2-D SEISMIC REFLECTION INTERPRETATION OF LINE NP-84-42 (SP: 518-200) AND ROCK PHYSICS ANALYSIS FOR RESERVOIR CHARACTERIZATION BY MAKING CROSS-PLOTS USING LAS DATA

Abstract

The Seismic line NP-84-42 given to me comprises of vibrator pcints from 518 to 200. It is a reverse-shooted line. To investigate the lateral and vertical variations of velocity within a layer average velocity and Iso-velocity graphs were prepared. The number of reflectors marked on the Seismic Section is four (4) of which first three contain 9 reverse faults with different orientations and the fourth (top of basement) with 3 normal faults. To see reflectors positions and to study their nature, seismic time and depth sections were prepared. Time and depth contour maps of Chorgali Formation were also prepared which shows anticlinal (i.e. a pop-up structu re) structu re present in the Study area. This structu re may act as a favorable trap for hydrocarbons. Also a descriptive analysis of Rock Physics using LAS Data of the RATANA-01 well has been made. Based on this LAS File, only two logs (Sonic & Density Logs) were used to calculate sonic wave velocity (Pwave) & the Bulk Density because of the limitation of the data. Then using these data some other rock physical properties are ca lculated (e.g. P-wave Impedance, S-wave Impedance, Poisson Ratio, acoustic Impedance, etc) for a particular zone whose depth ranges from 2000m to 3000m. Actually this analysis is made to seek for the hydrocarbon potential zone using cross plots of different physical properties as mentioned above. It is then concluded from these cross plots that probably no anomalous zone is present within this depth range (i.e. 2000m-3000m).