PALEOGEOGRAFI RESERVOIR BATUPASIR A, B, DAN C BERDASARKAN DATA LOG, BATUAN INTI, DAN DIPMETER: STUDI PADA FORMASI BEKASAP, LAPANGAN RJ, CEKUNGAN SUMATRA TENGAH: PALEOGEOGRAPHY OF SANDSTONE RESERVOIR A, B, AND C BASED ON LOG DATA, CORE SAMPLES, AND DIPMETER: A STUDY OF THE BEKASAP FORMATION, RJ FIELD, CENTRAL SUMATRA BASIN - Pangeran, Ragha Jabat; Herdiansyah, Firman; Setyorini, Dyah Ayu (Universitas Trisakti, 2026)
Cekungan Sumatra Tengah merupakan cekungan sedimen tersier krusial di Indonesia. Lapangan RJ yang berada di Cekungan Sumatra Tengah memiliki data yang menarik diantaranya data log dan batuan inti yang mampu memberikan informasi mengenai karakteristik litologi, lingkungan pengendapan, dan fasies sementara dipmeter memberikan informasi mengenai arus purba reservoir batupasir A, B, dan C. Meskipun penelitian paleogeografi di Cekungan Sumatra Tengah telah banyak dilakukan, akan tetapi penelitian yang menggunakan data dipmeter masih terbilang jarang, terlebih pada Formasi Bekasap dan lapangan RJ, serta potensinya masih belum sepenuhnya diperoleh. Penelitian ini bertujuan untuk mengetahui karakteristik litologi, fasies, dan arus purba reservoir batupasir A, B, dan C Formasi Bekasap, lapangan RJ, Cekungan Sumatra Tengah. Penelitian ini dilakukan dengan menggunakan metode integrasi analisis data log, deskripsi batuan inti, dan analisis dipmeter. Penelitian ini menghasilkan karakteristik litologi reservoir batupasir A dengan karakteristik litologi batupasir, kaolinit, putih, ukuran butir halus sampai kasar, tidak mengandung calcareous, sortasi buruk, reservoir batupasir B memiliki karakteristik litologi batupasir interlaminasi dengan batulanau, putih keabuan, ukuran butir sedang hingga halus, tidak mengandung calcareous, kekompakan keras, sortasi baik, dan reservoir batupasir C memiliki karakteristik litologi batupasir, very silty, clayey, glaukonit melimpah, abu-abu, hingga abu-abu muda, ukuran butir sangat halus, struktur calcareous, sortasi baik. Reservoir Batupasir A memiliki tiga jenis fasies yakni tidal bar axis, tidal bar off-axis, dan tidal bar margin, reservoir batupasir B dan C memiliki dua jenis fasies yakni tidal bar off-axis dan tidal bar margin. Reservoir batupasir A, B, dan C memiliki arus purba dominan arah timur laut-barat daya, dengan pola arus polymodal yang menunjukkan lingkungan pengendapan tidal bar. The Central Sumatra Basin is a crucial tertiary sedimentary basin in Indonesia. The RJ field in the Central Sumatra Basin has interesting data, including log data and core rock data that can provide information about lithological characteristics, sedimentary environments, and facies, while dipmeter data provides information about paleocurrents in sandstone reservoirs A, B, and C. Although paleogeographic research in the Central Sumatra Basin has been conducted extensively, research using dipmeter data is still relatively rare, especially in the Bekasap Formation and RJ field. Furthermore, its potential has not been fully explored. This study aims to determine the lithological characteristics, facies, and paleocurrents of sandstone reservoirs A, B, and C in the Bekasap Formation, RJ field, Central Sumatra Basin. This study was conducted using a method that integrated log data analysis, core rock description, and dipmeter analysis. This study produced the lithological characteristics of sandstone reservoir A with lithological characteristics of sandstone, kaolinite, white, fine to coarse grain size, and no calcareous content, poor sorting, sandstone reservoir B has interlaminated sandstone lithology characteristics with mudstone, grayish white, medium to fine grain size, does not contain calcareous, hard compactness, good sorting, and sandstone reservoir C has lithological characteristics of sandstone, very silty, clayey, abundant glauconite, gray to light gray, very fine grain size, calcareous structure, good sorting. Sandstone reservoir A has three types of facies, namely tidal bar axis, tidal bar off-axis, and tidal bar margin, while sandstone reservoirs B and C have two types of facies, namely tidal bar off-axis and tidal bar margin. Sandstone reservoirs A, B, and C have a dominant northeast-southwest paleocurrent, with a polymodal flow pattern indicating a tidal bar deposition environment.