Fluid level from an echometer survey
Depth of the annular fluid level from the travel time of the reflected acoustic pulse; the speed of sound comes from the echo of a marker at a known depth (a marker sub or the tubing collars).
v = 2 · H_ref / t_refH_dyn = v · t / 2 = H_ref · t / t_refThe speed of sound is taken as constant down to the level: the closer the marker to the level, the better. In associated gas it is usually 300–450 m/s (about 440 m/s in methane, less in heavier gas). The depth is measured along the hole; convert it to vertical depth with the directional survey for a deviated well.
Source: Acoustic fluid level measurement (echometer surveys)
Inputs
You can change a field's unit: the value is converted to the formula's units automatically.
From the shot to the fluid level echo on the chart — the round trip.
A marker sub, or N collars × joint length when counting tubing collars.
Unit converter for this formulaTime · Length · Velocity
- s1
- min0.0166667
- h0.000277778
- d1.15741·10⁻⁵
- yr3.17098·10⁻⁸
A day is 24 h, a year 365 days.
- v — Speed of sound in the annular gas–
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