US2194254A

US2194254A - Pressure equalizer for blowout preventers

Info

Publication number: US2194254A
Application number: US332280A
Authority: US
Inventors: Walter E King; James S Abercrombie
Original assignee: ABERCROMBIE
Current assignee: ABERCROMBIE
Priority date: 1929-01-14
Filing date: 1929-01-14
Publication date: 1940-03-19
Anticipated expiration: 1957-03-19

Description

which 19, 1940. w. E. KING El AL 2,194,254

PRESSURE EQUALIZER FOR BLOWOUT PREVENTERS Filed Jan. 14, 1929 6 W INVENTORS BY F34;

ATTORNEYS.

Patented Mar. 19.1940

' UNITED ,STATES PATENT OFFICE Walter E. King and James S. Abercrombie, Houston, Tex; said King assignor' to said Abcrcrombie Application January 14,1929, Serial No. 382,280

9 Claims.

Our invention relates to blowout preventers to be employed on well casings in deep well operations where gas under pressure is encountered, to prevent the danger of blowing out of the well and injury to the equipment.

Wherever gas pressure is encountered in .well drilling precautions must be taken when the well is being drilled in to prevent the gas from escaping upwardly from the well and increasing in force until the contents of the well are blown out and damage is caused to the drilling rig. The gas pressure may be some times kept from escaping by the force of the heavy mud pumped intothe well during the drilling operation but precautions must be taken even when the pumps are operating and blow out preventers of different kinds have been devised for closing the space about the drill stem and the casing to prevent the gas and liquid from escaping.

m It is diflicult to close the valves or rams which engage about the drill stem or tubing in well operations when the well has started blowing.

The pressure of the gas in the well against the valve members is so great that high pressure is a necessary to close the valves.

It is an object of the invention to provide means to equalize the gas or fluid pressure on opposite sides of the valves so that they may be closed readily when necessity arises. We contemplate so constructing the blowout preventer that the well pressures may be exerted equally on opposite sides of the valves or rams so that an operator may then very readily close the same with ease and dispatch.

It is an object to provide means whereby the blowout preventer may be closed into pipe-engaging position even under heavy gas pressures in the well.

In the drawing herewith a preferred embodio ment of the invention is disclosed.

Fig. 1 is a central vertical section through the apparatus equipped with our invention showing the valves in open position.

Fig. 2 is a similar view but showing the valves 5 in closed position.

The present invention is shown as applied to the type of blowout preventer disclosed in the prior application for patent of James S. Abercrombie, Serial No. 28,415, filed May '7, 1928. It

60 is possible, of course, to apply the invention to other similar types of apparatus.

The device is intended for attachment at the upper end of the casing and a flange or coupling member I is shown at the lower side of the appasa ratus threaded at 2 for engagement with the casing or an extension thereof. This flange is adapted to be secured to the lower flange 3 of the blowout preventer body I. The two are adapted to be secured together by means of bolts 5.

The said body 4 has a central passage 8 there- I through to accommodate the drill stem 1'. This passage has valve members I on each side thereof arranged to close about the drill stem and seal off the passage 8 between the drill stem and the body of the preventer. These valves 1 are cylinl0 drical in shape and adapted to be moved in cylinders 8 extending radially away from the passage 6. The said valves or rams may have the. forward end formed with cylindrical recesses to engage the drill stem 1. Packing strips 9 on said 15 pistons serve to preserve a tight seal so that the pressure fluid may not escape around the valves.

These valves are shown as being adapted to operate by fluid pressure. A piston rod Ill is' connected with each valve, said rod extending go through stufl'lng boxes II and I2 and having a piston l3 at the outer end thereof. The said piston l3 works in a cylinder l4 secured in fluid tight relation with a coupling member l5 through which the piston rod extends. 25

The cylinders H are closed on their outer ends except for an inlet port l6 for steam or other fluid under pressure. Said ports are connected with the pipe I! for pressure fluid.

On the inner ends of the cylinders M are passo sages l8 leading into the body of the connecting member [5 and forming ports for the entrance of pressure fluid on the inner side of the piston. These ports connect with the pipe l9 also leading to the source of fluid under pressure, not shown. 35 It will thus be seen that pressure fluid may be introduced on either side of each of the pistons l3 so that the same may be moved to and from the pipe in the operation of the valve members H. The further operation of these valves will be obvious without further description. The difflculty encountered with this type of tool is that the gas or other fluid under pressure from the well sometimes blows up through the passage 6 with such force that the piston valves 1 can not be advanced readily to close. the passage. We contemplate overcoming this difliculty by forming a bypass from the passage 5 below the valve around to a point behind the same, in this way equalizing the pressure on both ends of the valves. This is accomplished by means of a pipe 20 connecting with a port II in the wall of the body 4 and leading to a port 23 in the member I 5 on the rearward side of the valve so that the pressure may enter the cylinder 8 on the rearward'side thereof. A 56 valve 24 in the conducting line enables the operator to open or close this passage asdeslred. In ordinary practice this valve will be closed during the usual drilling operations to prevent the passage of mud or water into the cylinder 8 behind the piston. When danger of blowout occurs, however, this valve will be opened so that pressure of gas from the well may be exerted through said pipe to the outer end of the cylinder I behind the valve' so that the pressure thereon may be equalized on both ends.

When this device is operated the valves 1 will be in the position shown in Fig. 1, the valve 24 being closed. When formations are encountered in the drilling of the well in which gas is present in appreciable quantities it will be possible to open the valve 24 and proceed with the drilling. If the accumulation of gas increases so that a blowout is started, the valve 24 being open will allow the pressure of the gas in the well to be equalized on both sides of the valve 1. The operator will then turn on the steam through the pipes I! so that it may enter the ports I 6 on the outer ends of the pistons l3 and thereby force the valves into closed position quickly and with little difliculty.

It will be obvious that with the gas thus equalized in the body of the preventer that the valves may be closed by other means than steam pressure and with little diillculty on the part of the operator. We do not, therefore, wish to be confined to this particular embodiment of the invention.

It has been found that by the use of this attachment that much higher pressures may be contended with and larger and stronger types of valves may be employed and operated than is possible without the use of this expedient. Wells may be safely brought in which otherwise it would be exceedingly diillcult or impossible to handle.

Having thus described our invention, what we claim as new is:

1. In a blowout preventer, a tubular body having a longitudinal passage therethrough for a pipe, valves movable radially relative to said passage to close the same about said pipe, means to conduct fluid from said casing to points behind said valves to equalize the fluid pressure at-both ends of said valves and additional fluid operated means to move said valves, said last named means being independent of said equalizing means.

' 2. A blowout preventer including in combination a housing, a passage through said housing, rams movable transversely of said passage, means to move said rams including pressure-operated pistons. and additional means to co-operate with said first means in moving said rams whereby the fluid pressure in said passage may be admitted behind said rams.

3. A control head for well casings comprising a body portion having a central bore substantially aligned with the bore of the well casing and a chamber independent of and extending laterally from said central bore, a closure element in said independent chamber adapted normally to be moved into contact with a string of pipe located in said central bore by means independent of pressure existing in the well,.means to seal about said element and chamber, and means for con ducting pressure fluid from the well into the independent chamber at the rear end of said sealing element to equalize the pressure therein with the pressure existing in th central bore at the front end of said sealing element.

4. A control head for well casings comprising a body portion having a central bore substantially aligned with the bore of the well casing and a chamber independent of and extending laterally from said central bore, a sealing element in said independent chamber adapted normally to be moved into contact with a string of pipe located in said central bore by means independent of pressure existingin the well, means on said element to seal against said chamber, and a by-pass ali'ording passage for gas contained in the well casing from below the said sealing element to the outer end of the independent chamber in which the sealing element is located.

5. A control head for. well casings comprising a body portion having a central bore substantially aligned with the bore of the well casing and a plurality of chambers independent of and extending radially from said central bore, sealing ele ments located respectively in said independent chambers adapted normally to be moved into contact with a string of tubing located in said central bore by means independent of pressure existing in the well, and a by-pass extending from below said sealing elements to the outer end of each of the independent chambers in which the sealing elements are respectively located, to permit the flow of gas contained within the well casing to the outer ends of the respective sealing elements.

6. A control head for well casings comprising a body portion having a central bore substantially aligned with the bore of the well casing and a plurality of chambers independent of and extending radially from said central bore, sealing elements located respectively in said independent chambers in opposed relation to each other adapted normally to be moved into contact with each other and with a string of tubing located in said central bore by means independent of pressure existing in the well, and a by-pass extending from below said sealing elements to the outer end of each of the independent chambers in which the sealing elements are respectively located, to permit the flow of gas contained within the well casing to the outer ends of the respective sealing elements.

7. A control head for well casings comprising a body portion having a central bore substantially aligned with the bore of the well casing and a plurality of chambers independent of and extending radially from said central bore, sealing elements located respectively in said independent chambers in opposed relation to each other adapted normally to be moved into contact with each other and with a string of tubing located in said central bore by means independent of pressure existing in the well, a by-pass extending from below said sealing elements to the outer end of each of the independent chambers in which the sealing elements are respectively located, to permit the flow of gas contained within the well casing to the outer ends of the respective sealing elements, and means for controlling the fiow of gas through said by-passes.

8. A control head for well casings comprising a body portion having a central bore substantially aligned with the bore of the well casing and a plurality of chambers independent of and extending radially from said central bore, a closure head at the outer end of each independent chamber, sealing elements located respectively in said independent chambers in opposed relation to each other adapted normally to be moved into contact with each other and with a string of tubing located in said central bore by means independent of pressure existing in the well, and a by-pass extending from below said sealing elements to the outer end of each of the independent chambers in which the sealing elements are respectively located, to permit the flow of gas contained within the well casing to the outer ends of the respective sealing elements, said by-pass comprising a string 01 pipe tapped at its opposite ends into said body portion and the outer end of the chamber respectively.

9. A control head for well casings comprising a body portion having a central bore substantially aligned with the bore of the well casing and a plurality of chambers independent of and extending radially from said central bore, a closure head at the outer end of each independent chamber, sealing elements located respectively in said independent chambers in opposed relation to each other adapted normally to be moved into contact with each other and with I a string of tubing located in said central bore by means independent of pressure existing in the well, a by-pass extending from below said sealing elements to the outer end of each of the independent chambers in which the sealing elements are respectively located, to permit the flow of gas contained within the well casing to the outer ends of the respective sealing elements, said by-pass comprising a string of pipe tapped at its opposite ends into said body portion and the outer end of the independent chamber respectively, and a control valve in said by-pass between said body portion and said independent chamber.

WALTER E. KING.

JAMES B. ABERCROMBIE.