WO2006072616A1

WO2006072616A1 - Method of expanding a tubular element in a wellbore

Info

Publication number: WO2006072616A1
Application number: PCT/EP2006/050051
Authority: WO
Inventors: Paul Dirk Schilte
Original assignee: Shell Internationale Research Maatschappij B.V.; Shell Canada Limited
Priority date: 2005-01-07
Filing date: 2006-01-05
Publication date: 2006-07-13

Abstract

A method is provided of radially expanding a tubular element (26) extending into a wellbore formed in an earth formation, comprising the steps of arranging an expander (32) in the tubular element, the expander being operable to exert a radial force to the inner surface of the tubular element, and radially expanding the tubular element by pressurising the interior of the tubular element and simultaneously operating the expander to exert said radial force to the inner surface of the tubular element. The expander is operated to exert said radial force to the inner surface of the tubular element independently from pressurising the interior of the tubular element.

Description

METHOD OF EXPANDING A TUBULAR ELEMENT IN A WELLBORE

The present invention relates to a method of radially expanding a tubular element extending into a wellbore formed in an earth formation, whereby an expander located in the tubular element , is operable to exert a radial force to the inner surface of the tubular element .

Wellbores for the production of hydrocarbon fluid are conventionally provided with one or more casings to provide stability to the wellbore wall, and/or to provide zonal isolation between different earth formation layers . Generally, several casings are set at different depth intervals in a nested arrangement whereby the diameter of each subsequent casing is smaller than the diameter of the previous casing in order to allow lowering of the casing through the previous casing .

Recently it has become practice to radially expand tubular elements in the wellbore , for example as a clad against an existing casing section . Also, it has been proposed to construct a monodiameter well by radially expanding each subsequent casing to substantially the same diameter as the previous casing . It is thus achieved that the available diameter of the wellbore is kept substantially constant along (a portion of) its depth, as opposed to the conventional nested arrangement whereby the available diameter decreases stepwise with each subsequent casing . The monodiameter concept is particularly of interest for very deep wellbores or extended reach wellbores . To expand the tubular element , an expander of diameter substantially equal to the The presence of certain non-hydrogenated oxygenates in the otherwise hydrogenated products can reversibly deactivate the catalyst used in the hydrogenisation and/or the hydroisomerisation/hydrocracking unit (or heavy paraffin conversion (HPC) unit ) . In particular, complex oxygenates produced by an aldol type reaction, or acetals , are thought to be particularly responsible for the deactivation of the catalyst used in these reactions . In addition, it is sometimes desired to produce products which are completely free from oxygen compounds . This holds , for instance, for wax products , i . e . C30+ wax products , especially C40+ wax products .

An obj ect of the present invention is to mitigate the deactivation of the HPC catalyst, and especially the hydrogenation catalyst .

Thus , the present invention concerns a hydrogenation catalyst , especially for the hydrogenation ( i . e . the conversion of olefins and oxygenates into paraffins ) of heavy Fischer-Tropsch product streams . It has appeared that especially a nickel catalyst on a wide-pore alumina is able to hydrogenate the heavy wax fraction (e . g . C20+) of a Fischer Tropsch reactor in such a way that all oxygen compounds are removed. When using a catalyst comprising nickel on an acidic catalyst support , e . g . amorphous silica alumina, a certain amount of oxygen- containing compounds remain in the hydrogenated product . A relatively low amount of nickel may be used .

According to the present invention there is provided a hydrogenation catalyst , the catalyst comprising a metallic active portion in which the metal is a non-noble Group VIII metal and a support, characterised in that the support does not catalyse an acid catalysed reaction and wherein over 90% of the pores within the support are sized between 100 A-400 A.

The support has a sharp pore size distribution . Over 90% of the pores within the support are sized between 100 A-400 A. Preferably over 70% of the pores are sized between 120 A-350 A.

Typically the median pore diameter is around 150 A, preferably greater than 150 A. More preferably the median pore diameter is around 170 A, even more preferably over 170 A, around 190 A.

Preferably less than 25% , more preferably less than 11% of the pore volume is provided by pores with a diameter greater than 350 A. Even more preferably less than 8% of the pore volume is provided by pores with a diameter greater than 350 A. In some embodiments less than 6% of the pore volume is provided by pores with a diameter greater than 350 A.

The pore volume is determined using the Standard Test Method for Determining Pore Volume Distribution of Catalysts by Mercury Intrusion Porosimetry, ASTM D 4284-88.

Preferably the support comprises wide pore alumina, preferably the wide pore alumina disclosed in US 4 , 248 , 852 and which is incorporated herein by reference in its entirety . Alternatively wide pore alumina, as disclosed in US 4 , 562 , 059, may also be used. The preparation of the support may be as described in US 4 , 422 , 960. US 4 , 562 , 059 and 4 , 422 , 960 are incorporated herein by reference in their entirety . Preferably the two-lobe particle size diameter is less than 2 mm.

Preferably the active portion comprises nickel . Preferably the catalyst comprises less than 20% nickel .

Preferably the catalyst comprises around 12.7% nickel . Preferably the catalyst comprises more than 5% nickel .

Preferably the nickel crystallites are around 2.5 nm.

Preferably the active component comprises a dopant to suppress hydrogenolysis of paraffins to methane . Copper is one example of a suitable dopant .

The active portion is preferably substantially pure nickel with the dopant but can be, for example, nickel/molybdenum, nickel with palladium or platinum, and can be a nickel sulphide, a nickel molybdenum sulphide, or a nickel tungsten sulphide .

Alternatively the active portion may comprise noble metals such as palladium or platinum; cobalt, cobalt/molybdenum, cobalt/molybdenum sulphide . Preferably the catalyst is adapted to hydrogenate olefins . More preferably the catalyst is adapted to hydrogenate oxygen-containing compounds and olefins .

During manufacture, preferably the active portion is impregnated onto the support . Thus the invention provides a method for manufacturing a hydrogenation catalyst as described above, the method comprising : admixing a solution of a metal salt with a support ; drying and calcining the mixture . Preferably the metal is impregnated into the support . interconnecting the liner 26 and the drill pipe 30. The drill pipe 28 extends to a conventional drilling rig (not shown) at surface, and is connected to a fluid pump (not shown) for pumping fluid via the drill pipe 28 into the liner 26.

An expander 32 for radially expanding the liner 26 is positioned in the liner 26, whereby an expanded portion 34 of the liner 26 extends below the expander 32 , and an unexpanded portion 36 of the liner 26 extends above the expander 32. The lower end of the expanded liner portion 34 is closed by means of a packer 37. The expander 32 tapers in upward direction from a relatively large diameter corresponding to the inner diameter of the expanded liner portion 34 , to a relatively small diameter corresponding to the inner diameter of the unexpanded liner portion 34. There are no provisions to seal the outer surface of the expander 32 to the inner surface of the liner 26, so that pressurised fluid can flow between the expander 32 and the liner 26. To ensure free flow of fluid between the unexpanded liner portion 36 and the expanded liner portion 34 , the expander is optionally provided with a through-bore (not shown) similar to the through-bore 14 of the Fig . 1 embodiment .

The expander 32 is at its lower end provided with an extender 40 comprising a lower leg 42 and an upper leg 43 , the legs being axially movable relative to each other . The lower leg 42 is provided with a lower anchor 44 , and the upper leg 43 is provided with an upper anchor 45. Each anchor 44 , 45 is operable between a radially retracted position in which the anchor 44 , 45 is free from the inner surface of the liner 26, and a radially extended position in which the anchor 44 , 45 is anchored to the inner surface of the liner 26. The extender 40 is operable between an axially retracted position in which the anchors 43 , 45 are close to each other, and an axially extended position in which the anchors 43 , 45 are remote from each other . The extender 40 and the anchors 43 , 45 are electrically operated, whereby electric power is provided to the extender 40 and the anchors 43 , 45 through an electric power cable 46 extending from surface along the drill pipe 28 and passing, via an opening (not shown) in the side entry sub 30 , into the liner 26. The power cable 46 extends in a loop 48 below the extender 40 to allow for axial displacement of the expansion assembly relative to the side entry sub 30.

During normal operation of the embodiment shown in Fig . 1 , the fluid pump 20 is operated to pump fluid, via the conduit 22 and the wellhead 6 , into the interior of the casing 4 at the upper end thereof . The packer 13 prevents outflow of fluid from the lower end of the casing 4. As a result of the pumping operation, the fluid pressure in the casing 4 increases whereby the increase of fluid pressure in the expanded ( lower) casing portion 10 equals the increase of fluid pressure in the unexpanded (upper) casing portion 12 by virtue of the through-bore 14 of the expander 8. Also, the fluid pressure between the outer surface of the expander 8 and the inner surface of the casing 4 increases equally . Pumping of fluid into the casing 4 is continued until the fluid pressure in the casing 4 is about 90% of the burst pressure of the casing 4. It is to be understood that the burst pressure of the casing is the internal fluid pressure at which the casing 4 deforms in an uncontrolled manner, leading to rupture of the casing . For given casing characteristics , such as diameter, wall thickness , steel properties , and roundness , the burst pressure can be determined in a straightforward manner, either by calculation or by testing . Also, for most casings generally used the burst pressure is known or can be obtained from the manufacturer .

Upon the fluid pressure in the casing 4 reaching about 90% of the casing burst pressure, the winch 20 is operated to pull the expander 8 upwardly by means of the wireline 16. In view of the high fluid pressure in the casing 4 , the force required to pull the expander 8 upwardly through the casing, and thereby to radially expand the casing 4 , is relatively low . The pressurised fluid between the outer surface of the expander 8 and the inner surface of the casing delivers a maj or amount of the energy required to radially expand the casing 4.

Therefore the expander 8 only needs to exert a moderate radial force to the inner surface of the casing 4 to expand the casing . Since the internal volume of the casing 4 increases during the expansion process , it is necessary to continue pumping fluid into the casing 4 during the expansion process in order to keep the fluid pressure at about 90% of the burst pressure . The expansion process proceeds until the expander arrives at the upper end of the casing 4 , whereafter the expander 8 is retrieved from the wellbore 1.

During normal operation of the embodiment shown in Fig . 2 the fluid pump at surface is operated to pump fluid, via the drill pipe 28 and the side entry sub 30 , into the interior of the liner 26. The packer 37 prevents outflow of fluid from the lower end of the liner 26. As a result of the pumping operation, the fluid pressure in the liner 26 increases whereby the fluid pressure increase in the expanded ( lower) riser portion 34 equals the fluid pressure increase in the unexpanded (upper) liner portion 36. Also, the fluid pressure between the outer surface of the expander 32 and the inner surface of the liner 26 increases equally . Pumping of fluid into the liner 26 is continued until the fluid pressure in the liner 26 is about 90% of the burst pressure of the liner 26. The burst pressure is the internal fluid pressure at which the liner 26 deforms in an uncontrolled manner, eventually leading to rupture of the liner 26. Similarly to the burst pressure for casing, the burst pressure for liner can be determined in a straightforward manner, either by calculation or by testing . Alternatively the burst pressure can be obtained from the manufacturer . Upon the fluid pressure in the liner 26 reaching about 90% of the liner burst pressure, with the extender 40 in the retracted position, the lower anchor 44 is operated to move to its radially extended position so as to anchor the lower leg 42 to the inner surface of the liner 26. Then the extender 40 is operated to move to its axially extended position so as to move the expander 32 one stroke upwardly through the liner 26 and to further expand the liner 26. In view of the high fluid pressure in the liner 26, the force required to move the expander 32 upwardly through the liner 26, and thereby to radially expand the liner, is relatively low . The pressurised fluid between the outer surface of the expander and the inner surface of the liner delivers a maj or amount of the energy required to radially expand the liner 26. Therefore the expander 26 only needs to exert a moderate radial force to the inner surface of the liner 26 to expand the liner . Since the internal volume of the liner 26 increases during the expansion process , it is necessary to continue pumping fluid into the liner 26 during the expansion process in order to keep the fluid pressure at about 90% of the burst pressure . Upon the extender 40 arriving at the end of its stroke, the upper anchor 45 is moved to its radially extended position so as to anchor the upper leg 43 to the inner surface of the liner 26, and the lower anchor 44 is moved to its radially retracted position . The extender 40 is then moved to its axially retracted position whereby the lower leg 42 and lower anchor 44 move upwardly through the liner 26. The expansion process described above is then repeated so as to move the expander 32 a further stroke upwardly, etc . During the final stage of the expansion process , the upper end portion of the liner 26 is expanded against the casing 24 whereby the liner becomes firmly fixed to the casing 24. After the liner 26 has been completely expanded, the expander 32 , the extender 40 , the power cable 46, the side entry sub 30 and the drill pipe 28 are retrieved from the wellbore 1. Instead of using the electrically operated anchors described hereinbefore, self-activating anchors can be used . For example, an anchor can be used which anchors itself against the inner surface of the liner upon application of a downward force to the anchor, and which releases itself from the liner upon application of an upward force to the anchor . Such principle is similar to the principle of a conventional ball grabber .

Furthermore, instead of powering the extender and/or anchors electrically, the extender and/or anchors can be hydraulically powered using, for example, a coiled tubing . Also, a combination of electric and hydraulic powering can be applied . Instead of pulling the expander through the tubular element in upward direction, the expander can be operated to exert said radially outward force to the inner surface of the tubular element by allowing the expander to move through the tubular element by gravitational force . In order to enhance the gravitational force acting on the expander, the expander is suitably provided with additional weight means or with propelling means such as the extender described hereinbefore .

Claims

C L A I M S

1. A method of radially expanding a tubular element extending into a wellbore formed in an earth formation, comprising the steps of : arranging an expander in the tubular element , the expander being operable to exert a radial force to the inner surface of the tubular element ; radially expanding the tubular element by pressurising the interior of the tubular element and simultaneously operating the expander to exert said radial force to the inner surface of the tubular element , wherein the expander is operated to exert said radial force to the inner surface of the tubular element independently from pressurising the interior of the tubular element .

2. The method of claim 1 , wherein the tubular element includes an expanded portion and an unexpanded portion, and wherein the interior of the tubular element is pressurised both in the expanded portion and the unexpanded portion .

3. The method of claim 2 , wherein substantially the whole interior of the tubular element is pressurised .

4. The method of any one of claims 1-3 , wherein the interior of the tubular element is pressurised by pumping a fluid into the tubular element .

5. The method of claim 4 , wherein the tubular element has an upper end located substantially at surface, and wherein said fluid is pumped into the tubular element at or near said upper end of the tubular element .

6. The method of any one of claims 1-5 , wherein the interior of the tubular element is pressurised to a pressure of between 80%-95% of the burst pressure of the tubular element .

7. The method of claim 6 , wherein the interior of the tubular element is pressurised to a pressure of about 90% of the burst pressure of the tubular element .

8. The method of any one of claims 1-7 , wherein the expander has a largest diameter larger than the inner diameter of the unexpanded tubular element , and wherein the expander is operated to exert said radially outward force to the inner surface of the tubular element by moving the expander through the tubular element .

9. The method of claim 8 , wherein the expander is moved through the tubular element by pulling the expander through the tubular element by means of a pulling string .

10. The method of any one of claims 1-9 , wherein the expander is movable between a radially retracted mode and a radially expanded mode, and wherein the expander is operated to exert said radial force to the inner surface of the tubular element by moving the expander from said radially retracted mode to said radially expanded mode .

11. The method of any one of claims 1-10 , wherein the tubular element is a wellbore casing or a wellbore liner .

12. The method substantially as described hereinbefore with reference to the accompanying drawings .