CN112324379A

CN112324379A - Plug for oil and gas well

Info

Publication number: CN112324379A
Application number: CN202011215559.8A
Authority: CN
Inventors: 不公告发明人
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-11-04
Filing date: 2020-11-04
Publication date: 2021-02-05

Abstract

A plug for a hydrocarbon well, the plug comprising a retrievable upper component (202) and a lower component (204) connected to the upper component; said upper assembly (202) comprising a substantially tubular positioning sleeve (206) having a thread (208) at its upper end (207); the locating sleeve (206) houses a locating tool body (210) comprising an upper end (213) and a lower end (215); the lower assembly (204) is connected to the lower end (209) of the upper assembly (202); the lower assembly (204) includes a lower mandrel (238), the lower mandrel (238) being constructed of a composite material and having an upper end (240) terminating in a counterbore (224); the upper end (240) of the lower mandrel (238) is secured to the lower assembly locator sleeve (215) and the locator tool body (210) by an upper shear pin (220); the lower assembly (204) also includes upper and lower sliding cone assemblies (252, 254) and an elastomeric packer element (256). The plug solves the problem that the common recyclable plug is difficult to disassemble.

Description

Plug for oil and gas well

Technical Field

The present application relates to a downhole plug, and more particularly to a removable plug.

Background

In the completion of oil and gas wells, there are various downhole operations in which it may be necessary to isolate a particular zone within the well. Typically, this is accomplished by temporarily plugging the well casing with a plug at one or more given points. Plugs are often used to perform operations such as isolating a hole in one section of a well from a hole in another section, or isolating the bottom of a well from the wellhead. Conventional plugs merely isolate some portion of the well from another portion of the well.

However, in some cases, the plug is not necessarily used for isolation, but may be used, for example, to create a cement plug in the wellbore. The plug may be temporary or permanent. If temporary, it must be removable. The plug may be drillable or retrievable. Drillable plugs are typically made of brittle metals, such as drillable cast iron. One problem with conventional drillable plugs, however, is that without some sort of locking mechanism, the plug components may rotate with the drill bit, which may result in extremely long drilling times, excessive casing wear, or both. Longer drilling times result in less efficient drilling.

Retrievable plugs have been employed in the prior art in place of drillable plugs, which can be used to temporarily isolate a portion of a well before the well portion is completely removed from the well interior. The retrievable plug typically has an anchor and a seal that engage and secure it to the wall of the housing. To retrieve the plug, a retrieval tool is lowered into the casing to engage a retrieval latch that retracts the anchor and sealing element through a retrieval mechanism, allowing the plug to be pulled out of the wellbore. A common problem with retrievable plugs is the build up of debris on top of the plug which may make it difficult or impossible to engage a retrieval latch to remove the plug. Such debris accumulation may also adversely affect the relative movement of the various parts within the plug. Furthermore, with current retrieval tools, shock or friction on the wellbore may cause accidental unlocking of the retrieval tool or re-locking of the plug. It may also be difficult to separate the retrieval tool from the plug when it is removed, which requires the use of additional machinery. Problems such as this sometimes make it necessary to drill out plugs that are intended to be recyclable.

If meet special circumstances after the current stopper is sealed, can't realize this stopper emergency deblocking, can only complete deblocking earlier, handle and operate after accomplishing again, waste time and energy like this, seriously influence going on of creeping into. Accordingly, there is a need in the art for a plug that can be removed from a wellbore or removed urgently while ensuring that the plug's function is properly completed.

Disclosure of Invention

A plug for a hydrocarbon well, the plug capable of isolating a downhole casing, the plug comprising a retrievable upper assembly and a lower assembly coupled to the upper assembly, wherein the lower assembly comprises a drillable material.

The upper assembly includes a substantially tubular retaining sleeve having threads on its upper end. The positioning sleeve houses a positioning tool body comprising an upper end and a lower end, the positioning tool body carrying a selection tool having a neck portion housed at the upper end and a radial port housed at the lower end.

The lower assembly is connected to the lower end of the upper assembly. The lower assembly includes a lower mandrel composed of a composite material and having an upper end terminating in a counterbore. The upper end of the lower mandrel is secured to the lower assembly alignment sleeve and the alignment tool body by an upper shear pin. The lower end of the lower spindle terminates in a guide shoe. The guide shoe forms the lowermost end. The guide shoe has a central bore terminating in a conical seat that receives a lower piston mounted on a rod extending downwardly from the piston.

The lower assembly further includes a body lock ring housing disposed below the upper assembly around the lower mandrel. The body locking ring housing is formed of a metal or composite material and carries a locking ring. The locking ring includes a plurality of teeth that engage and secure the lower end of the positioning tool to the upper end of the lower mandrel.

The lower assembly also includes upper and lower sliding cone assemblies, and an elastomeric packer element. The upper sliding cone assembly includes an upper cone that includes an inclined sliding ramp and is secured to the lower end of the body lock ring housing by a shear pin. The tapered end of the upper cone engages a tapered surface of an upper slider that includes a plurality of teeth. The upper slider includes a notch that slidably engages the elongated end of the upper compression element. Thus, the upper cone is designed to slide downward under the upper slide to force the upper slide downward against the upper compression element and radially outward against the inner compression element. The upper slider and the upper compression element are formed from a composite material.

The lower sliding cone assembly is formed substantially similarly to the structural makeup of the upper sliding cone assembly, but is oriented opposite the upper sliding cone assembly. That is, the lower cone abuts the upper end of the guide shoe and the lower slider moves downward such that its tapered bore engages the tapered upper end of the upper compression element. The upper and lower cone assemblies are longitudinally spaced apart such that at least one elastomeric packer element may be retained between the upper and lower compression elements. While a single such packer element is shown, more or fewer packer elements may be used.

The plug is connected to the hydraulic tool by threads on the upper assembly and is driven to exert a downward force on the positioning tool body while pulling the body of the plug, including the upper and lower slips, and the packer element upward. This provides an upward force on the guide shoe which moves the upper and lower cones, further up and down the slide, down and forces the upper and lower slide axially closer to the upper and lower compression elements. As the upper and lower slides move closer to the upper and lower compression elements, they force the upper and lower compression elements closer to each other, which longitudinally compresses the packer elements so that they expand radially outward. Travel of the upper and lower cones, upper and lower slips, below also causes the upper and lower slips to expand radially outward, causing the teeth to "bite" into and engage the inner wall of the casing, which fixes the packer element in compression. At the same time, the body locking ring housing is forced downwardly relative to the stopper body and the locking ring teeth bite into the body locking ring housing to prevent upward movement which could release the downward force applied.

To allow fluid flow through the tool, a central bore is provided through the upper and lower slips, and the packer element and a portion of the upper assembly. The radial ports in the selection tool may be opened or closed depending on the relative axial positions of the upper and lower assemblies. To open the port, first, an upward force is applied to the locating sleeve and the fixed tool body to break the shear pin, allowing the fixed sleeve and the fixed tool body to be removed, exposing the upper neck for gripping onto the upper neck by a fishing tool and wireline so that an upward force can be applied to the selection tool. The plunger at the lower end of the selection tool is removed from the recess in the lower mandrel so that flow is permitted from the central bore through the recess and out the port. When the upward force is released, the plunger moves back into the recess, closing the port opening from flow.

Plug retrieval is also gripped onto the upper neck by a fishing tool and wireline. If the upper and lower slips are not releasable, sufficient upward force will break the lower shear pin so that the upper portion can then pull the upper assembly up out of the wellbore while the lower assembly, comprised primarily of composite material, can be milled out with the drill bit.

Drawings

Figure 1 is a longitudinal cross-sectional view of a stopper of the present invention.

Fig. 2 is a longitudinal cross-sectional view of the upper assembly of the stopper of the present invention.

Fig. 3 is a longitudinal cross-sectional view of the lower assembly of the stopper of the present invention.

Detailed Description

As shown in FIG. 1, the plug 200 of the present invention includes a retrievable upper assembly 202 and a lower assembly 204 connected to the upper assembly.

As shown in fig. 2, the upper assembly 202 includes a generally tubular locating sleeve 206, the locating sleeve 206 having threads 208 at an upper end 207 thereof. The locating sleeve 206 houses a locating tool body 210, the locating tool body 210 including an upper end 213 and a lower end 215, the locating tool body 210 carrying a selection tool 212, the selection tool 212 having a neck 214 housed at the upper end 213 and a radial port 216 housed at the lower end 215.

As shown in fig. 3, the lower module 204 is connected to the lower end 209 of the upper module 202. The lower assembly 204 includes a lower mandrel 238 that is constructed of a composite material and has an upper end 240 that terminates in the counterbore 224. The upper end 240 of the lower mandrel 238 is secured to the lower assembly locator sleeve 215 and the locator tool body 210 by the upper shear pin 220. The lower end 242 of the lower mandrel 238 terminates in a guide shoe 244. The guide 244 forms the lowermost end. Guide 244 has a central bore 245 that terminates in a tapered seat 247, which tapered seat 247 receives lower piston 223 mounted on a rod extending downwardly from piston 222.

The lower assembly 204 also includes a body lock ring housing 246 disposed about the lower mandrel 238 below the upper assembly 202. Body locking ring housing 246 is formed of a metal or composite material and carries a locking ring 248. The locking ring 248 includes a plurality of teeth 250 that engage the lower end 215 of the positioning tool 210 and secure it to the upper end 240 of the lower mandrel 238.

The lower assembly 204 also includes upper and lower sliding

cone assemblies

252, 254 and an elastomeric packer element 256. Upper sliding cone assembly 252 includes an upper cone 258, with upper cone 258 including an inclined sliding ramp and secured to lower end 247 of body lock ring housing 246 by shear pin 260. The tapered end 257 of the upper cone 258 engages the tapered surface 259 of the upper slider 262, which upper slider 262 includes a plurality of teeth 270. The upper slider 262 includes a recess 228, the recess 228 slidably engaging the elongate end 230 of the upper compression element 272. Thus, the upper cone 258 is designed to slide downward under the upper slide 262 to force the upper slide 262 downward against the upper compression element 272 and radially outward against the inner compression element. Upper slide 262 and upper compression element 272 are formed from a composite material.

The lower sliding cone assembly 254 is formed substantially similarly to the structural makeup of the upper sliding cone assembly 252, but is oriented opposite the upper sliding cone assembly 252. That is, the lower cone 278 abuts the upper end 245 of the guide shoe 244 and the lower slider 276 moves downwardly such that its tapered bore 277 engages the tapered upper end 279 of the upper compression element 272. The upper and lower sliding

cone assemblies

252, 254 are longitudinally spaced apart such that at least one elastomeric packer element 256 may be retained between an upper compression element 272 and a lower compression element 274. 3 such packer elements 256 are shown in FIG. 2, although more or fewer packer elements 256 may be used.

The plug is connected to the hydraulic tool by threads 208 on the upper assembly 202 and is actuated to exert a downward force on the positioning tool body 210 while pulling the body of the plug 200, including the upper and

lower slips

262, 276 and the packer element 256, upward. This provides an upward force on the guide shoe 244 which moves the upper and

lower cones

258, 278 further under the upper and

lower sliders

262, 276 and forces the upper and

lower sliders

262, 276 axially closer to the upper and

lower compression elements

272, 274. As the upper and

lower sliders

262, 276 move closer to the upper and

lower compression elements

272, 274, they force the upper and

lower compression elements

272, 274 closer to each other, which longitudinally compresses the packer element 256 so that they expand radially outward. The travel of the upper and

lower cones

258, 278 under the upper and

lower slips

262, 276 also causes the upper and

lower slips

262, 276 to expand radially outward such that the teeth 270 "bite" into and engage the inner wall of the casing, which fixes the packer element 256 in compression. At the same time, body locking ring housing 246 is forced downwardly relative to stopper body 200 and locking ring teeth 250 bite into body locking ring housing 246 to prevent upward movement which could release the downward force applied.

To allow fluid flow through the tool, a central bore is provided through the upper and

lower slips

262, 276 and the packer element 256 and a portion of the upper assembly 202. The radial ports 236 in the selection tool 212 may be opened or closed depending on the relative axial positions of the upper and

lower assemblies

202, 204. To open the port 236, first, an upward force is applied to the locating sleeve 206 and the fixed tool body 210 to break the shear pin 220, allowing the fixed sleeve 206 and the fixed tool body 210 to be removed, exposing the upper neck 214 for gripping onto the upper neck 214 by a fishing tool and wireline so that an upward force may be applied to the selection tool 212. The plunger 222 at the lower end of the selection tool 212 is removed from the recess 224 on the lower mandrel 236 so that flow is permitted from the central bore through the recess and out the port. When the upward force is released, the plunger moves back into the recess, closing the port opening from flow.

The plug 200 is retrieved and also grasped by the fishing tool and wireline onto the upper neck 214. If the upper and

lower slips

262, 276 cannot be released, sufficient upward force will break the lower shear pin 260 so that the upper portion can then pull the upper assembly 202 up out of the wellbore while the lower assembly 204, which is comprised primarily of composite material, can be milled out with the drill bit.

The present invention provides plugs that can be retrieved from the wellbore to a large extent. To this end, the design incorporates an emergency release device which allows retrieval of at least a portion of the plug if difficulties are encountered in disassembling the entire tool. In this case, those parts remaining in the wellbore are formed from a composite drillable material that can be milled to clean the wellbore. Thus, the difficulties of disassembly encountered with conventional prior recyclable plugs are resolved. By making only a portion of the plug drillable, and only drilling where removal difficulties make retrieval of the entire tool infeasible or impossible, the time and cost of drilling is significantly reduced.

Claims

1. A plug for oil and gas wells, the plug comprising an upper component (202) and a lower component (204) connected to the upper component, characterized by: the upper assembly (202) and the lower assembly (204) are retrievable;

said upper assembly (202) comprising a substantially tubular positioning sleeve (206), the positioning sleeve (206) having a thread (208) at its upper end (207); said positioning sleeve (206) housing a positioning tool body (210), the positioning tool body (210) comprising an upper end (213) and a lower end (215), the positioning tool body (210) carrying a selection tool (212), said selection tool (212) having a neck (214) housed at the upper end (213) and a radial port (216) housed at the lower end (215);

the lower assembly (204) is connected to the lower end (209) of the upper assembly (202); the lower assembly (204) includes a lower mandrel (238), the lower mandrel (238) being constructed of a composite material and having an upper end (240) terminating in a counterbore (224); the upper end (240) of the lower mandrel (238) is secured to the lower assembly locator sleeve (215) and the locator tool body (210) by an upper shear pin (220); a lower end (242) of the lower mandrel (238) terminating in a guide shoe (244); the guide shoe (244) forms a lowermost end;

the lower assembly (204) further comprising upper and lower sliding cone assemblies (252, 254) and an elastomeric packer element (256); the upper sliding cone assembly (252) includes an upper cone (258), the upper cone (258) including a sloped sliding ramp and being secured to the lower end (247) of the body lock ring housing (246) by a shear pin (260); the tapered end (257) of the upper cone (258) engages the tapered surface (259) of the upper slider (262), the upper slider (262) including a plurality of teeth (270); the upper slider (262) includes a notch (228), the notch (228) slidably engaging the elongated end (230) of the upper compression element (272).

2. A plug for oil and gas wells as claimed in claim 1, wherein: the upper cone (258) is designed to slide downward under the upper slide (262) to force the upper slide (262) downward against the upper compression element (272) and radially outward against the inner compression element.

3. A plug for oil and gas wells as claimed in claim 2, wherein: the upper slider (262) and the upper compression element (272) are formed from a composite material.

4. A plug for oil and gas wells as claimed in claim 3, wherein: the guide shoe (244) has a central bore (245) that terminates in a tapered seat (247), the tapered seat (247) receiving a lower piston (223) mounted on a rod extending downwardly from the piston (222).

5. A plug for oil and gas wells according to any one of claims 1 to 4, wherein: the lower assembly (204) further includes a body lock ring housing (246) disposed around the lower mandrel (238) below the upper assembly (202); a body lock ring housing (246) with a lock ring (248); the locking ring (248) includes a plurality of teeth (250), the plurality of teeth (250) engaging and securing the lower end (215) of the positioning tool (210) to the upper end (240) of the lower mandrel (238).

6. A plug for oil and gas wells according to any one of claims 1 to 4, wherein: the lower sliding cone assembly (254) is constructed substantially similar to the upper sliding cone assembly (252) but is oriented opposite the upper sliding cone assembly (252).

7. A plug for oil and gas wells as claimed in claim 6, wherein: the lower cone (278) abuts the upper end (245) of the guide shoe (244) and the lower slider (276) moves downward such that its tapered bore (277) engages the tapered upper end (279) of the upper compression element (272).

8. A plug for oil and gas wells as claimed in claim 7, wherein: the upper and lower sliding cone assemblies (252, 254) are longitudinally spaced apart such that at least one elastomeric packer element (256) may be retained between an upper compression element (272) and a lower compression element (274).

9. Use of a plug for oil and gas wells according to any one of claims 1 to 8, characterized by: the plug is connected to a hydraulic tool by threads (208) on the upper assembly (202) and is driven to exert a downward force on the positioning tool body (210) while pulling the body of the plug (200) upward, including upper and lower slips (262, 276) and a packer element (256); this provides an upward force on the guide shoe (244) that moves the upper and lower cones (258, 278) further under the upper and lower sliders (262, 276) and forces the upper and lower sliders (262, 276) axially closer to the upper and lower compression elements (272, 274); as the upper and lower sliders (262, 276) move closer to the upper and lower compression elements (272, 274), they force the upper and lower compression elements (272, 274) closer to each other, which longitudinally compresses the packer element (256) so that they expand radially outward;

the travel of the upper and lower cones (258, 278) under the upper and lower slips (262, 276) also causes the upper and lower slips (262, 276) to expand radially outward such that the teeth (270) "bite" into and engage the inner wall of the casing, which fixes the packer element (256) in a compressed state; simultaneously, forcing the body lock ring housing (246) downwardly relative to the stopper body, and the locking ring teeth (250) bite into the body lock ring housing (246) to prevent upward movement which might release the downward force applied;

to open the port (236), first, an upward force is applied to the locating sleeve (206) and the fixed tool body (210) to break the shear pin (220), allowing the fixed sleeve (206) and the fixed tool body (210) to be removed, exposing the upper neck (214) to grip onto the upper neck (214) by a fishing tool and wireline so that an upward force can be applied to the selection tool (212); the plunger (222) at the lower end of the selection tool (212) is removed from the recess (224) on the lower mandrel (236) so that flow is permitted from the central bore through the recess and out the port. When the upward force is released, the plunger moves back into the recess, closing the port opening from flow;

the plug is retrieved by gripping the fishing tool and wireline onto the upper neck (214); if the upper and lower slips (262, 276) cannot be released, sufficient upward force will break the lower shear pin (260) so that the upper portion can then pull the upper assembly (202) up out of the wellbore while the lower assembly (204) consisting primarily of composite material can be milled out with the drill bit.

10. A method of retrieving plugs for oil and gas wells as claimed in claim 9, wherein: to allow fluid flow through the tool, a central bore is provided through the upper and lower slips (262, 276) and the packer element (256) and a portion of the upper assembly (202).