PERHITUNGAN VOLUMETRIK CADANGAN HIDROKARBON BERDASARKAN ANALISIS PETROFISIKA DAN INTERPRETASI SEISMIK PADA LAPISAN SAND-A FORMASI TALANG AKAR DI LAPANGAN "WIRA" CEKUNGAN JAWA BARAT UTARA

DWI NOVI YANTO, Prof. Dr. Sismanto, M.Si

2014 | Skripsi | S1 GEOFISIKA

Analisis deterministik telah dilakukan pada enam sumur di lapangan pengembangan eksplorasi minyak dan gas bumi "WIRA" di cekungan Jawa Barat Utara. Berdasarkan data mudlog, beberapa sumur dilapangan tersebut menunjukkan adanya oil show, terutama pada lapisan batupasir SAND-A di formasi Talang Akar. Analisis tersebut bertujuan untuk mendapatkan nilai kandungan serpih, porositas efektif, saturasi air, dan permeabilitas pada lapisan batupasir SAND-A. Properti petrofisika tersebut akan digunakan dalam analisis nilai ekonomis dari lapisan batupasir SAND-A tersebut. Hasil analisis deterministik enam sumur pengeboran menunjukkan hasil bahwa lapisan batupasir SAND-A memiliki kandungan serpih 20% sampai 50%, porositas efektif 11% sampai 17%, saturasi air efektif 33% hingga 87%, dan permeabilitas 11 hingga 37 milidarcy. Analisis kemudian dilanjutkan pada peta sebaran impedansi akustik. Peta sebaran impedansi akustik tersebut digunakan untuk membuat peta sebaran porositas dan saturasi pada lapangan �¢ï¿½ï¿½WIRA�¢ï¿½ï¿½ yang betujuan untuk mengetahui penyebaran reservoir batupasir SAND-A dan estimasi besar cadangan dengan metode volumetrik. Berdasarkan analisis kedalaman Oil- Water Contact pada data sumur dan seismik, didapat cadangan STOIP pada lapangan �¢ï¿½ï¿½WIRA�¢ï¿½ï¿½ sebesar 650.000 meter kubik.

Deterministic analysis has been performed on six development wells of "WIRA" field in North West Java basin. Based on mudlog data, some of the wells in this field indicated the presence of oil shows, especially in the SAND-A layer, Talang Akar Formation. The analysis aims to obtain the value of the shale content, effective porosity, water saturation, and permeability of the SAND-A layer. The petrophysical properties will be used in the analysis of the prospects and economic value of the SAND-A layer. The deterministic analysis results of six drilling wells shows that the SAND-A has shale content about 20% to 50%, the effective porosity about 11% to 17%, effective water saturation about 33% to 87%, and permeability about 11 to 37 milidarcy. Analysis proceeded to the acoustic impedance distribution map. The acoustic impedance distribution map are used to create distribution map of porosity and saturation in the "WIRA" field which aims to determine the spread of SAND-A reservoir and estimate the oil reserves by volumetric methods. Based on the analysis of the depth of Oil-Water Contact on seismic and well data, obtained Stock-Tank Oil In Place reserves on the �¢ï¿½ï¿½WIRA�¢ï¿½ï¿½ field about 650,000 cubic metres.

Kata Kunci : petrofisika, analisis deterministik, impedansi akustik, volumetrik