In terms of structure and tectonics, the Biak and Supiori Island must be considered as one unit. Its tectonic history can be traced back to the Pre-Eocene, when a bed of metamorphic rock appeared on the surface. Volcanic activity during the Eocene and Oligocene then resulted in material being deposited on the eroded surface. During the Late Oligocene to Early Miocene this entire area experienced a decline. This downward movement continued until the Middle Miocene, when the opposite movement began. This movement is of course accompanied by displacement. The fault that forms the Sorendidori Strait, for example, shows horizontal and vertical movements so that Biak Island seems to be left behind by Supiori Island which is different across the strait.Since the Late Miocene, this whole area has been in slow and continuous depression. This depression continued until the Late Pleistocene, when the motion reversed and uplift occurred. This intermittent upward movement still continues today, as evidenced by the presence of several steps. Radiometric dating shows that the lifting rate is about 8 mm every year (Tjia, 1975).As a result, the peaks and heights on the two islands have reached a height of several hundred meters above sea level.The results of the analysis of gravity data show depocenters south of Biak and south and southwest of Yapen Island. The results of the analysis on Biak Island also show that there is a depocenter that extends in a northwest-southeast trend.MT analysis results on the north-south track of Biak Island show the flexural anticline which is truncated by the positive flower structure. MT analysis results on the west-east track of Biak Island show a giant anticline that is cut by positive flower structures and reverse faults

The results of the organic marl geochemical analysis from the Wainukendi Formation have a TOC value of 0.90%, from the results of the analysis plot diagram for the source rock potential, it shows that the organic material from the marl is included in kerogen type III (gas prone potential), with quite good hydrocarbon potential (Permana , 2013).The results of organic geochemical analysis of shale and marl from the Wafordori and Napisendi Formations show TOC values ranging from 0.52% - 1.38%, from the results of the analysis diagram plot for source rock shows that organic material is included in kerogen type III (gas prone potential), with quite good hydrocarbon potential (Permana, 2013).The Napisendi limestones are generally grainstone limestones, these rock units were deposited in a shallow water carbonate environment, namely on an open shelf. The types of porosity found in these rocks are intergranular porosity, vuggy porosity and channeled fracture. The results of the rock porosity analysis performed showed good to very good results.Wardo Limestone and Mokmer Limestone are generally in the form of packstone to rudstone with chalky characteristics. This rock unit was deposited in a deep water carbonate environment, namely the slope to margin reef facies. The results of the porosity analysis showed very good results which were also estimated from the secondary porosity of the limestone unit.The potential for reservoir rocks in the Biak Basin is limestone in shallow to deep marine environments (slope). This can be caused by the emergence of secondary porosity which is formed during diagenesis.The claystone and siltstone characteristics of the Wainukendi Formation, Wafordori Formation, Napisendi Formation, Wardo Formation and Korem Formation may have potential as overburden rocks. The results of petrographic analysis show that this rock unit is composed of carbonate mud with a matrix of carbonate mud mixed inseparably with clay minerals, so it is very good as a cap rock (Permana, 2013)