US3917008A

US3917008A - Apparatus and process for preventing blow-outs

Info

Publication number: US3917008A
Application number: US518828A
Authority: US
Inventors: William R Suter
Original assignee: Cities Service Co
Current assignee: Cities Service Co
Priority date: 1974-10-29
Filing date: 1974-10-29
Publication date: 1975-11-04
Anticipated expiration: 1992-11-04
Also published as: CA1020087A

Abstract

Blow-Out Prevention Apparatus for an oil well comprising a surface casing, a mud return means leading from the casing, a blow-out preventor means attached to the casing, and a mud diverter valve means connected with the casing. The valve means includes a cylindrical sleeve having a diverted-mud inlet end which leads into the casing, a biasing end, and a diverted-mud outlet opening in the side wall of the sleeve. A piston is housed in the sleeve which is slideable back and forth between the ends of the sleeve, and the piston has a mud contact end and a biased end. The valve means additionally comprises a mud diverter conduit leading from the sleeve through the outlet opening, and biasing means for resiliently biasing the piston from the biasing end thereof toward the mud-inlet end of the sleeve until the outlet opening thereof is covered by the piston. The process comprises passing diverted mud from the casing axially into the cylindrical sleeve and subsequently discharging the diverted mud from the sleeve through the outlet opening therein.

Description

United States Patent [191 Suter 1 APPARATUS AND PROCESS FOR PREVENTING BLOW-OUTS [75] Inventor: William R. Suter, Houston, Tex.

[73] Assignee: Cities Service Company, Tulsa,

Okla.

22 Filed: on. 29, 1974 21 Appl. No.: 518,828

Primary Examiner-James A. Leppink Attorney, Agent, or F irmJohn W. Carpenter Nov. 4, 1975 [5 7] ABSTRACT Blow-Out Prevention Apparatus for an oil well comprising a surface casing, a mud return means leading from the casing, a blow-out preventor means attached to the casing, and a mud diverter valve means connected with the casing. The valve means includes a cylindrical sleeve having a diverted-mud inlet end which leads into the casing, a biasing end, and a divertedmud outlet opening in the side wall of the sleeve. A piston is housed in the sleeve which is slideable back and forth between the ends of the sleeve, and the piston has a mud contact end and a biased end. The valve means additionally comprises a mud diverter conduit leading from the sleeve through the outlet opening, and biasing means for resiliently biasing the piston from the biasing end thereof toward the mudinlet end of the sleeve until the outlet opening thereof is covered by the piston. The process comprises passing diverted mud from the casing axially into the cylindrical sleeve and subsequently discharging -the diverted mud from the sleeve through the outlet opening therein.

17 Claims, 3 Drawing Figures U.S. Patent Nov. 4, 1975 Sheet 1 of2 3,917,008

F/GJ

Sheet 2 of 2 U8. Patent Nov. 4, 1975 BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a blow-out prevention apparatus and process. More specifically, this invention provides a diverter valve means and process for preventing blow-out of an oil well from underneath, around or through a surface casing, or the like, of the well.

2. Description of the Prior Art. I

When drilling shallow in the Gulf Coast area, high pressure gas sands are often encountered. This is a particularly dangerous situation because if the well is shut in during the kick the pressure will break down the casing shoe and a blow-out can occur around the outside of the casing. To prevent such blow-outs around the casing, a well is generally allowed to flow through lines which carry the gas and drilling mud away from the rig until the flow can be safely controlled. Such a system for diverting the flow of mud away from the rig is called a mud diverter system and normally includes a manually operated butterfly valve for controlling flow of the mud. These conventional diverter systems rely on human promptness in preventing a breakdown of the casing shoe and blow-out around the outside of the casing. They are also not fail-safe, non-automatic, and are easily plugged by the drilling mud. Therefore, what is needed and what has been invented by me is a diverter system which avoids the foregoing deficiencies of the prior art.

SUMMARY OF THE INVENTION This invention accomplishes the desired objects through an improvement in a blow-out prevention apparatus of the type which generally comprises a surface casing for a well, a mud return means leading from the casing, a blow-out preventor means attached to the easing, and a mud diverter valve means connected with the casing. In accordance withthe present invention the valve means has a cylindrical sleeve with a divertedmud inlet end which leads into the casing, a biasing end, and a diverted-mud outlet opening in the side wall of the sleeve. A piston is housed in the sleeve which is slideable back and forth between the ends of the sleeve, and the piston includes a mud contact end and a biased end. The valve means additionally includes a mud diverter conduit leading from the sleeve through the outlet opening, and a biasing means for resiliently biasing the piston from the biasing end thereof toward the mud-inlet end of the sleeve until the outlet opening thereof is covered by the piston. This invention also accomplishes the desired objects by improvements in the general process for preventing blow-out of an oil well from underneath, around or through a surface casing of the well. Accordingly, I have provided an improved method of diverting mud flow from the casing which comprises passing diverted mud from the casing axially into an elongated mud diverting channel which leads from the casing, the mud being diverted from the casing when the pressure therein. exceeds a predetermined limit. Subsequently, the diverted mud is discharged from the channel through an outlet opening therein, and the mud flow from the opening is in a direction which is substantially transverse with respect to the lon gitudianal axis of the channel.

Normally, the outlet opening of the channel is covered by a movable obstruction member in the diverting channel, and the member is urged to move in one direction along the longitudianal axisof the channel by pres sure exerted on one end of the member from within the casing, but the member is resiliently biased with a biasing pressure from the other end and urged to move in the opposite direction along the longitudianal axis of the channel and cover the outlet opening when the biasing pressure on the member exceeds a pressure within the casing which is below the predetermined limit; and whereupon development of a casing pressure which exceeds the limit, the obstruction member is caused to move within the channel so that the outlet opening is uncovered.

It is therefore an object of this invention to provide a diverter system which avoids the aforesaid deficiencies associated with the prior art. M I" It is another object of this invention to providea process and means for preventing blow-out of art-oil well from underneath, around or through a surface casing, or the like, of the well.

It is yet another object of this invention to provide a process and means for preventing high pressure formations from breaking down the casing shoe of an oil well as would result in a blow-out around the outside of the casing.

These, together with the various ancillary objects and features of the present invention will become apparent as the following description proceeds. Preferred ernbodiments of my novel apparatus and process for preventing blow-outs will be described with reference to the accompanying drawings, by way of example only, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF THE INVENTION With reference to the drawings, wherein like reference numerals designate similar or identical parts throughout the various views, and in particular to FIG. 1, there is seen a diverter system, generally illustrated as 10, consisting of a surface casing 12 which has am ud return bell nipple 14 leading therefrom and a blow-out preventer 16 attached thereto. A mud diverter valve means, generally illustrated as 18 is connected with the casing 12 and essentially comprises a diverter valve 20 having a mud diverter conduit 22 and a wash conduit 24 attached thereto. The mud diverter valve means 18 additionally includes aconduit 26 leading from the valve 20 to an air accumulator (not shown in the drawings). A regulator 30 and an automatic dump valve 28 are located in conduit 26 between the air accumulator and the valve 20. The blow-out preventer 16 is located between the bell nipple l4 and the mud diverter valve means 18.

Referring in particular now to FIG. 2 and FIG. 3, there is seen the diverter valve 20 including a cylindri cal sleeve 38 and having a diverted-mud inlet end 32 which leads directly into the casing 12, a biasing end 34, and a diverted-mud outlet opening 36 in the side wall of the sleeve 38. A piston 40 is housed in the sleeve 38 and is slideable back and forth between the ends of the sleeve. The piston 40 has a mud contact end 42 and a biased end 44. The mud diverter conduit 22 leads from the sleeve 38 through the outlet opening 36 in proximity to the mud inlet end 32. The wash conduit 24 leads from the sleeve 38 opposite the mud outlet opening 36. A biasing means for resiliently biasing the piston 40 from the biasing end 34 thereof toward the mudinlet end 32 of the sleeve 38 is in communication with the biasing end 34 via a port 44 situated in a flange 52 attached to the biased end 34 of the sleeve 38. This biasing means may be any suitable biasing means such as a spring (not shown in the drawings), or a fluid. In a preferred embodiment the biasing means 46 is pneumatic.

Piston 40 additionally has a piston position indicator, generally illustrated as 46, secured thereto. The piston position indicator 46 comprises a rod member 48 attached to the biased end 44 of the piston 40 and a stop plate 58 secured to the end of the rod member 48 which extends outside of the sleeve into the atmosphere. The rod member 48 slideably extends through a sealing plate 50 which removably connects to the flange 52 by nuts 54 and bolts 56. The sealing plate 58 encloses the biasing end 34 of the sleeve 38 and engages the stop plate 58 to prevent the piston 40 from sliding too far toward the mud-inlet end 32 after the outlet opening 36 is covered by the piston 40.

Biasing end 44 of piston 40 includes a cap member threadably attached to piston 40. Rod member 48 threadably engages the cap member 60. A plurality of packing means 62 is attached to the circumference of the piston 40. A flange member 64 is integrally bound to the diverted-mud inlet end 32 of the sleeve 38. The casing 12 has a flange member 66 attached thereto at the point where the diverted-mud inlet 32 leads into the casing 12. Flange 64 and flange 66 interconnect via nuts 54 and bolts 56 to connect the diverter valve with the casing 12.

With continuing reference to the drawings for operation of the invention, surface casing 12 is set in a shallow, high pressure gas sand. A drill string (not shown in the drawings) is being turned inside of the surface casing 12, and drilling mud is circulating through bell nipple 14 to remove the drill cuttings. Pneumatic pressure within conduit 26 and behind the biased end 44 of the piston 40 within the cylindrical sleeve 38 is a little greater than the hydrostatic pressure than that which exist in the region between the bell nipple 14 and the diverter valve 20. When high pressure is encountered by the drill bit and the hydril blow-out preventer'l6 is closed in an attempt to prevent a blow-out. In order to prevent the well from blowing-out around the casing as the pressure continues to build-up and exceeds the hydrostatic head between the bell nipple l4 and the diverter valve 20, mud is diverted through the mud inlet 32 and against the mud contact end 42 of the piston 40 to cause the piston to slide towards the biasing end 34 of the sleeve 38. As the piston 40 moves away from the mud-inlet end 32, air becomes pressurized within the biasing end 34 and the pneumatic conduit 26, thus causing the automatic dump valve 28 to commence bleeding-off air. Over pressured drilling mud continues to drive the piston 40 toward the biasing end 34 to permud-inlet end 32. The piston 40 is driven by 'pressur- I ized air towards the mu dinlet end 32 until the stop plate 58 engages the sealing plate 50. In this position the piston 40 has closed-off outlet opening 36. Periodically,

-mud-inlet end 32 and conduit 22 may be washed by the introduction of wash fluid via wash line 24.

Whilethe present invention has been described herein with reference to particular embodiment thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosure, and it will be appreciated that in some instances some features ofthe invention will be employed without a corresponding use of other features without departing from the scope of the invention as set forth.

I claim:

1. Blow-outprevention apparatus for an oil well comprising:

A. a surface casing,

B. a mud return means leading from said casing,

C. a blow-out preventer means attached tosaid casing,

D. a mud diverter valve means connected with said casing said valve means comprising:

a. a cylindrical sleeve having a diverted-mud inlet end which leads into said casing, a biasing end, and a diverted-mud outlet opening in the side wall of the sleeve b. a piston housed in said sleeve which is slideable back and forth between said ends of the sleeve, said piston having a mud contact end and a biased end v c. a mud diverter conduit leading from said sleeve through said outlet opening, and

d. biasing means for resiliently biasing said piston from the biasing end thereof toward said mudinlet end of the sleeve until said outlet opening thereof i's'covered' by 'said piston.

2. Apparatus as in claim 1 wherein said biasing means includes a fluidpressure supply means leading into said biasing end of the sleeve and further including means for regulating the pressure at which fluid is supplied to the biasing end.

3. Apparatus as'in claim 2 wherein said blow-out preventer means is positioned between said mud return means and said diverter valve means.

4. Apparatus as in claim 3 wherein the mud inlet end of said sleeve leads directly into said casing and the mud diverter conduit leads into said sleeve in the proximity of the mud inlet end thereof.

5. Apparatus as in claim 4 wherein said means for resiliently biasing comprises pneumatic means including a conduit for a pneumatic fluid which leads into said biasing end of said sleeve, a pneumatic regulator in said conduit, and a dump valve in communication with said pneumatic conduit.

6. Apparatus as in claim '5 and additionally including a plurality of packing means attached to thecircumference of said piston." Y

7. Apparatus as in claim and additionally including a piston position indicator secured to said piston.

8. Apparatus as in claim 7 wherein said piston position indicator comprises a rod member attached to said biased end of said piston, said rod member slideably extending through said biasing end of said sleeve into the outside atmosphere.

9. Apparatus as in claim 8 additionally including a wash conduit leading into said sleeve opposite said mud outlet opening therein.

10. Apparatus as in claim 9 wherein said rod member of the position indicator additionally includes a stop plate attached thereto on the outside of said sleeve, said stop plate engaging the outside of said biasing end of said sleeve to stop said piston from sliding further within said mud-inlet end after said outlet opening is covered by said piston.

11. Apparatus as in claim 10 wherein said dump valve is an automatic dump valve which upon closure of the blow-out preventer means dumps pneumatic fluid and thus reduces pressure at the biasing end of said sleeve, enabling said piston to slide toward said biasing end to open said diverted-mud outlet.

12. Apparatus as in claim 11 wherein said divertedmud inlet end of said sleeve includes a flange member, said casing has a flange member attached thereto at the point where said diverted-mud inlet leads into said casing, and said connection of said mud diverter valve means with said casing is effected by the mating and connecting of said flange member of said mud-inlet end and said flange member of said casing.

13. Apparatus as in claim 12 wherein said biasing end of said sleeve includes a flange member attached to the circumference thereof, a sealing plate removably connected to said biasing end flange member for enclosing the biasing end of said sleeve, said sealing plate having a structure defining an aperture wherethrough said rod member slides, and said stop plate engages the outside of said sealing plate to stop excess sliding travel of the piston within the mud-inlet end.

14. In a process for preventing blow-out of an oil well from underneath, around or through a surface casing of the well, the improved method of diverting mud flow from the casing which comprises:

a. passing diverted mud from said casing axially into an elongated mud diverting channel which leads from the casing, said mud being diverted from the casing when the pressure therein exceeds a predetermined limit,

b. subsequently discharging said diverted mud from said channel through an outlet opening therein, the mud flow from said opening being in a direction which is substantially transverse with respect to the longitudinal axis of the channel,

c. said outlet opening being coverable by a movable obstruction member in said diverting channel, said member being urged to move in one direction along the longitudinal axis of said channel by pressure exerted on one end of said member from within said casing, but which is resiliently biased with a biasing pressure from the other end and urged to move in the opposite direction along the longitudinal axis of said channel and hence cover said outlet opening when the biasing pressure on said member exceeds a pressure within said casing which is below said predetermined limit, and whereupon development of a casing pressure which exceeds said limit, said obstruction member is moved within said channel and said outlet opening is uncovered.

15. A method as in claim 14 wherein the biasing pressure applied to the other end of the obstruction member is a fluid pressure.

16. A method as in claim 15 wherein the biasing pressure is a pneumatic pressure.

17. A method as in claim 16 wherein said diverting channel is washed to remove residual mud following the diversion of mud through said channel and prior to recovering said outlet opening with said obstruction member.

Claims

1. Blow-out prevention apparatus for an oil well comprising: A. a surface casing, B. a mud return means leading from said casing, C. a blow-out preventer means attached to said casing, D. a mud diverter valve means connected with said casing, said valve means comprising: a. a cylindrical sleeve having a diverted-mud inlet end which leads into said casing, a biasing end, and a diverted-mud outlet opening in the side wall of the sleeve b. a piston housed in said sleeve which is slideable back and forth between said ends of the sleeve, said piston having a mud contact end and a biased end c. a mud diverter conduit leading from said sleeve through said outlet opening, and d. biasing means for resiliently biasing said piston from the biasing end thereof toward said mud-inlet end of the sleeve until said outlet opening thereof is covered by said piston.

2. Apparatus as in claim 1 wherein said biasing means includes a fluid pressure supply means leading into said biasing end of the sleeve and further including means for regulating the pressure at which fluid is supplied to the biasing end.

3. Apparatus as in claim 2 wherein said blow-out preventer means is positioned between said mud return means and said diverter valve means.

6. Apparatus as in claim 5 and additionally including a plurality of packing means attached to the circumference of said piston.

7. Apparatus as in claim 6 and additionally including a piston position indicator secured to said piston.

12. Apparatus as in claim 11 wherein said diverted-mud inlet end of said sleeve includes a flange member, said casing has a flange member attached thereto at the point where said diverted-mud inlet leads into said casing, and said connection of said mud diverter valve means with said casing is effected by the mating and connecting of said flange member of said mud-inlet end and said flange member of said casing.

14. In a process for preventing blow-out of an oil well from underneath, around or through a surface casing of the well, the improved method of diverting mud flow from the casing which comprises: a. passing diverted mud from said casing axially into an elongated mud diverting channel which leads from the casing, said mud being diverted from the casing when the pressure therein exceeds a predetermined limit, b. subsequently discharging said diverted mud from said channel through an outlet opening therein, the mud flow from said opening being in a direction which is substantially transverse with respect to the longitudinal axis of the channel, c. said outlet opening being coverable by a movable obstruction member in said diverting channel, said member being urged to move in one direction along the longitudinal axis of said channel by pressure exerted on one end of said member from within said casing, but which is resiliently biased with a biasing pressure from the other end and urged to move in the opposite direction along the longitudinal axis of said channel and hence cover said outlet opening when the biasing pressure on said member exceeds a pressure within said casing which is below said predetermined limit, and whereupon development of a casing pressure which exceeds said limit, said obstruction member is moved within said channel and said outlet opening is uncovered.