US3775739A — Method and apparatus for detecting fractures

Claim 1

Independent Claim 245 words

Apparatus for detecting the presence of fractures in a formation penetrated by a borehole, said apparatus comprising: a logging tool adapted to be lowered into said borehole adjacent the formation; a first pad member, said first pad member being disposed on said logging tool and biased into contact with said formation, four transmitting transducers being disposed in said first pad member to transmit acoustic waves in a horizontal plane; a second pad member, said second pad member being disposed on said logging tool diametrically opposite said first pad member and biased into contact with said formation, four additional transmitting transducers being disposed in said second pad member to transmit acoustic waves in a horizontal plane; third and fourth pad members, said third and fourth pad members being disposed in said logging tool midway between said first and second pad members and diametrically opposite each other, said third and fourth pad members being biased into contact with said formation, four receiving transducers being mounted on each of said third and fourth pad members, said receiving transducers receiving acoustic waves transmitted in the horizontal plane by said transmitting transducers; circuit means coupled to said receiving transducers for in-part amplifying and in-part eliminating the receiver signals resulting from the receiving of acoustical waves; and a recording system, said circuit means being coupled to said recording system to record said amplified receiver signals in a correlatable manner in relation to the position of the logging tool in the borehole.

Claim 2

Dependent Claim 245 words

Apparatus for detecting the presence of fractures in a formation penetrated by a borehole, said apparatus comprising: a logging tool adapted to be lowered into said borehole adjacent the formation; a first pad member, said first pad member being disposed on said logging tool and biased into contact with said formation, four transmitting transducers being disposed in said first pad member to transmit acoustic waves in a horizontal plane; a second pad member, said second pad member being disposed on said logging tool diametrically opposite said first pad member and biased into contact with said formation, four additional transmitting transducers being disposed in said second pad member to transmit acoustic waves in a horizontal plane; third and fourth pad members, said third and fourth pad members being disposed in said logging tool midway between said first and second pad members and diametrically opposite each other, said third and fourth pad members being biased into contact with said formation, four receiving transducers being mounted on each of said third and fourth pad members, said receiving transducers receiving acoustic waves transmitted in the horizontal plane by said transmitting transducers; circuit means coupled to said receiving transducers for in-part amplifying and in-part eliminating the receiver signals resulting from the receiving of acoustical waves; and a recording system, said circuit means being coupled to said recording system to record said amplified receiver signals in a correlatable manner in relation to the position of the logging tool in the borehole.

Claim 3

Dependent Claim 82 words

The apparatus of claim 1 wherein two of said transducers in said first and second pads are disposed to propagate substantially only transverse waves in the formation and the remaining two transducers in said first and second pads are disposed to propagate substantially only longitudinal waves in the formation, two of said transducers in said third and fourth pads are disposed to receive transverse waves and the remaining two transducers in said third and fourth pads are disposed to receive longitudinal waves.

Claim 4

Dependent Claim 51 words

The apparatus of claim 2 wherein the transducers disposed to propagate and receive transverse waves are mounted in said pads in a first horizontal plane and the transducers disposed to propagate and receive longitudinal waves are mounted in said pads in a second horizontal plane spaced from said first horizontal plane.

Claim 5

Independent Claim 121 words

A method for detecting the presence of vertical fractures in a formation penetrated by a borehole comprising: propagating transverse waves in the formation surrounding said borehole so that said transverse waves travel in a plane disposed at an angle to said fractures; receiving transverse waves after they have traveled through at least a portion of the formation the borehole; propagating longitudinal waves in the formations surrounding said borehole so that said longitudinal waves travel in a plane disposed at an an angle to said fractures; receiving said longitudinal waves after they have traveled through at least a portion of the formation surrounding the boreholes; and recording signals related to the amplitude of all of the received waves in a side-by-side relationship.

Claim 6

Independent Claim 121 words

A method for detecting the presence of vertical fractures in a formation penetrated by a borehole comprising: propagating transverse waves in the formation surrounding said borehole so that said transverse waves travel in a plane disposed at an angle to said fractures; receiving transverse waves after they have traveled through at least a portion of the formation the borehole; propagating longitudinal waves in the formations surrounding said borehole so that said longitudinal waves travel in a plane disposed at an an angle to said fractures; receiving said longitudinal waves after they have traveled through at least a portion of the formation surrounding the boreholes; and recording signals related to the amplitude of all of the received waves in a side-by-side relationship.

Claim 7

Dependent Claim 32 words

The method of claim 4 wherein said transverse and longitudinal waves are propagated at a plurality of locations to produce contiguous paths around the borehole for both said transverse and longitudinal waves.

Claim 8

Dependent Claim 42 words

ThE method of claim 4 and, in addition, producing and receiving longitudinal waves that travel primarily through the fluid, filling the borehole and recording a signal related to the amplitude of the received wave in a side-by-side relationship to said previously-recorded signals.

Claim 9

Dependent Claim 18 words

The method of claim 4 wherein signal related to the peak amplitude of the received waves are recorded.

Claim 10

Dependent Claim 40 words

The method of claim 4 wherein the transverse and longitudinal waves are propagated at a first position and received at a second position disposed in the same plant as the plane in which said transverse and longitudinal waves are propagated.

Claim 11

Dependent Claim 47 words

The method of claim 8 wherein both said transverse and longitudinal waves are produced at first and second position spaced substantially laterally and diametrically opposite each other, both said transverse and longitudinal waves being received at first and second position spaced laterally and diametrically opposite each other.

Claim 12

Dependent Claim 18 words

The method of claim 4 wherein signals related to the peak amplitude of the received waves are recorded.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1976-11-26	1977-05-28	1977-11-27	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1980-11-26	1981-05-28	1981-11-27	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1984-11-26	1985-05-28	1985-11-27	$7700.00	Window Closed / Lapsed

Method and apparatus for detecting fractures

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