US2288780A - Packer - Google Patents

Description

`July 7, 1942. 1

`.1. P. BRADNER Filed Feb. 21, 1940 IN V EN TOR.

A TTORNEY Patented July 7., 1942 UNITED .STATES PATENT OFFICE .rames r. Brauner, sen Francisco, oeuf.

Application February 21, 1940,'serie1 N0. 320,148

8 Claims.`

This invention relates to a packer, and especially to that type of packer known as a formation lpacke In drilling oil wells it is often necessaryto seat a packer in an open hole. This is particularly true when a new or different formation is encountered during the drilling of a well, and it is desired to obtain a sample of oil, if any, in that stratum or formation. At such times a hole of the required .diameter has already been-drilled, and in order to make a test of the formation a hole of relatively small diameter is drilled down into the formation for exploration or testing purposes. This smaller hole is commonly referred to as a rathole At the juncture between the well bore and a rathole a tapering seat or square shoulder is formed, the larger diameter of which is represented by the well bore and the smaller diameter by the rathole.

In drilling both the main well bore and the rathole, it is possible that high pressure gas or oil strata may be encountered which would tend to blow the hole. Hence, a heavy drilling fluid, usually called mud is employed to prevent blowing. This mud illls thev entire well bore and the rathole, and when a rathole packer, together with a string of testing tools, is lowered to seal of! the formation and to obtain a sample therefrom, the pressure in the rathole or below the packer may drop considerably while the mud column will maintain its high pressure, thereby tending to leak by the packer and cut the seat of the rathole to such an extent that the packer (Cl. 16B-1) loses its seal. For this reason it is important to drive or force the packer into. the rathole seat with considerable pressure in order that no leakage may occur, and consequently great diiculty is often encountered in removing the packer and connected string of testing or sampling tools after a sample has been taken.

The object of the present invention is generally to improve and simplify the construction and operation of tools of the character described, and particularly to provide a rathole packer which may be forced or firmly driven into the rathole seat prior to the taking of a sample, to form a substantially leakproof seal, and thereafter be readily released and removed when the sample Ahas been taken. The packer and the tools employed in connection therewith are shown by way of illustration in the accompanying drawing, in which:

Fig. l is a vertical section of a well bore, showing the packer and the testing tools in position to take a sample from a stratum or formation t0 be tested. A portion of the packer is shown in section in this view.

Fig. 2 is an enlarged vertical longitudinal section of the sampling tool, together with a portion of thestring or tubing from which it issuspended;

Fig. 3 is an enlarged vertical longitudinal section of the rathole packer;

Fig. 4 is an enlarged view of a packer sleeve;

Fig. 5 is an enlarged cross section of the packer sleeve prior to contraction; and

Fig. 6 is a similar section showing the packer sleeve after contraction.

In the drilling of oil wells, and in operations incident to testing the productivity of different formations which are being penetrated, it is desirable to provide apparatus which may be readily lowered into the well through the drilling mud contained therein, without the necessity of removal of the mud. Also, it is desirable to seal ofi the formation to be tested from the mud withfrom are removed from thewell, and the entrapped sample of iluid may then be drained out and tested.

The present invention provides an improved form of packer for sealing of! the formation to be tested, and while the packer may beused with dierent types of testing or sampling tools, a suitable form of tool is shown by way of illustration, and will be only briefly described, as a complete description of its structure will be found in Patent No. 2,073,107, entitled "Well testing method and apparatus, issued March 9, 1937, to

M. O. Johnston.

Referring to the drawing in detail, A indicates a packer; B, a mud by-passing valve; C, a main Ivalve; D, a trip valve; E, a portion of the upper drill string or tubing from which the tools are y 55 .have been drilled, and in order to make a test of the formation. a hole J of relatively small diameter isdrilied down into the formation. This smaller hole is commonly referred to as a rathole. At the Junction between the main well bore or hole and the rathole, a tapering seat K is formed, or a shoulder, and it is this seat into which the packer A is forced when the formation is to be sealed oil from the mud in the well and the strata above. a

Due to the high pressure exerted on the packer maintained until the packer reaches its seat, when it will be forced tightly into the seat by the weight and downward pressure of the tool string.

by the hydrostatic head of the mud above the packer, particularly in a deep well, there is considerable danger of mud leaking by the packer and cutting away the rathole seat, this being particularly true if a considerable pressure reduction takes place -below the packer while a sample is being taken. It is for this reason that the packer must be r-mly seated during the taking of a sample, and due to the rm seating it often happens that considerable trouble is encountered when the packer is to be removed. The trouble of removal will be entirely overcome by the use of the packer here illustrated. The packer consists of a head member 2 which is secured by means of a threaded coupler 3 to the lower end of the Valve body B containing vthe mud by-passing valve. Secured to the head 2 by a threaded connection 4 is a tube 5, and slidably mounted thereon is a sleeve 5 which carries the packer A. The sleeve 6 has a flange I formed at its upper end to act as a retainer for a series of packing discs 8 which are slipped over the sleeve. The lower end of the sleeve is threaded to receive a washer 9 and a nut I0, and by these the packing discs are held in co pressed condition. A

Formed in the sleeve G intermediate the flange 'I and the lower 'threaded end are a series of slots II which serve the function of permitting contraction or reduction in the diameter of the sleeve, and consequently the packing discs 8. when the packer is to be removed from its seat, as will hereinafter be described. The upper end of the tube 5 (see Figs. 1 and 3) presents an exterior diameter which snugly fits the interior of the sleeve 6, thus preventing contraction oit' the sleeve i. The lower end of the tube, on the other hand, is reduced in diameter, as indi cated at 5a, to permit contraction of the sleeve when the packer is to be released and removed from its seat. To permit such contraction as heretofore described, the tube 5 is pulled upwardly in the sleeve until a collar I2 on the lower end thereof engages the lower` end of the sleeve 5. When this position is assumed, the reduced diameter of the tube 5a will register with the slots II, permitting the sleeve wall to yield inwardly and assume the contracted position shown in cross section in Fig. 6. The reduction in diameter thus provided will be considerable, and the packer, which has previously been firmly driven, and which would present serious difficulty when removal thereof is attempted, is in this instance readily removed due to the amount of contraction provided.

In actual practice, when the rathole has been drilled and a sample is to be taken, the packer A, the mud by-passing valve B, the main valve C and the trip valve D are assembled and connected at the surface, and by means of the drill string or tubing E is lowered into the well. During the lowering operation the packer A will assume the position shown in Fig. 3, as it is held in this position by a pair of hooked pins secured to the collar 2, and this position will be During the lowering movement andwhile the packer is being forced into its seat the larger upper end 5 of the tube is in register with the slotted sleeve l, and as the larger end of tube 5 snugly fits the interior of the sleeve, contraction can not take place while the packer is forced into the seat.

During the lowering movement through the mud, 4bil-P2185 valve B is automatically maintained in open position, that is, with the ports I5 in register with the annular space I6 and the outlet .ports I1, so that mud may pass freely through the anchor tube I8, the tube 5. the head 2, the passage I9, and portsv I1 and I5, but when the packer becomes seated, sleeve 2l in -which the-ports I5 are formed telescopes and vmoves downwardly in the valve body B to the position shown in Fig. 2, thereby closing the bypass. Valves C and D are maintained in closed position during thel lowering movement, but when the packer has become firmly seated, valve C opens automatically on taking the weight of the drill string; valve D, on the other hand, is opened by manipulation from the surface, and fluid from the formation to be tested is thus free to flow up through the anchor tube, the connected tube 5 and the by-pass valve', which is now closed. 'I'hereafter the fluid flows through' the main valve C into the intermediate string or tubing F, which is of suflicient length and capacity to entrap and retain the quantity of fluid required for testing or sampling Ipurposes.

After the sample has been taken the whole string of tubing E, together with the sampling tool and packer, will have to be raised and removed from the well. 'I'he moment raising movement commences, valve C closes, thereby entrapping the fluid sample; the by-pass valve B opens, and head 2 through means of the hooked pins 30 will exert an upward pull on the packer, but as this is firmly seated the hooks will yield or straighten out, thereby releasing the packer and permitting the tube 5 to be pulled upwardly through the packer until the collar I 2 engages the same. The reduced diameter 5a of the tube now registers with the the pull continues the slotted wall of the sleeve yields and contracts, thereby permitting the packing discs to contract, and the packer is thus released with comparative ease. and the entire string of tubing and tools is readily removed.

When the packer is being forced into the rathole seat the packing gaskets or discs l tend to assume a dished or curved shape, such as indicated by the dotted line a-a in Fig. 3. Hence when the packer is being removed they tend to straighten out and thus exert an inward force which is utilized to collapse or contract the slotted sleeve 6. In Figs. 5 and 6 the sleeve is shown as surrounded by two overlapping semi-circular sections of thin sheet metal, as indicated at 25 and 25. These sections of metal cover the slotted packer sleeve 6, and asv hooked pins are made of heavy wire or smalldiameter rods which have ample strength to secure the packer to the head 2 during the lowering operation, but when the packer is to be released and pulled out of its seat, they are ineffective to do so, as the hooked ends will yield y and pull out of the hole formedl in flange 1, thereby permitting upward movement of tube 5 and transfer of the entire pulling operation to in g medium I and the slotted sleeve 8, is to bev treated and considered as a unit; this packer l being characterized by the provision of a contractible seal with a tapering exterior and having a central passage in it, of uniform diameter throughout the length of the packer. Essential to fthe operation of the packer is the rigid tube whichpresents two diameters, one which snugly fits-the packer to prevent inward movement of the same when being seated in the formation,

and a second portion of reduced diameter to provide an annular space so that the packer may contract when it is to be removed from the formation. The packing medium A is at no time expanded. It is provided with a tapering exterior surface, which is set by the great weight of the tool string into the seat a-a of the formation to form a seal. When so seated, the packer is compressed, and, therefore, tends to yield inwardly, or in other words, to become reduced in diameter. Such reduction in diameter must be properly limited when thepacker is being set or seated into the formation to insure a tight seal. To limit this tendency to inward yielding movement while the packer is in its operative positioii in the well, the enlarged diameter portion of the tube I ts snugly within the packer.

When the packer is to be removed, the rigid tube is pulled upwardly and the portion 5a of smaller diameter will thus enter the central passage of the packer. There will thus be provided an annular space around the portion 5a which will permit inward contraction of the packer, and

larger or the smaller diameter portion within the sleeve.

2. A well packer of the character described comprising an elongated sleeve surrounded by a packing medium, said sleeve being of uniform diameter throughout its length and `being provided with a plurality of slots which extend throughout the greater portion of its length to form a yieldable wall. a rigid tube extending through the sleeve and slidable therein, said tube presenting a uniform diameter throughout approximately half of its length which iltsthe interior of the sleeve to prevent yielding of the sleeve wall, and a second portionvof reduced diameter throughout the remainder of its length, which provides space to permit inward yielding of the sleeve wall. and means for connecting one end of the rigid tube with a tool string whereby it may be manipulated toposition either the larger or the smaller diameter portion within the sleeve. Y

3. A well packer of the character described comprising an elongated sleeve, said sleeve being provided with a plurality of spaced slots which extend substantially from end to end of the sleeve, a iiange on one end of the sleeve, a nut on the opposite end, a plurality of packing discs carried by the sleeve, and maintained under compression by the flange and nut, a rigid tube extending through the sleeve and slidable therein, said tube presenting a diameter throughout a portion of the length which lits the interior of the sleeve to prevent yielding of the sleeve wall, and a second portion of reduced diameter which provides space to permit yielding oi the sleeve wall, and means for connecting one-end of the rigid tube with a tool string whereby it may be thereby permit it'to be released when it is to be removed.

While certain features of my invention have been more or less specifically described and illustrated I nevertheless wish it understood that changes may be resorted to within the scope of the appended claims.

Having thus described and illustrated my invention, whatV I claim vand desire to secure by Letters Patent is:

l. A well packer of the character described comprising an elongated sleeve surrounded by a packing medium, said sleeve being of uniform diameter throughout its length and having a yieldable annular wall, a rigid tube extending through` the sleeve and slidable therein, said tube presenting a uniform diameter throughout approximately half of ,its length which fits the interior of the sleeve to prevent yielding of the sleeve wall, and a second portion of reduced diameter throughout the remainder of its length, which provides space to permit .inward yielding of the sleeve wall, and means for connecting one end of the rigid tubewith a tool string whereby it may be' manipulated to position either the manipulated to position either the larger or the smaller diameter portion within the sleeve.

4. A well packer of the character described comprising an elongated sleeve, said sleeve being provided with a plurality of spaced slots which extend substantially from end to end of the sleeve, a ilange on one end ofthe sleeve, a nut on the opposite end, a plurality of packing discs carried by the sleeve, and maintained under compression by the ange and nut, a rigid tube extending through the sleeve and slidable therein, said tube presenting a diameter throughout a portion of the length which ts the interior ofwhen a raising movement is imparted to the tool l string.

5. A well packer of the character described comprising an elongated sleeve surrounded by a packing medium, said sleeve having a yieldable annular wall, a rigid tube extending through the sleeve and slidable therein, said tube presenting a diameter throughout a portion of its length which fits the interior of the sleeve to prevent yielding of the sleeve wall, and a second portion of reduced diameter which provides space to permit yielding of the sleeve wall, a head member secured to one end of the rigid tube to connect the tube with la tool string, whereby it may be manipulated to position either the larger or the smaller diameter portion within the sleeve, and

a detachable connection formed between the head member and the sleeve.

6. lA well packer of the character described comprising an elongated yieldable packing member permissibly yieldable under external pressure,

' said member presenting an exterior tapering aurface and having an interior central passage of uniform diameter throughout its length, a rigidA tube extending through the central passage of the 'packing member and being slidable therein, said tube presenting a uniform diameter throughout approximately half its length, to ilt the central passage ofthe packing member and to prevent yielding of the said member, and a second portion of reduced diameter throughout the remainder of its length, which provides space to permit inward yielding-of the packing member.,

v -contraction of the packing medium when seated in position in the well, andl having the. remaining portion of its length of l uniform but substantially less diameter than the in ner diameter of said packing member tol permit reduction in diameter and ready removal ofsaid packer when the tube is positioned with said portion o f lesser diameter within the packing member.

8. In a well packer having an elongated, radially contractible sleeve surrounded by a conical packing medium which is yieldable under. external pressure, a rigid tube extending through said sleeve and slidable therein, la cylindrical portion of the tube making a'snug t with the inner diameter of said sleeve, another cylindrical portion of its length being substantially less in diameter than the inner diameter of said sleeve, a head member secured to one end of said tube forconnection to a tool string and arrangedfor axial movement of said tube within said sleeve, and a detachable connection formed between said head member and said sleeve, said connection being broken on the upward movement of the tube and permitting said sleeve to contract about the portionof lesser diameter of the tube by external pressure when said lesser diameter tube portion is moved into the space within the packing member'.

JAMES r. BRADNER.

Images