US3086746A - Kelly valve dynamically balanced in open position - Google Patents

Description

April 23, 1963 W. K. HOLLERON KELLY VALVE DYNAMICALLY BALANCED IN OPEN POSITION Filed March 25. 1960 2 Sheets-Sheet 1 W////am //a//e/'o/7 INVENTOR.

BY ,S M,

ATTORNE'VI April 3, 1963 w. K. HOLLERON 3,086,746

KELLY VALVE DYNAMICALLY BALANCED IN OPEN POSITION Filed March 23. 1960 2 Sheets-Sheet 2 Wz/flom /f. //0 //@/0/7 INVENTOR.

ATTORNEY) United States Patent 3,086,746 KELLY VALVE DYNAMICALLY BALANCED El ()PEN lGSiTlON William K. Holler-on, Houston, Tex., assignor to U. S. Industries, Inc., a corporatien of Delaware Filed 23, 1960, Ser. No. 17,126 1 Claim. (Cl. 251-83) This invention is an improved ball check valve for handling abrasive liquids. It is particularly useful as a kelly valve for controlling wells which are subject to trouble from blowout and back pressure through the drill pipe in rotary drilling of deep oil and gas wells.

It is customary to carry out deep rotary drilling of oil and gas wells with a drill string extending into the well through a blowout preventer. When unexpected high pressure is encountered, which often may be high enough to blow the drilling mud out of the well, the blowout preventer is closed upon the drill string thus sealing the annular space between the drill stern and wall of the well and preventing drilling mud from being blown upward from this space.

While a blowout preventer prevents upward flow of mud in the well bore outside the drill stern, there is still communication of high bottom hole pressure with the interior of the drill string through openings at the bit. Unexpected high pressure may force inud up through the drill stem against the pressure normally exerted by mud pumps.

A suitable check valve to prevent upward flow of mud through the drill string is a very desirable element of rotary drilling equipment. Check valves have been used, and are frequently installed in the standpipe. At this location a check valve is effective against high back pressure, provided that the check valve has not been so eroded by abrasion of hard, sharp particles carried by the mud so that it is inoperative when needed, and provided further that the mud hose, normally connecting the upper end of the standpi e with the mud swivel, does not burst. A mud hose bursting from high back pressure easily may result in a well getting out of control and perhaps becoming ignited with ensuing great damage to property and danger to the crew.

The upper end of the kelly would be a better location for a check valve, since back pressure would be checked between its source and the mud hose, but this location is subject to certain disadvantages. A kelly frequently rotates at some three or four hundred revolutions per minute and it is ditlicult to arrange a check valve so that it does not badly unbalance the upper end of the kelly and cause undue vibration of the rotary table. Location of the check valve on the vertical axis of rotation of the kelly places it in position, subject to maximum erosion from grit laden mud flowing at high velocity.

Two general types of kelly valves have been used for controlling fluctuating back pressures in the past. The first type of kelly valve is an ordinary plug valve having a flowway communicating with the kelly and mud swivel which is closed by manual revolution of the plug. A valve of this type is disadvantageous when used with wells subject to sudden fluctuations of back pressure because it is not automatic and is necessarily slow and belated in operation.

The second type of valve which has been used in combination with kelly joints, is a flapper-type check valve having a flapper hung in the mud flowway. A valve of this type overcomes the disadvantage of manual operation but is frequently ineffective at the time its use becomes critical, because of wear and abrasion to which it has been subjected.

Drilling fluids, Whether of oil, aqueous or emulsion 3,fl86,746 Patented Apr. 23, 1963 types, contain a great deal of abrasive material. This abrasive material is derived from the clays from which the muds are originally compounded, and from the strata of rock through which the drill string penetrates. Since large volumes of mud heavily loaded with abrasive particles circulate rapidly through the kelly and drill string during drilling operations, a conventional check valve installed in the mud flowway is rapidly worn away, and then when the checking operation is urgently required, the valve is ineffective.

It is an object of this invention to provide an automatic check valve especially useful for controlling blowout or back .pressure through drill pipe caused by sudden back pressures encountered in rotary drilling operatrons.

Another object is to provide a check valve for controlling drilling fluid which will still be in good condition and operative when high pressure zones are encountered after a drill string has penetrated thousands of feet of low pressure strata.

Another object is to provide a check valve for grit laden fluid wherein a back pressure operable valve closure member may be moved into or out of efiective position in a flowway through the valve at will.

Another object is to provide a valve of the class described which may be approximately dynamically balanced during a large part of the drilling operation.

Still another object is to provide a valve of the class described in which the valve closure member and a seat cooperable therewith are easily formed from abrasion resistant materials.

In the attached drawings, FIG. 1 is a vertical section through one preferred type of valve constructed according to the principles of my invention. FIG. 2 is a verti cal section of the valve of FIG. 1 taken at a right angle to the section of FIG. 1.

In both FIG. 1 and FIG. 2, the reference numeral 5 indicates a principal valve body member which is, together with a later described cover member, substantially globular in shape, and has an upper projecting part substantially centered on the vertical axis of the body which preferably comprises an API standard tool joint box 6 threaded on its interior at 7 to receive a corresponding pin it} of the tool joint carried by a swivel. A flowway 8 for drilling fluid extends entirely through the valve body pin and box to provide communication between a mud swivel and a kelly. The kelly may be attached to the downward projecting part 12 threaded at 13 to form a pin of an API standard tool joint by means of a standard tool joint box 13a at the upper end of the kelly.

An annular valve seat 9 is disposed to surround the flowway 8 in the upper part of the body. This valve seat is made of an abrasion resistant material such as abrasion resistant carbide, preferably tungsten carbide. The annular valve seat 9 has a flat upper surface adapted to fit snugly against shoulder 11 of the upper portion of the valve body. The outer surface 14 of the valve seat contains a pair of slots 15 having an O-ring 16 disposed in each of the slots, and is provided with a notch 1'7 adapted to receive a suitable retaining member, which preferably is a pair of Allen screws 18 arranged as shown.

A cover member 19 is disposed to form one side of the globular valve body and is attached to body member 5 by a suitable retaining device illustrated as a series of machine screws 21 threaded into principal body member 5. The face of cover member 19 contacting body member 5 has a suitable annular slot and an O-ring seal 22 disposed .therein to prevent leakage of fluid under pressure from the hollow interior of the body through the joint formed by abutting faces of cover 19 and body member 5.

V A rotary spindle 23 is disposed through the globular body, preferably through cover member 19, and has a non round, preferably square or hexagonal socket in its outer surface for insertion of a handle to turn the spindle. Spindle 23 carries an eccentric arm 24 and is adapted to the lubricated through grease fitting 26.

V Spindle 23 is retained in cover member 19 by shoulders 27 which bear upon an annular sealed thrust bearing 28 and by a suitable retaining assembly designated generally as 29 disposed at the exterior end of spindle 23. The retaining assembly 29 may comprise a plate carrying a pointer 37, as shown, and a pair of annular lock nuts or other suitable retaining device.

, The eccentric arm 24 carries a ball cage 31 in position to bring a ball 32 in line to seat upon valve seat 9 and close flowway 8 when the spindle is rotated into operative position. The ball 32 is mounted on a spring 33 within the cage which has sufficient resilient force to support the weight of ball 32 and bring the ball into contact with the valve seat at low back pressure, thus permitting the ball to be depressed and the flowway opened by very little force of mud applied from above the ball and at the same time permitting the ball to be seated and close the fiowway when pressure below the ball slightly exceeds that above the ball. The ball cage 31 is attached to eccentric arm 24 by any suitable attach ment means illustrated as a machine screw 34, and has a plurality of openings 30 in it to permit free application of pressure to the lower side of the ball.

The fiowway 8 has an enlarged part forming a cavity 35 within the body, best shown in FIG. 2. This cavity is of such size and shape as to permit spindle 23 to be rotated to move arm 24, ball cage 31 and ball 32 entirely outside direct line of flow of fluid through flowway 8, and to one side thereof. In operation with the valve of my invention, the ball, eccentric arm and cage are rotated to the position illustrated by broken lines in FIG. 2 so long as the drill is penetrating strata not subject to difficulties due to back pressure, or likely to cause a blowout. It will readily be seen from FIG. 2 that in this position the ball is entirely out of the main flowway and is protected to some degree against eddy currents by the surrounding cage 31. Although both ball 32 and seat 9 preferably are made of tungsten carbide, they would become badly worn during ordinary drilling operations in which large volumes of mud carrying abrasive particles would, of necessity, fiow by them under pressure and impinge upon their surfaces except for the out-of-line position occupied by them. When the ball is in position, there is substantially streamline flow across the valve seat and relatively little wear since there is little constriction or increase of velocity in this location.

As the drill bit approaches a stratum in which variable back pressures are likely to be encountered, the spindle is rotated into the position illustrated in full lines in FIG. 2. In this position, the unworn ball and substantially unworn seat are in position to cooperate to close the flowway on development of back pressure. The troublesome formation then can be drilled without danger of sudden back pressure blowing mud out of the drill stem. When the troublesome strata have been drilled through and sealed on, and it is desired to continue drilling to a deeper level, the spindle is again rotated to bring the ball out of the principal fiowway into cavity 35, the position shown by broken lines in FIG. 2.

Flowway -8 and cavity 35 are so proportioned that the valve is substantially in dynamic balance when ball 32 is rhoved into cavity 35; i.e., the weight of the globular body, and the dimensions of the cavity 35 therein which includes :a section of flowway 8, cooperate with the dimensions and weight of eccentric arm 24, ball cage 31 and ball 32 to dynamically balance the valve in rotation around a vertical axis when the arm, cage and ball are in the ineifectivevalve-closing position in the cavity outside flowway 8 shown by broken lines in FIG. 2. Drilling always will be conducted with the ball in this position at the beginning, when imbalance of the kelly would noticeably increase vibration at the rotary table. As the hole deepens, a longer and longer drill string is suspended from the kelly and dynamic balance of the valve becomes less important, until at depths where troublesome back pressure is likely to be encountered, imbalance of the valve is of substantially no importance. When the ball is moved into efiective valve closing position, as shown in FIG. 1, the valve is no longer in dynamic balance, but by the time this position is desirable, many tons of drill string are suspended along the central vertical axis of the valve (projected) and the slight imbalance of the valve is of no importance.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which-are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claim.

As many possible embodiments may be made of the invention without departing from'the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed An improved kelly valve which comprises in combi nation a substantially globular body attachable between a mud swivel and an upper end of a kelly, said body in-' cluding a detachably connected cover plate forming at least a part of a side of the body; a vertical flowway through the body, said flowway having an enlargement providing a cavity within the body outside direct line of how of fluid through the body; an annular valve seat around the flowway within the body, the lower end of said valve seat forming a part of an upper wall defining said cavity; an externally operable spindle rotatably mounted through the cover plate; an eccentric arm car ried by the spindle within the cavity; a ball cage carried upon a side of the eccentric arm radially outward from said spindle; a ball-valve-closure member made of tungsten carbide carried within the ball cage and movable therein toward and away from said eccentric arm; a spring in the ball cage disposed to press the ball away from said eccentric arm, the spindle being rotatable through an arc moving the ball and ball cage upward to effective backpressure-responsive valve-closing position in the flowway adjacent to said valve seat and downward to ineffective valve-closing position in thecavity outside the flowway, the weight of the globular body and dimensions of the cavity therein and the weight and dimensions of the eccentric arm, cage and ball being cooperative to dynamically balance the valve in rotation on a vertical axis when the valve-closure member is in the ineffective valve-closing position in the cavity outside the flowway.

References Cited in the file of this patent UNITED STATES PATENTS 1,312,839 Dembowsky Aug. 12, 1919 1,711,519 Cox May 7, 1929 2,196,503 McFee Apr. 9, 1940 2,752,948 St. Clair July 3, 1956 FOREIGN PATENTS 390,165 Frahce of 908

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