La0,8-xKxBa0,05Sr0,15MnO3 (x = 0 dan 0,05) telah berhasil disintesis menggunakan metode sol-gel. Analisis hasil karakterisasi X-Ray Diffractometer (XRD) menunjukkan bahwa material La0,8-xKxBa0,05Sr0,15MnO3 (x = 0 dan 0,05) yang telah disintesis merupakan material fasa tunggal dengan struktur rhombohedral dan space group R-3c. Hasil karakterisasi XRD juga diperkuat oleh hasil karakterisasi Energy Dispersive X-ray (EDX) dan X-ray Photoelectron Spectroscopy (XPS) yang telah menunjukkan bahwa semua jenis senyawa kimia yang terdapat pada material La0,8-xKxBa0,05Sr0,15MnO3 (x = 0 dan 0,05) merupakan senyawa yang diinginkan. Observasi morfologi menggunakan Scanning Electron Microscope (SEM) menujukkan bahwa substitusi ion potasium berdampak pada terjadinya perbesaran ukuran grain. Karakterisasi Magnetic Properties Measurement System (MPMS) menunjukkan bahwa substitusi ion potasium menyebabkan terjadinya peningkatan temperatur Curie dari 320 K, untuk nilai x = 0, menjadi 335 K, untuk nilai x = 0,05. Peningkatan ini disebabkan karena menguatnya interaksi double-exchange pada sampel dengan nilai x = 0,05. Substitusi ion potasium juga berdampak pada terjadinya peningkatan nilai perubahan entropi magnetik (A𝑆𝑀) dan nilai Low Field Magnetoresistance (LFMR). Nilai −Δ𝑆𝑀 material La0,8-xKxBa0,05Sr0,15MnO3 (x = 0 dan 0,05) meningkat dari 4,21 J/kg K menjadi 4,98 J/kg K pada medan magnet eksternal lima Tesla. Sementara itu, nilai LFMR mengalami peningkatan dari 9% menjadi 14% pada medan magnet eksternal satu Tesla. Berdasarkan hasil analisis perilaku kritis dari material La0,8-xKxBa0,05Sr0,15MnO3 (x = 0 dan 0,05) dapat disimpulkan bahwa substitusi ion potasium mempengaruhi perilaku kritis dari material La0.8-xKxBa0,05Sr0,15MnO3 (x = 0 dan 0,05). Hal ini dibuktikan dengan berubahnya nilai parameter kritis dari material tersebut. Nilai parameter kritis untuk x = 0 adalah 𝛽 = 0,248; 𝛾 = 1,048; dan 𝛿 = 3,342 sedangkan nilai parameter kritis untuk x = 0,05 adalah 𝛽 = 0,226; 𝛾 = 1,183; dan 𝛿 = 4,518. Karakterisasi ESR menunjukkan adanya fasa magnetik yang tidak homogen pada material La0,8-xKxBa0,05Sr0,15MnO3 (x = 0 dan 0,05). Keberadaan fasa magnetik yang tidak homogen ini merupakan bukti terjadinya fenomena phase separation yang berkorelasi kuat terhadap terjadinya peningkatan nilai A𝑆𝑀 dan nilai LFMR.

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Exploration on the magnetic properties of polycrystalline La0.8-xKxBa0.05Sr0.15MnO3 (x = 0 and 0.05) manganite have been reported. The samples have been synthesized using sol-gel method. Powder diffraction analysis shows that both samples crystallized in rhombohedral structure with R-3c space group. Furthermore, rietveld refinement analysis proves that the obtained samples are single phase, without any detectable impurities. This argument is also supported by the characterization result from Energy Dispersive X-ray (EDX) and X-ray Photoelectron Spectroscopy (XPS). Morphological observation using Scanning Electron Microscope (SEM) shows that potassium substitution increases the average grain size of the studied samples. Magnetization measurement with respect to temperature shows that the curie temperature (𝑇𝐶) of sample with potassium ion is larger compared to the undoped sample. The reported 𝑇𝐶 was be 320 and 335 K for x = 0 and x = 0.05, respectively. Detailed inspection upon the magnetocaloric property of the samples shows that potassium substitution increases the magnetic entropy change (A𝑆𝑀) of the sample. The reported −Δ𝑆𝑀 value was 4.21 and 4.98 J/kg K for x = 0 and x = 0.05, respectively. It was found that both samples exhibit a Low Field Magnetoresistance (LFMR) phenomenon at low temperature and low external magnetic field (< 1T). Moreover, potassium substitution increases the estimated LFMR value from 9 to 14% for x = 0 and x = 0.05, respectively. The analysis on the critical behavior of both samples shows that potassium substitution affects the critical behavior of the studied samples. This is shown by the different critical parameters for each sample. The reported critical parameter for x = 0 are 𝛽 = 0.248; 𝛾 = 1.048; 𝛿 = 3.342 and the critical parameters for x = 0.05 are 𝛽 = 0.226; 𝛾 = 1.183; and 𝛿 = 4.518. Electron Spin Resonance (ESR) characterization reveals that there is a presence of magnetic inhomogeneity inside both samples. The presence of magnetic inhomogeneity suggests that both samples exhibit a phase separation phenomenon. This phenomenon is believed to greatly influence the increase of A𝑆𝑀 and LFMR value in the studied samples."

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Tesis ini menghadirkan penelitian mengenai kontribusi penerapan Inversi Seismik post-stack model-based 3D broadband PSDM dan atribut seismik 3D broadband PSDM dengan hanya berdasarkan data seismik, dikarenakan belum adanya informasi sumur pada kedalaman target ekplorasi. Sebuah studi kasus telah dilakukan pada umur kapur akhir – kapur awal yaitu pada interval batupasir serpih laut dangkal pada lapangan penelitian di perairan Arafura, Indonesia Timur. Hasil tesis menunjukkan bahwa atribut seismik yang dapat digunakan untuk membantu interpretasi struktur adalah: impedansi akustik relatif, cos phase, dan dip (untuk interpretasi fault). Kemudian penggunaan atribut seismik yang dapat mengurangi resiko ketidakberhasilan dalam pengeboran dengan menunjukkan keberadaan indikasi langsung hidrokarbon adalah: sweetness, amplitudo rata-rata (rms), frekuensi sesaat dan dekomposisi spektral. Lalu berdasarkan sayatan horizon seismik dari hasil komponen absolute post-stack model based inversi seismik dapat membantu memberikan informasi distribusi secara lateral paket sedimentasi dan secara vertikal menunjukkan reservoar berpori dan kualitas bagus berdasarkan properti impedansi akustik bawah permukaan.

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The thesis investigates the contribution of applying 3D broadband PSDM post-stack model-based seismic inversion and 3D broadband PSDM seismic attributes independently based on seismic data-driven, due to no well information at reservoir exploration target. A case study from the late cretaceous – early cretaceous shallow marine sand-shale interval in Arafura Sea, Eastern Indonesia has been perform in this thesis. The thesis work have showed that the most promising seismic attributes capable to support structural interpretation are: relative acoustic impedance, cos phase, and dip (for fault interpretation). After that application of seismic attributes to low the drilling risk as a direct hydrocarbon indication are atttributes; sweetness, root mean square (rms) amplitude, instantaneous frequency and spectral decomposition. And then based on the horizon slice of absolute post-stack model based inversion results able to provide the lateral distribution sedimentary packages information and vertically denoting their high porous and good quality reservoir based on the subsurface acoustic impedance properties.

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