US4566544A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Firing system for tubing conveyed perforating gun
Assignee: Schlumberger Technology Corp
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Filing: 1984-10-29
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Granted: 1986-01-28
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Expires: 2004-10-29
Abstract
Abstract A drop bar firing system is provided with a drop bar retracting means that insures that the lower end of the drop bar cannot come into contact with the firing head after a misfire, as the drop bar is fished or the tubing string removed. A safe arm mechanism requires the pressure in the well as the perforating gun is lowered into the well to arm the tubing conveyed perforating firing means. A safe position is automatically developed by the safe arm as the perforating gun is brought out of the well if a live gun must be retrieved. A specially shaped device to fire the tubing conveyed perforating detonator includes a probe of small diameter requiring a heavy impact on center.
Inventors
- 👤 James T. Bagley
- 👤 Maurice L. Simon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:30
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/11; E21B43/116; E21B43/1185; E21B43/11855
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
264 words
A system for firing a tubing conveyed perforating gun suspended in a well utilizing a drop bar and comprising: (a) a percussion activated firing means attached between a tubing string and at least one perforating gun, said firing means including a first end adjacent the tubing string for receiving an activating force and a second end adjacent said at least one perforating gun for transmitting an explosive force to said at least one perforating gun; (b) a drop bar for introducing into the tubing and contacting the first end of said firing means, said drop bar including a housing with an attached stop means, a mandrel movably attached to the housing, and a contacting end attached to the mandrel and movable in relation to the stop means, said drop bar further comprising a retracting means for moving the contacting end toward the stop means after the retracting means is activated; (c) guide means for receiving said drop bar and directing said contacting end toward the first end of said firing means; and, (d) abutment means fixed in relation to said firing means for receiving said stop means, whereby after said retracting means is activated said retracting means moves the contacting end of said drop bar toward said stop means to such an extent that contact of the stop means and the abutment means prevents the contacting end of the drop bar from reaching and detonating the firing means, so that the drop bar may be safely fished from the tubing or the guns safely removed from the well in the event of a misfire.
Claim 2
Independent Claim
264 words
A system for firing a tubing conveyed perforating gun suspended in a well utilizing a drop bar and comprising: (a) a percussion activated firing means attached between a tubing string and at least one perforating gun, said firing means including a first end adjacent the tubing string for receiving an activating force and a second end adjacent said at least one perforating gun for transmitting an explosive force to said at least one perforating gun; (b) a drop bar for introducing into the tubing and contacting the first end of said firing means, said drop bar including a housing with an attached stop means, a mandrel movably attached to the housing, and a contacting end attached to the mandrel and movable in relation to the stop means, said drop bar further comprising a retracting means for moving the contacting end toward the stop means after the retracting means is activated; (c) guide means for receiving said drop bar and directing said contacting end toward the first end of said firing means; and, (d) abutment means fixed in relation to said firing means for receiving said stop means, whereby after said retracting means is activated said retracting means moves the contacting end of said drop bar toward said stop means to such an extent that contact of the stop means and the abutment means prevents the contacting end of the drop bar from reaching and detonating the firing means, so that the drop bar may be safely fished from the tubing or the guns safely removed from the well in the event of a misfire.
Claim 3
Dependent Claim
23 words
The firing system of claim 1 wherein the retracting means is activated prior to insertion of the drop bar into the tubing string.
Claim 4
Dependent Claim
39 words
The firing system of claim 2 wherein the retracting means comprises a spring loaded piston attached to said mandrel which leaks oil from an oil chamber, retracting the piston and mandrel into the oil chamber as the oil leaks.
Claim 5
Dependent Claim
17 words
The firing system of claim 1 wherein the retracting means is activated by a drop in pressure.
Claim 6
Dependent Claim
20 words
The firing system of claim 1 wherein the abutment means comprises a beveled upper end portion of the guide means.
Claim 7
Dependent Claim
28 words
The firing system of claim 1 further comprising well pressure activated safe arm means interrupting a detonating cord between said first and second ends of said firing means.
Claim 8
Dependent Claim
70 words
The firing system of claim 6 wherein the safe arm means comprises a safe arm barrier with an open segment which may be moved into alignment with boosters attached to the ends of the interrupted detonating cord by the pressure of the well fluid as the firing means is lowered into the well, and out of alignment into a safety position as the firing means is raised from the well.
Claim 9
Dependent Claim
34 words
The firing system of claim 1 wherein said contacting end comprises a firing pin of relatively small diameter providing heavy impact upon the center of the first end of said firing means during firing.
References Cited (Backward Citations)
US3189094A
Cited
US3706344A
Cited
US3706344B1
Cited
US4007798A
Cited
US4158334A
Cited
US4299287A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-01-27 | 1989-07-29 | 1990-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-27 | 1993-07-29 | 1994-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-27 | 1997-07-29 | 1998-01-28 | $7700.00 | Window Closed / Lapsed |