Seismic 2D Reflection Processing and Interpretation of ... - Posiva

More documents

Recommendations

Info

38Figure 31. 3D view (from the south-west) of interpreted surfaces, boreholes (KR), OL-BFZ098 (turquoise) and ONKALO (yellow).In Figure 32 the picked surfaces are shown with the results of 3D survey (Juhlin &Cosma 2006) on stacked sections (same processing phase). The reflection amplitudemaxima are seen on the same arrival times in both sections. The 3D survey suggeststhat many of these reflectors seen in 2D lines, are discontinuous in character overlonger distances.
39Figure 32. Matching events in the stacked 2D (Line S46, see APPENDIX 1) and 3Dsections (for 3D before dip moveout and migration, Juhlin & Cosma 2006). View to theSoutheast.Evidently the reflecting surfaces correspond to geological structures, e.g., brittle faultzones met at the borehole intersections. These can be confirmed e.g. from KR4, KR7,KR25 and KR29 at borehole depths shown in Table 5 above. The discontinuities on thesurfaces suggest slight vertical displacements (faults), though the large scale continuityof the surfaces on the same depth level can be confirmed.According to location, ref9 (dark blue in Figures 28 - 32) can be met in KR4, and maycontinue on slightly different level to borehole KR29, matching with BFZ098 withslight vertical offset (330 m). The ref10 (light blue in Figures 28 – 32) is met upper inthe borehole KR7 and would match well HZ20A. The ref1 (red) is fitting well withHZ21. There is no direct borehole control for the reflector nearby, but evidently thestrongly fractured section in KR4 and KR7 would match this feature. It is not seencontinuously in 2D line sections due to low S/N, but in 3D the event is clear andcontinuous.In Figure 33 is shown line number S46 and boreholes KR4 and KR7 with P-wavevelocity and density logging results. The velocity minima in logging match with thereflectors marked with red arrows. The reflectors ref3, ref5, ref9, ref10 and ref11 seemto correlate to this feature, being slightly offset (or faulted) in different parts, andshowing slightly varying orientations 128 -140/11-19 in different locations. Projectedintersection point is in KR4 290 m and in KR7 230 m, slightly above true position, likeat 315-320 m in KR4.
Page 1 and 2: Working Report 2006-114Seismic 2D R
Page 3 and 4: Seismic 2D Reflection Processing an
Page 5: 1TABLE OF CONTENTSABSTRACTTIIVISTEL
Page 9 and 10: 52 SOURCE DATA2.1 Surface seismic d
Page 11 and 12: 7Figure 2. Survey array. At the lin
Page 13 and 14: 93 DATA PROCESSINGThe aim was to pe
Page 15 and 16: 11Processing was performed using fr
Page 17 and 18: 13Figure 7. Original spectrum from
Page 19 and 20: 15new datum and elevation differenc
Page 21 and 22: 1750-200 mslower cutoff frequency:
Page 23 and 24: 19Original first breaks were picked
Page 25 and 26: 21Figure 17. Shot gather from the l
Page 27 and 28: 23a)CDP position b)CDP numberFigure
Page 29 and 30: 25a) b)Figure 21. a) Final stacked
Page 31 and 32: 27Figure 23. Stacked section withou
Page 33 and 34: 294 INTERPRETATIONAfter the seismic
Page 35 and 36: 31events) indicates presence of off
Page 37 and 38: 33Table 4. Positions and dips for m
Page 39 and 40: 35In Figure 28 are shown the picked
Page 41: 37Figure 30. 3D view (from the sout
Page 45 and 46: 415 CONCLUSIONSAim of this work was
Page 47 and 48: 43REFERENCESAhokas, H. & Vaittinen,
Page 49 and 50: 45APPENDIX 1. STACKED SEISMIC SECTI
Page 51 and 52: 47Figure 3. Stacked section from th
Page 59 and 60: 55Figure 11. Stacked section from t
Page 89 and 90: Figure 41. Stacked section from the
Page 93 and 94:
Figure 45. Stacked section from the
Page 95 and 96:
91Figure 47. Stacked section from t
Page 97 and 98:
93Figure 49. Stacked section from t
show all

Seismic 2D Reflection Processing and Interpretation of ... - Posiva

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?