Oset it is displayed as a vercally changing velocity

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Unformatted text preview: a further refined look at subsurface geometry can be achieved by performing a ‘brutestack’. Brutestack •  A ‘brutestack’ is performed by applying a normal move ­out correc(on to a selected group of CMPs •  Normal moveout (NMO) correc(on stretches each trace to mimic zero offset; reflectors are flaaened and mul(ples are undercorrected •  NMO equa(on assumes that : Tx2 = To2 + x2/v2rms Second Look at Subsurface: Brutestack 3/24/2006 Lindsay Lowe and Hunter Danque 38 Near Offset Gather vs Brutestack 3/24/2006 Lindsay Lowe and Hunter Danque 39 Stacking: Velocity Analysis •  Aqer CMP sor(ng, velocity analysis is performed in order to more accurately correct for normal moveout •  The velocity is different than the NMO, because it does not assume a constant velocity along the trace Velocity Analysis The result of velocity analysis is a two ­ dimensional velocity profile that changes with (me and offset. It is displayed as a ver(cally changing velocity model CMP Stack: Third look at subsurface The Aqer a new velocity field is derived from the signal to noise ra(o should be improved over the common offset gathers and the velocity analysis performed in the above sec(on, the CMPs are stacked brutestack and reflector mul(ples should be minimized in the CMP stack view CMP Stack vs. Brutestack Migra(on •  Stacking improves veri(cal resolu(on, migra(on improves horizontal resolu(on: •  Moves dipping reflectors to their true subsurface posi(on •  And collapses diffrac(ons Migra(on •  There are mul(ple different migra(on schemes, each with its own u(lity •  The one used in processing this dat...
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