Patent Application
20130140022
The present invention relates to a method and a device for repairing a liner hanger with a view to making it leak-tight. It also concerns a blank used for this repair.
The invention notably applies to hydrocarbon production wells (oil or gas) or to water catchment wells.
In the appended drawings, the scale in the radial dimension (i.e. perpendicular to the well axis) has been notably over-sized compared with the scale in the longitudinal direction, for the sole purpose of improving legibility.
Appended
P designates the wall of a hole drilled in the ground, in which a steel casing A is installed having an inner diameter ΦA.
B designates a liner, also in steel, of inner diameter ΦB smaller than the diameter of the casing, and which extends the casing (coaxially) towards the bottom of the well.
Reference D designates the liner hanger.
This is a more or less sophisticated device known per se and whose particular structure is not of importance. It is schematized here simply by a section that is approximately trapezoidal, capping the upper edge of the liner B with a conical entry wall PE.
The essential function of the liner hanger is to hold the liner in centred, leak-tight position.
Reference C designates cement cast between A and B.
The liner often projects beyond the end of the casing, towards the bottom of the well.
Over time, degradation of the liner hanger D is observed, with the onset of leaks. Undesirable fluids may then rise and enter into the casing as symbolized by the arrows R.
The liner hanger D must then be replaced, which is difficult and costly.
The main objective of the present invention is to allow repair of the liner hanger D simply and efficiently, to make it fully leak-tight, without too great a reduction in the diameter ΦB of the passageway used for passing tools and various components for operation of the well.
For this purpose, it proposes a repair method and device, and a blank which is used for this repair.
This method for repairing a liner hanger with a view to making it leak-tight, this liner being placed inside and in the continuation of a well casing, is characterized by the fact that it firstly comprises the axial positioning in the well of a metal tubular blank having a solid wall and radially deformable beyond its elastic limit, this blank comprising an upper cylindrical portion whose outer diameter is slightly smaller than the inner diameter of the casing, a lower portion that is also cylindrical whose outer diameter is slightly smaller than the inner diameter of the liner, and an intermediate portion with a diameter varying between these two diameters, this positioning being performed so that said lower portion comes to house itself in the mouth of the liner whilst said upper portion comes to position itself facing the zone of the casing located above the hanger, then during a second phase the method comprises causing radial expansion of at least one of these two cylindrical portions beyond its elastic limit so that it is applied closely and firmly and in leak-tight manner against the inner side of the wall facing the casing and liner, and so that subsequent to said expansion the intermediate portion of the blank covers the hanger.
Advantageously, use is made of a blank whose upper cylindrical portion has a wall whose mean thickness is greater than the thickness of said lower cylindrical portion, this upper portion being provided with at least one annular seal in swellable or expandable material, and radial expansion is only applied to the lower cylindrical portion beyond its elastic limit so that it is applied closely, firmly and in leak-tight manner against the inner side of the wall of the liner, followed by swelling or expansion of said seal to that it is applied it in leak-tight manner against the inner face of the casing wall.
In one preferred embodiment, a blank is used whose lower portion has an outer diameter that is very slightly smaller, almost equal (to the nearest insertion clearance) to the inner diameter of the mouth of the liner, previously machined and smoothed, and this lower portion is positioned by sliding into said mouth, with inter-positioning of seals, whilst radial expansion is only applied to the upper cylindrical portion beyond its elastic limit so that it is applied closely, firmly and in leak-tight manner against the inner face of the casing wall.
According to another variant, radial expansion is applied to each of the two cylindrical portions beyond their elastic limit so that they are applied closely, firmly, and in leak-tight manner against the inner faces of the walls respectively facing the casing and the liner, and so that subsequent to this expansion the intermediate portion of the blank, also deformed, covers the hanger.
According to other advantageous characteristics:
The tool for repairing a liner hanger according to the invention, with a view to making it leak-tight, this liner being placed inside and in the continuation of the casing of a well, is characterized by the fact that it consists of a tool comprising a control rod which carries a pair of inflatable packer bladders placed one above the other, and sized so that the upper bladder is adapted to expansion of the upper cylindrical portion of the blank whilst the lower bladder is adapted to expansion of the lower cylindrical portion.
According to particular embodiments:
Finally, the invention concerns a blank used to repair a liner hanger, with a view to making it leak-tight, this liner being placed inside and in the continuation of the casing of a well, characterized by the fact that it comprises a metal tubular sleeve whose wall is radially deformable beyond its elastic limit, with coaxial upper and lower cylindrical portions, the diameter of the lower portion being smaller than the diameter of the upper portion, and an intermediate portion having a diameter varying between the diameters of the cylindrical portions.
According to advantageous characteristics:
Other characteristics and advantages of the invention will become apparent on reading the following description of a preferred embodiment of the invention. This description is given with reference to the appended drawings in which:
The blank 1 in
A suitable metal is stainless steel.
This blank 1 comprises:
These four elements can be joined to each other by welding.
The “bi-conical” intermediate portion (funnel or hopper shaped) ensures progressive transition between the two cylindrical portions, which reduces risks of rupture or cracking at this point during expansion of the blank.
The cylindrical portions 10 and 13 are advantageously surrounded by a series of bonded seals 100, 130, in flexible, elastic, optionally swellable material.
These could also be O-rings housed in receiver grooves (not illustrated) cut in the outer wall of these cylindrical portions.
As shown in
After expansion, the blank 1′ has top 10′ and bottom 13′ cylindrical portions that are tightly and firmly applied against these inner faces, with inter-positioning of seals which have been compressed.
The intermediate portion 100′, initially bi-conical, has assumed a curved shape and covers the hanger D, conforming to the desired objective.
In
The tool for placing the blank in position, illustrated
The membrane of each bladder 2, 3, via each of its top and bottom ends, is joined to a pair of end-pieces 20-21, respectively 30-31, of which at least one is able to slide freely on the rod 4, to offset the difference in axial length resulting from the variation in diameter of the bladder on inflating/deflating.
The diameters of the non-inflated packers 2 and 3 are slightly smaller than the inner diameters of the cylindrical portions 10, relatively 13, of the blank 1. Their length (axial dimension) is sufficient to cooperate with each of these portions, respectively, to achieve their expansion over their entire length. At its lower end, the rod 4 carries a supporting member 6 provided with a series of fingers 7 adapted to give support to the lower edge of the blank 1 while it is being lowered and placed in position in the well.
For example, there are four fingers 7 extending radially and horizontally, and arranged at 90° relative to the vertical axis of the rod 4.
They are retractable, the member 6 being connected to the rod 4 via a link system 5 symbolized by a square with diagonal lines. This system is designed to cause retracting of the fingers 7 by radial inward movement when the rod 4 is subjected to an upward traction force of excessive value which exceeds a determined threshold.
The member 6 has a smooth, cylindrical wall surface, adapted to fit into the lower opening of the blank 1 without any notable clearance, and more precisely into the lower portion 13 thereof of small diameter. This member thereby ensures good centering of the blank relative to the control rod 4, along the well axis, when the blank is placed in position in the well resting on the supporting fingers 7.
The arrow F1 in
The lowering of the blank 1 is halted when its truncated cone portion 12 meets the upper edge of the liner B, and the tool continues its downward travel alone until the packer 3 is correctly positioned opposite portion 13 of the blank (
The lower packer 3 is then supplied with high pressure liquid causing inflation thereof—arrows i, FIG. 7—which causes radial expansion of this portion (now referenced 13′) and firm application thereof against the upper zone of the inner wall of the liner B.
The packer 3 is then deflated and the tool is again lowered (Arrow F2,
This packer 2 is then supplied with high pressure liquid causing inflation thereof—arrows k, FIG. 9—which causes radial expansion of this portion (now referenced 10′) and firm application thereof against the zone of the inner wall of the casing B which is located above the hanger D.
Finally, after deflating the upper packer 2, the tool can be withdrawn by upward axial traction (arrow G,
Throughout this withdrawal, the supporting member 6—including its projecting retaining fingers 7—pass normally through the expanded blank 1′, provided this expansion is properly and sufficiently performed, notably at the lower portion 13′.
If this is not the case, these fingers 7 come to strike the lower edge of this portion 13′, and they can no longer be lifted.
In this hypothesis, the connection system 5 is subjected to a substantial traction force which causes retracting of these fingers so that the tool can nevertheless be withdrawn.
The member 6 is a solid body with cylindrical wall and 60 and distal 60a and proximal 60b faces of truncated cone shape (forming chamfers capable of facilitating positioning and limiting friction). It contains a series of radial fingers 7 housed in ad hoc receiving holes 62 formed in the body 6. These are rods with domed head 71 (the head lying inwardly inside the body 6) and with truncated cone-shaped tip 70 which normally projects outside the body 6 to retain the lower edge of the blank, as illustrated in
It will henceforth be noted that the rod 4 has a lower end portion (distal) 9 of smaller diameter than the diameter of the main part thereof which holds the fingers in their active position in
The rod 4 has an annular collar 51 which acts as shoulder for the base of the proximal (upper) face 60b, of truncated cone shape, of the body 6. The axial thrust forces exerted on the rod 4 are therefore transmitted to the body 6 from top downwards via this bearing zone.
The rod 4 has another annular collar 53 positioned lower than the first 51 in a cylindrical housing 61 arranged axially inside the body 6. The rod portion 4 located between the collars 51 and 53 carries reference 52.
This collar 53 is pierced with small radial bore holes 63, e.g. two in number, diametrically opposite (hence coaxial)—or four distributed at 90°. In each bore hole 63 a metal pin 8 is housed in the form of a small rod provided with a head which is fully driven into an opposite-facing bore hole pierced in the body 6.
The rod of these pins 8 has a calibrated cross-section so that it can withstand a given shear force and break on and after this value (frangible pins).
The housing 61 has a certain axial length in which the collar 53 is able to move from bottom upwards, when said pins are sectioned, until it comes to abut the upper end 610 of this housing 61.
In normal rest position (
It is to be noted that the length of the end portion 9 of the rod 4 is a little longer than the length of the axial travel distance of the collar 53 in the housing 61.
This device operates as follows.
When in operation, the status of the device is as illustrated in
The thrust forces, from top downwards, on the maneuvering rod 4 are directly transmitted to the supporting member 6 by the collar 51.
The frangible pins have sufficient resistance so as not to break should undue traction forces develop during operation, which may be related to vibratory phenomena for example or Archimedes thrust which may be exerted on the member 6 (if the well or conduit contains fluid).
In the event of any difficulty such as mentioned above, when the blank is only partly expanded, the device can be withdrawn by traction on the rod 4 from bottom upwards, this traction being symbolized by arrow g in
The body 6 is therefore hoisted until its fingers 7, which are in projecting position, come into contact with the lower edge of the non-expanded portion 11 of the blank.
Hoisting is therefore blocked, inducing sufficient forces at the pins 8 to cause shearing at the base of their head 8′—which remains in the body 6.
The maneuvering rod 4 therefore comes to be separated from this body 6 and can be hoisted, whilst the body 6 remains immobilized subsequent to the abutment of the fingers 7 against the lower edge of the blank.
The collar 53, which contains the rods 8″ of the sectioned pins, therefore moves axially from bottom upwards inside the housing 61, until it comes to abut against the face 610.
Throughout this movement, the end portion 9 of smaller diameter has arrived opposite the fingers 7 which have therefore been pushed inwardly (arrows j) under urging by the springs 70, and have retracted into a retracted position which is inscribed within a circular section of smaller diameter than the inner diameter of the non-expanded portion 11 of the blank.
In this manner passing becomes possible, and the assembly can be withdrawn.
As will be explained with reference to
In this case, expansion must be made step-by-step, with successive inflating/deflating phases, progressing in steps.
Control elements can be provided to block progression of the tool in the event that expansion does not take place correctly.
The blank 1 is shown non-expanded in this figure, supported by the supporting fingers 7 of the supporting member 6.
The two packers 2, 3 are carried by the control rod 4 on which the control elements 22, 32 are also mounted.
The control element 22 is located just above the upper packer 2. It is in the form of a disc whose diameter is slightly larger than the inner diameter of the upper cylindrical blank portion 10.
This diameter is nonetheless slightly smaller than the inner diameter of this portion 10′ after expansion.
Similarly, the control element 32 is located just above the lower packer 3. It is in the form of a disc whose diameter is a little larger than then the inner diameter of the lower cylindrical blank portion 13.
This diameter is nevertheless a little smaller than the inner diameter of this portion 13′ after expansion.
The tool operates step-by-step from top downwards (Arrow F).
The two packers can work in synchronism, and can be inflated/deflated simultaneously.
The packers 2 and 3 therefore cause progressive expansion of parts 10 and 13 of the blank at the same time.
At least one of the two packers is advantageously mounted “floating” on the rod 4. In the illustrated example, this is the lower packer 3 on whose end pieces 30, 31 demand is placed by the elastic return members (compression springs) 300, 301 which respectively bear against the control element 32 and against a ring 33 joined to the rod 4.
This allows automatic offsetting of differences in radial expansion (and correlatively axial contraction) of the two packers 2 and 3, which tend naturally to draw them away or towards each other during each operational phase, thereby avoiding the onset of harmful mechanical stresses on the rod 4 and/or on the blank 1.
If one of the portions 10 or 13 is incorrectly or insufficiently expanded, the lowering of the corresponding control disc 22 or 32 becomes blocked, which alerts the operators and the expansion operation must be adjusted to arrive at the desired positioning diameter.
In the embodiment illustrated
A control element 32 associated with the lower packer 3 is attached to the lower end of the rod 4; here it also acts as support for the blank 1 when it is placed in position in the well.
In the event of incorrect and/or insufficient expansion of the lower portion 13, this element 32 cannot pass through this portion, which blocks the rising of the tool.
On the other hand, in this embodiment there is no similar control element associated with the upper packer 2, which would ensure proper expansion of portion 10 of the blank.
According to FIG. 16,—in addition to the seals 100, 130 which line the upper 10 and lower 13 portions of the blank—provision is made for similar seals 15 which surround the intermediate portion thereof 11-12.
With reference to
In this figure, the seals 100 and 130 are not illustrated for reasons of simplification.
During a first phase, illustrated in the left half of
The blank 1 is then immobilized at this point, held in translation.
During the remainder of radial expansion, from bottom upwards, illustrated in the right half of
Since the lower part 13A is immobilized, downward traction is observed of the remainder of the blank (Arrow Z), the effect of which is to apply the seals 15 of the intermediate portion 11-12 against the conical entry wall PE of the hanger D.
The configuration and the dimensions of the blank are naturally determined so that, on completion of expansion of the lower portion 13, these seals 15 are suitably compressed to ensure an optimal seal at this point.
Expansion of the upper portion 10 is then conducted.
It can also be envisaged to expand the intermediate zone 11-12 of the blank by means of a packer to ensure or reinforce this perfect sealing.
It is to be noted that the same packer could be used for each of the two operations (expansion of the upper 10 and lower 13 portions) provided it has sufficient radial expanding capacity.
On the contrary, two separate tools (each with a packer) could in principle be used in turn, even if at first sight this appears to be less advantageous.
The intermediate zone between the two cylindrical portions of the blank is not necessarily bi-conical.
It could be “mono-conical”—as in FIG. 16—or of progressively variable shape by means of an intermediate element with curved profile and point of inflection.
In this case, the central element could be formed by stamping a cylindrical blank (on a press between punch and die) and then welded to the two cylindrical elements.
With respect to the tool, pre-inflation of at least one of the two packers should allow the blank to be retained simply by friction when it is placed in the well (since the weight of the blank is not very high) which would eliminate the need for the supporting member 6-7.
With reference to
A blank 1 is inserted therein whose lower cylindrical portion 13 has an outer diameter Φ2 which is very slightly smaller than, practically equal to diameter ΦB, to the nearest insertion clearance.
The outer wall of the portion 13 is provided with O-rings 130.
This lower portion is positioned by sliding into the mouth, as can be seen in
The upper cylindrical portion 10 of the blank 1 then occupies the position illustrated on the left side of
In this case, only the upper portion 10 is radially expanded to beyond its elastic limit, in the manner described above, so that it is applied closely and firmly and in leak-tight manner against the inner face of the wall of the casing A.
Once this operation is completed, the blank occupies the position shown on the right side of
In the embodiment shown in
This upper portion comprises an annular groove cut in its outer face in which a seal 100 in swellable material is received.
With said blank, only the lower portion 13 is expanded beyond its elastic limit, so that it is applied closely and firmly, and in leak-tight manner, against the inner face of the liner B.
The seal 100 is then caused to swell until it is applied closely and in fully leak-tight manner against the inner face of the casing A.
This type of swelling seal is well known per se for applications in the area of oil well operation.
The swelling thereof is obtained simply by contacting with a determined fluid, which may be a fluid specially injected into the well or already present in the well.
This fluid may be water for example, mud, a hydrocarbon or a mixture of these substances.
In this respect, useful reference may be made to the document “Swelling Packers solve zonal-isolation challenge in Oman High pressure wells” (JPT March 2007), and to patent U.S. Pat. No. 3,918,523 (which provides information on the composition of swelling agents which can be used).
In the embodiment illustrated in
Simply as examples, possible values of some parameters of the invention are given below:
Diameters ΦA and ΦA: respectively 226 and 166 mm;
Wall thickness of casing A and liner B: respectively 9 and 6 mm;
Diameters Φ1 and Φ2: respectively 205 and 150 mm;
Wall thickness of the blank 1: 5 mm;
Axial dimensions (=lengths) of portions 10, 11, 12 and 13 of this blank: respectively 3, 0.3, 0.3 and 3 metres;
Value of angles α1 and α2: respectively 30° and 10°;
Length of each deflated packer 2-3: 1.5 metres;
Pressure developed in these packers to expand the blank: 400 bars.
Value of the axial traction force causing rupture of the frangible pins in the connection system 5: 1.5 tonnes.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1050079 | Jan 2010 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2010/070851 | 12/29/2010 | WO | 00 | 9/26/2012 |
