EVOLUTION OF WEST SALAWATI BASIN (KOFIAU AREA) DURING LATE PLIOCENE AGE TO RECENT

• Main Author: NURHASAN
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/16742
• Institution: Institut Teknologi Bandung

Basin evolutions study of Kofiau area which is part of West Salawati Basin has been <br /> conducted with target interval from Middle Pliocene Unconformity (MPU) to recent. <br /> Pliocene silisiclastic sedimen deposit is a new play in this area that needs to be explored <br /> to comprehend more about its hydrocarbon potential. <br /> During Pliocene time, Salawati Basin especially Kofiau area was a transtensional <br /> divergent pull-apart basin as a result of left lateral movement of strike-slip Sorong fault <br /> which was episodically active since Late Miocene and becoming more active since the <br /> Middle Pliocene. This tectonic activity resulted in the basin evolution with several <br /> restructuration phases. <br /> Sequence stratigraphic framework has been constructed based on seismic sequence <br /> boundaries and information from well depositional environment. The result is <br /> identification at least three stratigraphic sequences. Each sequence has different <br /> characteristics seismic fasies and thicknesses from Middle Pliocene Unconformity <br /> (MPU) 2.2 Ma to recent. <br /> First phase of the basin evolution, 2.2-1.9 Ma (MPU- Late Pliocene) is characterized by <br /> MPU angular unconformity which marks the beginning and opening of accommodation <br /> space followed by sedimentary filling from southwest to northeast. This is evidenced <br /> from the thickening of sediments in the northeast direction and indicate potential <br /> reservoir and trap for the new play Pliocene silisiclastic. <br /> Second phase of the basin evolution, 1.9-1.0 Ma (Late Pliocene – Pleistocene) is phase <br /> of filling sedimentation accommodation space with influx sediment from direction SW <br /> and SE. Sedimentation pattern during this phase showed sediment thickening in Kofiau <br /> area. <br /> Third Phase of basin evolution, 1.0 Ma - recent shows a change in accommodation <br /> space from previously thick to relatively thin in Kofiau area and depocenter was shifted <br /> further to the North East.