US2274940A - Squeeze cementing of wells - Google Patents

Description

March 3, 1942 A. D. sToDDARD SQUEEZE CEMENTING OF WELLS Fle'd Sept. 5, 1939 INVENTo-R. Albert D. Soddrd BY. Ng l 2 A TToRNE'Ys.

Patented `Mar.4 3, 19.42

vSfiumtzr: CEMENTING or WELLS Albert pisacane, Duncan. Okla., assigner to Halliburton Oil Well Duncan, Okla.

Cementing Company,

Application September 5, 1939, Serial No. 293,371

8 Claims. This invention relates to apparatus adapted for use in oil wells or the like, and more particularly to packers and means for removably securing the same to the casing in' a well while forcing cement into the well under pressure.

In the cementing of oil wells, it is sometimes desirable to perform what is known as a.

squeezejoh By this, it is meant that cement slurry is forced or squeezed" by pressure into or against a permeable formation or through perforations in casing and liners for the purpose of shutting on water orl for reducing gasoil ratio, or for otherpurposes.

In squeeze cementing, it'is customary and usually desirable to fix and seal a tubing or other conduit to the casing above the point where the cement slurry` is to be forced under pressure. For this purpose, a cement retainer may be employed. Some cement retainers must be drilled up in order toremove them from the well. In other cases, it has been proposed that a removable packer and slips be employed. An example of this latter type of device for retainingthecementisdisclosedinthepatenttolal- 1iburton,-No. 3,138,157, granted November 2 1938, for "Removable packer for wells. l In all Larrangements heretofore proposed for the purpes outlined above, the arrangement has been auch' that-the packer is securedto the casing and held in xed relation to the casing until after the cement sl through tubing or other conduit has hardened.

pumped down Inr accordance with the present invention, it is proposed to remove the tubing and packer and slips, which secure the packer to the casing, as soon as the cement slurry has been squeered."

*retainer must be so used asto 01d the cement h slurry'in place until it sets. It has been ccvered,however, that this is case, and the present apparatus and'` has beendevlsed for use in cases where cement retainer need not be employed to the slurry in place, hydraulic pressure ofiiuid in the hole is employed for this purpose.

Accordinaly. it is an object oi' the present invention to provide a device capable for use in the squeeze cementing oi oil wells or the like vise means for securing tubing and a packer to the casing in a well in which said securing means may be released by the application of a predetermined iiuld pressure to the fluid beneath the packer.

It is still another object of the invention to devise a novel method for squeezing cement or other sealing fluid in oil wells in which a packer is employed on tubing or other conduit and is secured to the casing of the well but is released automatically from the casing'. when a predetermined pressure is applied to iiuid in the well, or when a predetermined tension is taken in the tubingror 'when both uid pressure and tension injthe,,tubing are exerted on the securing means.

Other objects reside in certain novel features of the arrangement, combination of parts and method as will be more apparent from the following description taken in connection with the accompanying drawing, in which:

Figure i is a vertical cross-sectional view of the casing of a well with packing and securing apparatus constructed in accordance with the principles of the present invention' located therein, the parts being shown in the position which they occupy after they have been lowered through the casing and are about to be set;

Figure 2 is a vertical cross-sectional view -of the apparatus oi.' Figure 1 but il1ustratlng the relative positions of the parts when the apparatus isset and secured to the casing ,inl the well. in which position cementslurry may be forced downwardly throughffthe tubing to' `a 1 point beneath the packer; and

trates at Il. within the casing, apparatus eon structed in accordancewith the present invention may be located. This may be lowered into the easing on tubing or other eonduitmeans, the

lower end o! which is shown at i2.

lBetween 'the tubing and the `packer and se-P curing means which constitute the present invention, a circulating sub is provided. In the form illustrated. this consists of two telescoping members Il and Il, the inner telescoping member l being threaded at its upper end and connected to the tubing i2, and th'e other telescoping memlber il being threaded at its lower end and conl nected to the mandrel i501 the slip actuating means which will presently be described. The threaded connection between, the members: I4 and I5 is preferablya left hand thread vso that these parts may be disconnectedv if desired in case the packer `I5 and the slipassembly become stuck in thewell. I

Asuitabl'e packing gland I6 is provided between the members I3 and I4 to prevent leakage when th'e'parts are4 iny the position shown in the drawing, that is', telescoped together. When the parts vare, extendedlongitudinally. ports I1 in the lower end of` the inner member I3 move above the packing I6 and permitthe flow of fluid outwardly'through ports -l8 inthe outer telescoping member I4. The amount 'of longitudinal extension of the members I3 and I4is limitedlby the shoulder I9 lwhich abuts against a seat 29 in a nut 2| connected to th'e top `of the member I4.

The parts I3 and .I4 are normally held locked in the collapsed or telescoped positions shown in the drawing by means of pin and J-slot connections, the pins being connected to themember I4 as illustrated at 22, and the slots being provided as shown at 23 in van enlargement 24 on `the inner member I3. The'arrangement may be such that upon slight rotation to theright, the pins 22 will -be brought into the longitudinally extending portions of the J-slots so that upon lifting of the' tubing I2 and the inner member I3l culating sub in the string of `tubing so that it may be used if desired.

The mandrel I5 which is connected to the lower end of the circulating sub, as described above, is provided with suitable means for setting slips 25 in the casing. The particular means for setting the slips and for releasing the back pressure valve in the mandrel I5 is similar to that disclosed and claimed in the patent to R. K. Henderson, No. 2,2l'1,747,.granted October l5, 1940, for Drillable packers." As herein shown.- it consists of an inner removable sleeve A26 connected inside of the mandrel I5 by means of a shear pin 21. The sleeve 26 is provided with a number of longitudinally extending. grooves 28 which receive the heads of pins 29 and positively control movement of the pins as long as the headsthereof are in the grooves. Thus, if. the sleeve 26 is drawn upwardly, the pins 429 are moved inwardly. v

The sleeve 26 is also provided with a depending rod 30 which holds the back pressurev valve open until the sleeve is moved upwardly. The back pressure valve may consist of a ball 3I resting on a `spider 32 which carries a coil spring 33 which tends to move the vball 3l upwardly against a seat 34 provided'in the lower end of the mandrel I5. As long as the sleeve 26 is inthe position illustrated in Figure 1, fluid can pass eithe" upwardly or downwardly through the mandrel I5, but upon the sleeve 26 being pulled upwardly the valve 3| engages the seat 34 and prevents while still permitting downward :'fl'ow therethrough. It is possible to construct and operate apparatus in accordance with the present invention without the use of any back pressure valve at all, but -it is preferable to provide the back pressure valve.

To shear the pin 21 and pull the sleeve 26 upwardlyl at any desired' time, a special weight member 35 is connected to Athelower end of a measuring line 36 and lowered downward through the tubing I2 and the circulating sub. The

weight member 35 is provided with spring lpressed latch dogs 31 near its lower end which are adapted to secure the weight member 35 to a ring 38 secured to the sleeve 26 by means of longitudinally extending bars 39. Figure 1 illustrates the position ofthe weight member 35 just before it engages the ring 38. As soon as the weight member 35 is lowered farther into the well, it will be latched to the sleeve 26; and by taking tension in the measuring line 36, the sleeve 26 can be pulled upwardly. The 'operator will know by the amount of tension in the line when vthe weight 35 has been latched to the sleeve 26, and will know when the pin 21 shears because,

of the sudden decrease in tension in the line. Y By means of suitable depth measuring apparatus,

such as that illustrated and described in the' mounted on the wedge body 44, which is formed on the lower portion ofthe enlargement 42 on the mandrel I5. It will be noted that the wedge body 44 is tapered downwardly whereas thev wedge members 43 are tapered upwardly. In accordance with the yusual' practice, the slips v26 are `dovetailed or splined tothe wedge members 43.. In turn, the wedge members may be dovetailed or splined to the wedge body 44.

Shearable means is provided between the wedge members 43 and the wedge .body 44. This may consist'of a split ring-or any other Ashearable passage of uid upwardly through the mandrel means, but in the formshown pins 45 are provided between these members. The lower end ol' the wedge members 43 may be provided with shoulders 46 for preventing the slips from movl ing downwardly too far thereon, as will be ex' plained later in connection with `Figure 3- of the drawing.

Beneath the slip actuating means, the mandrel I5 connects to the valve housing 41 which carries a tubular member 48 which, in turn, carries a. packer 49. The packer 49 may be of`a type in common use inthe oil nelds. It is called a swab rubber and consists essentially of a ilexible cup of rubber, fabric or the like. When used inthe present invention, it is mounted inverted upon the tubular member 48', being clamped in position by a collar 50 shaped to conform with the outer surface of the packer 49 and an inner ring 5I. In addition to these members, spring fingers 52 may be employed to hold the swab rubber 49 in place and prevent it turning inside out. In the arrangement illustrated, the packer will prevent the iiow of uid upwardly in the casing Il but permit fluid to flow downwardly on the outside thereof. It will 4be noted thatv with the particular packer shown no operation is required to effect a seal between the tubing and the casing. However, if other types of packers are used they may be set when the slips are set, as will be obvious to those skilled in the art.

The operation of the apparatus shown in performing a squeeze cementing job is as follows:

With the parts in the position shown in Figure l, the tubing, packer, slips and operating assembly are lowered into the well. When the desired depth has been reached and it is desired to secure the packer and tubing against upward movement with respect to the casing, the lmeasuring line 38 and weight 35 are lowered into the well and the sleeve 26 pulled upwardly, as described above, to release the slips `25. The tubing may then be lifted slightly to cause the wedge members 43 to force the slips 25 to bite into the casing to some extent. After the measuring line, the weight 35 and the sleeve 26 are removed from the well, the apparatus is ready to perform the squeezing operation. Before squeezing cement into the formation,I the formation is first broken down." 'I'his is usually performed by pumping water down through the tubing to a point beneath the packer and building up pressure on the pumps until it is determined that the water isowing into the formation. When this occurs, cement may be pumped down through the tubing. If it slurry in the tubing shallnot be forced back into the formation, the circulating sub described above may then be opened until the cement slurry is circulated down to some point not far above the circulating sub. However, in some cases, there is no objection to forcing the water into the formation ahead of the cement, and in that case the circulating sub would not be opened.

In Figure 2, the parts are shown in the position which they occupy when cement slurry is being forced downwardly through the tubing without the circulating sub being opened. It is common experience in squeeze cementing tohave the pressure gradually build up as the cement isforced into the formation. The pressures differ in different formations and in different fields, butin most cases the pressure gradually increases until no more cement can be forced into the formation. The shear pins 45 which connect the wedge members 43 to the wedge body 44 are so designed as to take this pressure and a certain additional pressure necessary to effect a factor of safety. However, vafter as much cement has been forced into the formation as is desired, the pump pressure may be increased until the pins 45 shear. The pins 45 may be sheared, however, merely by pulling upwardly on the tubing I2 or by taking tension in the tubing at the same time that the pump pressure is increased. It is, of course, within the purview of the present invention to provide arotary jar in the tubing l2 at` some point above the circulating sub as an aid in shearing the pins 45 when desired.

When the pins 45 shear, the tubing, packer and slips Vare entirely disconnected from the casing inasmuch as the wedge body 44 is then free to move upwardly relative to the wedge members 43; and as it does so the slips 25 are drawn inwardly radially due to the spline connections between them and the wedge members 43 and the wedge body- 44. The parts are then in the position shown in Figure 3 of the drawing and are ready to be removed from the well. Y It is desirable in is desired that the water beneath the cement accordance with the 'present invention to move the tubing, slips and packer upwardly at least some distance in the well immediately after the cement has been squeezed and before it has had a chance to harden. 'I'he mud or other fluid which followed the cement into the well and which was used to exert pressure on the cement in-squeezing it may flow downwardly through the tubing and the back pressure valve 3| as the tubing is moved upwardly. Also, mud outside of the tubing but within the casing may ilow 'downwardly past the packer 49 as the assembly is moved upwardly. This mud pressure may be sufcient to hold the cement slurry which has been squeezed" into the formation in place until it hardens and prevent it from flowing back into the well. However, if additional pressure is necessary or desirable, the tubing I2 may be run into the well through a blowout preventer or other packing means at the surface. Mud or other fluid can then be forced downwardly'under pressure through the tubing while the tubing is being removed from the well and the mud pressure on the'formation into which the cementvhas been squeezed thus ,maintained higher than that which prevails inside the tubing l2 while it is being disjointed at the surface, this excess pressure being held upon the formation by the back pressure valve. In other words, 4the tubing and packer assembly may be pumped out of the well.

in the drawing, it is possible to circulate cement Aslurry out of the tubing if -it is found that there is more .cement in the tubing than ycan be squeezed into the formation. The circulating sub is such that it may be opened for any desired length of time and then again closed and held in locked position by the pin and J-slot arrangement.

While only one embodiment of the invention has been shown and described herein, it is obvious that various changes may be made both in the structure and method without departing from the spirit of the invention or the scope of the annexed claims.

I claim:

l. Apparatus adapted for use in forcing sealing uid under pressure into an oil well, including a conduit, a packer mountedon the conduit, slips also mounted o'n the conduit, and mechanism for operating said slips to cause the same to secure the conduit and packer to casing in the well, said mechanism including wedge means for actuating the slips and means connecting said wedge means to said conduit, said connecting means being adapted to shear upon a predetermined shear stress being exerted thereon and means mounted on the conduit and engaging said wedge means and adapted to draw the wedge means inwardly to entirely disconnect said packer and conduit from the casing when said connecting means is sheared.

2. Apparatus adapted for use in forcing fluid under pressure into an oil well, including a ccnduit, a packer mounted on the conduit and mechanism for connecting the conduit and packer to casing in the well, said mechanism including slip means for gripping the casing and an actuating device for operating said slip means, said actuating device including a wedge member connected to said packer and operable to release said conduit and packer upon the exertion of a predetermined upward pressure upon said packer.

ing the lower end of said conduit to casing'in the well, said arrangement including a packer mounted on the conduit, casing gripping means mounted on the conduit adjacent said packer, means for setting the gripping means and means operable inresponse to fluid pressure conditions inthe well beneath said packer to release said gripping means.

4. Apparatus adapted .for use in lforcing sealing fluid under pressure into an oil well including a conduit adapted to be lowered down through casing in the well, a swab rubber mounted inverted upon thelower end of said conduit, means for securing the lower end of said conduit to 'the casing whereby the swab rubber may be held against movement while iluidvis forced downwardly through the conduit, said means including slips and mechanism operable in response to 4 variations to fluid pressure above and beneath said swab rubber for releasing said slip, the arrangement being such that said securing means and said swab rubber may be removed from the well. l

5. 'I'he method of sealing a formation beneath casing in a well which consists of lowering into the well a conduit, securing and sealing the lower end of the conduit to the casing in the well at a point above the formation to be sealed, placing sealing fluid in the conduit, forcing the sealing fluid down through the conduit by placing in the conduit a following fluid, increasing the pressur' on the following fluid to squeeze somewr all of the sealing fluid into the formation, disconnecting the conduit from the casing and moving the conduit upwardly while holding the sealing fluid in place vin the formation by exerting` pressure onthe following fluid in the well.

6. Apparatus adapted -for use in forcing iluid under pressure into an oil well including a conduit and an arrangement fors'ecuringand sealing the lower end of said conduit to casing. in the well, said arrangement including casing gripping means, a packer, means for actuating said casing-gripping means and meansfor releasably maintaining said casing gripping means in casing gripping position releasably by predetermined iluid pressure beneath said packer in excess of the fluid pressure on the outside of 'said conduit above said packer. v

7. Apparatus adapted for use in squeeze cementing wells, comprising,in combination, a conduit adapted -to be run into a well, a circulating sub incorporated in said conduit, a packer mounted on the'conduit above the discharge end thereof and below the circulating sub and means for securing said conduit, and said packer to the casing to hold the same against movement while the cementing operations are carried on, said securing meansbeing releasable hydraulically in response to a pressure vdifference above and below said packer, whereby the entire assembly can be removed from the well after the cementing operations are completed. v

8. Apparatus adapted for use in squeeze cementing wells, comprising, in combination, a conduit adapted to be run into a well, a circulating sub incorporated in said conduit, an inverted swab cup mounted on the conduit above the discharge end thereof and below said circulating sub and means for securing said conduit and said swab cup to the casing, to hold the same against movement while the cementing opera-V tions are carried on, said securing means being releasable hydraulically, whereby the entire combination can be removed from the well after the cementing operations are completed.

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