FULL DEPTH DRILLING SYSTEM AND METHOD

Abstract

A system for drilling a cased wellbore includes a casing string and a drill bit coupled to the casing string, an end of the casing string being substantially aligned with an end of the drill bit. The system also includes a telescoping section formed in the casing string, the telescoping section having a variable length between a first open position and a second closed position, the first open position forming a longer overall casing string length than the second closed position.

Description

BACKGROUND

1. Field of the Invention

The present disclosure relates to oil and gas drilling operations, and more specifically, to full depth drilling systems, such as drilling with casing systems.

2. Description of Related Art

During oil and gas exploration operations, a wellbore may be drilled into a formation through or near a potential hydrocarbon-bearing region. Often, wellbores include casing to line the walls of the wellbore to stabilize pressure within the formation. Typical operations include drilling a wellbore, installing casing, drilling through the casing, installing a slightly smaller diameter casing, and so on until a desired depth is reached. Casing may be extended into the wellbore and attached to an intermediate structure, such as a hanger, in certain instances. This process is time consuming and expensive. Other methods may include drilling with casing, where a drill bit is coupled to a segment of casing, which enables installation of the casing during drilling. However, these systems may not be drilling to full depth. In other words, the wellbore is not drilled beyond a depth of the casing, which is undesirable for subsequent casing installation.

SUMMARY

Applicants recognized the problems noted above herein and conceived and developed embodiments of systems and methods, according to the present disclosure, for drilling operations.

In an embodiment, a system for drilling a cased wellbore includes a casing string and a drill bit coupled to the casing string, an end of the casing string being substantially aligned with an end of the drill bit. The system also includes a telescoping section formed in the casing string, the telescoping section having a variable length between a first open position and a second closed position, the first open position forming a longer overall casing string length than the second closed position.

In another embodiment, a wellbore system includes a first casing positioned within a wellbore, the first casing being secured to an underground formation at a first landing location. The method also includes a second casing, extending through a bore of the first casing, the second casing having a drill bit positioned at an end to extend a borehole formed downhole of the first casing. The second casing includes a first segment and a second segment, arranged radially outward from the first segment, at least a portion of second segment overlapping the first segment and the first and second segments being axially movable relative to one another to adjust a second casing length. A second casing length is reduced after the borehole is extended to a predetermined location and the second casing is landed at a second landing location.

In an embodiment, a method for drilling a full depth wellbore includes positioning a first casing string in a wellbore at a first landing location. The method also includes positioning a second casing string through the first casing string, the second casing string including a drill bit. The method further includes extending a borehole length, via the drill bit, to a predetermined location. The method also includes landing the second casing string at a second landing location, wherein the borehole length extends beyond a second casing string end after the second casing string is positioned at the second landing location.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing aspects, features, and advantages of the present disclosure will be further appreciated when considered with reference to the following description of embodiments and accompanying drawings. In describing the embodiments of the disclosure illustrated in the appended drawings, specific terminology will be used for the sake of clarity. However, the disclosure is not intended to be limited to the specific terms used, and it is to be understood that each specific term includes equivalents that operate in a similar manner to accomplish a similar purpose.

FIG. 1 is a schematic side view of an embodiment of an offshore drilling operation, in accordance with embodiments of the present disclosure;

FIG. 2 is a schematic side view of an embodiment of a cased wellbore, in accordance with embodiments of the present disclosure;

FIGS. 3A and 3B are schematic cross-sectional views of embodiments of a casing system including a telescoping section, in accordance with embodiments of the present disclosure;

FIGS. 4A-4F are schematic diagrams of embodiments of a telescoping section, in accordance with embodiments of the present disclosure; and

FIG. 5 is a flow chart of an embodiment of a method for drilling a wellbore using a casing system, in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION

The foregoing aspects, features, and advantages of the present disclosure will be further appreciated when considered with reference to the following description of embodiments and accompanying drawings. In describing the embodiments of the disclosure illustrated in the appended drawings, specific terminology will be used for the sake of clarity. However, the disclosure is not intended to be limited to the specific terms used, and it is to be understood that each specific term includes equivalents that operate in a similar manner to accomplish a similar purpose.

When introducing elements of various embodiments of the present disclosure, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Any examples of operating parameters and/or environmental conditions are not exclusive of other parameters/conditions of the disclosed embodiments. Additionally, it should be understood that references to “one embodiment”, “an embodiment”, “certain embodiments”, or “other embodiments” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Furthermore, reference to terms such as “above”, “below”, “upper”, “lower”, “side”, “front”, “back”, or other terms regarding orientation or direction are made with reference to the illustrated embodiments and are not intended to be limiting or exclude other orientations or directions.

Embodiments of the present disclosure include a telescoping section of a tubular (e.g., pipe, casing, high pressure housing, etc.) that enables selective collapse of a casing string. As a result, casing hangers and/or high pressure housing may be provided that are sturdy enough to achieve total depth while drilling, yet also allow sufficient weight to properly land and lock into respective landing locations. Embodiments may save a return trip for the rig while drilling a wellbore and installing casing.

Embodiments of the present disclosure provide a telescoping joint in a casing string to provide a sufficient weight at a land out point. A structural member contained within the telescoping joint provides sufficient strength for drilling, yet collapses when setting the equipment. By way of example, the structural member may include shear pins, J-slots, dissolvable components, resilient members (e.g., springs, bellows), triggers, sliding sleeves, and the like.

FIG. 1 is a side schematic view of an embodiment of subsea drilling operation 100. The drilling operation includes a vessel 102 floating on the sea surface 104 substantially above a wellbore 106. It should be appreciated that the vessel 102 is shown for illustrative purposes only, and in various embodiments, other structures such as drilling platforms may be utilized with embodiments of the present disclosure. Furthermore, subsea operations are also for illustration only and surface exploration may also utilize embodiments of the present disclosure. A wellbore housing 108 sits at the top of the wellbore 106 and is connected to a blowout preventer (BOP) assembly 110, which may include shear rams 112, sealing rams 114, and/or an annular ram 116. One purpose of the BOP assembly 110 is to help control pressure in the wellbore 106. The BOP assembly 110 is connected to the vessel 102 by a riser 118. During drilling operations, a drill string 120 passes from a rig 122 on the vessel 102, through the riser 118, through the BOP assembly 110, through the wellhead housing 108, and into the wellbore 106. The lower end of the drill string 120 is attached to the drill bit 124 that extends the wellbore 106 as the drill string 120 turns. It should be appreciated that while a drilling operation is illustrated, embodiments of the present disclosure may also be incorporated into logging operations, stimulation operations, recovery operations, and the like. Additional features shown in FIG. 1 include a mud pump 126 with mud lines 128 connecting the mud pump 126 to the BOP assembly 110, and a mud return line 130 connecting the mud pump 126 to the vessel 102. It should be appreciated that the illustrated mud pump 126 is at a subsea location, but in other embodiments, the mud pump 126 may be arranged on the vessel 102. Moreover, in embodiments, the mud pump 126 may receive a mud supply from a pit or mud shake on the vessel 102. A remotely operated vehicle (ROV) 132 can be used to make adjustments to, repair, or replace equipment as necessary. Although the BOP assembly 110 is shown in the figures, the wellhead housing 108 could be attached to other well equipment as well, including, for example, a tree, a spool, a manifold, or another valve or completion assembly.

One efficient way to start drilling the wellbore 106 is through use of a suction pile 134. Such a procedure is accomplished by attaching the wellhead housing 108 to the top of the suction pile 134 and lowering the suction pile 134 to a sea floor 136. As interior chambers in the suction pile 134 are evacuated, the suction pile 134 is driven into the sea floor 136, as shown in FIG. 1, until the suction pile 134 is substantially submerged in the sea floor 136 and the wellhead housing 108 is positioned at the sea floor 136 so that further drilling can commence. As the wellbore 106 is drilled, the walls of the wellbore are reinforced with steel casings 138 that provide stability to the wellbore 108, and may also be cemented to the formation, and help to control pressure from the formation.

During operations, such as drilling operations, mud is injected into the wellbore 106 via the drilling string 120. For example, the mud pump 126 may receive drilling mud from the vessel 102 and direct the mud through the drill string 120. The mud flows through the drilling string 120 and exits at the drill bit 124, carrying rock cuttings away from the bit 124 and also cooling the bit. The mud enters an annulus 140 surrounding the drill string 120. Advantageously, this mud may be utilized to provide pressure control within the wellbore 106, for example, to balance pressures from the formation. The mud may fill the wellbore 106 and the riser 118, where it is returned to the vessel 102 for processing and reuse.

While the illustrated embodiment shows drilling operations where casing 138 is installed as a subsequent step, drilling with casing provides the benefit of potential timesaving by not requiring an additional trip to install casing after a hole has been drilled. Typically, a hole is drilled deeper than the expected depth of the casing to be installed and then the bit is removed for subsequent casing installation. One potential solution is drilling with casing. However, in a subsea wellhead, for example, sufficient weight for installation and proper seating at respective landing locations is important. Drilling with casing does not allow for a deeper hole than the length of the casing string, thereby introducing potential problems trying to properly land equipment. Embodiments of the present disclosure overcome these problems by incorporating the telescoping section having sufficient structural strength for drilling while also ensuring enough weight is available during landing of the equipment to achieve successful installation.

FIG. 2 is a cross-sectional side view of a cased wellbore 200. As described above, in various embodiments, wellbores may include sections of casing 202 that decrease in diameter. For example, a first casing 202A may be positioned radially outward from a second casing 202B, which is radially outward from both a third casing 202C and a fourth casing 202D. In embodiments, cement 204 may be positioned between the casings. In this embodiment, a tubular 206 extends through the annulus 208 and may include a drill bit 210. As shown, the drill bit 210 has an end 212 that is substantially aligned with a tubular end 214. As a result, drilling will not extend beyond the tubular end 214. However, extending the borehole beyond the casing is often desirable for subsequent installation where weight may be utilized to proper set the casing. As will be described, embodiments of the present disclosure enable drilling beyond the casing end, while also providing sufficient weight to set the casing at respective landing locations.

FIG. 3A is a cross-sectional side view of an embodiment of a casing section 300. The illustrated embodiment includes an outer casing 302, which may be preferred to as a low pressure casing and an inner casing 304, which in this embodiment corresponds to a high pressure casing. It should be appreciated that embodiments may also be directed toward high and low pressure housing sections, as noted above. The illustrating casing section 300 illustrates the outer casing 302 and the inner casing 304 axially aligned along a wellbore axis 306, which the inner casing 304 being arranged radially closer to the wellbore axis 306 than the outer casing 302.

In this embodiment, the outer casing 302 is a stationary component, for example due to its position at a respective landing location 308, where a top 310 is at a first location 312, represented by the broken line. As will be described below, the inner casing 304 may be axially moved relative to the outer casing 302 when the inner casing 304 is set at a respective landing location. FIG. 3A illustrates a segment 314 of the inner casing 304 at a second location 316, represented by a broken line, which may correspond to a top of the inner casing 304 and/or to another location along the inner casing 304. As shown, a distance 318 separates the first location 312 and the second location 316.

The illustrated inner casing 304 includes a telescoping section 320, which is shown in an expanded or deployed position in FIG. 3A. As a result, a casing length 322 is shown between the second location 316 and a string bottom 324. The telescoping section 320 includes a structural member 326 arranged within a void 328 formed between a first segment 330 and a second segment 332. As will be described below, in operation, a void length 334 is maintained during drilling operations and reduced when the inner casing 304 lands at a respective landing location, thereby enabling the inner casing 304 to collapse axially and reduce the casing length 322.

In the illustrated embodiment, at least a portion of the first segment 330 is overlapped by the second segment 332, with the first segment 330 being positioned radially inward from the second segment 332 (e.g., closer to the axis 306). In various embodiments, at least a portion of the first segment 330 and/or the second segment 332 may include an extension or a slot to facilitate coupling between the first and second segments 330, 332. For example, a tongue and groove fitting or tracks may be arranged between the first and second segments 330, 332 to facilitate coupling while maintaining freedom of axial movement. The structural member 326 may be coupled to or otherwise positioned within the void 328 to prevent movement or inadvertent collapse or the inner casing 304 during drilling operations. However, as will be described below, once at a predetermined or desired position, the structure member 326 may be collapsed or otherwise removed to facilitate further operation. It should be appreciated that the structural member 326 may not be positioned within the void 328 in all embodiments, and such an arrangement is described for illustrative purposes. For example, the structural member may extend through the first and second segments 330, 332, such as shears pins, or the like.

FIG. 3A may correspond to a drilling operation where the drill bit 210 advances through the formation and past the outer casing 302. As shown, the inner casing 304 is positioned in an expanded position such that the casing length 322 is longer than the casing length when in a collapsed position, as will be described below. In certain embodiments, drilling may continue beyond a respective landing location and/or to a landing location. The telescoping section 320 may then be activated to position the inner casing 304 in a desired orientation, as shown herein.

FIG. 3B is a cross-sectional view of the casing section 300 where the inner casing 304 is transitioned to the collapsed or set position such that the void 328 is gone or substantially gone. In other words, the void length 334 is approximately zero in the illustrated embodiment. As shown, the inner casing 304 has shifted with respect to FIG. 3A such that the casing length 322 is shorter in FIG. 3B than in FIG. 3A. Furthermore, the distance 318 between the first location 312 and the second location 316 is decreased. In operation, the outer casing 302 may remain in a fixed position as the inner casing 304 moves, such as movement of the first segment 330 with respect to the second segment 332 and/or movement of the second segment 332 with respect to the first segment 330.

In various embodiments, the inner casing 304 may transition to the collapsed position based at least in part on a weight of the first segment 330, which facilitates setting the inner casing 304. For example, in embodiments, a shoulder 336 of the second segment 332 may engage a second landing location, which may block continued downward movement of the second segment 332. A force may be applied, which may at least partially incorporate the weight of the first segment 330, to facilitate collapse of the telescoping section 320. As a result, the casing and/or borehole may extend beyond the second landing location.

It should be appreciated that, in other embodiments, the casing landing location may be previously selected based on one or more properties of the drilling operation, such as formation properties, mud weight, and the like. Accordingly, the inner casing 304 may be installed to the desired location, and thereafter, activated to collapse the telescoping section 320. In certain embodiments, activation may be driven by uphole activities, such as closing in and pressuring the well, by the outer casing 302, or any other reasonable method. In this manner, the inner casing 304 may be set to continue with additional drilling and/or production operations.

Furthermore, it should be appreciated that, in various embodiments, the inner casing 304 may be actuated such that the bottom 324 is moved axially upward (e.g., toward the surface), thereby providing additional drilled area axially lower than the end of the inner casing 304. For example, the inner casing 304 may be lifted and coupled to a casing hanger at an uphole location, or the casing hanger may be rotated in order to couple to another uphole component.

FIGS. 4A-4F are schematic diagrams of embodiments of the telescoping section 320 including various components, which may or may not be incorporated into the structural member 326, to facilitate operation. It should be appreciated that certain features may be combined into a single embodiment and, therefore, illustration of the components separately is not intended to indicate that features may not be utilized together. Embodiments of the present disclosure may provide improved strength and stability for the telescoping section 320 during drilling operations while also selectively collapsing to enable full depth drilling with casing. As noted above, various embodiments may facilitate axially downward movement of the first segment 330 and/or axially upward movement of the second segment 332.

FIG. 4A is a cross-sectional view of an embodiment of the telescoping section 320 including shear pins 400 extending through the first segment 330 and the second segment 332. It should be appreciated that the illustrated pair of shear pins 400 is for illustrative purposes only and there may be more or fewer shear pins 400 in other embodiments. The illustrated shear pins 400 may provide structural stability during drilling operations by securing movement between the second segment 332 and the first segment 330. However, upon activation of the inner casing 304, a force may be applied to break the shear pins 400 and facilitate collapse of the void 328, thereby moving the first segment 330 axially downward and/or moving the second segment 332 axially upward.

Further illustrated in FIG. 4A is a blocking shear pin 402 which does not extend through the first segment 330. As an example, the blocking shear pin 402 is positioned within the void 328 and blocks movement of the first segment 330 in an axially downward direction. However, sufficient force may break the blocking shear pin 402, thereby driving the first segment 330 into the void 328.

FIG. 4B is a cross-sectional view of an embodiment of the telescoping section 320 including a dissolvable component 404 arranged within the void 328. The dissolvable component is formed from a material that has structural rigidity and/or certain properties until being exposed to certain fluids or compounds. Moreover, the dissolvable material may be any material configured to dissolve in the presence of a certain fluid, for a certain amount of time, at a certain temperature, or any combination thereof. For example, the dissolvable material may start dissolving when exposed to a predetermined temperature and/or a predetermined fluid, such as wellbore fluid. By way of example, the dissolvable material may be or include a magnesium, thermoplastic, dissolvable aluminum, a water soluble, synthetic polymer composition including a polyvinyl, alcohol plasticizer and mineral filler, or a combination thereof. In other embodiments, the dissolvable material may be a matrix of two or more materials. The first material of the matrix may be configured to dissolve at a first rate and a second material may dissolve at a second rate.

In the illustrated embodiment, the dissolvable component 404 fills substantially all of the void 328. However, it should be appreciated that the dissolvable component 404 may be formed in any reasonable shape and fill only a portion of the void 328. Accordingly, in operation, the inner casing 304 may be set at a certain location and then exposed to one or more dissolving conditions, noted above. When the dissolvable component disintegrates and is removed from the void 328, the inner casing 304 may be set at the landing location as the void 328 collapses.

FIG. 4C is a side view of an embodiment of the telescoping section 320 including a J-slot 406 to facilitating collapse of the void 328. In the illustrated embodiment, the J-slot 406 includes an extension 408 extending off the first segment 330 and a slot 410. The extension 408 is positioned within the slot 410 and, in operation, rotation may facilitate collapse of the void 328. For example, rotation may drive the extension 408 through the slot 410 in the direction of the arrows, thereby facilitating collapse in the axial direction.

FIG. 4D is a cross-sectional view of an embodiment of the telescoping section 320 including a resilient member 412 positioned within the void 328. The resilient member 412 may include a spring or bellows that blocks collapse of the void 328 absent a force or pressure that exceeds threshold quantity. Accordingly, upon positioning the inner casing 304 at the desired location, a sufficient force to overcome the resilient member 412 may be applied, thereby setting the inner casing 304.

FIG. 4E is a cross-sectional view of an embodiment of the telescoping section 320 including a trigger or activator 414 that interacts with the outer casing 302 to facilitate collapse of the void 328. In this embodiment, the activator 414 is coupled to a structural body 416. Upon activation, the structural body 416 may be pivoted and move into a slot formed in the first segment 330, thereby enabling collapse of the void 328.

FIGS. 4F is a cross-sectional view of an embodiment of the telescoping section 320 including the trigger or activator 414. In this embodiment, a vessel 418 is positioned within the void 328, which may include a pressurized fluid within resilient walls. Upon activation, an opening 420 in the vessel 418 may facilitate outward flow of the fluid, thereby leading to collapse of the void 328.

FIG. 5 is an embodiment of a flow chart of a method 500 for drilling a cased wellbore. It should be appreciated that this method, and other methods described herein, may include more or fewer steps. Furthermore, the steps may be performed in a different order and/or may be performed in parallel, unless otherwise specifically stated. In this example, a portion of a wellbore is formed in a formation 502. The portion may include a first section of casing, which may be secured to the formation via cement or the like. A second section of casing is tripped into the wellbore along with a drill bit, which may be referred to as performing a portion of a casing while drilling operation. A hole, formed by operation of the drill bit, is extended into the formation to a location beyond an end of the first section of casing 504. In various embodiments, a telescoping section of the second section of casing is activated 506. As described above, activating the telescoping section may include collapsing a void within the telescoping section. The second section of casing is then landed at a landing location, for example, using a weight from above 508. In this manner, casing may be installed during drilling operations, which may save trips out of the wellbore to retrieve casing, thereby reducing rig time.

The foregoing disclosure and description of the disclosed embodiments is illustrative and explanatory of the embodiments of the invention. Various changes in the details of the illustrated embodiments can be made within the scope of the appended claims without departing from the true spirit of the disclosure. The embodiments of the present disclosure should only be limited by the following claims and their legal equivalents.

Claims

1. A system for drilling a cased wellbore, comprising:

a casing string;

a drill bit coupled to the casing string, an end of the casing string being substantially aligned with an end of the drill bit; and

a telescoping section formed in the casing string, the telescoping section having a variable length between a first open position and a second closed position, the first open position forming a longer overall casing string length than the second closed position.

2. The system of claim 1, wherein the telescoping section comprises:

a first segment of casing string;

a second segment of the casing string, the second segment arranged radially outward from the first segment and at least partially overlapping the first segment; and

a void between an end of the first segment and the second segment, wherein a void length between the end of the first segment and the second segment is greater in the first open position than in the second open position.

3. The system of claim 2, wherein the first segment moves into the void when the telescoping section transitions to the second closed position.

4. The system of claim 1, wherein the telescoping section further comprises:

a structural member maintaining the first open position.

5. The system of claim 4, wherein the structural member comprises a dissolvable component.

6. The system of claim 4, wherein the structural member comprises a shear pin.

7. The system of claim 1, wherein the telescoping section further comprises a j-slot, comprising:

an extension extending from a radially inward portion of the casing string; and

a slot formed in a radially outward portion of the casing string, the extension moving through the slot in response to rotation of at least a portion of the casing string.

8. A wellbore system, comprising:

a first casing positioned within a wellbore, the first casing being secured to an underground formation at a first landing location;

a second casing, extending through a bore of the first casing, the second casing having a drill bit positioned at an end to extend a borehole formed downhole of the first casing, the second casing comprising: a first segment; and a second segment, arranged radially outward from the first segment, at least a portion of second segment overlapping the first segment and the first and second segments being axially movable relative to one another to adjust a second casing length;

wherein a second casing length is reduced after the borehole is extended to a predetermined location and the second casing is landed at a second landing location.

9. The wellbore system of claim 8, wherein at least a portion of the first segment and at least a portion of the second segment forms a telescoping section of the second casing.

10. The system of claim 9, wherein the telescoping section further comprises:

a structural member arranged between the first segment and the second segment, the structural member maintaining an extended second casing length during a drilling operation.

11. The system of claim 10, wherein the structural member is configured to disengage to facilitate movement between the first segment and the second segment to form a collapsed second casing length.

12. The system of claim 10, wherein the structural member comprises a dissolvable component.

13. The system of claim 10, wherein the structural member comprises a shear pin.

14. The system of claim 10, wherein the structural member comprises a resilient member.

15. The system of claim 10, wherein the second casing further comprises:

an extension extending from the first segment; and

a slot formed in the second segment, the extension moving through the slot in response to rotation of at least a portion of the second casing string.

16. The system of claim 10, wherein engagement between the first casing and the second casing drives axial movement of the first segment and the second segment relative to one another.

17. A method for drilling a full depth wellbore, comprising:

positioning a first casing string in a wellbore at a first landing location;

positioning a second casing string through the first casing string, the second casing string including a drill bit;

extending a borehole length, via the drill bit, to a predetermined location; and

landing the second casing string at a second landing location, wherein the borehole length extends beyond a second casing string end after the second casing string is positioned at the second landing location.

18. The method of claim 17, further comprising:

collapsing a telescoping section of the second casing string.

19. The method of claim 18, wherein collapsing the telescoping section of the second casing string comprises:

disengaging a structural member of the second casing string; and

axially moving a first segment of the second casing string and a second segment of the second casing string relative to one another, the movement reducing a second casing string length.

20. The method of claim 19, wherein the structural member comprises at least one of a shear pin, a dissolvable component, a resilient member, or a j-slot.