Defining the minimum and maximum velocity

On the V0 and Vmax form (1D MODEL > Pore Pressure > Bowers Method) you can define the minimum and maximum velocity used in the Bowers equation. To aid in determining the velocity values you can open the Bowers Method view from the Input Logs and Filtering form and use the probe tool or a trend line to pick the values.

To define V0 and Vmax

  1. For the TVD Reference, select RT, SS or GL, depending on the type of well.

  2. Specify the following velocity values as needed.

    V0  The velocity at the mud line. By default, the Bowers method uses an initial velocity of 5000 ft/sec or 1524 m/s (which is the water velocity) and can be used if the log data does not include valid values at this depth. In other cases, it is recommended to open the Bowers Method view and create a linear trend to extrapolate the behavior of the log to the surface. You can then zoom in on the mud line depth or use the probe tool to determine a suitable V0. Type this value into the V0 field in the form.

    After you have specified V0, a red point appears in the Bowers Method view representing the value. If the value needs to be changed you can drag this point to the new value or edit the value in the form. Generally, values will fall in between a range of 1,800 and 4,350 m/s. If the specified V0 is outside of this range the cell in the V0 and Vmax form will change colors to represent a warning: you can proceed through the Bowers Method workflow using the value, though it is not recommended.

    TVD (V0)  The depth corresponding to the initial velocity. The value for the mud line is used for offshore wells, while the ground level depth is used for onshore wells. This value is read-only.

    Vmax  Vmax is defined as the maximum value of the velocity and acoustic converted shale filtered log. If a velocity and acoustic log are provided, the greatest value of the two logs is taken by default and pre-populated in the form. This maximum value is represented in the view by a red point. You can modify Vmax by dragging this point to a suitable location; the corresponding value and depth will be set in the form. Note that this point cannot be dragged in the view unless V0 has already been specified. As an alternative to using the red point, you can also type the Vmax value into the form.

    TVD (Vmax)  The depth corresponding to the maximum velocity. This value can be specified manually or by changing the position of the red point in the Bowers Method view.

  3. (Optional) If you need to return the V0, Vmax and TVD(Vmax) values to their defaults, click the reset button ().
  4. Click OK to move to the next form, Effective Overburden.