WO2017058220A1

WO2017058220A1 - Modified filter screen

Info

Publication number: WO2017058220A1
Application number: PCT/US2015/053312
Authority: WO
Inventors: William Jay CANTRELL; Faraz Ali
Original assignee: Reme, L.L.C.
Priority date: 2015-09-30
Filing date: 2015-09-30
Publication date: 2017-04-06

Abstract

A modified filter screen for use in a downhole drilling operation is disclosed. The filter screen is able to be installed at the surface of a well, and is pin-loaded for easy access and maintenance. The modified filter screen may be retained within a section of pipe below the top drive above the rig floor by allowing dowel pins on the section of pipe to engage with latch slots on the filter screen.

Description

NON-PROVISIONAL PATENT APPLICATION

MODIFIED FILTER SCREEN

INVENTORS: William Jay Cantrell, Faraz Ali

BACKGROUND

1. Field of the Invention

[0001] The present invention relates to filter screens used in downhole drilling technologies in the oil and gas industry.

2. Description of the Related Art

[0002] In the oil and gas industry, downhole drilling operations may drill boreholes that extend thousands of feet into the ground. A fluid called drilling mud is used to facilitate drilling. As shown in Figure 1, drilling mud circulates through the drilling system. Mud pumps 110 pump the mud from mud tanks 105 located at the surface. The mud gets pumped through the kelly hose 1 15 and the top drive 120. The mud is further pumped through the drill string, or drill pipe, 125 to the bottom hole assembly 130. As it reaches the bottom of the borehole, the mud acts to cool and clean the drill bit 135. The mud also picks up rock formation cuttings and circulates them back up through the annulus 140 between the drill string and casing back through the blowout preventers 145 to the surface. At this point, the mud gets processed through a shale shaker 150 before returning to mud tanks 105 to start the process of being pumped downhole again.

[0003] As the mud circulates through this system, it may pick up significant amounts of debris, which can affect the flow of the mud and the operation of the drill bit and other tools. A filter screen subassembly may be installed in the drill string to help collect and filter debris. Downhole filter screens are often run during directional drilling and are typically installed near the drill bit at the bottom of the drill string, and thus are not easily accessible during drilling. To remove or clean out a downhole filter screen, the entire drill string must be pulled out of the wellbore. Downhole filter screens typically employ flanges to be secured in a section of drill string. The flanges necessitate the insertion and removal of the existing filter screens from the box end (i.e., uppermost end) of a drill string section.

[0004] Additionally, downhole filter screens are easily damaged during drilling operations. If a filter screen fills with debris and is not properly maintained or cleaned, then it can cause blockages in the fluid flow or potentially "wash out." In other words, the filter screen may shear off due to excess debris buildup or excess vibration during drilling operations. The broken filter screen can be pushed by the fluid flow of the drilling mud and may end up at the bottom of the borehole. Due to the inconveniences from factors such as installation, cleaning, and maintenance, filter screens are often not used by drilling operators despite the benefits they provide in filtering drilling mud.

[0005] Surface pipe screens are also sometimes used to filter drilling mud. These pipe screens are installed in the drill string above the surface at the drilling rig, and they are designed to catch finer particulates than downhole filter screens. However, they are typically not built as robustly as downhole filter screens and require constant maintenance. They typically installed at the box end of a pipe segment and are held in place using a flange. Surface pipe screens also require constant maintenance. Each time a new drill pipe segment is ready to be added to the drill string, the top drive must be disconnected from the drill string. Before connecting the new drill pipe segment, the installed surface pipe screen must be removed from the topmost exposed segment (i.e., box end) of drill pipe in the drill string. After the new drill pipe segment is connected to the drill string, the surface pipe screen can be reinstalled into the new drill pipe segment's box end, and the top drive can be reconnected with the drill string. If the surface pipe screen is ever forgotten when adding new segments of pipe, the surface pipe screen may become "lost" in the drill string, making its retrieval difficult and tedious. Further, if a surface pipe screen ever shears off, it may become lodged along with debris anywhere in the drill string.

[0006] Additionally, surface pipe screens can present safety issues. Many drilling operators enforce a safety zone around the drill string when the top drive is disconnected from the drill string because it is a pinch point. Many operators forgo the use of surface pipe screens, rather than risk the safety of personnel during the frequent insertion and removal of a surface pipe screen during drilling operations.

[0007] Accordingly, there exists a need for the safe and easy attachment and removal of a filter screen that is constantly positioned at the surface of a drilling rig.

SUMMARY OF THE INVENTION

[0008] The following invention presents a novel modified filter screen design. The filter screen is able to be installed at the surface of a well, it does not need to be removed and reinstalled when additional segments are added to the drill string, and it may be loaded into the pin end (i.e., the bottom end) of a segment near the top drive for easy access and maintenance.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Various aspects and attendant advantages of one or more exemplary embodiments and modifications thereto will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

[0010] Figure 1 is a flow diagram illustrating how drilling mud may flow through a drilling system as per the prior art.

[0011] Figure 2 is a flow diagram illustrating how drilling mud may flow through a drilling system using the present invention.

[0012] Figure 3 is a diagram of a drilling system illustrating the use of the present invention.

[0013] Figure 4A illustrates the positioning of a modified filter screen in a top assembly.

[0014] Figure 4B illustrates the positioning of a modified filter screen in a top assembly with an inner shoulder.

[0015] Figure 5 illustrates the latching mechanism by which the modified filter screen is held in the top assembly.

DETAILED DESCRIPTION

[0016] It is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms "connected," "coupled," and "mounted," and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. In addition, the terms "connected" and "coupled" and variations thereof are not restricted to physical or mechanical connections or couplings.

[0017] As referenced above, Figure 1 shows a typical flow diagram of how drilling mud may flow through a downhole drilling system as per the prior art. Figure 2 shows a flow diagram of how drilling fluid may flow through a downhole drilling system using the modified filter screen 220B. Elements in Figure 2 are analogous to their similarly numbered counterparts in Figure 1. The top drive 220A is a portion of the drill rig that includes one or more motors used to rotate the drill string during drilling. The top drive 220A connects to the drill string 225 by a section of pipe sometimes referred to as the quill. The modified filter screen 220B is inserted into the quill or into a filter sub that may be installed just below the top drive assembly 220A. In Figure 3, the location of the modified filter screen 320B is shown in the context of a top drive assembly 320A and the drilling rig floor 360.

[0018] Figures 4A and 4B show two embodiments of a filter sub 400 that may be used to house the modified filter screen. The filter sub remains connected to the top drive when the top drive is disconnected from the drill string. The modified filter screen is inserted into the filter sub from the pin end— the bottom end— of the filter sub. This allows for ease of insertion and removal of the modified filter screen from the filter sub. Because the top drive can be locked out, inserting the filter screen or filter sub from the pin end does not pose the same safety risks that occur when inserting or removing a traditional surface pipe screen from the box end of the drill string. Referring briefly again to Figure 3, the drill string 325 may be disconnected from the top drive 320A to add, remove, or service sections of drill string. When this occurs, the top drive assembly 320A and filter sub will be hanging from the drill rig structure, and the modified filter screen 320B may be inserted or removed into the filter sub. If the filter sub has not been installed, the filter sub may be installed at such times as well. The top drive 320A employs a handling arm (not shown) that is used to make up the connection between the top drive 320A and the drill string 325. The filter sub, when it is installed at the top drive 320A, should be shorter than the length of the handling arm to allow the handling arm to access the drill string 325 during make up. Because handling arms are typically at most three feet in length, the filter sub may preferably be two feet in length, and the modified filter screen 320B may be shorter than the filter sub.

[0019] Returning to Figure 4A, one embodiment of a filter sub 400 with a modified filter screen 420B is shown. The modified filter screen 420B is shown with slots to filter debris, and various combinations of slots and holes may be used. As mentioned above, the modified filter screen 420B is able to be inserted from the pin side 465 of the filter sub 400. The modified filter screen 420B is pushed until it engages with dowel pins 470 installed in the side wall of the filter sub. The dowel pins 470 engage with J-latches at the top end of the modified filter screen, as will be described in further detail below. The dowel pins 470 may be made of a steel alloy or another alloy with a high strength rating, such that the dowel pins will not shear and cause the modified filter screen to wash out during drilling operations.

[0020] During drilling operations, mud will flow into the modified filter screen 420B from the top drive. As debris collects at the bottom of the modified filter screen, mud flow may be diverted through the sides of the modified filter screen 420B into the annular passage 475 within the filter sub 400 with a slightly larger diameter than the outside diameter of the modified filter screen 420B. The mud will then flow through the remainder of the filter sub into the drill string. In the embodiment shown in Figure 4A, the top of the modified filter screen which engages with the dowel pins 470 in the filter sub 400 is not flush with the internal wall of the filter sub, potentially exposing it to wear caused by mud flow during drilling operations. In other words, the inner diameter of the modified filter screen 420B may be smaller than the inner diameter of the filter sub 400.

[0021] The embodiment of the filter sub 400 shown in Figure 4B limits this potential wear. In this embodiment, the filter sub has a beveled internal shoulder 480. The internal shoulder 480 acts as a stop for the modified filter screen 420B during insertion, and also acts to allow the internal diameter of the filter sub to be substantially similar to or the same as the internal diameter of the modified filter screen 420B.

[0022] Referring to Figure 5, the J-latch 585 of the modified filter screen 500 is shown. The design of the J-latch 585 for the modified filter screen 500 allows for the entire modified filter screen 500 to be a cylinder with consistent inner and outer diameters, which allows for insertion of the modified filter screen from the pin end of the filter sub. In some embodiments, the modified filter screen may be tapered or not completely cylindrical. For insertion, the modified filter screen 500 is inserted into the pin end of the filter sub, pushed and rotated until the opening longitudinal channel in the J-latches engage with the dowel pins of the filter sub. The modified filter screen should be pushed and rotated until it follows the "J" path and is locked in the filter sub. For removal, the reverse path of the J-latch is followed until the modified filter screen is free from the dowel pins. In some embodiments, paths other than a "J" path may be used to lock the modified filter screen into the dowel pins of the filter sub. [0023] A specialized tool may be used to insert and remove the modified filter screen from the filter sub. Because the modified filter screen is inserted through the pin end of the filter sub, the insertion/removal tool connects to the bottom end of the modified filter screen. In one embodiment, the insertion/removal tool may include fingers that align with slots or holes at the bottom of the modified filter screen. The fingers of the insertion/removal tool are inserted into the bottom of the filter screen, and the modified filter screen may be pushed up through the pin end of the filter sub to engage the J-latches with the dowel pins. During removal, the "J" path is traversed in reverse, and gravity allows the filter sub to be removed. In one embodiment of the insertion/removal tool, the tool has a latch mechanism to hold the modified filter screen and allow it to be pulled out of the filter sub.

[0024] Although the concepts disclosed herein have been described in connection with the preferred form of practicing them and modifications thereto, those of ordinary skill in the art will understand that many other modifications can be made thereto. Accordingly, it is not intended that the scope of these concepts in any way be limited by the above description.

Claims

1. A top drive assembly used for downhole drilling, the top drive assembly comprising: a filter sub housing, the filter sub housing comprising one or more dowel pins; and a filter screen, the filter screen having a top end with one or more latch slots, wherein the one or more latch slots engage with each of the one or more dowel pins to lock the filter screen in the filter sub housing.

2. The top drive assembly of claim 1, wherein the filter sub housing further comprises an internal shoulder, the internal shoulder disposed above the one or more dowel pins.

3. The top drive assembly of claim 2, wherein the internal diameter of the filter sub above the internal shoulder is substantially similar to the internal diameter of the filter screen.

4. The top drive assembly of claim 2, wherein the internal diameter of the filter sub above the internal shoulder is substantially similar to the internal diameter of the filter screen at the point where the one or more latches engage with each of the one or more dowel pins to lock the filter screen in the filter sub housing.

5. The top drive assembly of claim 1, wherein the filter screen is substantially cylindrical and the external diameter of the filter screen is substantially consistent.

6. The top drive assembly of claim 1, wherein the internal diameter of the filter screen decreases away towards the bottom end of the filter screen.

7. The top drive assembly of claim 1, wherein the one or more latch slots of the filter screen comprise one or more J-latch slots.

8. The top drive assembly of claim 1, wherein the internal diameter of the filter sub above the filter screen is greater than to the internal diameter of the filter screen.

9. The top drive assembly of claim 1, wherein the number of one or more latch slots is greater than the number of one or more dowel pins.

10. The top drive assembly of claim 1, wherein the one or more dowel pins are made of a steel alloy.

11. The top drive assembly of claim 1, wherein the one or more dowel pins are integrally incorporated into the filter sub.

12. A method of locking a filter screen into a filter sub housing, the method comprising: inserting a filter screen into the pin end of a filter sub housing;

aligning one or more latch slots on the top end of the filter screen to each of one or more dowel pins secured in an outer wall of a filter sub housing; and orienting the filter screen to allow the one or more dowel pins to traverse a path of the one or more latch slots.

13. The method of claim 12, further comprising:

orienting the filter screen to allow the one or more dowel pins to traverse an opposite path of the one or more latch slots; and

removing the filter screen from the pin end of a filter sub.

14. The method of claim 12, wherein inserting a filter screen into the pin end of a filter sub housing comprises inserting, using an insertion tool, a filter screen into the pin end of a filter sub housing.

15. The method of claim 12, wherein the filter sub housing comprises an internal shoulder, the internal shoulder disposed above the one or more dowel pins.

16. The method of claim 12, wherein the internal diameter of the filter sub above the internal shoulder is substantially similar to the internal diameter of the filter screen.

17. The method of claim 12, wherein the filter screen is substantially cylindrical and the external diameter of the filter screen is substantially consistent.

18. The method of claim 12, wherein the internal diameter of the filter screen decreases away towards the bottom end of the filter screen.

19. The method of claim 12, wherein the one or more latch slots of the filter screen comprise one or more J-latch slots.

20. The method of claim 12,

wherein inserting a filter screen into the pin end of a filter sub housing comprises inserting, using an insertion tool, a filter screen into the pin end of a filter sub housing,

wherein removing the filter screen from the pin end of a filter sub housing comprises removing, using the insertion tool, the filter screen from the pin end of a filter sub housing.