This disclosure describes centralizers for drilling, and in particular centralizers having selectively deployable longitudinal bow springs.
Centralizers are commonly used in oil and gas wellbore installations and generally serve to center a pipe or casing within a wellbore or previous casing string during run-in, installation, or cementing procedures. Conventional centralizers typically are characterized by a pair of opposed stop collars or stop rings with a number of outwardly-bowed springs extending longitudinally there between to contact the wellbore sidewalls and exert a centering force on the pipe or casing segment. Bow spring centralizer subs generally comprise a casing segment with pin and box connections and an integral bow spring centralizer. The centralizer sub is run as part of a casing string.
In under-reamed applications, the casing string (with centralizers) is passed through a smaller casing string (restriction) before opening up to a larger hole. Significant force is required to compress a bow spring centralizer and push it through a restriction. As drilling projects push to greater and greater depths, increased drilling angles, and through a greater variety of geological formations, more challenging demands are placed on centralizers and other down-bore equipment. For example, deeper wells require more stages and passage of centralizers through a greater range and number of corresponding restrictions.
Subjecting compressible bow strings to varied and varying pressures as it is passed down a well results in inconsistent, imperfectly predictable, and repeated strains.
Conventional bow springs can therefore suffer from a number of disadvantages in such installations. As the bore restrictions become tighter, the starting or insertion force and running forces required to pass restrictions increase. Additionally, compression of the bow springs through particularly tight restrictions can exceed the elastic range of the material, can lead to deformation of bow springs, and compromise the ability of the bow springs to restore and to center. Similarly, damaged or forced centralizers can damage down-bore surfaces and down-bore equipment. The repeated compressions and decompressions of the bow springs of the centralizers compromise the integrity and reliability of the centralizer.
Accordingly, the following discloses and enables improvements for reducing and controlling insertion forces and running forces and preserving centralizer integrity and down-bore surfaces and equipment against the increasing demands of deep-well drilling.
The present disclosure describes and enables a centralizer with bow springs selectively deployable down a wellbore. The bows of the centralizer are elongated and compressed into a lower profile state and retained by a releasable locking mechanism. Maintaining a lower centralizer profile reduces frictional resistance and operational forces during tool insertion and run-in as the compressed centralizer bow springs more readily clear restrictions. The locking mechanism can then be selectively released to allow the restorative forces of the springs to centralize the casing within the bore. The locking mechanism can be released by controlled cyclical pressurization of the casing to actuate as described a rotational ratcheting release mechanism.
In one preferred embodiment, a portion of a locking mechanism is affixed to one of the centralizer stop collars while an interlocking portion is affixed to the casing. The locking mechanism is released by alignment of a release notch defined in a ratcheting ring with the interlocking portion of the locking mechanism affixed to the casing. Rotational misalignment of the ratcheting ring release notch and locking mechanism maintains the locked engagement of the lock mechanism portions while alignment results in release of the lock mechanism and deployment of the centralizer.
In another preferred embodiment, cyclical casing pressurization tensions one or more actuator bands wrapped about the casing with one actuator band end affixed to the casing and a free actuator band end acting on a ratcheting ring. Circumferential movement of the free end of the wrapped band during pressurization actuates the ratcheting band to decrease misalignment between the release notch and the lock mechanism and ultimately to release the lock mechanism and centralizer resulting in release of bow spring compression.
Accordingly, a deployable centralizer is maintained in a low-profile configuration with elongated, compressed bow springs until cyclical casing pressurization is selectively used to release a lock mechanism and allow for deployment of the centralizer bow springs.
A more complete understanding may be derived by referring to the detailed description and claims when considered in connection with the Figures, wherein like reference numerals refer to similar elements throughout the Figures, and
The following description is of exemplary embodiments, but is not intended to limit the scope, applicability or configuration of the claims. Rather, the following description provides a convenient illustration for implementing various embodiments. Various changes may be made in the function and arrangement of the elements described in these embodiments without departing from the scope of the claims as set forth hereafter. This detailed description may be adapted and employed with alternatively configured devices having different shapes, components, material, or mechanisms, and the like, and still fall within the scope of the present claims. Thus, this detailed description of preferred embodiments describes and enables the claimed inventions and is for purposes of illustration and not limitation. Therefore, reference in the specification to “one embodiment” or “an embodiment” indicates that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least an embodiment of the invention. The phrase “in one embodiment” or “an embodiment” do not necessarily refer to the same embodiment.
In the following description, certain terminology is used to describe certain features of one or more embodiments of the invention. For example, a “bow spring” as described herein may include, but is not necessarily limited to, a distinct formed component assembled with a pair of stop collars or an integral component formed from the same material stock as the stop collars. The stop collars and bow springs may be constructed from a wide variety of materials including, but not necessarily limited to, spring steel, metal, composite materials, carbon fiber, plastics, or any combination thereof. Any number of bow springs or combination of bow spring profiles or bow spring positions may be used in accordance with various embodiments.
Aspects of the invention provide mechanisms for a centralizer 10 to be run down-hole in a low-profile, compressed state, and then deployed upon reaching a desired position or after clearing a particular bore restriction. A bow spring centralizer 10 has longitudinal bows 12 and a ratchet/lock mechanism 14 selectively actuatable to deploy longitudinal bow springs 12 about casing 16 once said centralizer 10 is positioned down-hole. With reference to
In some embodiments, longitudinal bow springs 12 extend between two collars 20, 22 secured about casing 16. Collars 20, 22 are mechanically separated along the longitudinal axis of casing 10, e.g., via compression, to retract bow springs 12 into a configuration adjacent casing 16. Collars 20, 22 are maintained separated, and thereby bow springs 12 are in a retracted position via lock by ratcheting mechanism 14. Ratcheting mechanism 14 is selectively actuatable to release or deploy bow springs.
With reference now to
In one such preferred embodiment the components of ratcheting mechanism 14 are stackably arranged as illustrated in
After centralizer 10 has reached a desired position or cleared a particular restriction, ratcheting mechanism 14 can be released to deploy bow springs 12. While various embodiments are described in terms of pressure activation, release of ratcheting mechanism 14 can be accomplished also using any number or combination of mechanical actuators, thermal actuators, pressure actuators, or other suitable selective means for actuation of devices down-hole.
When sufficient pressure is applied inside of casing 16, the outside diameter of the casing 16 expands. A predetermined increase in pressure will result in a determinable expansion of the diameter of casing 16. The extent of expansion depends on the casing size, its wall thickness, and materials used. The activation pressure may be measurably different for a 7″ casing, or a 16″ casing, or a 13⅜″ casing. Therefore target activation pressures can be determined and the locking mechanism designed to be activated by the predicted pressure at a predetermined depth or location. Designing the system around the casing expansion that will occur at a desired depth or location provides flexibility and reliability. As casing 16 expands, wrap band springs 30 are tensioned between casing 16 and outer ratchet band 24, causing rotation of outer ratchet band 24 about casing 16. Rotation of outer ratchet band 24, in turn causes rotation of interlocking inner ratchet band 26. (See
A ratchet spring lock 31 engages inner ratchet 26 to ensure unidirectional rotation and prevent inner ratchet 26 from rotating backwards with the outer ratchet band 24 when the pressure is released. Ratchet spring lock 31 is protected from debris by ratchet spring lock cover 33. Thus, selective cyclical pressurization of casing 16 causes outer ratchet band 24 to rotate back and forth, which in cooperation with spring lock 31 produces a ratcheting reaction between outer ratchet band 24 and inner ratchet band 26.
With reference to
Tab 44 is biased by a spring 56 to retract from receptacle 46 when aligned with release notch 58 defined on the inner ratchet band 26. Upon predetermined rotation of inner ratchet band 26, nose 52 of tab 44 retracts from receptacle 46 as tail 60 of tab 44 withdraws into release notch 58. Upon withdrawal of nose 52 of tab 44 from receptacle 46, ball bearings 48 are dislodged from recesses 54, allowing centralizer bow springs 12 to deploy.
With continued reference to
Alternate embodiments include the use of multiple locking mechanisms to selectively release the bow spring centralizer. Such embodiments include a plurality of release notches 58 formed in inner ratchet ring 26, a plurality of tabs 44, and plurality of receptacles 46, and related components.
With reference to
While various embodiments are described in the context of wellbore applications, centralizer 10 and ratcheting mechanism 14 described herein may provide similar advantages in other applications. Finally, while this description describes and enables various exemplary embodiments, many changes, combinations, and modifications may be made to any of the exemplary embodiments without departing from the scope of the claims. These alternatives can be suitably selected depending upon the particular application or in consideration of any number of factors associated with the operation of the device. These and other changes or modifications are intended to be included within the scope of the present claims.
This is the U.S. National Stage of PCT/US2016/050670, filed Sep. 8, 2016, which in turn claims priority to U.S. Provisional Patent Application No. 62/215,604, filed Sep. 8, 2015 and U.S. patent application Ser. No. 15/258,671, filed Sep. 7, 2016, the entire contents of all applications are incorporated herein by reference in their entireties.
Filing Document | Filing Date | Country | Kind |
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PCT/US2016/050670 | 9/8/2016 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2017/044560 | 3/16/2017 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
6719063 | Adams et al. | Apr 2004 | B2 |
7775272 | Nelson et al. | Aug 2010 | B2 |
20020112853 | Buytaert | Aug 2002 | A1 |
20110168388 | Linaker | Jul 2011 | A1 |
20150027684 | Jewett et al. | Jan 2015 | A1 |
20150034336 | Morrison et al. | Feb 2015 | A1 |
Entry |
---|
International Search Report and the Written Opinion of the International Searching Authority as issued in International Patent Application No. PCT/US2016/050670, dated Nov. 28, 2016. |
Notice of Allowance as issued in U.S. Appl. No. 15/258,671, dated Oct. 12, 2018. |
Non-Final Office Action for Related U.S. Appl. No. 15/258,671 dated Jun. 28, 2018, pp. 1 to 12. |
Number | Date | Country | |
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20180245407 A1 | Aug 2018 | US |
Number | Date | Country | |
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62215604 | Sep 2015 | US |
Number | Date | Country | |
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Parent | 15258671 | Sep 2016 | US |
Child | 15758270 | US |