Method and apparatus for acoustically investigating a borehole casing cement bond

Patent · Tue Nov 24 04:00:00 EST 1987

OSTI ID:5729154

Maki, Jr, V E

This patent describes a method for determining a selected characteristic of a casing cemented in a borehole penetrating an earth formation from a reflection signal from an acoustic pulse directed from within the casing at a radial segment thereof comprising the steps of: selecting from the reflection signal a reverberation segment substantially representative of acoustic reverberations between the casing walls at the radial segment; selecting from the reverberation segment an input signal, a first time delayed signal, and a second time delayed signal; multiplying the first and second time delayed signals by first and second filter parameters, respectively; adding (i) the product of the first time delayed signal and the first filter parameters, (ii) the product of the second time delayed signal and the second filter parameter, and (iii) the inverse of the input signal to obtain an output signal; selectively adjusting the first and second filter parameters to minimize the output signal; and utilizing at least one of the selectively adjusted adjustable filter parameters to determine the selected characteristic.

• Assignee: Gearhart Industries, Inc., Fort Worth, TX
• Patent Number(s): US 4709357
• OSTI ID: 5729154
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
03 NATURAL GAS
030300 -- Natural Gas-- Drilling
Production
& Processing
ACOUSTIC TESTING
BUILDING MATERIALS
CEMENTING
CEMENTS
MATERIALS
MATERIALS TESTING
NATURAL GAS WELLS
NONDESTRUCTIVE TESTING
OIL WELLS
REFLECTION
SOUND WAVES
TESTING
WELL CASINGS
WELL COMPLETION
WELLS