US4762067A — Downhole perforating method and apparatus using s…

Claim 1

Independent Claim 101 words

A detonator for use in a well borehole for detonating explosives, comprising: (a) conductive metal foil sized and shaped to conduct current therethrough wherein said foil, on current flow in excess of a specified level forms a detonating shock wave; (b) secondary explosive charge means; (c) housing means supporting said foil to form a shock wave from said foil toward said charge means to impinge thereon for detonation of said charge means; and (d) a detonating cord fixedly supported by said housing means and in sufficient proximity to said charge means to serially detonate said detonating cord from said charge means.

Claim 2

Dependent Claim 101 words

A detonator for use in a well borehole for detonating explosives, comprising: (a) conductive metal foil sized and shaped to conduct current therethrough wherein said foil, on current flow in excess of a specified level forms a detonating shock wave; (b) secondary explosive charge means; (c) housing means supporting said foil to form a shock wave from said foil toward said charge means to impinge thereon for detonation of said charge means; and (d) a detonating cord fixedly supported by said housing means and in sufficient proximity to said charge means to serially detonate said detonating cord from said charge means.

Claim 3

Dependent Claim 27 words

The apparatus of claim 1 wherein current conducting means delivers a current flow in excess of a specified energy level to vaporize a portion of said foil.

Claim 4

Dependent Claim 27 words

The apparatus of claim 2 wherein said foil has a wider portion and a comparatively narrow portion and the narrow portion is vaporized by the electric current.

Claim 5

Dependent Claim 31 words

The apparatus of claim 1 wherein said housing means incorporates a passage therein for directing the flyer driven by the shock wave from said foil toward said charge means spaced therefrom.

Claim 6

Dependent Claim 21 words

The apparatus of claim 1 including externally located boot means enclosing said housing means to exclude entry of external fluid thereinto.

Claim 7

Dependent Claim 41 words

The apparatus of claim 1 wherein said housing means includes wall means supporting said charge means spaced from said foil, and holes formed in said wall means to admit well fluid into the space between said charge means and said foil.

Claim 8

Dependent Claim 36 words

The apparatus of claim 1 including first and second cooperative current carrying conductors extending into said housing means wherein said conductors are exposed to be shorted by well fluids in the vicinity of said housing means.

Claim 9

Dependent Claim 28 words

The apparatus of claim 1 including an internally located shoulder abutting the end of said detonating cord to fix said detonating cord in said housing means against movement.

Claim 10

Dependent Claim 25 words

The apparatus of claim 8 including a fastening crimp between said detonating cord and a surrounding fixed sleeve to secure said detonating cord in location.

Claim 11

Dependent Claim 89 words

For use with a detonator connected to detonate explosives in a well borehole apparatus, an electrical impulse circuit comprising: (a) output means for connection to an electrically operated detonator; (b) current forming means forming a current pulse flowing from said output means wherein the current is (1) in excess of a specified level; (2) exceeds a specified duration; and (3) substantially uninterrupted; (c) static grounding means for preventing static current flow from said output means; and (d) AC current input means said current forming means for controlling operation thereof.

Claim 12

Dependent Claim 89 words

For use with a detonator connected to detonate explosives in a well borehole apparatus, an electrical impulse circuit comprising: (a) output means for connection to an electrically operated detonator; (b) current forming means forming a current pulse flowing from said output means wherein the current is (1) in excess of a specified level; (2) exceeds a specified duration; and (3) substantially uninterrupted; (c) static grounding means for preventing static current flow from said output means; and (d) AC current input means said current forming means for controlling operation thereof.

Claim 13

Dependent Claim 31 words

The impulse circuit of claim 10 wherein said output means includes current blocking means rendered conductive only in the event of applying a voltage thereto in excess of a required level.

Claim 14

Dependent Claim 27 words

The apparatus of claim 11 further including a grounded resistor parallel to said current forming mesns for continuously bleeding to ground any charge which might accumulate thereon.

Claim 15

Dependent Claim 41 words

The apparatus of claim 10 wherein said static grounding means connects to an input voltage multiplying ladder means providing charge to be stored on a storage capacitor incorporated in said current forming means, and wherein charge is accumulated on said capacitor.

Claim 16

Dependent Claim 22 words

The apparatus of claim 13 wherein said ladder means connects with said AC current input means, and includes a DC blocking capacitor.

Claim 17

Dependent Claim 15 words

The apparatus of claim 14 further including a grounded resistor connected across said storage capacitor.

Claim 18

Dependent Claim 36 words

The apparatus of claim 15 further including a spark gap connected to said output means for providing current flow thereto when the charge on said storage capacitor exceeds the level triggering operation of said spark gap.

Claim 19

Dependent Claim 42 words

The apparatus of claim 10 wherein said circuit means is connected to receive AC current flow through a wireline suspendable in a well borehole, and said output means connects with a detonator for detonation of shaped charges in a perforating gun assembly.

Claim 20

Independent Claim 101 words

A method of controllably detonating a detonator in a well borehole, comprising the steps of: (a) placing a current conductive wireline in a borehole; (b) conducting AC current along the wireline for a specified time; (c) charging a capacitor with current received through the wireline; (d) increasing the voltage as charge is accumuleted across the capacitor until a specified voltage is achieved; (e) dumping charge from the storage capacity at a specified minimum current and for a specified minimum interval; and (f) wherein the current from the capacitor creates an impacting flyer for detonation of a detonator in the well borehole.

Claim 21

Independent Claim 101 words

A method of controllably detonating a detonator in a well borehole, comprising the steps of: (a) placing a current conductive wireline in a borehole; (b) conducting AC current along the wireline for a specified time; (c) charging a capacitor with current received through the wireline; (d) increasing the voltage as charge is accumuleted across the capacitor until a specified voltage is achieved; (e) dumping charge from the storage capacity at a specified minimum current and for a specified minimum interval; and (f) wherein the current from the capacitor creates an impacting flyer for detonation of a detonator in the well borehole.

Claim 22

Dependent Claim 34 words

The method of claim 18 including the step of applying an AC voltage on the wireline and multiplying that voltage to achieve a specified maximum voltage for forming a charge on the storage capacitor.

Claim 23

Dependent Claim 18 words

The method of claim 18 further including the step of blocking static voltage spikes from the storage capacitor.

Claim 24

Dependent Claim 26 words

The method of claim 18 including the step of continuously bleeding charge from said storage capacitor at a minimal rate to prevent long term charge accumulation.

Claim 25

Dependent Claim 23 words

The method of claim 18 wherein the current is applied to a foil to create a flyer from an insulating disc for detonation.

Claim 26

Dependent Claim 34 words

The method of claim 18 wherein the current is directed through a conductive metal foil of limited cross-sectional area and the current is sufficient that the foil in the cross-section is heated to vaporization.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1991-08-09	1992-02-08	1992-08-09	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1995-08-09	1996-02-08	1996-08-09	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1999-08-09	2000-02-08	2000-08-09	$7700.00	Window Closed / Lapsed

Downhole perforating method and apparatus using secondary explosive detonators

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