US1444230A - Oil-well-casing tightener - Google Patents

Description

Feb. 6, 1923..

S. CRAWFORD.

OIL WELL CASING TIGHTENER.

FILED FEB. 231922.

V YKMA 1/ mwnz w, 602721191 6 0/701 (2 Patented Feb. 6, 1923.

PATENT SAMUEL CRAWFORD, OF MENOMINEE'JJIICHIGAN.

OIL-WELL-CASING TIGHTENER.

Application filed February 23, 1922.

T all whom it may concern:

Be it known that I, SAMUEL CRAWFORD, a citizen of the United States, residing at Menominee, in the county of Menominee and State of Michigan, have invented a certain new and useful Improvement in Oil-Vell- Casing Tighteners, of which the following is a specification.

My invention relates to means for preventing the seepage or leakage of water under the casing of an oil well, and particularly to means for keeping such casing in so close contact with the bottom of the bore that a sealing water-tight connection is made and the water cannot leak in about the open bottom of the casing and flow upward y into said casing. Other objects will appear from time to time in the course of the specification.

My invention is illustrated more or less diagrammatically in the accompanying drawings, wherein Figure 1 is a vertical section through an oil derrick, diagrammatically illustrating the casing and the bore;

Figure 2 is an enlarged section on the line 22 of Fig. 1;

Figure 3 is a section on the line 3-3 of Fig. 2;

30 Figure 4c is a section on the line l4 of Fig. 2;

Figure 5 is a section corresponding to Fig. 1, through a slightly difierent arrangement of the holding means.

Like parts are illustrated bylike characters throughout the drawings.

A is any suitable oil drilling derrick, comprising in part the heavy beams or sills B and the floor C, upon which rests any suitable hoisting machinery D, comprising in part a drum E and the cable F. Upwardly projecting through the floor, which is apertured substantially to fit it, is the easing pipe G, which projects downwardly intothe bore H and is formed of sections joined by any suitable collars I. The bore is diagrammatically illustrated as considerably larger than the casing, but in fact the fit is closer than shown in the drawings. J J diagrammatically illustrate water-bearing strata through which the bore and casing pass downwardly toward the oil-bearing stratum at the bottom.

About t e uppermost collar 1 is secured.

Serial No. 538,517.

any suitable ring or clamp K, from which project diametrically opposed arms L L, of sufficient strength and rigidity to support a very considerable weight. The purpose of the ring and arms is to permit the casing to be forced downwardly through the bore, and any suitable means may be provided for exerting constant and heavy pressure upon the top of the casing to keep the bottom sealed against the bottom of the bore. In Fig. 1 I have diagrammatically illustrated one means of applying the pressure, wherein one of the arms L is pivoted to a link M which, in turn, is pivoted as at N to a memher i 1 adapted to grasp the sill beam B. The opposite arm L is penetrated by a screw-threaded shaft 0 having a crank arm P and being in screw-threaded engagement with the member R, which is in rigid relation with another sill beam.

Fig. 4 illustrates an alternative arrangement wherein the arms L L pass beneath the sill beams B B and may be wedged downwardly, as, for example, by the wedge S. Obviously, any suitable number of wedges or blocks might be interposed between the arms L and the beams, in order to maintain and adjust the downward pressure upon the casing.

It will be obvious that while I have shown and described an operative device, many changes might be made in the number, size, shape and relation of parts without departing from the spirit of my invention. I wish, therefore, that the drawings be taken as in a large degree diagrammatic.

The use and operation of my invention are as follows:

In drilling oil wells it is frequently, if not generally, necessary to drive the well through water-bearing strata. This water naturally tends to seep into the bore and either fill the bore with water or mix with and vitlate the oil when the oil has begun to flow. I have determined that an easy and simple method of keeping the casing free of water is provided by the applicationpf heavy pressure upon the top of the casing, which drives the bottom against the bottom of the bore and thus seals it. The water wh1ch fills or trickles down the outer bore is thus prevented from leaking around the bottom of the casing, whereas in present practice, @Pd Without such pressure, the casing may be either in sufiiciently loose contact with the bottom, or may be lifted by the vibration of the machinery or by the pressure or the water suiiiciently to permit the damaging water seepage around and into the bottom.

The ease with which a long and heavy casing may be lifted is surprising, and applicant can, from experience, state that a cas ing hundreds of feet in length and weighing thousands of pounds may be manually lifted and-jiggled up and down by an operator standing on the floor of the derrick while the bottom of the casing is closed. The probable explanation of this is that the long casing, with the closed bottom the inte rior 01 large cubic capacity, which is kept pumped free of water, acts in some sort like a metal ship, which is intrinsically heavier than the water as to the material of which it is composed, but floats because it displaces a weight of water greater than the weight of the ship. The long casing, then, is in the nature of a floating vessel, an 1 one in which the weight of the casing and of the displaced water are delicately balanced; but whatever the explanation, the phenon enon undoubtedly exists. The movement of the casing being thus easy, obviously the play inside of the casing of the hoisting and boring machinery, and the various vibrations and plays caused by the operation of the machinery on the platform, are suillcient to loosen the contact of the casing with. the bottom of the bore. Therefore, the application of a weight or pressure to the top is necessary to hold it down and to seat it firmly on the bottom before breaking out the disc which closes the bottom of the casing, to continue the boring operation. I therefore show means for applying such pressure, consisting of a collar or ring which rests on a collar near the top of the top'section of the casing, and preferably under the derrick floor, as shown in Figure 4:. This collar may form a unit 'in the middle of a lever arm extending from one sill beam to the other, as shown in Figure 1. The whole weight out the scaffolding may be exerted downwardly upon the casing by rotation of the crank P. In practice it will be more convenient to have the leverage provided for beneath the sill beams and beneath the floor, and in Fig. 4E1 have illustrated an arrangement wherein the lever arm or arms are thus positioned. Any suitable means may be used to force the casing down, but I have illustrated a wedge driven between one of the arms and the beam above it. Obviously a number of wedges It has been the custom in the past to deal.

with the leakage problem in a number of ways, and, among others, by cementing the casing in place at the bottom of its bore. This particular method is expensive and iiiconvenient, since in case or iailure, oi or any other. cause for removing the casing, it lined in place and must be cut away above the cemented portion. Packers of rubber have also been used but are expensive and inconvenient. All the old methods are dithcult and expensive, and in case of failure the casing must be withdrawn, but by my process the tightening operation is carried out from the top of the casing, although without preventing withdrawal in case withdrawal is for other reasons necessary.

It will be obvious that while I have described and illustrated a process and an apparatusin which the weight of the derrlck is applied to the top 0]": the casing, any other means of applying weight or pressure to the top of the casing might be used. For er:- ample, members might be sunk in the ground and the casing be secured to them, or a heavy weight might be hung about the end of the casing, but the described process and apparatus is particularly applicable to that large class of wells in which a relatively large and heavy scafi'olding is employed.

I claim:

l. The process of preventing water leakage in an oil well, which consists in sealing the bottom or the well casing to the bottom of the bore by the application of heavy pressure to the top of "the casing.

2. The process of preventing water leakage in an oil well, which consists in applying heavy pressure to the top oi the well. casing.

The process of preventing water leak a e in anoil well, which consists in sealing the bottom of the well casing to the bottom of the bore by the application of heavy pressure to the top of the casing and in sehuring said casing permanently under pres sure. I

4. The process of preventing water leakage in an oil well, which consists in applying heavy pressure the top of the well casing and in securing said casing perma nently under pressure.

5. The process of preventing water leakage in an oil well, which consists in sealing the bottom of the well casing to the bottom of the bore by the adjustable application oi heavy pressure to the top of the casing.

6. The process of preventing water leakage in an oil Well, which consists in adjustably applying heavy pressure to the top of the Well caslng.

7. A Water leakage preventer for Oll Wells, which comprises a member adapted to engage the top of the oil Well casing and menihers connected thereto adapted to be secured to the superstructure oi the Well.

8. The process of preventing Water leakage in an oil Well, which consists in applying to the top of the Well casing the Weight of the derrick.

9. The process of preventing Water leakage in an oil Well, which consists in applying heavy pressure to the top of the casing and in bracing said casing against the derrick frame in order to maintain such pres sure.

10. Means for preventing Water leakage in an oil Well, "which comprises a member secured to the top of the oil Well casing, lever members connected thereto, and means for securing one of said levers in relation to the Well derrick, and means for applying pressure to the opposite lever member.

11. Means for preventing Water leakage in an oil Well casing comprising a member securel to the top of the oil Well casing, members outwardly projecting therefrom and means for securing them in relation to the Well derrick structure, and means for applying pressure to said members.

Signed at Chicago, county of Cook and State of Illinois, this 17th day of February SAMUEL CRANFQRD.

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