US2945676A

US2945676A - Hydraulic weight control and compen-sating apparatus for subsurface well bore devices

Info

Publication number: US2945676A
Application number: US621158A
Authority: US
Inventors: Jr Archer W Kammerer
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-11-08
Filing date: 1956-11-08
Publication date: 1960-07-19
Anticipated expiration: 1977-07-19

Description

y 1960 A. w. KAMMERER, JR 2,945,676

HYDRAULIC WEIGHT CONTROL AND COMPENSATING APPARATUS FOR SUBSURF'ACE WELL BORE DEVICES Filed Nov. 8, 1956 ORIFICE Ezsze va/e 1.

INVENTOR. flea/ale 7V. MA /[1e52, Jie.

Kathi-iii Patented July 19, 1960 HYDRAULIC WEIGHT CQNTROL AND COMPEN- SATING APPARATUS FOR SUBSURFACE WELL BORE DEVICES Archer W. Kammerer, Jr., Fullerton, Califl, assignor of three-fifths to Archer W. Kammerer and one-fifth to Jean K. Lamphere, both of Fullerton, Calif.

Filed Nov. 8, 1956, Ser. No. 621,158

4 Claims. (Cl. 255-19) The present invention relates to apparatus particularly useful in the drilling, completion and production of wells.

An object of the present invention is to provide improved apparatus capable of maintaining a substantially uniform or constant tension in a running-in string, such as drill pipe, drill casing or tubing, disposed in a well bore and usually operatively connected to a device in the well bore, such as a drill bit or milling tool.

Another object of the invention is to provide an apparatus capable of maintaining a substantially constant weight on a drill bit, milling cutter, and the like, disposed in a well bore.

A further object of the invention is to provide an apparatus for maintaining a substantially constant weight on a drill bit, milling cutter, and the like, despite vertical movement of the dnilling equipment at the top of the well bore, such as occurs when the drilling equipment is mounted on a floating barge.

An additional object of the invention is to provide an apparatus for maintaining a substantially constant tension in a running-in string disposed in a well bore, in which the tension can be readily changed, whenever desired, in

a simple manner.

Yet another object of the invention is to provide apparatus for maintaining a substantially constant tension in a runningin string disposed in a well bore, the apparatus being located above the top of the well bore, thereby avoiding design limitations which would be imposed in the event it were necessary to locate the apparatus in the well bore, which is usually of relatively small diameter.

Still a further object of the invention is to provide a hydraulically operated apparatus for maintaining a substantially constant tension in a runningdn string disposed in a well bore, the tension being readily changed by the expedient of altering the hydraulic, pressure in the apparatus.

Another object of the invention is to provide an apparatus for maintaining a substantially constant weight on a drill bit, milling cutter, and the like, which also indicates the extent of footage drilled or milled away by the bit or cutter.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification.

It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to 'be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings: Figure l is a diagrammatic view of one application of the invention;

Fig. 2 is a diagrammatic view of the weight control and compensating apparatus forming part of the equipment illustrated in Fig. l.

The weight controland compensating apparatus A is disclosed in the drawings as being applied to the drilling of a well bore B. It is located between the traveling block 'C of a drilling rig, which may be mounted on land or on a floating barge D appropriately anchored in place. The traveling block is associated with the usual lines E passing over the crown block F at the upper end of the derrick G secured in place on the floating barge shown. The lower portion of the weight control apparatus .A may be secured to a swivel H, of any desired type, which is, in turn, connected to a string of drill pipe I, the upper portion of which is usually a Kelly or grief stern slidably splined to the rotary table L of the apparatus for rotating the drill stem, in order to rotate the drill bit M connected to the lower end of the latter. As is usual in the rotary drilling of well bores, suitable drilling fluid is pumped down the string of drill pipe I and will exit from the drill bit M, carrying the cuttings upwardly out of the hole B.

in lieu of drill pipe, other drill stnings I may be used, such as drill casing or even tubing. Moreover, in lieu of a rotary drill bit M for drilling'the hole, the drill string may be connected to a milling tool, or the like, which is used for milling away metallic and other devices in the well bore, casing sections, etc.

The weight control and compensating apparatus A is shown diagrammatically in Fig. 2. it includes a cylinder 10 of the required length and cross-sectional area having an upper cylinder head 11 and a lower cylinder head 12. The lower cylinder head is provided with a suitable connection 13, such as an eye, by virtue of which it is attached to the upper portion of the rotary swivel H. A piston 14 is reciprocably mounted in the cylinder 10, the piston being secured to a piston rod 15 extending upwardly through the upper cylinder head 11, this rod having a suitable eye or bail 16 at its upper end to receive the hook 17 of the traveling block C. For the purpose of preventing leakage from the cylinder, a rod packing 18 is provided in the upper cylinder head 11 to slidably and sealingly engage the piston rod 15. Leakage around the piston 14 is prevented by a suitable packing or seal ring device 19 mounted in a piston groove 2% and sealingly engaging the wall of the cylinder 10.

The cylinder is filled with a suitable liquid, such as oil, completely between the piston 14 and the upper cylinder head 11. The liquid is derived from a suitable reservoir 21 that is connected to a motor driven pump 2'2, preferably of a high pressure centrifugal type, the liquid discharging from the pump through an inlet line 2 3 opening into the upper portion 24 of the cylinder 10. An outlet line 25 is also connected to the upper portion of the cylinder, this outlet line returning the liquid to the reservoir 21. The outlet line includes a choke orifice 26 to enable a back pressure to be built up in the inlet line 23 and cylinder 24 above the piston 14, so that liquid under a desired pressure is contained in the cylinder space 24 to enable the cylinder lit to be supported by the piston 14 through the liquid medium. 7

The weight control and compensating apparatus A is a telescopic joint for supporting a portion of the weight of the running-in string or drill string 1. Thus, the drill string is suspended from the swivel H, the swivel, in turn, being carried by the cylinder 16', the load being transferred from the cylinder head 11 through the liquid medium in the cylinder space 24 to the piston 14 and the piston rod 15, and from the latter to the traveling block C and the usual lines E connected in a known manner to the drawworks (not shown). The pressure of the liquid in the cylinder space 24 will determine the lifting force on its cylinder head 11 and on the drill string I depending from and connected to the cylinder. The greater the pressure, the greater will be the lifting force; whereas, contrariwise, the lesser the pressure, the less will be the lifting force. Thus, by controlling the liquid pressure in the cylinder space 24, the net weight of the string of drill pipe J imposed on the dnill bit M to force it against the bottom of the well bore B can be regulated, and this netweight, is maintained constant provided the pressure of the liquid in the cylinder space 24- is maintained constant.

By way of example, if the internal diameter of the cylinder is made about one foot, its cross-sectional area above the piston will be about one hundred square inches, neglecting the area of the piston rod. If it is assumed that the drill string J has a total weight when in the well bore of about 90,000 lbs., and if the drilling weight on the drill bit M is to be 10,000 lbs., then a pressure of about 800 p.s.i. in the liquid in the. cylinder space 24 will result in a supporting force on the drill string J in an upward direction of 80,000 lbs., leaving a net of 10,000 lbs. imposed on the drill bit. If this pressure is maintained in the cylinder space, the drilling weight on the drill bit M will remain at the constant value of 10,000 lbs., provided, of course, that the cylinder connected to the drill string I does not lower sufiiciently as drilling proceeds to bring the upper cylinder head 11 into contact with the piston 14. Before this occurs, the drawworks will be suitably manipulated so as to lower the piston 14 within the cylinder 10 to the proper extent. By way of example, the cylinder may be five to ten feet in length, allowing approximately that much relative downward movement of the cylinder 10' in the drill string with respect to the piston 14 without any necessity for operating the dravwvorks and the lines E and traveling block C connected thereto. So long as the pressure in the cylinder space 24 is maintained at the required value, a constant drilling weight will be imposed on the bit M. Moreover, as the cylinder 10 moves downwardly along :the rod 15, an indication of the footage being drilled is imparted to the operator at the top of the well bore by observation of the relative position of'the cylinder along the rod.

The centrifugal pump 22 is operating constantly to force fiuid into the cylinder 10, a back pressure being built up in the cylinder by virtue of the throttling action of the choke orifice 26, which, however, allows liquid pumped into the cylinder space 24 to return through the exhaust line 25 to the reservoir 21. The pressure in the cylinder can be ascertained by means of a suitable pressure gauge 30 that may be connected anywhere in the inlet line 23. By varying the speed of the pump 22, the pressure can be changed to the desired value. Another way of altering the pressure is to provide a variable choke orifice 26. In any event, the pressure can be maintained at the desired value in the cylinder space 24 for the purpose of hydraulically supporting the desired portion of the 'weightof the drill string J, leaving the balance of the weight available for imposition on the drill bit M to penetrate its cutters into the bottom of the well bore B.

The apparatus A will maintain a constant drilling weight when used under conditions in which the derrick G may partake of some vertical movement, as is associated with the mounting of the derrick on a floating barge D that may be anchored against lateral displacement, but which will still partake of up and down movement under the action of ocean waves, and the like. A direct con nection between the traveling block C and the swivel H would cause alternate raising and lowering of the entire drill string J, varying the drilling weight of the bit M against the bottom of the well bore, either reducing the drilling weight considerably or imposing too heavy a drilling Weight thereon. In fact, that drill bit could be lifted completely off the bottom of the hole as the barge D rises, and an excess of drilling weight might be imposed on the drill bit as the barge descends.

The apparatus disclosed. permits lowering and elevation. of therbarge D-without correspondingly lowering and elevating the drill string J, since the apparatus A embodies a telescopic joint in the form of the piston 14 and piston rod 15, on the one hand, and the cylinder 10, on the other hand. Thus, as the barge D and derrick G move upwardly, the piston 14 will be moved upwardly therewith with respect to the cylinder 10; whereas, downward movement of the barge D. and derrick G results in a downward movement of the piston 14 withrespect to the: cylinder :10. Despite such upward and. downward movements, the cylinder 10 does not move vertically to any significant extent, and the pressure in the cylinder space 24' can still be maintained substantially constant, so that aconstant elevating force by the liquid in the cylinder is maintained thereon, to insure the same net downward drilling weight of. the rotary drill bit M against the bottom of the hole.

Assuming that the barge D rises, to shift the piston rod 15 and piston 14 in an upward direction within the cylinder 10, the liquid pressure in the cylinder space 24 would tend to increase, but the excess pressure is promptly and rapidly dissipated by being forced through the choke orifice 26, returning to the reservoir 21. On the other hand, should the barge D descend, the piston rod 15 and the piston 14 connected thereto would also lower in the cylinder 10. However, the centrifugal pump 22 is operating at a sufiicient volumetric rate as to supply the required added volume of liquid to the cylinder space 24 promptly and rapidly. Under these conditions, a lesser amount of liquid will pass through the choke orifice 26', the pressure in the cylinder, at best, only dropping momentarily and then ,being built up to the required value. Thus, the upward and downward movements of the barge D under wave action are not transmitted to the drill string J, the piston 14 merely constantly telescoping within the cylinder, with the cylinder liquid thereabove being maintained at a substantially constant pressure, to retain the desired upward supporting force on the drill string J, which results in the appropriate down weight on the rotary drill bit M against the 'bottom of the hole B being produced.

As disclosed in Fig. l of the drawings, the well bore B is being drilled in the bottom or floor of the ocean N under such conditions that it may be desired to use drill casing instead of a drill pipe to rotate the rotary drill bit M. When the hole is completed, the casing need not be pulled from the well bore B, but can be cemented in place. Regardless of the use of drill pipe, drill casing, or any other string of tubing, the compensating device A will still function to insure a substantially constant applic-ation of drilling weight on the bit, As drilling pro,- gress proceeds, the gradual lowering of the cylinder head 11 along the piston rod 15 will indicate to the operator at the top of the hole the extent of footage that is being made.

If desired, the cylinder space 31 on the low pressure side of the piston 14 may be sealed off, containing air at atmospheric pressure that would be compressed sl ghtly during downward movement of the piston 14 in the cyhnder. However, to insure that any liquid in the cylinder above the piston 14 which might leak by the piston will not fill the cylinder space 31, a suitable drain hole 32 may be provided in the lower cylinder head 12 through which the leakage can be dissipated.

Although the invention has been described particularly with respect to the drilling of a well bore B, or the mill ng of equipment in the well bore, it can. be used for maintaining a constant desirable drilling weight on any type of running-in string, such as a tubular string that is to be maintained in tension in a well bore. It is merely necessary to provide the proper desired liquid pressure in the cylinder 10 and maintain such pressure constant to insure the maintenance of a constant tension in the tubular string J. In. order to supply therequired tension throughout the entire length of the tubing string, the pressure, in the cylinder space 24 would be sutficient to more, than overcome the dead weight of the tubular string.

The inventor claims:

1. In an apparatus for maintaining a predetermined stress in a running-in string disposed in a well bore which is supported by a rig including a suspension mechanism: elongate cylinder means; piston means slidable in said cylinder means; one of said means having a device thereon for operative connection to the running-in string; the other of said means having a device thereon for operative connection to the suspension mechanism, whereby said cylinder means and piston means are disposed between the suspension mechanism and running-in string; means for constantly feeding fiuid under pressure to said cylinder means, whereby the stress of the running-in string and of said one means is transmitted through the fluid to said other means and suspension mechanism; and means for constantly conducting such fluid from said cylinder means, said conducting means including flow restricting instrumentalities for creating a back pressure in the fluid in said cylinder means.

2. In an apparatus for maintaining a predetermined stress in a running-in string disposed in a well bore which is supported by a rig including a suspension mechanism: elongate cylinder means; piston means slidable in said cylinder means; one of said means having a device thereon for operative connection to the running-in string; the other of said means having a device thereon for operative connection to the suspension mechanism, whereby said cylinder means and piston means are disposed between the suspension mechanism and running-in string; means for constantly feeding fluid under pressure to said cylinder means, whereby the stress of the running-in string and of said one means is transmitted through the fluid to said other means and suspension mechanism; and means for constantly conducting such fluid from said cylinder means,

said conducting means including a flow restricting orifice for creating a back pressure in the fluid in said cylinder means.

3. In an apparatus for maintaining a predetermined stress in a running-in string disposed in a well bore which is supported by a rig including a suspension mechanism: elongate cylinder means; piston means slidable in said cylinder means; one of said means having a device thereon for operative connection to the running-in string; the other of said means having a device thereon for operative connection to the suspension mechanism, whereby said cylinder means and piston means are disposed between the suspension mechanism and running-in string; a source of fluid; a pump connected to said source and cylinder means for constantly forcing fluid under pressure into said cylinder means; whereby the stress of the running-in string and said one means is transmitted through the fluid to said other means and suspension mechanism; and means for constantly conducting such fluid from said cylinder means to said source, including flow restricting instrumentalities for creating a back pressure in the fluid in said cylinder means.

4. In an apparatus for maintaining a predetermined stress in a running-in string disposed in a well bore which is supported by a rig including a suspension mechanism: elongate cylinder means; piston means slidable in said cylinder means; one of said means having a device thereon for operative connection to the running-in string; the other of said means having a device thereon for operative connection to the suspension mechanism, whereby said cylinder means and piston means are disposed between the suspension mechanism ad running-in string; a source of fluid; a pump connected to said source and cylinder means for constantly forcing fluid under pressure into said cylinder means, whereby the stress of the running-in string and said one means is transmitted through the fluid to said other means and suspension mechanism; and means for constantly conducting such fluid from said cylinder means to said source, including a flow restricting orifice for creating a back pressure in the fluid in said cylinder means.

References Cited in the file of this patent UNITED STATES PATENTS 839,656 Sharp Dec. 25, 1906 1,311,108 Beckwith July 22, 1919 1,938,690 Burmist Dec. 12, 1933 2,109,297 McMurry et al Feb. 22, 1938 2,225,515 Wood Dec. 17, 1940 2,259,019 Carr et al Oct. 14, 1941 2,353,293 Brooking July 11, 1944 2,497,083 Hildebrand Feb. 14, 1950 2,712,932 Gould July 12, 1955 2,772,085 Dodge Nov. 27, 1956 FOREIGN PATENTS 77,087 Netherlands Jan. 15, 1955