RESERVOIR CARBONAT PRE RIFT CHARACTERIZATION IN GARUDA FIELD, NORTH WEST JAVA BASIN

• Main Author: NURI, FUAD
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/15738
• Institution: Institut Teknologi Bandung

Garuda field located in West Java block is operated by PT Pertamina EP has been producing oil and gas from the pre rift reservoar carbonate rocks. Garuda field consists of 11 wells and several wells which have been produced on pre rift carbonate reservoar rocks with an average oil rate of 1000 bopd and 5.5 MMscfd of gas rate. <br /> <br /> The results from several drilling show that the reservoar carbonate distribution is limited due to the northward onlapping on bedrock wells GRD-11 and eastward onlapping on bedrock wells GRD-06. Based on the overlay between map top depth structure and isopah pre rift carbonate suggests a form monocline to the southwest, it can be concluded that the trap is developed on a Garuda Field is stratigraphic trap. <br /> <br /> Based on the distribution map and isopah pre rift carbonate reservoar in the Field Garuda still suggest the potential of hydrocarbons in pre rift carbonate reservoar that have not been picked up, but the main problem is to know the type and distribution of the existing porosity pre rift reservoar carbonate rocks so it is becoming a challenges. <br /> <br /> To determine the type of porosity in carbonate reservoar then do core analysis interpretation, FMI data analysis and petrophysical calculations so that it can be seen that hat the pre rift carbonate reservoar has dual porosity is vuggy-matrix porosity and fracture porosity. <br /> <br /> Matrix-vuggy porosity is formed when pre rift carbonate rocks undergo diagenesa causing leaching process and having to expose the surface to form a very intense vuggy porosity whereas fracture porosity formed due to the influence of the tectonics events that exist in the study area. <br /> <br /> Tectonic events that occurred since the early Oligocene rifting to Plio-Pleistocene compression will affect the process of the formation of faults in the area of research and faults that occur will affect the formation of open fractures in the pre rift carbonate reservoar rocks. <br /> <br /> Based on the data analysis of the structure of the data FMI can be concluded that the pattern of the existing fracture occurs due to the fault and have had relative direction North – South (NNE – SSW). Open fracture pattern direction is parallel to the main direction of force (Hmax) and parallel to the fault directions that exist in the study area.