US2033560A - Refrigerating packer - Google Patents

Description

March 10, 1936..

w. T. WELLS 4REFRIGERATING PACKER original Fiied Nw*A 12, 1932 EE-E55 till "uw INVENTOR' TM/ZAS @/L. ORNE Y o c ...'.i

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Patented Mar. 1o, 1936 UNITED STATE-s PATENT OFFICE REFRIGERATING PACKER Walter T. Wells, Glendale, Calif., assignor to The Technicraft Engineering Corporation, Los Angeles, Calif., a corporation of California.

Application November 12, 1932, Serial No. 642,369 Renewed August 20, 1934 11 Claims.

The present invention relates to refrigerating packers andis a renewal of my previous application entitled: Means for packing oil wells and the like`, iild: November 12, 1932, Serial No.A

First, to provide a packer of this characterA which has a wide range of application, it being subsequent drilling Y producing stratum 4. y

The device hereinafter described is operated -in association with a dividedtubing string wheres.

useful in performing for such operations as formation testing or testing for shoe leaks, location of water intrusion in oil or gas wells, fractures in cement jobs, and segregation or orientation of oil or water producing zones in bores of great depth, breaking up cement that has been setto facilitate its removal, cleaning the well bore of mud accumulations, and many other USGS;

Second, to provide a packer of this character which provides an adequate and positive seal in open holes, yet may t quite loosely in the well bore so that danger of hanging up in the well is practically eliminated;

` Third, to provide a'packer of this character which in no manner damages or interferes with or other operations in the well bore; i

Fourth, to provide a refrigerating packer which incorporates a sampler or formation ltesting instrumentality; and

Fifth;v to providevon the whole a novelly arranged refrigerating packer which is simple of construction proportional to its functions and which will not readily deteriorate 'or fail' in use. i With these and other objects in view as may' appear hereinafter, attention is directed to the accompanying drawing in which Figure 1 is a substantially diagrammatical vertical cross sectional Vview of my refrigerating packer in posiin two sections of said tubing are provided with meansrpermitting relative movement of the sections and said movement is utilized to expel a refrigerating agent for the purpose of solidifying all water-bearing matter cognate to said tubing string. Y

Butone-sting of tubing is employed and it serves several purposes. Said string is run into the well dry, that is to say, closed at the b ottom to'keep it empty of fluid as it is lowered into drilling fluid or the like.

It thus provides a conduit for the dischargev refrigerating agent at substantially atmospheric pressure. When subsequently opened,it affords 'a means of communication with the producing zone below the frozen area for the recovery of a sample of iiuid therefrom, and for circulating, from the mouth of the well, a stream of liquid to expedite thawing or to create hydraulic pressure in the zone below the frozen core.

The lower end of tubing I (upper section) is threaded to receive collars 6 and 1. Between said collars is a piston 8, provided with ringsv 9 and cup leathers II. f

Slidable within the tubing I is the upper end h member I2 of the lower section of tubing string I. Welded or suitably secured to member I2 is a cylinder head I3 to which is threaded, at I I, one end of a cylinder I6, the opposite end of which is threaded at I1 to a cylinder head I8,

'provided with a packing gland I9 through which slides the tubing I.

`The structure so far described provides a cylindrical chamber 2I which is loaded, before the device is lowered into the well 2, with a refrigerant 22, which may be anhydrous ammonia, carbon dioxide, sulphur dioxide, or other suitable equivalent. I

The member I2 ls threaded into a bore 23 in a connector 24.' Said bore is enlarged from below and tapped to admit therein a threaded collar' 28, a'valve cage 21, and one end of a pipe 28 provided with perforations 29.

A rigid connection is thus formed between perforated pipe 28 and member I2 and it results from this that, when pipe 28 encounters the bottom of well 2, cylinder I6 is held stationary and the weight of the entire upper-section of the tubing string I is effective to move piston 8 through said cylinder and expel the refrigerant 22 through an expansion-valve 3l which, under urge of a spring 32, normally closes one end of a pipe coil 33, here shown as a double lng in a valve cage 34.

I indicated at 5I.

As the weight of tubing string I moves piston 3 downwardly, the space behind said piston is filled with drilling fluid 36, from well bore 2, which enters through passages 31 and 38 normally closed by a spring actuated check valve 39.

The refrigerant 22, under pressure, unseats expansion valve 3|, passes through coil 33, lifts a flapper valve 4I (in valve cage 34) to its dotted line position and exhausts into member I2 of the dry tubing string.`

The rapid expansion of the refrigerant, thus released, congeals the liquid surrounding the coil 33 and solidifles an area of considerable size in the adjacent formation as indicated by the broken line shaded area A in Figure 1.

This means of sealing or packing an open hole or formation bore, which has no casing, assures a.fluid tight seal between'the tubing string and a surrounding wall which is completely effective, irrespective of inequalities or irregularities of surface, or formation characteristics, which so often defeat mechanically operated packers.

The tubing string I has been kept dry up to this point by a membrane or disc 42 compressed between collar 26 and pipe 23 in a manner obstructing passage of liquid into member I2.

When the refrigerating action has taken place, a go-devil indicated in dotted lines at 43 is dropped through tubing string I, from the mouthl of the well, and it strikes the top of a piston valve 44, which rests on said disc 42 and is thereby prevented from seating in its cage 21 until said disc is broken out as described.

As soon as said disc is broken, fluid in the zone below the frozen area isA released at substantially atmospheric pressure, and it rushes into member I2 of the tubing string, lifting piston 44 until it abuts collar 26. Said piston is provided with quadrilaterally disposed channels 46, Figures 2 and 3, which communicate with a bore 41 in collar 26.

Fluid continues to rise in the tubing string until it reaches its normal head, being relieved of hydrostatic pressure of drilling fluid in the well by the frozen area 33.

When the pack thaws 33 sufllciently to permit raising of the tubing string, .piston valve 44 acts as a foot valve, entrapping the fluid content of the tubing, as the lower tapered end of said valve seats in cage 21 and closes channels 46.

Check valve 31 prevents escape of drilling fluid from cylinder I6 and said fluid, being entrapped, forms a connecting link between the upper and lower sections of tubing string I, automatically responsive to the first lifting strain.

Said check valve 31 also provides a means for applying pump pressure to piston 3 as shown in Figure 3. Should it be desirable to augment the pressure provided by the weight of tubing string I, a pump 43 is connected, by a pipe line 29, to the well 2 which is closed at the mouth as As the pump increases the pressure inthe well, valve 3| is unseated and piston 8 moved downwardly to discharge refrigerant 22.

It is of course recognized that heat resulting from compressing of the refrigerant before opening of valve 3| must be dissipated to obtain an efficient refrigerating action in coil 33. This may be accomplished in severalj ways. First. the refirigerant may be introduced in the cylinder 2| under pressure; but such pressure being lower than that necessary to open valve 3|. Then upon applying additional pressure either through tubing string I or hydraulically through valve 31, the valve 3| is caused to open. .The additional pressure need not be such as to heat the refrigerant materially; furthermore, the chamber 2| is quite elongated and the pressure therein may be maintained fairly uniform after the valve 3| is open so that a large percentage of such additional heat will be dissipated through the walls of the cylinder. Very little of this heat will be absorbed by the chilling coil as heat tends to be dissipated upwardly.

Second, as the refrigerator is lowered, the liquid in the well bore tends to maintain an equality of pressure between the exterior of the refrigerator and the upper end of the piston 3, providing valve 31 does not oer too much resistance. This pressure increase lifts the refrigerator structure relative to the tubing string, moving the piston relatively downwardly and compressing the refrigerant. In this case as in the flrst, valve 3| is designed to withstand this pressure. The movement of. the piston is gradual and the heat of compression is dissipated to the well fluid as fast as it is generated, so that the temperature of the refrigerant does not increase materially. When the refrigerator is in position, additional pressure either hydraulically or by gravity is applied to open valve 3|.

Third, valve 31 may be designed to remain closed against the pressure of the well fluid. After the refrigerator is in position, the tubing string is moved downwardly, shifting the piston a predetermined distance calculated to compress the refrigerant but not open valve 3|, and is then held until the resulting heat is dissipated; whereupon the additional pressure is applied.

Pump pressure can also be applied to tubing string I to flush the formation below the frozen zone, or to increase pressure at that point.

A check valve 52 is provided in the piston valve 44 and' said valve normally closes a port 53 under urgeof a spring 54. However, when said check valve is unseated, fluid enters the port 53 and finds its way through passages 56 which open into a bore 51 in valve cage 21, when the piston valve is seated in said cage.

The piston valve '44, check 52, and cage 21 are also shown and described in my co-pending application for patents, filed September 6, 1932, Serial Number "631,781,

In order to prevent accumulation of frost around expansion valve 3| and its orifice I load coil 33 with an inert fluid containing no moisture. Said fluid is also placed in the lower portion of pipe I2 to a level indicated by the dotted line 58, Figure 1. Said fluid isA driven out of coil 32 by the release of refrigerant 22 vahead of piston 8. l

It will be seen that pipe 26 can be removed from the foot member 24 and other anchoring means substituted therefor. n

I employ a standard thread which makes possible the interchangeable use of either a rat-hole packer of the type illustrated in my co-pending application, Serial Number 634,599, filed September 23. 1932, or a hook-wall packer such as is described in my application Serial Number 614,731, filed June l, 1932.

The operation of my invention is as follows:

Formation test-During the drilling of an oil well, the bit progresses into the ground or formation, passing through various strata. The obk:lect is to terminate the well when a formation has been reached containing a supply of oil or gas in quantity sumcient for practical production. While the lwell is being drilled it contains a quantity of mud-laden iiuld, known as drilling fluid. This fluid exerts pressure, dependent upon the height of the fluid, which opposses the natural pressure of the oil or gas contained in the formation through which the well is being drilled.

. Oil is `usually encountered in formations at considerable depth and at pressures insufcient l to overcome the pressure of the fluid in the Well.

As the driller does not know the depth at which oil may be present, and to prevent drilling on past an oil bearing -stratum or formation without knowledge of its existence, a formation test is made to determine the productivity at a given depth. A

My apparatus is assembled as shown in Figure 1 and lowered into the well 2 on the lower end of tubing-string I, the lower section of which is movable with respect to the upper section, said movement being limited to the degree of travel of piston 8 in cylinder I6..

When the lower end member 28 of the bottom section encounters the bottom of the well, the weight of the upper section moves piston 8 and displaces the refrigerant 22, the rapid dissipation of which lowers the 4temperature in the zone surrounding the coil 33 until a pack or seal A is solidified and seals oi the drilling fluid 3 from formation below.

When the well has been packed in this manner, go-devil 43 is dropped through tubing string I 'and its impact shatters the frangible disc 42,

opening the tubing string I to the inux of fluid from the formation 4. Said uid, being now opposed by no pressure other than atmospheric, rises within the tubing string I to its natural head or level.

extrusion of water from upper levels into oil producing formation. Laws, enacted in the interest of the eld as a whole, require a test furnishing proof that this water shut off is complete.

A cementitious material is introduced through the casingl and allowed to set around the casing and below its lower end for a considerable distance. The cement plug so formed is then drilled through, the bore extending beyond the casing and into formation below. As it is impracticablev to bail out the casing at great depths owing to danger of collapse of casing under external pressure, it is necessary to` pack within the casing and near the shoe and thereafter recover a sample of the content of formation below.

In this instance, only the relatively small volurne of fluid between the casing and the drill stem need be solidified to effect a pack.

A quantity of refrigerant 22 is injected through a loading bore 59, Figure l, through the cylinder head i3, and said bore is closed by a plug 6I.

The device is lowered as before and the drill-- ing fluid solidified at a point above the shoe of the casing, go-devil 43 is dropped to open the tubing string I to admit a sample of fluid through pipe 28. The seal is allowed to thaw and the entrapped sample recovered as previously described.

Removing coated accumulations from formation waZl.-Formation walls become plastered or encrusted with drilling fluid which impedes ltration of oil into the bore. The weight of the co1- umn of dense fluid and the action of the boring tool combine to produce this eiect.

As the accumulation contains water it can be removed by submitting itto alternate freezing and thawing and the solid content of the encruscomprising a refrigeration unit which includes a chamber adapted to hold an isolated body of rerigerant when the tool is lowered into the well, means for operatively connecting said unit with a contractable tubing string, andrmeans, responsive to contraction of said tubing string for operating said refrigeration unit.

2. Apparatus for testing a well comprising a tubing string, means dividing said tubing string into sections connected in a manner pron viding a limited degree of relative movement, means, associated with said sections, for storing an isolated batch of refrigeration agent while the apparatus including this means is lowered into a well, means, automatically operable in response to relative movement of said sections for circulating around and for liberating said refrigerant v through said tubing string, and means excluding pressure, other than atmospheric, from said tubing string.

3. Apparatus for testing a well comprising a tubing string, means dividing said tubing string into sections connected in a manner providing a limited degree of relative movement, means, asso-v ciated with said sections, for storing an isolated batch of refrigerating agent while the apparatus including this means is lowered into a well, means, automatically operable in response to relative movement of said sections for circulating around and for liberating refrigerant through said tubing string, means for excluding well fluid from said tubing string, and means, operable from the open end of said tubing string, for rendering said exclusion means inoperative.

4. The combination with a tubing string, of means dividing said string into connected sections provided with relative movement, a container for an isolated batch of refrigerating agent adapted to be lowered into position with a batch of refrigerant therein, means responsive to movement of one of said sections for expelling refrigerating agent from said container, closure means for excluding, from said tubing string,

fluid in which it is submerged, and means, con-l trolled from the open end of said string, for

opening said closure.

5. A well tool comprising tubing string sections connected in a manner providing a degree of relative movement, a cylinder for holding an isolated batch of refrigerant and carrying it into the well, said cylinder being movable with one of said sections, a piston reciprocable in said cylinder and movable with an adjacent section, a refrigeration coil connected at its intake -end with said cylinder and at its discharge end with one of salti tubing string sections, valve means, yieldable in response to relative movement of said cylinder and piston, controlling the release of said refrigerating agent, and closure means in the tubing positioned below the discharge orice of said coil for excluding pressure, other than atmospheric, from said tubing string.

6. A well tool comprising tubing string sections connected in a manner providing a degree of relative movement, a cylinder for holding an isolated batch of refrigerant and carrying it into the Well, said cylinder being movable with one of said sections, a piston reciprocable in said cylinder and movable with an adjacent section, a refrigeration coil connected at its intake end with said cylinder andat its discharge end with one of said tubing string sections, valve means, yieldable in response to relative movement of said cylinder and piston, controlling the release of said refrigerating agent, and closure means in the tubing positioned below the discharge orice of said coil for excluding pressure, other than atmospheric, from said tubing string, said closure constituting a disc of frangible material adapted to shatter under impact of a weight dropped through said tubing string. v

'7. In a Well apparatus for operation in conjunction With a tubing string havingtelescoping portions, a refrigeration device comprising a refrigerant container for holding an isolated batch of refrigerant and carrying .it into the well and a freezing coil, adapted to be lowered in a Well with said tubing string, and means, responsive to movement of a portion of said tubing string, for discharging refrigerant from said container through said coil and into said tubing string.

8. A refrigerating means for Well bores comprising: a sealed refrigerant container for holding an isolated batch of refrigerant and carrying it into the Well, a chilling element connected With said container, an expansion valve interposed between said container and element, said contalner and element adapted to nt within a well bore. means for lowering said container/and element as a unit into a well bore and means for causing discharge of a refrigerant from said container into said element.

9. In an apparatus for producing refrigeration Within a well bore, a refrigerator unit shaped to fit within a well bore and including; a receptacle initially containing an isolated quantity of refrigerant and adaptedto carry this refrigerant into the well bore, and a chilling element connected with said receptacle to receive refrigerant therefrom; and means tending to cause a pressure drop in said refrigerant as it enters said chilling element from said receptacle; and an arrangement for lowering into a well bore said refrigerator unit in its entirety.

10. In an apparatus for producing refrigeration within a well bore, a refrigerator unit shaped to t within a Well bore and including a receptacle initially containing an isolated quantity of refrigerant and adapted to carry this refrigerant into the well bore, and a chilling element connected with said receptacle to receive refrigerant therefrom and means tending to cause a pressure drop in said refrigerant as it enters said chilling element from said receptacle; an arrangement for lowering into a well bore said refrigerator unit in its entirety; and an instrumentality operative from the mouth of the Well to cause operation of said refrigerator unit.

11. An apparatus for producing refrigeration Within a well bore, comprising: a refrigerator unit shaped to fit Within a Well bore and including, a compressor, chilling element and means tending to maintain a pressure difference between said compressor and chilling element upon discharge of a refrigerant from said compressor into said chilling element; and an arrangement for lowering into a Well bore said refrigerator unit in its entirety.

WALTER T. WELLS.

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