Select relevant interval velocity functions for each layer from the scroll down menu. Selecting
interval velocity functions is a choice based on your a priori knowledge about the geology
(e.g. previous analysis of well velocity profiles).
Contact Seisquare® support if you would like to see additional functions added to the existing list:
| V0 | Useful when layers are very homogeneous and/or when there is a limited amount of well data available. |
| V0 + α T | Useful when geology presents non-linear compaction from the surface. |
| A . V0map + α T |
Same as V0 + αT model, introducing an additional V0map parameter. You may consider α to be relatively constant for a considered layer, and V0 to be variable. Introducing a V0map with possible spatial variation, linked with seismic information, enables to minimize well depth mismatches. |
| V0 + α D T |
Same as V0 + αT, except that V0 is linked to the top of the considered layer. Useful when you are in a layered model and the V0 at reference datum does not reflect a possible change of V0 values at the top of the layer. For example, when there is an important dip effect at the top of the layer. |
| A.V0map + α D T |
Same as V0 + αDT, introducing an additional V0map parameter. You may consider α to be relatively constant for a considered layer, and V0 to be variable. Introducing a V0map with possible spatial variation, linked with seismic information, enables to minimize well depth mismatches. For example, you can introduce a seismic V0 map based on your available seismic velocity map. |
| V0 + K Z | Useful when geology presents linear compaction (often confirmed by measurements at least in clastic environments). |
| V0 . exp(K × T) |
Approximation of V0+KZ in multi-layer context. Equivalent to V0+KZ if use for first layer, less sensitive to shallower conversion if deeper. |
| A . V0map . exp(K × T) |
Same as V0 × exp(K × T) model, introducing an additional V0map parameter. You may consider k to be relatively constant for a considered layer, and V0 to be variable. Introducing a V0map with possible spatial variation, linked with seismic information, enables to minimize well depth mismatches. For example, you can introduce a seismic V0 map based on your available seismic velocity map. |
| A.V0map + K Z |
Same as V0 + kZ model, introducing an additional V0map parameter. You may consider k to be relatively constant for a considered layer, and V0 to be variable. Introducing a V0map with possible spatial variation, linked with seismic information, enables to minimize well depth mismatches. For example, you can introduce a seismic V0 map based on your available seismic velocity map. |
| V0 + k (Z−Z0) |
Same as V0 + kZ, except that V0 is linked to the top of the considered layer. Useful when you are in a layered model and the V0 at reference datum does not reflect a possible change of V0 values at the top of the layer. For example, when there is an important dip effect at the top of the layer. |
| A.V0map + K (Z−Z0) |
Same as V0 + k(Z-Z0), introducing an additional V0map parameter. You may consider k to be relatively constant for a considered layer, and V0 to be variable. Introducing a V0map with possible spatial variation, linked with seismic information, enables to minimize well depth mismatches. For example, you can introduce a seismic V0 map based on your available seismic velocity map. |
| A.Vseis | Useful when seismic velocities are available and rescaling is required for coherence with well velocities. |
| A.Vseis + B |
Useful when seismic velocities are available and rescaling is required for coherence with well velocities. Adding a shift to the seismic velocities enables to introduce seismic time as a correcting factor for the seismic velocities. This is relevant if you think that the seismic velocities do not properly capture geological velocity variations. |
| V0 + Z0 / T |
Can also be read as Z=V0×T + Z0; useful when the depth of the given horizon appears as a simple linear transformation of seismic time. This is a simple model which can be used for reference or large scale basin study. |
| α.DT + Vint0 | Useful when there is a relation due to the opposition between fast and slow facies in an aggradational basin. |