SUBSURFACE

Earthquake Relocation Using the Double Difference Method in The Banten Area Case Study

Deya Isma Wardhani — 2024-08-31

Banten Province is part of a konvergent movement between the Indo-Australian Oceanic Plate and the Eurasian (Europe-Asia) continental plate. The Indo-Australian Ocean Plate is moving north and colliding with the Eurasian Continental Plate. The earthquake on January 14, 2022 in Banten with a magnitude of 5.7 and a depth of 72 km was identified as a subduction lineation earthquake. Earthquake relocation is required to obtain accurate hypocenter results for tectonic conditions analysis. The hypocenter relocation method used in this study is the double difference method, which takes into account the travel time of the earthquake pair to the station. To obtain the best relocation results, the damping value test and several velocity models are also used. The best results were obtained. The best results were obtained using the MAXDIST 300, MAXSEP 50, and damping 25 parameters with the AK-135 speed model.

SENSITIVITAS SAGD: PENGARUH PRE-HEATING DAN JARAK VERTIKAL SUMUR TERHADAP PRODUKTIVITAS LAPANGAN A

Yoshua Chandra — 2025-02-11

Penelitian ini berfokus pada penerapan metode Thermal Enhanced Oil Recovery (Thermal EOR), yaitu Steam Assisted Gravity Drainage (SAGD), untuk menganalisis pengaruh preheating terhadap produktivitas reservoir selama periode 6 tahun. Studi dilakukan pada Lapangan A, sebuah reservoir sandstone homogen dengan kandungan bitumen sebesar 85%, viskositas tinggi hingga 20.000 cP, dan nilai API rendah sebesar 12° API. Simulasi menggunakan perangkat lunak Computer Modelling Group (CMG) dilakukan pada kondisi clean sandstone, meliputi permodelan awal (base case) hingga analisis sensitivitas terhadap parameter preheating period dan vertical well spacing. Hasil menunjukkan bahwa preheating period optimal adalah 45 hari, yang menghasilkan recovery factor (RF) sebesar 71%, setara dengan 4,15 MMBBL, sedangkan reservoir tanpa sumur injeksi hanya mencapai RF sebesar 8%. Analisis sensitivitas terhadap jarak vertikal antara sumur injeksi dan produksi menunjukkan bahwa parameter ini tidak memberikan pengaruh signifikan terhadap recovery factor. Penelitian ini memberikan pemahaman mendalam mengenai efektivitas preheating dalam meningkatkan produktivitas reservoir bertipe viskositas tinggi.

ANALYZING THE EFFECT OF WAX DEPOSITION IN PIPELINES AT WELL X USING OLGA SIMULATOR

Hafid Aslam S — 2024-08-31

This design/research discusses wax, with the aim of determining what parameters affect the deposition of wax along the X well pipe network and knowing the starting position of the formation of wax deposition that occurs along the X well pipe network. One of the causes of the decrease in production rate is the presence of a deposit derived from the crude oil content due to changes in the temperature of the fluid which results in the formation of deposits along the production pipeline to the surface. The method used in this research is to use real field data and assumption data from literature studies. The results of this study found that based on the simulations that have been carried out, the parameters that affect the presence of wax deposits along the WIDB-WIDP platform pipe are temperatures that decrease below WAT 103.38 °F. Supported by an increase in wax thickness when the fluid temperature value reaches the WAT temperature value. As well as the back pressure along the pipe flow at well X which causes wax to form before the fluid temperature touches the WAT value. And the composition of the wax content can affect the shape and thickness of the wax in the X well flow based on the assumptions made. The length of the flowline pipe on the WIDB-WIDP platform is 6082.02 ft. The initial position for the formation of wax deposits is on flowline pipes that have different geometries. As a result of this difference in geometry, there is an accumulation of wax. The beginning of this wax accumulation is at the 1501 ft flowline pipe point. There is also a change in the geometry of the pipe along the WIDB-WIDP platform, which causes friction between the pipe wall and the fluid which can result in the accumulation of wax deposition.

STUDY OF DELTA SEDIMENT DEPOSITS AT THE CITARUM RIVER MOUTH, BEKASI REGENCY, WEST JAVA

Firman Aldilah — 2024-08-31

Delta Muara Bendera is a meeting place between the Citarum river and the North coast of Northwest Java Basin which is known as one of the producers of hydrocarbons on the island of Java. The purpose of this study was to determine the relationship between environmental morphology, sediment characteristics, and microfauna characteristics found at the mouth of the Citarum River. The methods used during this study were field sampling, satellite imagery analysis, stratigraphic column analysis, granulometric analysis, hydrometric analysis, and foraminifera analysis.

Based on satellite imagery analysis. It is divided into 3 morphological sections namely: Delta Plain, Delta Front, and Pro Delta. Stratigraphic column analysis on sample codes CDAF 1 to CDAF 5, the sediment characteristics are interbedded sediments from carbonic mud at the bottom to siliciclastic mud at the top. The carbonic mud in this sample is rich in organic material, there are also plant fragments such as roots, leaf bones, and twigs. The CDAF 6 to 10 have similarities with the previous samples but there are differences with high activity of bioturbation in sediment layer. CDAF 11 to 15 show a deltaic deposition pattern in the form of a fine and coarse pattern in sediments with a range of silt grains to medium sand. Sediment grain analysis in the sand fraction showed the presence of fine sand grains with moderate sorting, based on microscopic observations of sand grains having rounded roundness and low sphericity. Analysis of the mud fraction showed medium sand to medium silt, based on the overall sample the percentage of the fine sand fraction in the sample only had less than 60%. Benthic foraminifera found on research area has dominated by genus Ammonia

ANALISIS GEOLOGI TEKNIK REMBESAN DAN KESTABILAN LERENG DI BENDUNGAN LOGUNG, KABUPATEN KUDUS, PROVINSI JAWA TENGAH

Zakki Hilal Chalqi — 2024-08-31

Bendungan Logung merupakan bendungan urugan tanah di Kabupaten Kudus sebagai pengendali banjir saat musim penghujan serta penyedia air baku hingga air irigasi untuk menghadapi kekeringan. Dalam operasionalnya, bendungan akan memiliki kondisi muka air fluktuatif pada reservoir di hulu. Kondisinya dapat berupa kondisi air banjir hingga tanpa air sekalipun. Penelitian ini bertujuan untuk menganalisis rembesan baik dari pola aliran hingga debitnya serta mengetahui nilai kestabilan lereng berdasarkan pengaruh muka air di reservoir. Metode dalam penelitian ini berupa teori Cassagrande dan metode Darcy untuk karakteristik rembesan serta metode Morgenstern-Price untuk nilai kestabilan lereng. Dari hasil analisis didapatkan bahwa garis freatik dalam aliran rembesan lebih menunjam pada kondisi muka air yang lebih tinggi. Rembesan pada hilir bendungan juga akan memiliki debit yang lebih tinggi ketika muka air reservoir lebih tinggi. Sementara itu untuk analisis kestabilan lereng untuk semua kondisi dinyatakan hampir aman. Akan tetapi terdapat satu kondisi dengan nilai yang tidak aman pada kondisi surut cepat ketika air di reservoir tiba-tiba menyurut habis.