Publications

Akasia Bagus structure is a discoveries in Cemara – Tugu Area, located in North West Java Basin. Exploration activity within this structure had begun since 1994 with 2D seismic acquisition, followed by exploration well on 2009, 3D seismic acquisition on 2011, and continued with delineation wells on 2014 and 2016. In general, Akasia Bagus structure possess multiple vertical reservoir layer especially in Upper Cibulakan Formation, among them is carbonate reservoir known as Z-16. The Z-16 layer is a limestone reservoir with 111 m gross thickness, this contains porous zone as thick as 54 m, the accoustic impedance inversion of this layer shows a facies barrier between the Akasia Bagus Structure and the other structures to the north, which also confirm the difference of fluid contact between those two structures. For this paper writer used one seismic composite and inverted seismic section, three Wells data and laboratory analysis results from A-1, A-2, and A-3 wells. Two conventional core and rotary sidewall core samples from A-2 and A-3 wells were used for routine core analysis, while the special core analysis only perform on selected conventional core plug from A-2 Well. From FMI analysis it is known that the lateral facies development within the Z-16 layer in A-3 well is more complex compare to A-1 and A-2 wells, characterized by the thickening of limestones sediments. The lateral facies distribution in A-2 well dominated by the red algae, and large foram as fragments embedded in grain supported matrix (packstone-grainstone) (Dunham., 1962), while the Z-16 layer in A-3 well showed that the original matrix is replaced by dolomite. Dissolution, dolomitization, and the formation of stylolite become diagenetic stage markers that indicate the mesogenesis stage. Vuggy and mouldic are the main porosity in A-2 well, it ranges from 1.20 % to 26 %, the permeability ranges from 0.0001 md to 481 md, and the density ranges from 2.70 to 2.74 g/cc. The porosity system in A-3 well is mainly vuggy with intercrystalline pores, cementation and compaction during diagenetic stage were the determining factor that reduce the porosity (3.7 % to 9 %), permeability ranges from 0.025 md to 5.28 md, and the density ranges from 2.70 to 2.79 g/cc.