Method and system for characterization of subsurface cavities using joint inversion of gravity and ground penetrating radar data

Patent metadata

Field	Value
Publication number	US-2016313443-A1
Application number	US-201514697394-A
Country	US
Kind code	A1
Filing date	Apr 27, 2015
Priority date	Apr 27, 2015
Publication date	Oct 27, 2016
Grant date	—

Abstract

A system and associated methodology determines the porosity and water saturation of a cavity using a joint inversion of gravity and ground penetrating radar data. The system exhibits high accuracy. In one embodiment, the cavity is spherical.

First claim

1 . A method for characterizing subsurface cavities, the method comprising:
receiving, via a network, ground penetrating radar measurements; receiving, via the network, gravity measurements; calculating a porosity of cavity filling materials based on the ground penetrating radar measurements and the gravity measurements using a data inversion approach; calculating a water saturation of the cavity filling materials based on the ground penetrating radar measurements and the gravity measurements using the data inversion approach; and sending the porosity and the water saturation to an external device to provide geological characterizing of the subsurface cavities to host applications.

2 . The method of claim 1 , wherein the subsurface cavities are spherical.

3 . The method of claim 2 , further comprising:
calculating the porosity as a function of a half width of a gravity anomaly curve, a travel time from ground surface to bottom of a host layer through center of the cavity, an electromagnetic wave velocity through the host layer, a distance from ground surface to the top of the cavity, a thickness of the host layer, densities of the cavity filling materials and permittivities of the cavity filling materials.

4 . The method of claim 3 , wherein the porosity is calculated using

φ
=

CM
-
AD

CN
-
BD

where

A
=

1.27


(

x

1
/
2

)

2



g
max

π




G


(

1.305


x

1
/
2

-

H

s



1

)

3

+

ρ
s

-

ρ
g

,

B
=

ρ
a

-

ρ
g

,



C
=

ρ
w

-

ρ
a

,

D
=

ɛ
w

-

ɛ
a

,



M
=

0.3


(

v
s



T
c

-

2


H
s

+

4


(

1.305


x

1
/
2

-

H

s



1

)

)

4


Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Al-Shuhail Abdullatif A
• Abdullah Fathi M

Classifications

• G01S13/885 Primary

  for ground probing (prospecting or detecting using electromagnetic waves G01V3/12) · CPC title

• G01V7/00

  Measuring gravitational fields or waves; Gravimetric prospecting or detecting · CPC title

• G01S13/86

  Combinations of radar systems with non-radar systems, e.g. sonar, direction finder · CPC title

• G01S7/41

  using analysis of echo signal for target characterisation; Target signature; Target cross-section · CPC title

• G01V3/12

  operating with electromagnetic waves {(operating with millimetre waves G01V8/005)} · CPC title