US3381756A - Well tools - Google Patents

Description

y 7, 1968 J. E. REAGAN 3,381,756

WELL TOOLS Filed Sept. 5, 1965 2 Sheets-Sheet l INVENTOR James E. Reagan BY www Fig.| wd m United States Patent 3,381,756 WELL TOOLS James E. Reagan, Dallas, Tex., assignor to Otis Engineering Corporation, Dallas, Tex., a corporation of Delaware Filed Sept. 3, 1965, Ser. No. 484,791 19 Claims. (Cl. 166224) ABSTRACT OF THE DISCLOSURE Selective stage cementing tools having a full opening bore provided with lateral outlet passages providing communication between the bore of the tool and the exterior thereof, and having a valve member restrained in closed position by shear means, actuated by piston means subjectcd to fluid pressure resisting opening movement of said valve means in addition to said shear means, in one case having a confined fluid pressure charge resisting movement of the piston means and the valve member and in another case having a pressure area on the piston means exposed to pressure exteriorly of the tool for resisting movement of the valve means to open position, the outlet passages being closed by closure members floated into the lateral flow passages with the cement slurry being pumped therethrough. The strength of the shear screws and the pressure force resisting movement of the piston means controlling the opening of the valve to permit flow of cement outwardly through the passages.

This invention relates to well tools and more particularly relates to tools for controlling fluid flow from a flow conduit into a well bore.

It is a particularly important object of the invention to provide a fluid flow control device for controlling fluid flow from a flow conduit positioned within the bore of a a well into the annulus within the well bore around the conduit.

It is another important object of the invention to provide a fluid flow control device which is connected in a string of casing disposed in a well bore to control the flow of cement slurry from the casing into the annular space within the well bore around the casing.

It is another object of the invention to provide a stage cementing tool which is connected in a casing string disposed in a well bore to control the displacement of cement slurry from the casing string into an annular space within the well bore around the casing string.

It is still another object of the invention to provide a stage cementing tool through which cement slurry is displaced when a predetermined fluid pressure is exceeded.

It is still another object of the invention to provide a stage cementing tool which includes a valve? element held in a releasably closed position by a compressible gas in a charge chamber.

It is another object of the invention to provide a stage cementing tool operable responsive to a fluid pressure level in excess of the pressure of a charge of compressible gas in a charge chamber of the tool.

It is an additional object of the invention to provide a stage cementing tool including an annular piston type valve member to control fluid flow from a central bore through the wall of the tool outwardly.

It is still another object of the invention to provide a stage cementing tool through which fluid flow is initiated by exceeding a predetermined fluid pressure and tenninated by the seating of ball shaped valve elements deposited in the fluid flowing through the tool against seats provided around flow passages through the tool.

It is a still further object of the invention to provide ice a stage cementing tool having a valve system which may be adjusted to an opening pressure correlated with the fluid pressure around the tool.

It is another object of the invention to provide a stage cementing tool having a valve system including an annular piston type valve element which is subjected to a pressure differential between the inside and outside of the tool with the area of the annular piston exposed to the pressure around the tool being greater than the area of the piston exposed to the pressure within the tool.

It is another object of the invention to provide a stage cementing system for use in a well bore which includes a plurality of stage cementing tools each of which is operated in response to 'a different fluid pressure.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of a device constructed in accordance with the invention, and reference to the accompanying drawings thereof, wherein:

FIGURE 1 is a longitudinal view partially in section and partially in elevation illustrating one embodiment of a stage cementing tool in accordance with the invention;

FIGURE 2 is a view in section along the line 22 of FIGURE 1;

FIGURE 3 is a fragmentary cut-away view in perspective illustrating one of the lateral flow ports through the wall of the tool and a portion of the longitudinal flow passage system of the tool;

FIGURE 4 is a fragmentary view in perspective and section of the annular valve member and piston of the tool of FIGURE 1;

FIGURE 5 is a fragmentary view in section showing the annular piston and valve assembly of the stage cementer illustrated in FIGURE 1 moved to an open position to permit fluid flow through the tool;

FIGURE 6 is a fragmentary schematic view illustrating a stage cementing system including a plurality of the stage cementing tools illustrated in FIGURES 1-4; and,

FIGURE 7 is a fragmentary view in section of an alternate form of valve arrangement which may be used in the stage cementer shown in FIGURE 1.

Referring to FIGURES l4, a stage cementing tool in accordance with the invention includes a tubular mandrel 21 which is threaded along its upper and lower end sections 2-2 and 23, respectively, to permit connection of the tool in a string of fluid conduit such as a well casing. The mandrel has a plurality of circumferentially spaced ports 23 each of which comprises three sections graduated in size with the smallest 23a opening into the longitudinal bore 24 of the mandrel while the next larger section 23b encircles the sec-tion 23a to receive a resilient washer or diaphragm 25. The diaphragm 25 has a central aperture 26 which is smaller in diameter than the port section 23a. An outer and largest section 230 of each port 23 encircles the section 2312 to receive a rigid washer or diaphragm retainer suitably secured as by welding to the mandrel over the diaphragm 25 to hold the diaphragm in position. The retainer 29 has a central opening 30' which is larger than the port section 2311 to permit the diaphragm 25 to flex outwardly to allow passage of the ball valve elements 31 as will be explained hereinafter.

An annular head 32 is suitable secured, as by welding, around the mandrel above the ports 23. The head has an external, annular, downwardly opening recess 34 which receives the upper end section of an upper sleeve 35 held on the head by a plurality of set screws threaded through the sleeve into the head. An O-ring 41 disposed in an external annular recess 42 in the head below the set screws seals between the head and the sleeve. Below the lower end 32a of the head the sleeve 3-5 is spaced apart from the mandrel 21 forming an annular space around the mandrel in the sleeve over the radial ports.

An annular body 43 is supported around the mandrel below the ports 23. The body has a plurality of longitudinally extending circumferentially spaced bores 44 which communicate at their lower ends with an annular slot 45 opening through the lower end of the body. The upper end of each of the bores 44 is chamfered providing a seat surface around each bore. A plurality of longitudinal circumferentially spaced fingers 51 extend upwardly from the body 43 with one finger positioned between each pair of adjacent bores 44 as best seen in FIGURE 2. The fingers 51 divide the annular space around the mandrel within the sleeve 35 between the head 32 and the body 43 into a plurality of circumferentially spaced chambers 52 each of which communicates with a port 23 and a bore 44. The fingers 51 are slightly spaced apart along their inner edges 51a from the mandrel and at their upper ends 51b are spaced below the lower end 32a of the head 32 so that each chamber 52 communicates with the other chambers 52 on each side of it. An external annular flange 53a formed around the body 43 is received between the lower end of the upper sleeve 35 and the upper end of a middle sleeve 53 which extends downwardly from the body in spaced apart relationship around the mandrel. The sleeves 35 and 53 are suitably secured together and to the body 43 by an annular weld at 54 and hold the body 43 against movement. Two Orings 55 are each disposed in an external annular recess around the mandrel to seal between the mandrel and the body 43.

The middle sleeve 53 is reduced in thickness along a lower end section forming a downwardly extending skirt 61 which overlaps an upwardly extending reduced section forming a skirt 62 on the lower sleeve 63 which is fitted in spaced apart concentric relationship around the mandrel 21. The sleeves 53 and 63 combine to define the outer walls of an annular flow chamber 64 and an annular charge cylinder '65. The annular recess 45 opens into the annular chamber 64 while the circumferentially spaced ports in the sleeve 53 communicate with the annular chamber. The lower outer sleeve 63 is secured at its lower end to an inner sleeve 71 which is held on the mandrel by an annular retainer ring 72 threaded on the section 23 of the mandrel and held against rotation by the set screw 73. A lower end section of the sleeve 63 is received in an upwardly and outwardly opening annular recess 74 in a thickened lower end section 7111 of the sleeve 71 and is suitably secured to the sleeve 71 by an annular weld 75. The sleeve 71 is substantially reduced in thickness along a central section to provide the inner wall of the annular cylinder or charge chamber 65. Both the sleeves 71 and 63 are slightly increased in thickness along sections 81 and 63a respectively, forming a connecting annular passage of substantially uniform thickness cornmunicating between the annular cylinder 65 and the annular chamber 64. A longitudinal flow passage 81 is formed in the lower end section 71a of the sleeve 71 communicating with a lateral flow passage 82 which is sealed by a removable plug 83 to permit charge gas to be injected through the passages 82 and 81 into the cylinder.

'An annular valve member is slidably disposed within the annular chamber 64 around the mandrel to co-act with the lower end of the body 43 over the slot 45 to control fluid flow from the slot into the chamber 64. The valve member 90 has an annular crown 91 molded of a rubber or rubber-like material to provide a sealing surface on the valve member for engagement with the lower end of the body 43 to seal over the opening of the slot 45 into the chamber 64 when the valve member is in the upper position illustrated in FIGURE 1. The valve member has a plurality of circumferentially spaced laterally extending holes 92 through which the material forming the crown flows or is extruded during the molding of the crown on the valve member to aid in holding the crown on the member. A plurality of circumferentially spaced ports 93 are formed in the valve member below the crown to equalize the pressure within the chamber 64 across the valve member.

A downwardly extending annular piston 94 formed on the valve member 90 is fitted in sliding relationship 'between the sleeve sections 63a and 81 into the annular cylinder 65. An O-ring 95 in an external annular recess in the inner sleeve section 81 and an O-ring 101 in the internal annular recess '102 in the outer sleeve section 63a provide seals on the opposite sides of the annular piston. The valve element 90 along with the integrally formed annular piston are initially held in the upper closed position, as shown in FIGURE 1, by a plurality of shear screws 103 each of which is threaded through, the sleeve 63 into the blind hole 10% of the valve member 90. The shear screws hold the valve member 90 in close-d position during assembly of the tool and provide some protection against accidental opening of the valve until the charge chamber 65 is filled with gas which provides the major force holding the valve closed until the desired pressure is reached in the casing. The screws also provide some protection against accidental valve opening due to transient pressure waves which may develop while building the casing pressure to the desired level for opening the valve.

In operation the stage cementing tool 29 is incorporated in a fluid flow system as illustrated in FIGURE 6. The stage cementing tools are connected in the well casing string which is cemented within the well bore 111 by forcing cement slurry downwardly from the surface through the string of casing and outwardly from the casing through the float shoe 112 and the cementing tools into the annular space 113 within the well bore around the casing where the cement is allowed to harden to form a seal between the outer wall of the casing and the wall of the well bore. Most wells upon completion of drilling remain filled with drilling fluid which is used during the drilling procedure to wash the cuttings from the well bore, to cool the drill bit, and to maintain pressure on the formations being drilled to minimize the escape of fluids from the formations through the well bore to the surface during the drilling procedure. To reduce the force of the weight of the string of casing on the surface well equipment from which the casing is supported and lowered a float shoe 112 is connected on the lower end of the casing string to control the flow of drilling fluid into the casing string as the string is lowered into the well bore. The float shoe is a special form of check valve which controls upward flow into the casing while permitting fluid within the casing to be displaced from the casing outwardly through the lower end of the casing string. Suitable float shoes which may be employed are illustrated and described at pages 2176-2178 of the Composite Catalog of Oil Field Equipment and Services, 1964-65 Edition, published by World Oil, Houston, Tex. The stage cementing tools 20 are connected in the casing string as the string is run into the well to position a tool at each desired depth when the complete casing string is installed. Stage cementing permits the cement slurry to be more readily placed at the depths within the well bore at which it is needed and facilitates obtaining a uniform cement seal along the length of the casing which is to be cemented. Pumping the cement slurry up the annular space between the casing and the borehole wall from the lower end of the casing string is minimized by injection of the cement atidesired depths in the bore hole. Stage cementing is particularly useful Where zones tend to preferentially take the cement slurry and prevent the build up of the necessary pressure to properly pump the cement up the annulus to the desired height. Frequently the casing is cemented within the well bore along its lower end section while the annulus around the casing above such section is left filled with drilling fluid except in the vicinity of a producing formation where the annulus is cemented by use of stage cementing techniques and the casing and cement are then perforated into the producing formation to allow formation fluid flow into the casing. The cement in the annulus along the producing formation prevents migration of the formation fluids upwardly and downwardly in the annulus thus restricting their flow to the flow paths provided by the perforations through the cement sheath into the casing.

In planning a stage cementing program a determination is made of the depth or depths at which cement is to be injected through the casing into the annulus so that each stage cementing tool may be connected into the casing string to place it at the proper depth in the Well bore when the casing string is run into the well.

Each stage cementing tool to be connected into the casing string is prepared for use at the depth at which it is to be positioned in the well bore by injecting a compressible fluid such as a gas through the flow passages 82 and 81 into the annular charge cylinder or chamber 65 and sealing the charge of gas within the cylinder with the plug 83 which is threaded into the bore 82. The cylinder 65 is charged to a pressure to provide a force on the piston 94 which in combination with the resistance of the shear screws 103 will hold the annular valve member 90 in an upper closed position until the fluid pressure within the casing string at the cementing tool has been raised to the level at which the cement is to be pumped into the formation. For example, it may be preferred that the lowest of the cementing tools illustrated in the system of FIGURE 6 open to permit cement injection when the pressure within the casing at the cementing tool is about 1000 psi. in excess of the pressure within the annular space around the casing. If the shear screws 103 are selected to shear when a pressure of 200 psi. is applied to the crown 91 through the slot 45, the remaining :force necessary to hold the valve 90 closed until the casing pressure exceeds the annulus pressure by 1000 p.s.i. is

provided by the charge gas in the cylinder 65. The charge chamber is charged at the surface to a pressure which at the temperature in the well at the depth the tool is operated will provide the required pressure to hold the valve closed. For example, the tool may be charged at a temperature of 80 deg. F. for use at a temperature of 144 deg. F. and thus the pressure at the time of charging at the surface will be substantially less than the pressure which will develop in the chamber at the appreciably higher operating temperature. Generally each of the cementing tools used will employ shear screws 103 of the same strength and thus variations in the opening pressure for each tool is established by the pressure of the charge gas in the cylinder 65.

Since the cementing of an annulus Within a well bore around a conduit generally begins at the bottom of the well, the stage cementing tools incorporated in a casing string have opening pressures established at values such that the lowest of the tools will open at the lowest fluid pressure with each succeeding tool up the casing string requires a higher pressure to open it to permit cement slurry to be injected into the annulus. For example, in the system illustrated in FIGURE 6 the bottom cementing tool may have an opening pressure of 1,000 p.s.i. in excess of the pressure within the annulus 113; the middle tool may open at a pressure of 1,500 psi. above the annulus pressure; and the top tool may open at a pressure of 2,000 p.s.i. above the annulus pressure. Each cementing tool is charged with gas to a pressure at surface temperature to hold the valve member closed until a predetermined pressure is attained in the casing string at the depth at which the cementing tool will be operated. Each cementing tool to be used in the casing string is properly charged and connected into the casing string 110 as the string is lowered into the well bore.

As the casing string is being lowered into the well bore each cementing tool is connected into the string at a location within the string which will position the tool at the desired depth in the well bore when the entire casing string is fully inserted into the well bore to the depth at which it is to be cemented. Generally, a bore hole is already filled with drilling fluid when a cementing process is begun and as the casing string with the float shoe 113 on its bottom end is lowered through the fluid filled well bore the float shoe will permit drilling fluid in the bore hole to enter the string of casing at a rate which only partially fills the casing so that the casing has suflicient buoyancy to partially float the casing string and thereby relieve the wellhead supporting apparatus of the full Weight of the string while it is being inserted into the well bore. When the casing string is at the desired depth in the well bore it is secured in a suitable conventional manner at the surface and the procedure of cementing the annulus 113 within the well bore around the casing string is initiated.

The desired length of the lower end section of the casing string is cemented by pumping a charge of cement slurry downwardly through the casing string, outwardly through the float shoe 113, and upwardly in the annulus until the desired lower end section of the casing string has been cemented. The slurry is generally displaced through the casing string and into the well bore by drilling fluid. A suitable wiper or plug element may, if desired, be pumped through the casing between the body of cement slurry and the displaced drilling fluid to minimize mixture of the two fluids during the pumping process.

When the desired amount of cement slurry has been displaced through the float shoe the tubing is suitably plugged at or above the float shoe by a conventional pump down plug element to stop fluid flow from the float shoe. The slurry is then displaced through the lower stage cementing tool 20 by increasing the pressure within the casing string to the level required to open the valve in the lower cementing tool. The pressure within the bore 24 of the tool is applied outwardly through the ports 23 and the openings 26 of the diaphragms 25 into the circumferentially positioned chambers 52. The pressure is applied from the chambers 52 downwardly through the longitudinal bores 4-4- into the annular slot 45 against the upper end of the crown 91 on the valve member 90. The force of the pressure within the slot 45 against the upper end of the crown is opposed by the shear screws 103 and the pressure of the charge fluid in the cylinder 65. When the pressure acting on the annular area of the crown exposed to the slot 45 provides a downward force on the crown in excess of the resistance provided by the shear strength of the screws and the pressure within the cylinder 65 the screws shear permitting the valve member to be displaced downwardly with the piston 94 compressing the gas within the cylinder 65. The valve member and piston move downwardly with the crown moving away from the opening of the slot 45 into the annular chamber 64 permitting cement slurry to flow from the bore 24 of the mandrel 21, through the ports 23 and the diaphragm openings 26 into the chambers 52, and downwardly through the longitudinal bores 44 and the slot 45 into the annular chamber 64. The slurry flows radially outwardly into the annulus 113 through the radial ports 70. After the screws 103 are sheared the valve member is biased toward the closed position by the gas pressure within the cylinder 65. So long as the pressure within the cement slurry is maintained at a value suflicient to keep the piston 94 in the downward position compressing the gas in the cylinder 65 the valve member remains in the open position allowing the cement slurry to flow into the annulus. When the quantity of cement to be displaced into the annulus through the lower cementing tool has entered the casing string a plurality of the ball elements 31 are deposited in the casing at the surface behind the slurry. Ball elements are selected with a density approximately the same as the density of the cement slurry so that the ball elements will remain at the desired position in the last of the body of slurry to be displaced from the lower tool as the slurry is pumped through the casing string.

The ball elements may be formed of nylon, rubber, or any other material which is resilient enough to seat on the surfaces 50 to prevent flow into the passages 44. The ball elements must not be so resilient, however, that they will be extruded through the passages by the operating pressures in the casing string. At least twice the number of ball elements as the ports 23 may be deposited in the cement slurry in order to insure that at least one ball element will pass through each of the ports. The cement slurry is displaced from the cementing tool through the ports 23 until a ball element 31 passes through each of the ports 23 into the chambers 52 and downwardly into seated relationship against the surface 50 at the end of each of the longitudinal flow passages 44. As each ball element passes through the opening 26 in each diaphragm 25 the diaphragm is deformed expanding the hole 26 to permit the ball to pass through the diaphragm and contracting after each ball element passes through to trap the ball within the chamber 52. A ball element seats against the upper end of each of the passages 44 to prevent further flow through the cementing tool into the annulus.

Generally the pressure within the cementing tool will be maintained at a suflicient level to prevent any tendency of the cement slurry to back flow into the tool until the cement has set, which may be a period of several hours. If the pressure within the cementing tool is reduced to a level below the pressure within the charge chamber 65 while the cement is still fluid the valve member 90 is forced by the pressure within the cylinder 65 upwardly to the closed position. While such a pressure reduction is not a normal step in the cementing procedure the pressure might inadvertently be reduced or an equipment break down might result in such a pressure reduction. If such a pressure reduction occurs before the cement is set the back flow of fluids through the chamber 64, the annular slot 45, and the longitudinal flow passages 44 will unseat the ball element 31 at the upper end of each. of the longitudinal flow passages. Since the opening 26 through each of diaphragms 25 is smaller than the diameter of the ball elements 31, each ball element is trapped within its chamber by the rubber diaphragm and will not normally be displaced back through the diaphragm into the bore 24 of the tool with the minor amount of back flow which might occur during the closing of the valve members 90. The ball elements are retained within the flow paths leading to the longitudinal flow passages 44 so that upon a subsequent increase of the pressure within the cementing tool the ball elements will again be forced against the seat surfaces 50 to prevent fluid flow from within the cementing tool outwardly into the annular space.

If the middle cementing tool is a substantial distance up the casing string from the lower cementing tool, the cement forced through the lower tool will normally be displaced by drilling fluid which will substantially fill the casing to the middle cementing tool. The batch or charge of cement slurry to be displaced through the middle cementing tool is introduced into the casing at the surface following the drilling fluid used to displace the cement through the lower cementing tool. When the ball elements 31 close the lower cementing tool an increase in pressure will be evident at the surface with the cessation of flow through the casing string. At this time the cement slurry to be displaced through the middle cementing tool Will have arrived at the tool. The pressure within the casing string is then raised to the level required to open the middle cementing tool. As previously discussed, the opening pressure for the middle cementing tool is established by the pressure of the gas within the cylinder or charge chamber 65 and may be, for example, 500 pounds higher than the opening pressure for the lower cementing tool and 500 pounds below the opening pressure for the upper cementing tool. When the opening pressure for the middle cementing tool is reached within the fluid at the cementing tool the valve element 90 of the tool is forced downwardly against the pressure within the charge chamber and the shear screws to shear the screws and compress the charge gas to open the valve and allow the cement slurry to flow into the annular space around the casing string. While the pressure is being maintained at the level sufiicient to displace the cement through the middle cementing tool the lower tool remains in a closed condition due to the seating of the ball elements 31 on the surfaces 50 at the upper end of the longitudinal flow passages 44 of the tool. Since the pressure at which the middle cementing tool operates is below the operating pressure for the upper tool the upper tool remains closed. The ball elements 31 are injected into the cement slurry passing through the middle cementing tool at a position within the stream of slurry which will close the flow passages through cementing tool when the desired amount of slurry has been displaced into the annular space.

The cementing procedure is continued with the pressure within the casing string being again raised to the level required to open the valve in the upper cementing tool when the step of displacing the slurry through the middle cementing tool is completed. While the cement is being displaced through the upper cementing tool the pressure within the casing string is appreciably above the operating pressure 'for the middle and lower cementing tools which are maintained in a closed condition by the ball elements 31 in the compartments 52 of each of the tools. When the desired amount of cement slurry has been displaced through the upper cementing tool the flow through the tool will be shut off by use of the ball elements in the same manner as followed with the lower and the middle cementing tools. The fluid pressure is then maintained in the casing string at a level sufficient to maintain the ball elements in a seated relationship within the lower, middle, and upper cementing tools until the cement slurry has sufliciently set within the annular space 11.3. It may be necessary to hold the pressure Within the casing string for a period of several hours to allow for the proper setting of the cement.

The major portion of the cement slurry introduced into the casing string is preferably displaced from the string through the stage cementing tools and any cement remaining Within the casing string is drilled out preparatory to completing the well for production by conventional procedures. The stage cementing tools are an integral part of the casing string and thus are cemented in place with the casing string by the cement within the annular space. The cementing tools remain therefore permanently within the well bore. The cement slurry will set within the valve mechanism of each of the cementing tools and thereafter prevent any fluid flow through the stage cementing tools.

It will now be seen that there has been illustrated and described a new and improved well tool for controlling fluid flow from a conduit into an annular space within a well bore around the conduit.

It will also be seen that there has been illustrated and described a new and improved fluid flow control tool which is operative responsive to a predetermined pressure differential applied across the conduit between the bore of the conduit and the annular space within the well bore around the conduit.

It will now be seen that a new and improved flow control device for controlling fluid flow from a flow conduit positioned within the bore of a well into an annulus within the well bore around the conduit has been illustrated and described.

It will also be seen that the fluid flow control device is connected in a string of casing disposed in a well bore to control the flow of cement slurry from the casing into the annular space within the well bore around the casing.

It will be further seen that a new and improved stage cementing tool has been illustrated and described for use in a casing string in a well bore to control displacement of cement slurry from the casing into an annular space within the well bore around the casing.

It will be further seen that the stage cementing tool includes means operable responsive to a predetermined fluid pressure for releasing cement slurry through the tool into the annular space around the tool in a well bore.

-It will also be seen that the stage cementing tool includes a valve element which is releasably held in "a closed position by a compressible fluid within an annular charge chamber.

It will additionally be seen that the stage cementing tool is operable responsive to a fluid pressure in excess of a predetermined pressure level controlled by a charge of compressible gas in an annular cylindrical charge chamber of the tool.

It will additionally be seen that the stage cementing tool includes an annular piston type valve member to control fluid flow from the bore of the tool to the exterior of the tool.

It will be further seen that fluid flow is initiated through the cementing tool when a predetermined fluid pressure is exceeded within the tool and the flow is terminated by the seating of a ball shaped valve element disposed within the fluid flowing through the tool against each of the seat surfaces provided at the upper end of each ot" the longitudinal flow pass-ages through the tool.

It will also be seen that the opening pressure for the tool is adjusted in accordance with the pressure to which the annular cylindrical charge chamber is charged with a compressible fluid.

It will additionally be seen that the annular valve of the tool is held in a closed position by a combination of the force from the pressure within an annular charge chamber and by a plurality of shear screws releasably engaged between the slidable valve member and a fixed sleeve member of the tool.

It will also be seen that the major force holding the annular valve in closed position results from the pressure of the fluid within the annular charge chamber.

It will be seen that there has been described and -illustrated a new and improved well cementing system including a plurality of stage cementing tools each of which is operable in response to a different tfluid pressure differential applied between the bore of a casing string and the annular space within a well around the casing string.

It will additionally be seen that each stage cementing tool in the system has a different opening pressure as determined by the pressure of the fluid in the annular charge chamber.

An alternative form of control valve for use in the stage cementing tool is illustrated in FIGURE 7 wherein components identical to those illustrated in FIG- URE 1 are referred to by the same reference numerals. The annular valve member 90 is slidably positioned within the annular flow chamber 64 and initially held against longitudinal movement by the shear screws 103 extending into the valve member through an outer lower sleeve 130 which, like the sleeve 63 of the tool shown in FIG- URE 1, fits in overlapping relationship within the lower end section 61 of the sleeve member 53. The inner sur face of the outer sleeve 13!) and the outer surface of an inner sleeve 131 form an annular cylinder 132 around the mandrel. The cylinder 132 communicates to the outside of the lower sleeve through the port 133 which is covered by a porous element 134 secured within the recess 135 around the port to keep debris from entering the cylinder. The sleeve 130 is slightly reduced in thickness along a lower section 130a to provide the outer wall of the annular cylinder 132 while the inner sleeve 131 is similarly reduced in thickness along a central section 131a threaded on the upper section to facilitate assembly and providing the inner wall of the annular cylinder. The inner sleeve is appreciably increased in thickness along its lower end section 1311; providing an upwardly facing annular shoulder 131c which forms the lower end of the annular cylinder 132. An upwardly and outwardly opening annular recess 131d is formed around the lower end section of the inner sleeve to receive the lower end section of the outer sleeve which is secured on the inner sleeve by the set screws 136. The sleeves 130 and 131, respectively, are spaced apart along a section 131e of the inner sleeve and a section 13Gb of the outer sleeve providing an annular space 136 connecting the annular flow chamber 64 and the annular cylinder 132. An annular connecting sleeve 140 threaded on the valve member 90 is slidably disposed through the annular space 137 connecting the annular valve member with an annular piston 141 which is slidably disposed within the annular cylinder. An O-ring 142 within an external annular recess 143 around the inner sleeve 131 and an O-ring 144 within an internal annular recess 145 in the outer sleeve fonn inner and outer seals, respectively, with the connecting sleeve 140. An internal O-ring within an internal annular recess 151 in the piston 141 and an outer O-ring 152 within an outer annular recess 153 around the piston form inner and outer seals, respectively, with the walls of the annular cylinder 132.

The assembly including the sleeves 130 and 131 is secured on the mandrel by the retainer ring 72 threaded on the lower end section 23 of the mandrel and held against rotation by the set screw 73.

Fluid pressure within the bore 24 tending to open the valve 90 acts downwardly on an annular area of the crown 91 enclosed between the lines of sealing engagement of the lower end of the body 43 with the crown. The valve 90 is held in the upper closed position by both the shear screws 103 and the pressure within the annular cylinder 132 below the piston 141. The pressure within the annular cylinder acts against an annular area of the piston as defined by the lines of sealing engagement between the O- rings 150 and 152 with the inner and outer walls respectively, of the annular cylinder. The cylinder is exposed through the port 133 and the porous member 1334 to the pressure around the tool. In the system of FIGURE 6 the pressure within the annular cylinder is the same as the pressure within the annulus 113 around the casing string in the well bore. Thus, the relationship between the sealed area of the valve crown exposed to the pressure within the bore of the tool mandrel when the valve is closed and the sealed area of the annular piston 141 determines the required relationship between the pressure within the bore of the tool and the pressure within the annular space around the tool to open the valve 99. For example, in a cementing tool where the effective sealed area of the piston 141 within the cylinder 132 exceeds by ten percent the effective sealed area of the crown 91 with the lower end of the annular body 43 around the seal annular slot 45, it is necessary that the pressure Within the bore of the cementing tool exceed the pressure within the space around the tool by more than ten percent in order to hold the annular valve in the open position against the annular cylinder pressure. The relationship between the sealed areas of the piston and the crown of the valve and the portion of the resistance to the opening of the valve provided by the shear screws is varied as desired by the design of each particular cementing tool. It will be obvious, of course, that in order to vary the pressure differential between the bore of the tool and the annulus required for operation of the valve it is necessary that the valve design be altered to provide a different relationship between the sealed area of the annular piston and the sealed area of the crown of the valve. Thus, the sizes of the valve components for each valve in a system are dependent upon the depth at which the tool is to be used.

A stage cementing system utilizing one or more cementing tools having the valve arrangement illustrated in FIGURE 7 is operated in exactly the same manner as the system previously described with each cementing tool in the system actuated by a predetermined pressure differential between the pressure within the tool and the annulus pressure around the tool. Flow is terminated 1 1 through each tool by the ball valve elements disposed in the cement slurry as discussed above.

It will now be seen that there has been described and illustrated a new and novel stage cementing tool utilizing a valve which opens responsive to a predetermined pres sure relationship between the fluid pressure within the bore of the tool and the pressure within the annular space around the tool within a well bore.

It will also be seen that the head of the annular valve member of the cementing tool is exposed to the pressure within the bore of the tool while the force tending to hold the valve member in closed position is determined by a plurality of shear screws and the cross sectional area of an annular piston exposed within an annular cylinder to the fluid pressure within the space surrounding the tool.

The foregoing description of the invention is explanatory only, and changes in the details of the construction illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. A tool for controlling fluid flow from a conduit comprising: a tubular mandrel adapted to be connected in and become a part of said conduit, said mandrel having a longitudinal bore therethrough and lateral ports communicating with said bore; body means around said mandrel providing an annular flow passage between said body means and said mandrel communicating with said lateral ports of said mandrel and having outlet port means from said annular flow passage opening to the exterior of said body means; an annular seat surface in said annular passage between said lateral ports and said outlet port means; said annular seat surface communicating with said lateral ports and said annular passage; an annular valve member in said annular passage between said seat surface and said outlet port means for engagement with said annular seat surface to control fluid flow through said passage; means providing an annular pressure chamber in said body means below said outlet port means; an annular piston opcratively associated with said annular valve member on the side thereof opposite the seat surface, said piston having its end opposite said valve member slidably disposed in said pressure chamber in sealed relationship therewith; and means for providing fluid pressure within said annular pressure chamber to act on said end of piston to bias said piston and said valve member toward said annular seat surface; said valve member being movable to open said flow passage in response to fluid pressure within said tubular mandrel and being movable to closed position in response to fluid pressure within said pressure chamber acting on said piston.

2. Apparatus in accordance with claim 1 wherein said means for providing fluid pressure comprises means for injecting a charge of fluid into said annular chamber and sealing said fluid within said annular chamber to hold said annular valve member at a closed position on said annular seat surface until the fluid pressure within said bore of said mandrel exceeds a predetermined value.

3. Apparatus in accordance with claim 1 wherein said means for providing fluid pressure comprises flow passage means from said annular chamber in communication with the space exteriorly of said tool whereby said annular piston is biased toward said annular valve member by fluid pressure exteriorly of said tool.

4. A stage cementing tool comprising: a tubular mandrel adapted to be connected in and become a part of a well conduit, said tubular mandrel having a plurality of circumferentially spaced radial ports; an annular body disposed around said mandrel provided with a plurality of longitudinally extending flow passages and an annular seat surface around each of said longitudinal flow passages at the end thereof adjacent to said radial ports adapted to receive a ball valve element for preventing fluid flow through each of said flow passages; said annular body having an annular lower seat surface at the other end thereof opening into said longitudinal flow passages; annular sleeve means around said mandrel securing said annular body in position and providing flow passage means communicating said radial ports with said longitudinal flow passages in said body; said annular body and said mandrel providing an annular passageway therebetween communicating with the annular lower seat surface and with the exterior of the body; an annular valve member slidably positioned in said annular passageway to engage said lower annular scat surface to control fluid flow through said longitudinal flow passages in said annular body; means providing an annular chamber in said sleeve communicating with said annular passageway; an annular piston slidably disposed in said chamber and connected with said annular valve member; and means for providing a fluid pressure within said annular chamber to bias said annular piston toward said annular seat surface.

5. A stage cementing tool according to claim 4 wherein said means providing a fluid pressure within said annular chamber to bias said annular piston toward said annular seat surface includes means provided in said sleeve for injecting and sealing a charge of fluid in said annular chamber.

6. A stage cementing tool according to claim 4 wherein said means providing a fluid pressure in said chamber for biasing said piston toward said seat surface includes means providing fluid communication from said annular chamber to the outside of said tool whereby said annular piston is biased toward said annular seat surface by the pressure exteriorly of said tool.

7. A stage cementing tool comprising: a tubular mandrel having a bore therethrough adapted to be connected in a well conduit; said mandrel having a plurality of circumferentially spaced radial ports; a flexible diaphragm secured over each of said radial ports, each. said diaphragm having a central opening therethrough smaller than said radial port; annular sleeve means secured around and spaced apart from said mandrel providing flow chambers communicating with said radial ports and providing an annular cylinder longitudinally spaced along said mandrel from said radial ports; annular body means supported around said mandrel within said sleeve means, said body being provided with longitudinal flow passages communicating with said flow chambers and with a seat surface around the end of each of said flow passages adjacent said radial ports; said annular body means being further provided with an annular opening from said longitudinal flow passages through the other end of siad body; said annular body means being spaced from said annular cylinder providing an annular flow passage within said sleeve; said annular sleeve means having a plurality of radial circumferentially spaced ports communicating the exterior thereof with said annular flow passage; an annular valve member sildable within said annular flow passage adapted to engage said annnlar body means around said annular opening controlling fluid flow from said radial ports, through said flow chambers, said longitudinal flow passages, and said annular slot; and an annular piston slidable in said annular cylinder connected with said annular valve member, said annular piston being exposed to fluid pressure within said annular cylinder on the side of the piston opposite to said valve member biasing said annular piston and said annular valve member toward a closed position in seated relationship against said annular body means.

8. A stage cementing tool according to claim 7, including means for injecting a fluid into said annular cylinder and sealing said fluid within said cylinder to provide fluid pressure for biasing said annular piston and said annular valve member toward closed position.

9. A stage cementing tool according to claim 7 including means providing fluid communication from exteriorly of said sleeve means into said annular cylinder whereby fluid pressure from exteriorly of said sleeve means acts on 13 the end of said annular piston opposite the valve means to bias said piston and said valve member toward closed position.

10. A squeeze cementing tool comprising: a tubular mandrel adapted to be connected within and form a part of a well conduit, said mandrel having a longitudinal bore therethrough and a plurality of radial circumferentially spaced ports for lateral displacement of fluid from said bore through said mandrel; annular sleeve means spaced around and spaced apart from said mandrel providing an upper annular space around and communicating with said radial ports, an intermediate annular flow chamber, and a lower annular cylinder; an annular body secured within said sleeve means around said mandrel below said radial ports; a plurality of longitudinally extending fingers supported on said annular body circumferentially spaced around said body, each of said fingers extending between adjacent radial ports dividing said upper annular space into a plurality of flow chambers, each of said chambers communicating with one of said radial ports; said annular body being further provided with a plurality of longitudinally extending circumferentially spaced flow passages, each of said flow passages communicating with one of said flow chambers; said annular body being also provided with a valve seat surface at the end of said body adjacent to said radial ports around each of said longitudinal flow passages to receive a ball valve element for shutting off fluid flow through each of said longitudinal flow passages; said annular body being also provided with an annular slot opening through the other end of said body into said longitudinal flow passages of said body to communicate said flow passages with said central annular flow chamber; said sleeve means being provided with radial ports opening into said central annular flow chamber; an annular valve member slidably positioned within said central annular flow chamber adapted for longitudinal movement, the end of said valve member adjacent to said annular body being adapted to engage said body over said annular slot for controlling fluid flow from said longitudinal flow passages into said central annular flow chamber; an annular piston formed on the other end of said annular valve member extending in sliding relationship into said lower annular cylinder adapted to respond to fluid pressure within said annular cylinder for biasing said piston toward said annular body to bias said annular valve member toward closed position; and said sleeve means being provided with means for supplying said annular cylinder with fluid pressure to bias said piston toward said annular body.

11. A stage cementing tool in accordance with claim wherein said means for supplying fluid pressure to said annular cylinder comprises flow passage means and sealing means for charging said annular cylinder on the side of said piston opposite said valve member with gas under pressure and sealing said gas within said annular cylinder.

12. A stage cementing tool according to claim 10 wherein said means for supplying fluid pressure to said annular cylinder comprises flow passage means communicating said annular cylinder on the side of said piston opposite said valve member with the space exteriorly of said tool.

13. A stage cementing tool comprising: a tubular mandrel having a longitudinal bore extending therethrough and a plurality of circumferentially spaced radial ports, said mandrel being adapted to be connected in and form a part of a well conduit; an annular head member secured around said mandrel above said radial ports; an upper sleeve section secured to said head member around and spaced apart from said mandrel providing an upper annular space around said mandrel within said sleeve member over said radial ports; an annular body secured with said upper annular sleeve below said radial ports, said annular body having a plurality of longitudinal circumferentially spaced flow passages, a seat surface around each of said flow passages at a first end of said body adjacent to said radial ports, and an annular slot extending into said annular body from the second end of said body communicating with said longitudinal flow passages; a plurality of longitudinal fingers supported on said annular body between said body and said annular head member dividing said annular space around said radial ports into a plurality of circumferentially spaced flow chambers, each of said chambers communicating with one of said radial ports and with one of said longitudinal flow passages through said annular body; a flexible diaphragm secured to said mandrel over each of said radial ports, said diaphragm having a central opening smaller than said radial port associated with said diaphragm; a central sleeve secured with said upper sleeve around said mandrel and annular body spaced apart from said mandrel and having a plurality of radial ports below said annular body; a lower outer sleeve supported below said central sleeve spaced apart from said mandrel; a lower inner sleeve around said mandrel within said lower outer sleeve; a lower portion of said central sleeve and an upper section of said lowe outer sleeve defining an annular central flow chamber around said mandrel below said annular body; said lower inner sleeve and said lower outer sleeve being spaced apart from each other providing a lower annular cylinder and an annular space communicating between said cylinder and said central annular flow passage; an annular valve member slidably disposed within said central flow chamber adapted to move into and out of engagement with the said second end of said annular body over said annular slot for controlling fluid flow from said longitudinal flow passages through said slot into said central annular flow chamber; an annular piston formed on said annular valve member extending through said annular space between said central flow chamber and said lower cylinder into said cylinder; seal means supported by said lower, inner and outer sleeves to seal between said sleeves and said annular piston; and means provided in said tool for applying fluid pressure within said annular cylinder for biasing said annular piston toward said annular body.

14. A stage cementing tool in accordance with claim 13 wherein said means for applying fluid pressure in said annular cylinder comprises means for filling said annular cylinder with a charge of gas and sealing said charge of gas within said annular cylinder on the side of said annular piston opposite said valve member.

15. A stage cementing tool in accordance with claim 13 wherein said annular piston has a lower end section within said annular cylinder having a cross-sectional area greater than the portion of said piston exposed in said annular flow chamber and said means for applying fluid pressure in said annular cylinder comprises flow passage means communicating said annular cylinder on the side of the piston opposite said valve member with the exterior of said cementing, whereby fluid pressure from exteriorly of said tool acts on said piston to bias the valve member toward closed position.

16. A stage cementing tool in accordance with claim 15 wherein the cross-sectional area of said annular piston within said annular cylinder is greater than the crosssectional area of said piston exposed to fluid pressure in said annular flow chamber.

17. A system for displacing cement slurry from a well conduit positioned within a well bore into the annular space within said well bore around said conduit at a plurality of preselected depths comprising: a well conduit positioned within said well bore; and a plurality of stage cementing tools connected in said conduit spaced apart each from the other along the length of said conduit at selected intervals at which cement slurry is to be displaced from said conduit, each of said cementing tools having means providing an annular cylinder in said tool and an annular piston slidably disposed therein; an annular valve member connected with said piston and biased toward a closed position by fluid pressure within said annular cylinder acting on said piston and being actuatable to open said valve member responsive to a predetermined pressure level 1 5 within said well conduit, each of said cementing tools being so arranged that the annular valve of the tool above the lowest of said tools opens in response to a pressure within said conduit in excess of the pressure required to open the annular valve of the cementing tool immediately therebelow.

18. A stage cementing system as defined in claim 17 wherein the annular cylinder of each of said cementing tools is closed and a charge of gas under pressure is confined to said cylinder acting on the piston therein, whereby the valve member in each cementing tool is biased toward the closed position by said charge of gas in said sealed annular cylinder.

19. A stage cementing system as defined in claim 17 wherein each of said cementing tools has means communicating the annular cylinder on the side of the piston opposite said valve member with the exterior of said tool whereby fluid pressure from exteriorly of the tool enters the cylinder to act on the piston therein, whereby the valve member in each cementing tool is biased toward a closed position by the fluid pressure within the annular space exteriorly of said tool within the bore hole.

References Cited UNITED STATES PATENTS 1,601,239 9/1926 Crowell 137516.15 1,684,551 9/ 1928 Manning 166154 X 1,854,518 4/1932 Little.

2,178,845 11/1939 Baker l66224 X 2,251,977 8/1941 Burt 16626 X 2,374,169 4/1945 Boynton 166224 X 2,837,165 6/1958 Roberts 166-224 X 3,010,514 11/1961 FOX 16621 3,022,829 2/1962 Hodges 166-224 3,049,759 7/1962 Garrett et a1 166-224 3,097,699 7/1963 Orr 166-26 X 3,270,765 9/1966 Waters 137155 CHARLES E. OCONNELL, Primary Examiner.

I. A. CALVERT, Assistant Examiner.

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