RESERVOIR DISTRIBUTION ANALYSIS ON INTERVAL SYN RIFT IN PENYU BASIN, BLOCK GURITA WEST NATUNA

• Main Author: RUFAIDA (NIM: 22014027), DIAH
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/26594
• Institution: Institut Teknologi Bandung

<p align="justify">Penyu Basin is a Cenozoic rift basin which is a part of Sunda Microplate that is based on continental lithosphere. The basement structure mapping result at Penyu Basin indicates three sub-parts of the basin namely Cherating, East Jemaja, and West Jemaja. Penyu Basin is a intra-continent basin fold from Eocene Sunda shelf which consists of half-graben folds with relatively north east-southwest direction. <br /> <br /> 24 exploration wells have been drilled since 1972 in the Penyu Basin in both Indonesia and Malaysia. 16 wells targeted Miocene inversion-related structures and were largely unsuccessful with a failure rate of more than 80%.5 wells were drilled to test Upper Oligocene post-rift structural traps. The cause of the 3failed wells and 2 wells succeededdiscover Hydrocarbon (HC). <br /> <br /> In 2011, a test toward play synrif was conducted at Penyu Basin in the Malaysia territory at Arby-1 well and successfully discovered HC. The success of Arby-1 well has opened up the opportunity for target exploration search in the interval syn rift at Penyu Basin in the <br /> <br /> territory of Indonesia. In order to support that, thus a study on the rift basin development and hydrocarbon play potential identification is needed so that maximum exploration target could be achieved. <br /> <br /> From the analysis result that was conducted previously, there are 5 stages in basin development in relation with tectonostratigraphy namely interval early syn-rift, internal mid syn-rift, interval late syn-rift, immediate phase post syn-rift, and late phase post-rift. This research is limited to interval syn rift. In order to know the limits of tectonostratigraphy, an analysis is conducted on a seismic data of 3D Pre Stack Time Migration (PSTM) within 450 sqkm surveyed an processed in 2012. <br /> <br /> The analysis to be conducted is to examine the character of the seismic in order to obtain the characteristics of seismic facies for each interval. <br /> <br /> The analysis outcome on the seismic data interval early syn-rift has characteristics in the form of aggradations seismic facies on the side near the fault, downlap toward pre-rift, hummocky and thinning on the flexture margin. Interval mid syn-rift shows aggradations facies, retrogradation, sigmoid and facies changes from strong reflector to weaker reflector is visible. Interval late syn-rift as the last interval that is affected by the movement of the main fault shows oblique-shingled and chaotic seismic character. <br /> <br /> The thickness map between early syn-rift and pre-rift, mid syn-rift and early syn-rift and between mid syn-rift and late syn-rift is made after the creation of time map and depth map. The result of the thickness map is expected to be able to see the shape of the <br /> <br /> sedimentation environment. <br /> <br /> Geophysical modeling (inversion) is done by model making by utilizing sonic log data, density of Arby-1 well, Kelud-1 and Ratai-1, horizon data on each interval (early syn-rift, mid syn-rift and late syn-rift) and 3D seismic PSTM. Then, proceed with inversion process <br /> <br /> base model. The validation result between acoustic seismic impedance with acoustic impedance of Ratai-1 weel shows the good correlation. <br /> <br /> The AI map is obtained by conducting extraction at each interval. From the results of the AI could be obtained the sediment environment and reservoir distribution on each 2 synrift intervals (early syn-rift, mid syn-rift and late syn-rift).<p align="justify">