US2207345A

US2207345A - Means and method of cementing wells

Info

Publication number: US2207345A
Application number: US197631A
Authority: US
Inventors: Hammer Otto
Original assignee: SECURITY ENGINEERING CO Inc
Current assignee: SECURITY ENGINEERING Co Inc
Priority date: 1938-03-23
Filing date: 1938-03-23
Publication date: 1940-07-09
Anticipated expiration: 1957-07-09

Description

July 9,1940. o. HAMMER 2,207,345

MEANS AND METHOD OF CEMENTING WELLS -YWLWWILQLM July 9 1940- o. HAMMER i 2,207,345

MEANS AND METHO 0F CEMENTING WELLS Filed March 25, 1938 2 Sheets-Sheet 2 L2-G, .4 EG, 5

EKG,

077-0 A2M/m96 Patented July 9, 1940 UNITED STATES PATENT OFFICE Otto Hammer, Whittier,

Calif., assignor to Security Engineering Co., Inc., Whittier, Calif., a corporation of California Application March 23, 1938, Serial No. 197,631

Claims.

This invention relates to a means and method for cementing casings andthe like in wells.

An object of the invention is to provide an irnproved means and method for cementing casings 5 which will assure that clean, mud-free cement will be positioned and set up around the casing shoe so as to secure a dense, tight cement structure around the casing shoe in all types of formations. l A conventional practice heretofore employed in cementing casings in wells is to force cement slurry down through the casing to be discharged at or very close to the bottom of the casing shoe. When this practice is indulged in, there is a decided tendency for the cement slurry, as it is discharged, to ow unevenly up past the casing shoe and tochannel. The uneven flow has a tendency to -set up eddy currents which are apt to cut the walls of the hole near the casing shoe and cause the slurry to become contaminated. Also, there is danger of opening large, irregular cavities around the bottom of the casing and there is danger that the poorest cement, namely the mud cut tailings, will remain at the casing lshoe where the strongest and densest cement should be. In other words, the charge of cement slurry is usually forced down through the casing by means of a cementing plug which is intended to isolate the cement from the mud on top of the cementing plug which is forcing the cement down through the casing. However, these cementing plugs frequently leak and the top of the charge thus frequently becomes contaminated with the mud that is forcing the cementing plug downwardly. The contaminated cement immediately below the plug forms the tailings which are the last of the charge to be discharged from the casing. Consequently, the contaminated tailings will remain adjacent the casing shoe, whereas the 0) densest and strongest cement of the charge should be positioned around the casing shoe.

It is an object of the present invention to provide an improved means and method for cementing casing wherein mud or well fluid in the well will be displaced inwardly from around the casing shoe by the cement and the tailings kept in such a position in the well that they will be capable of subsequently being drilled up and re-f moved, leaving only dense and strong cement around the casing shoe.

Another object of the invention is' to provide a means and method for cementingA casing which makes provision for holding the casing centrally of the well hole while the cementing operation is taking place.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Figure 1 is a vertical section through the bottom of a well illustrating the casing and the attached guide forming a part of the present invention in side elevation therein and illustrating the parts in the position when cementing is about to take place;

Fig. 2 is a view similar to Fig. 1, parts of the casing and guide being broken away and shown u in vertical section, and illustrating cement as having been discharged from the casing into the well.

Fig. 3 is a sectional view illustrating the manner in which the guide and tailings are removed after the cement has set;

Fig. 4 is a sectional view through a well, parts being broken away to illustrate a slightly modiiied form of construction of guide that may be employed;

Fig. 5 is a sectional view through the bottom of a well, illustrating a modied form of construction and method wherein provision is made for holding the casing centrally of the well while the cementing is taking place;

Fig. 6 ls an enlarged vertical section through the valve shown in Fig. 4; and

Fig. 7 is a horizontal section taken substantially upon the line 'l-I upon Fig. 6.

Referring to the accompanying drawings, wherein similar reference characters designate similar parts throughout, and referring specifically to Figs. 1, 2, and-3, I0 designates the walls of a well which has been drilled to the bottom I I and in which it is desired to cement casing I2 having a casing shoe I3. To accomplish the cementing of the casing, in accordance with the present invention, the casing shoe I3 is provided with a reducer I4 and a suitable length of tubing I5. The reducer I4 and the tubing I5 may be of any suitable length but in the preferred form of construction, their length is'from six to twelve feet overall. 'I'hese parts are formed of a readily drlllable material. The preferred material used in that alloy or composition now known on the market as Securaloy. This Securaloy -is in the nature of an aluminum alloy possessing considerable strength but which has the property of being readily drilled up by conventional well drilling tools. Any other material may be substituted therefor which possesses the property of being capable of being quite readily drilled up.

'I'he reducer I4 and the tubing I5 cooperate to form a downwardly extending drillable guide extending downwardly from the casing shoe. In

the preferred form of construction, the diameter of the tubing I5 is somewhat smaller than the diameter of the casing I2, hence the requirement for the reducer I4. The small diameter `provides a relatively large clearance or space I6 between the guide and the well walls I0. The casing with its attached guide are positioned in the well so that the casing shoe I3 is some distance above the bottom II, while the bottom of the guide I5 is positioned very close to bottom II. The charge of cement is then placed in the casing and the cement plug positioned thereover. Drilling mud is then used to force the charge and the cement plug downwardly through the casing. The cement is discharged at the very bottom of the well through the bottom of the guide or tubing I5 with the result that the cement will displace the mud or well uid in the well upwardly around the guide I5 and upwardly around the casing shoe I3 and the bottom of the casing I2. As the space I6 is relatively large as compared with the space between the casing shoe I3 and the well walls I0, the discharged cement has an opportunity to smooth out as it ows upwardly around the drillable guide I5. In this way, the tendency of eddy currents being set up is materially reduced. The danger of channelling is also reduced and as the mud or well iluid at the bottom of the well is displaced upwardly by the cement slurry, the danger of contamination of .the cement is minimized.

ployed in the charge, however, so as to completely flll the bottom of the hole around the drillable guide I5 and to extend up well above the casing shoe I3. When the cement is discharged, it is allowed to set and thereafter, a drilling bit indicated at I8, is lowered on drill pipe I9 through the casing and drills out the drillable reducer I4 and the drillable guide I5. The tailings which remain in the drillable guide and which may have become contaminated, are, drilled out at the same time leaving a clean cemented bottom in the well below the casing shoe. The remaining cement .which is not drilled up is dense and lvery strong and the cement positioned on the outside of the casing shoe I3 will be found to be uncontaminated and hard and clean. When the drillable guide and its contained cement are removed, the well is then in condition for further drilling operations.

In Fig. 4, I have illustrated the adaptability of the present invention to situations requiring that the casing be oated into the well. In this form of construction the casing has the casing shoe 2|, the drillable reducer 22, and the drillable pipe orguide 23. A float valve generally designated at 24, is positioned at the juncture of the reducer and the drillable guide. 'I'his float valve comprises a drillable disc which may be formed o1' Securaloy, compressed fiber, or any equivalent readily drillable material. "It provides a seat 26-for an upwardly closing valve 21 having an attached spider 28 made up of radial ribs equipped with shoulders 29 adapted to engage the top of the disc 25 to keep the valve associated with the disc. The spider may be threadably attached to the valve 21 as by threads 30.

In this form of construction, when the casing is lowered into the well, the fioat'valve closes upwardly so as to close the bottom entrance to the casing, enabling it to be floated into the well into position. When the construction is positioned as shown in Fig, 4, the cement is forced downwardly through the casing and is discharged from the bottom of the drillable pipe or guide 23. vThe discharged cement displaces the mud or well fluid 4upwardly as previously explained and the tailings are allowed to remain in the guide. When the cement has set, the drillable reducer and the tube or guide 23, together with the float valve 24, are drilled up as previously explained, leaving the casing shoe tightly cemented in place in the well with very dense, clean cement.

In Fig. 5, I have illustrated an alternative form of construction which facilitates the centering of the casing in the well. In cementing the casing in accordance with this means and method,

the well has a rat hole 3l drilled in the bottomthereof centrally of the well 32. The casing 33 has the casing shoe 34, the drillable reducer 35, and a drillable tube or pipe 36. A float valve corresponding to float Valve 24 may or may not be employed, as desired. 'I'he rat hole 3| has a diameter slightly larger than lthe exterior diameter of the drillable guide or tube 36, and

when the casing is lowered into the well, the bottom of the guide or tube 36 is caused to enter the rat hole. In this form of construction, the bottom of the guide 36 is preferably closed by means of a drillable bull nose 31, and the outlet from the guide is provided by a series of apertures 38 so arranged as to be positioned at the top of the rat hole or at the bottom of the well 32. In this form, the cement is discharged into the-well in the same manner as that previously described, with the exception that the cement, instead of being discharged through the bottom of the drillable guide or pipe 36, is discharged through the apertures 38 and displaces the mud or well fluid in the well from the top of the rat hole upwardly. Whenthe cement has set, the reducer 35, the drillable guide 36, and the drillable bull nose 31, together with the contained tailings are drilled up as previously described. This form of construction has the advantage that the lower portion of the drillable guide 36 which enters the rat hole 3| servesto hold the casing 33 and the casing 34 centrally of the well hile 32 while the cementing operation is taking p ace.

From the above-described means and method, it will be appreciated that by the present invention it is possible to position clean, dense, uncontaminated cement around the casing so as to effectively form a tight water seal around the casing shoe. Thereafter, as the guide is readily drillable, the guide and its contained tailings can be readily removed by the conventional well drilling equipment, leaving the hole below the cement seal free and open for further drilling operations.

Various changes may be made in the details of construction Without departing from the spirit or scope of the invention as defined by the appended claims.

I claim:

1. 'Ihe method of cementing casings in wells which comprises attaching to the lower end of the casing a readily drillable guide, the outlet from which is spaced a minimum distance below u the bottom of the casing of approximately six feet, lowering the casing with the attached guide into the well in such a manner that the bottom of the casing and at least the top of the guide will be in spaced relation to the well walls to afford an unobstructed annular .space around the top of the guide and the bottom of the casing through which cement may freely ow upwardly, forcing cement down through the casing and through the guide and causing it to be discharged through the outlet from the guide to displace fluid in the well above the outlet in an upward direction thus filling the annular space between the guide and the well walls above the outlet and between the bottom of the casing and the well walls and allowing the cement to harden or set.

2. The method of cementing casings in wells which comprises attaching to the lower end of the casing a readily drillable guide, the outlet from which is spaced a minimum distance below the bottom of the casing of approximately six feet, lowering the casing with the attached guide into the well in such a manner that the bottom of the casing and at least the top of the guide Will be in spaced relation to the well walls to afford an unobstructed annular space around the top of the guide and the bottom of the casing through which cement may freely flow upwardly, forcing cement down through the casing and through the guide and causing it to be discharged,

through the outlet from the guide to displace fluid in the well above the outlet in an upward direction thus filling the annular space between the guide and the well walls above the outlet and between the bottom of the casing and the well walls and allowing the cement to harden or set, and subsequently drilling up the guide and cement below the bottom of the cemented casing.

3. The method of cementing casings in wells which comprises attaching to the lower end of the casing a readily drillable guide of smaller diameter than the casing, the outlet from which is spaced at least approximately six feet below the bottom of the casing, lowering the casing with the attached guide into the well in such a manner that the bottom of the casing and at least the top of the guide will be in spaced relation to the well walls permitting cement to ow freely up around the guide and the bottom of the casing to lll the space between the bottom of the casing and the well walls, forcing cement down through the casing and through the guide and discharging it through the outlet in the guide to displace fluidv in the well above the outlet in an upward direction thus filling the space between the guide and the well walls above the outlet and between the bottom of the casing and the well walls, and allowing the cement to harden or set.

4. The method of cementing casings in wells which comprises attaching to the lower end of the casing a readily drillable guide of smaller diameter than the casing, the outlet from which is spaced at least approximately six feet below the bottom of the casing, lowering the casing with the attached guide into the Well in such a manner that the bottom of the casing and at least the top of the guide will be in spaced relation to the well walls permitting cement to ow freely up around the guide and the bottom of the casing to fill the space between the bottom of the casing and the well walls, forcing cement down through the casing and through the guide and discharging it through the outlet in the guide to displace fiuid in the well above the outlet in an upward direction thus lling the space between the guide and the well walls above the outlet and between the bottom of the casing and the well walls, stopping the discharge of cement from the guide when the tailings are within the guide, and allowing the cement to harden or set.

5. The method of cementing casings in wells which have rat holes formed in the bottom thereof which comprises attaching to the lower end of the casing a readily drillable guide capable of entering a rat hole and having an outlet which is spaced at least approximately six feet below the bottom of thel casing, lowering the casing with the attached guide into the well in such a manner that the guide will be caused to enter the rat hole and thus hold the top of the guide and the bottom of the casing in spaced relation to the well walls providing an annular lspace between the top of the guide and the well walls and between the bottom of the casing and the Well walls through which cement may be freely forced upwardly, forcing cement down through the casing and through the guide and discharging it through the outlet so a's' to displace fluid in the well above the outlet in an upward direction thus filling said annular space, and allowing the cement to harden or set.

6. The method of cementing which includes forming a rat hole in the bottom of the well, attaching to the casing to be cemented a readily drillable guide capable of entering the rat hole to hold the casing centrally of the well hole, forcing cement downwardly through the casing. and causing it to be discharged from the guide adjacent the top of the rat hole and to ow therefrom upwardly around the guide and casing, allowing the cement to set, and thereafter drilling up the guide through the casing.

7. An apparatus useful in cementing casings comprising an elongated tubular drillable guide attachable to the bottom of a casing shoe and having its outlet spaced a substantial distance downwardly from thebottom of the casing shoe.

8. An apparatus useful in cementing casings comprising a drillable reducer and an elongated drillable guide attachable to the bottom of a casing shoe and having an outlet spaced a substantial distance downwardly from the bottom of the casing shoe.

9. An apparatus useful in cementing casings comprising a drillable reducer and an elongated drillable guide attachable to the bottom of a casing shoe and having an outlet spaced a substantial distance downwardly from the bottom of the casing shoe, said guide being equipped with a drillable float valve.

10. An apparatus useful in cementing casing comprising a drillable guide having an elongated drillable float valve, said drillable guide being attachable to a casing shoe and having an outlet spaced a substantial distance downwardly from the casing shoe.

11. An apparatus useful in cementing casings comprising an elongated tubular drillable guide attachable to the bottom of a casing shoe and of smaller diameter than the casing to which it is attached, said guide having outlets in the side walls thereof spaced a substantial distance downwardly from the bottom of the casing shoe.

12.'An apparatus useful in cementing'casings comprising a drillable reducer and an elongated drillable guide attachable to the bottom of the casing shoe, said guide having outlets in the side walls thereof spaced a substantial distance downwardly from the bottom of the casing shoe.

13. An apparatus useful in cementing casings comprising' a drillable reducer and an elongated drillable guide attachable to the bottom of the' casing shoe and having an outlet spaced a substantial distance downwardly from the bottom of the casing shoe, and a valve permitting downward flow through the reducer and guide but preventing reverse flow upwardly therethrough.

14. An apparatus useful in cementing casings comprising an elongated tubular drillable guide attachable to the bottom of a casing shoe and having its outlet spaced a substantial distance downwardly from the bottom of the casing shoe.

15. An apparatus useful in cementing casing comprising a drillable reducer and an elongated drillable guide attachable to the bottom of the casing shoe and having an outlet spaced a substantial distance downwardly from the bottom of the casing shoe.

16. An apparatus useful in cementing casngs comprising a drillable reducer and an elongated drillable guide attachable to the bottom of the casing shoe and having an outlet spaced a substantial distance downwardly from the bottom of the casing shoe, said guide being equipped with a drillable float valve.

17. An apparatus useful in cementing casings comprising an elongated drillable guide having a drillable oat valve, said drillable guide being attachable to a casing shoe and having an outlet spaced a substantial distance downwardly from the casing shoe.

18. An apparatus useful in cementing casings comprising a drillable reducer and an elongated drillable guide attachable to the bottom of a casing shoe located at the bottom of a casing and having an outlet spaced a substantial distance downwardly from the bottom of the casing shoe, a drillable oat valve being interposed between the casing and the outlet.

19. An apparatus useful in cementing casings comprising an elongated drillable guide attachable to a casing shoe located at the bottom of a casing, and having an outlet spaced a substantial distance from the casing shoe and a drillable oat valve interposed between the casing and the outlet. i

20. The method oi cementing casings in wells which comprises attaching to the lower end of the casing a readily drillable guide the outlet from which is spaced a minimum distance below the bottom of the casing of approximately six feet, lowering the casing with the attached guide into the well and suspending the casing in the Well without seating it, forcing cement down through the casing and through the guide while the casing is thus suspended, and causing the cement to be discharged through the outlet from the guide to displace fluid in the well above the outlet in an upward direction thus filling the space between the guide and the well walls above the outlet and between the bottom of the casing and the well walls, and allowing the cement to harden or set.

O'I'IO HAMMER.