Method and apparatus for dropping a pump down plug or ball

[0001] This is a continuation in part of co-pending U.S. patent application Ser. No. 11/749,591, filed May 16, 2007, and co-pending U.S. patent application Ser. No. 11/951,802 filed Dec. 6, 2007.

[0002] Not applicable

[0003] Not applicable

[0004] 1. Field of the Invention

[0005] The present invention relates to a method and apparatus that is of particular utility in cementing operations associated with oil and gas well exploration and production. More specifically the present invention provides an improvement to cementing operations and related operations employing a plug or ball dropping head.

[0006] 2. General Background of the Invention

[0007] Patents have issued that relate generally to the concept of using a plug, dart or a ball that is dispensed or dropped into the well or “down hole” during oil and gas well drilling and production operations, especially when conducting cementing operations. The following possibly relevant patents are incorporated herein by reference. The patents are listed numerically. The order of such listing does not have any significance.

[0008]

TABLE
PATENT
NO.	TITLE	ISSUE DATE
3,828,852	Apparatus for Cementing Well Bore Casing	Aug. 13, 1974
4,427,065	Cementing Plug Container and Method of	Jan. 24, 1984
	Use Thereof
4,624,312	Remote Cementing Plug Launching System	Nov. 25, 1986
4,671,353	Apparatus for Releasing a Cementing Plug	4,671,353
4,722,389	Well Bore Servicing Arrangement	Feb. 02, 1988
4,782,894	Cementing Plug Container with Remote	Nov. 08, 1988
	Control System
4,854,383	Manifold Arrangement for use with a Top	Aug. 08, 1989
	Drive Power Unit
4,995,457	Lift-Through Head and Swivel	Feb. 26, 1991
5,095,988	Plug Injection Method and Apparatus	Mar. 17, 1992
5,236,035	Swivel Cementing Head with Manifold	Aug. 17, 1993
	Assembly
5,293,933	Swivel Cementing Head with Manifold	Mar. 15, 1994
	Assembly Having Remove Control Valves
	and Plug Release Plungers
5,435,390	Remote Control for a Plug-Dropping Head	Jul. 25, 1995
5,758,726	Ball Drop Head With Rotating Rings	Jun. 02, 1998
5,833,002	Remote Control Plug-Dropping Head	Nov. 10, 1998
5,856,790	Remote Control for a Plug-Dropping Head	Jan. 05, 1999
5,960,881	Downhole Surge Pressure Reduction System	Oct. 05, 1999
	and Method of Use
6,142,226	Hydraulic Setting Tool	Nov. 07, 2000
6,182,752	Multi-Port Cementing Head	Feb. 06, 2001
6,390,200	Drop Ball Sub and System of Use	May 21, 2002
6,575,238	Ball and Plug Dropping Head	Jun. 10, 2003
6,672,384	Plug-Dropping Container for Releasing a	Jan. 06, 2004
	Plug Into a Wellbore
6,904,970	Cementing Manifold Assembly	Jun. 14, 2005
7,066,249	Plug-Dropping Container for Releasing a	Jan. 06, 2004
	Plug into a Wellbore

[0009] The present invention provides an improved method and apparatus for use in cementing and like operations, employing a plug or ball dropping head of improved configuration.

[0044] FIG. 9 shows generally an oil well drilling structure 10 that can provide a platform 11 such as a marine platform as shown. Such platforms 11 are well known. Platform 11 supports a derrick 12 that can be equipped with a lifting device 21 that supports a top drive unit 13. Such a derrick 12 and top drive unit 13 are well known. A top drive unit 13 can be seen for example in U.S. Pat. Nos. 4,854,383 and 4,722,389 which are incorporated herein by reference.

[0045] A flow line 14 can be used for providing a selected fluid such as a fluidized cement or fluidized setable material to be pumped into the well during operations which are known in the industry and are sometimes referred to as cementing operations. Such cementing operations are discussed for example in prior U.S. Pat. Nos. 3,828,852; 4,427,065; 4,671,353; 4,782,894; 4,995,457; 5,236,035; 5,293,933; and 6,182,752, each of which is incorporated herein by reference.

[0046] A tubular member 22 can be used to support plug dropping head 15 at a position below top drive unit 13 as shown in FIG. 9. String 16 is attached to the lower end portion of plug dropping head 15.

[0047] In FIG. 9, the platform 11 can be any oil and gas well drilling platform 11 such as a marine platform shown in a body of water 18 that provides a seabed or mud line 17 and water surface 19. Such a platform 11 provides a platform deck 20 that affords space for well personnel to operate and for the storage of equipment and supplies that are needed for the well drilling operation.

[0048] A well bore 23 extends below mud line 17. In FIGS. 10 and 11, the well bore 23 can be surrounded with a surface casing 24. The surface casing 24 can be surrounded with cement/concrete 25 that is positioned in between a surrounding formation 26 and the surface casing 24. Similarly, a liner or production casing 32 extends below surface casing 24. The production casing 32 has a lower end portion that can be fitted with a casing shoe 27 and float valve 28 as shown in FIGS. 10-16. Casing shoe 27 has passageway 30. Float valve 28 has passageway 29.

[0049] The present invention provides an improved method and apparatus for dropping balls, plugs, darts or the like as a part of a cementing operation. Such cementing operations are in general known and are employed for example when installing a liner such as liner 32. In the drawings, arrows 75 indicate generally the flow path of fluid (e.g. cement, fluidized material or the like) through the tool body 34. In that regard, the present invention provides an improved ball or plug or dart dropping head 15 that is shown in FIGS. 1-8, 10-17 and 18-33. In FIGS. 1A, 1B, 1C and 2-8, ball/plug dropping head 15 has an upper end portion 31 and a lower end portion 33. Ball/plug dropping head 15 provides a tool body 34 that can be of multiple sections that are connected together, such as with threaded connections. In FIGS. 1A-1C, the tool body 34 includes sections 35, 36, 37, 38, 39. The section 35 is an upper section. The section 39 is a lower section.

[0050] Ball/plug dropping head 15 can be pre-loaded with a number of different items to be dropped as part of a cementing operation. For example, in FIGS. 1A, 1B, 1C there are a number of items that are contained in ball/plug dropping head 15. These include an upper, larger diameter ball dart 40, 41 and smaller diameter ball 42. In FIGS. 18-26, an alternate embodiment is shown which enables very small diameter balls, sometimes referred to as “frac-balls” 102 (which can have a diameter of between about ½ and ⅝ inches) to be dispensed into the well below toll body 34.

[0051] The tool body 34 supports a plurality of valving members at opposed openings 90. The valving members can include first valving member 43 which is an upper valving member. The valving members can include a second valving member 44 which is in between the first valving member 43 and a lower or third valving member 45. Valving member 43 attaches to tool body 34 at upper opening positions 61, 62. Valving member 44 attaches to tool body 34 at middle opening positions 63, 64. Valving member 45 attaches to tool body 43 at lower opening positions 65, 66.

[0052] Threaded connections 46, 47, 48, 49 can be used for connecting the various body sections 35, 36, 37, 38, 39 together end to end as shown in FIGS. 1A, 1B, 1C. Tool body 34 upper end 31 is provided with an internally threaded portion 50 for forming a connection with tubular member 22 that depends from top drive unit 13 as shown in FIG. 9. A flow bore 51 extends between upper end 31 and lower end 33 of tool body 34.

[0053] Sleeve sections 52 are secured to tool body 34 within bore 15 as shown in FIGS. 1A, 1B, 1C. Sleeves 52 can be generally centered within bore 51 as shown in FIGS. 1A, 1B, 1C using spacers 67 that extend along radial lines from the sections 35-39.

[0054] Each valving member 43, 44, 45 is movable between open and closed positions. In FIGS. 1A, 1B, 1C each of the valving members 43, 44, 45 is in a closed position. In that closed position, each valving member 43, 44, 45 prevents downward movement of a plug, ball 40, 42, or dart 41 as shown. In FIG. 1A, the closed position of valving member 43 prevents downward movement of larger diameter ball 40. Similarly, in FIG. 1B, a closed position of valving member 44 prevents a downward movement of dart 41. In FIG. 1B, a closed position of valving member 45 prevents a downward movement of smaller diameter ball 42. In each instance, the ball, dart or plug rests upon the outer curved surface 68 of valving member 43, 44 or 45 as shown in the drawings.

[0055] Each valving member 43, 44, 45 provides a pair of opposed generally flat surfaces 69, 70 (see FIGS. 3, 6, 17). FIG. 17 shows in more detail the connection that is formed between each of the valving members 43, 44, 45 and the tool body 34. The tool body 34 provides opposed openings 90 that are receptive the generally cylindrically shaped valve stems 54, 55 that are provided on the flat sections or flat surfaces 69, 70 of each valving member 43, 44, 45. For example, in FIGS. 6 and 17, the flat surface 69 provides valve stem 54. Openings 90 are receptive of the parts shown in exploded view in FIG. 17 that enable a connection to be formed between the valving member 43, 44 or 45 and the tool body 34. For the stem 55, fastener 91 engages an internally threaded opening of stem 55. Bushing 92 is positioned within opening 90 and the outer surface of stem 55 registers within the central bore 95 of bushing 92. Bushing 92 is externally threaded at 93 for engaging a correspondingly internally threaded portion of tool body 34 at opening 90. O-rings 60 can be used to interface between stem 55 and bushing 92. A slightly different configuration is provided for attaching stem 54 to tool body 34. Sleeve 94 occupies a position that surrounds stem 54. Sleeve 54 fits inside of bore 95 of bushing 92. The externally threaded portion 93 of bushing 92 engages correspondingly shaped threads of opening 90. Pins 99 form a connection between the stem 54 at openings 98 and the sleeve 94. Fastener 96 forms a connection between bushing 92 and an internally threaded opening 97 of stem 54. As assembled, this configuration can be seen in FIG. 1A for example. The flat surfaces 69, 70 enable fluid to flow in bore 51 in a position radially outwardly or externally of sleeve or sleeve section 52 by passing between the tool body sections 35, 36, 37, 38, 39 and sleeve 52. Thus, bore 51 is divided into two flow channels. These two flow channels 71, 72 include a central flow channel 71 within sleeves 52 that is generally cylindrically shaped and that aligns generally with the channel 53 of each valving member 43, 44, 45. The second flow channel is an annular outer flow channel 72 that is positioned in between a sleeve 52 and the tool body sections 35, 36, 37, 38, 39. The channels 71, 72 can be concentric. The outer channel 72 is open when the valving members 43, 44, 45 are in the closed positions of FIGS. 1A, 1B and 1C, wherein central flow channel 71 is closed.

[0056] When the valving members 43, 44, 45 are rotated to a closed position, fins 73 become transversely positioned with respect to the flow path of fluid flowing in channel 72 thus closing outer flow channel 72 (see FIG. 5). This occurs when a valving member 43, 44, 45 is opened for releasing a ball 40 or 42 or for releasing dart 41. FIG. 4 illustrates a closed position (FIG. 4) of the valving member 45 just before releasing smaller diameter ball 42. Fins 73 are generally aligned with bore 15 and with flow channels 71, 72 when flow in channel 72 is desired (FIG. 4). In FIG. 4, valving member 45 is closed and outer flow channel 72 is open.

[0057] In FIGS. 2-3, 5 and 7-8, a tool 74 has been used to rotate valving member 45 to an open position that aligns its channel 53 with central flow channel 71 enabling smaller diameter ball 42 to fall downwardly via central flow channel 71 (FIG. 8). In FIG. 5, outer flow channel 72 has been closed by fins 73 that have now rotated about 90 degrees from the open position of FIG. 4 to the closed position. Fins 73 close channel 72 in FIG. 5. It should be understood that tool 74 can also be used to rotate valving member 44 from an open position of FIG. 1B to a closed position such as is shown in FIG. 5 when it is desired that dart 41 should drop. Similarly, tool 74 can be used to rotate upper valving member 43 from the closed position of FIG. 1A to an open position such as is shown in FIG. 5 when it is desired to drop larger diameter ball 40.

[0058] FIGS. 7-16 illustrate further the method and apparatus of the present invention. In FIG. 8, lower or third valving member 45 has been opened as shown in FIG. 5 releasing smaller diameter ball 42. In FIG. 8, smaller diameter ball 42 is shown dropping wherein it is in phantom lines, its path indicated schematically by arrows 75.

[0059] FIG. 10 shows a pair of commercially available, known plugs 76, 77. These plugs 76, 77 include upper plug 76 and lower plug 77. Each of the plugs 76, 77 can be provided with a flow passage 79, 81 respectively that enables fluid to circulate through it before ball 42 forms a seal upon the flow passage 81. Smaller diameter ball 42 has seated upon the lower plug 77 in FIG. 10 so that it can now be pumped downwardly, pushing cement 80 ahead of it. In FIG. 11, arrows 78 schematically illustrate the downward movement of lower plug 77 when urged downwardly by a pumped substance such as a pumpable cement or like material 80. Each of the plugs 76, 77 can be provided with a flow passage 79, 81 respectively that enables fluid to circulate through it before ball 42 forms a seal upon the flow passage 81 (see FIG. 11). When plug 77 reaches float valve 28, pressure can be increased to push ball 42 through plug 77, float valve 28 and casing shoe 27 so that the cement flows (see arrows 100, FIG. 11) into the space 101 between formation 26 and casing 32.

[0060] In FIG. 12, second valving member 44 is opened releasing dart 41. Dart 41 can be used to push the cement 80 downwardly in the direction of arrows 82. A completion fluid or other fluid 83 can be used to pump dart 41 downwardly, pushing cement 80 ahead of it. Once valves 44 and 45 are opened, fluid 83 can flow through openings 84 provided in sleeves 52 below the opened valving member (see FIG. 7) as illustrated in FIGS. 7 and 12. Thus, as each valving member 43 or 44 or 45 is opened, fluid moves through the openings 84 into central flow channel 71.

[0061] When valve 44 is opened, dart 41 can be pumped downwardly to engage upper plug 76, registering upon it and closing its flow passage 79, pushing it downwardly as illustrated in FIGS. 14 and 15. Upper plug 79 and dart 41 are pumped downwardly using fluid 83 as illustrated in FIGS. 14 and 15. In FIG. 16, first valving member 43 is opened so that larger diameter ball 40 can move downwardly, pushing any remaining cement 80 downwardly.

[0062] The ball 40 can be deformable, so that it can enter the smaller diameter section 86 at the lower end portion of tool body 34. During this process, cement or like mixture 80 is forced downwardly through float collar 28 and casing shoe 27 into the space that is in between production casing 32 and formation 26. This operation helps stabilize production casing 32 and prevents erosion of the surrounding formation 26 during drilling operations.

[0063] During drilling operations, a drill bit is lowered on a drill string using derrick 12, wherein the drill bit simply drills through the production casing 32 as it expands the well downwardly in search of oil.

[0064] FIGS. 18-26 show an alternate embodiment of the apparatus of the present invention, designated generally by the numeral 110 in FIGS. 22-23. In FIGS. 18-26, the flow openings 84 in sleeves 52 of ball/plug dropping head 110 of FIGS. 1-17 have been eliminated. Instead, sliding sleeves 111 are provided that move up or down responsive to movement of a selected valving member 112, 113. It should be understood that the same tool body 34 can be used with the embodiment of FIGS. 18-26, connected in the same manner shown in FIGS. 1-17 to tubular member 22 and string 16. In FIGS. 18-26, valving members 112, 113 replace the valving members 43, 44, 45 of FIGS. 1-17. In FIGS. 18-26, sleeves 111 replace sleeves 52. While two valving members 112, 113 are shown in FIGS. 22, 23, it should be understood that three such valving members (and a corresponding sleeve 111) could be employed, each valving member 112, 113 replacing a valving member 43, 44, 45 of FIGS. 1-17.

[0065] In FIGS. 18-26, tool body 34 has upper and lower end portions 31, 33. As with the preferred embodiment of FIGS. 1-17, a flow bore 51 provides a central flow channel 71 and outer flow channel 72. Each valving member 112, 113 provides a valve opening 114. Each valving member 112, 113 provides a flat surface 115 (see FIG. 20). Each valving member 112, 113 provides a pair of opposed curved surfaces 116 as shown in FIG. 20 and a pair of opposed flat surfaces 117, each having a stem 119 or 120.

[0066] An internal, generally cylindrically shaped surface 118 surrounds valve opening 114 as shown in FIG. 20. Each valving member 112, 113 provides opposed stems 119, 120. Each valving member 112, 113 rotates between opened and closed positions by rotating upon stems 119, 120. Each of the stems 119, 120 is mounted in a stem opening 90 of tool body 34 at positions 61, 62 and 63, 64 as shown in FIG. 22.

[0067] In FIG. 19, valving member 122, 123 is similar in configuration and in sizing to the valving members 43, 44, 45 of the preferred embodiment of FIGS. 1-17, with the exception of a portion that has been removed which is indicated in phantom lines in FIG. 19. The milled or cut-away portion of the valving member 112, 113 is indicated schematically by the arrow 121. Reference line 122 in FIG. 19 indicates the final shape of valving member 112, 113 after having been milled or cut. In FIGS. 20 and 21, a beveled edge at 123 is provided for each valving member 112, 113.

[0068] When a valving member 112, 113 is in the closed position of FIG. 22, flow arrows 124 indicate the flow of fluid through the tool body 34 bore 51 and more particularly in the outer channel 72 as indicated in FIG. 22.

[0069] In FIG. 23, the lower valving member 113 has been rotated to an open position as indicated schematically by the arrow 134, having been rotated with tool 74. In this position, fins 73 now block the flow of fluid in outer channel 72. Flat surface 115 now faces upwardly. In this position, the cut-away portion of valving member 113 that is indicated schematically by the arrow 121 in FIG. 19 now faces up. Sliding sleeve 111 drops downwardly as indicated schematically by arrows 130 when a valving member 112 or 113 is rotated to an open position (see valving member 113 in FIG. 23). In FIG. 22, a gap 129 was present in between upper valve 112 and sleeve 111 that is below the valve 112. The sleeve 111 that is in between the valves 112, 113 is shown in FIG. 22 as being filled with very small diameter balls or “frac-balls” 102.

[0070] When valving member 113 is rotated to the open position of FIG. 23, the gap is now a larger gap, indicated as 135. Gap 135 (when compared to smaller gap 129) has become enlarged an amount equal to the distance 121 illustrated by arrow 121 in FIG. 19. The frac-balls 102 now drop through valving member 113 as illustrated by arrows 127 in FIG. 23. Arrows 125, 126 in FIG. 23 illustrate the flow of fluid downwardly through gap 135 and in central channel 71.

[0071] A sleeve 111 above a valving member 112 or 113 thus move up and down responsive to a rotation of that valving member 112 or 113. Spacers 28 can be employed that extend from each sleeve 111 radially to slidably engage tool body 34. In FIGS. 20 and 21, each stem 119, 120 can be provided with one or more annular grooves 131 that are receptive of o-rings 60 or other sealing material. As with the preferred embodiment of FIGS. 1-17, openings 132 in each stem 119, 120 are receptive of pins 99. Likewise, each stem 119, 120 provides internally threaded openings 133. Thus, the same connection for attaching a valving member 112, 113 to tool body 34 can be the one shown in FIGS. 1-17.

[0072] FIGS. 27A-33 show another embodiment of the apparatus of the present invention wherein the tool body 136 provides an upper sleeve 140 that differs in construction from the sleeve of the embodiments of FIGS. 1-26. Further, the tool body 136 of FIGS. 27A-33 provides an indicator 147 that indicates to a user whether or not a ball or dart 145, 146 has in fact been discharged from the tool body 136. Further, the embodiment of FIGS. 27A-33 provides specially configured inserts or sleeves 160, 163 that are positioned below the lower valve 113, this additional sleeve or insert 160 is configured to prevent a build-up of material within the flow bore 51 below lower valving member 113.

[0073] In FIGS. 27A-33, tool body 136 provides upper end portion 137 and lower end portion 138. As with the embodiments of FIGS. 1-26, the tool body 136 can be formed similarly to the tool body 34, having multiple sections 35, 36, 37, 38 and 139. The section 139 is similar to the section 39 of FIGS. 1-26. However, the section 139 is configured to accept sleeve or insert 160 and sleeve or insert 163.

[0074] Sleeve 140 is similar to the sleeves 111 of FIGS. 18-26. The sleeve 140 provides a cap 141 that can be connected to the sleeve 140 using threaded connection 142. Cap 141 provides one or more longitudinally extending and circumferentially spaced apart openings 143. The cap 141 can also provide a tool receptive socket 144 that enables rotation of cap 141, relative to sleeve 140, using a tool (e.g. allen wrench) during assembly of cap 141 to sleeve 140.

[0075] In FIGS. 27B, 28-33 indicator 147 is shown. The indicator 147 indicates to a user whether or not a dart 145, 146 has passed the indicator 147, thus indicating a discharge of the dart 145, 146 from the tool body 136.

[0076] In FIGS. 27B and 28-33, indicator 147 provides a shaft 148 that extends horizontally relative to flow bore 51 of tool body 136. Lever arm 149 moves between an extended position as shown in FIG. 27B and a collapsed position as shown in FIG. 29. The lever arm 149 is initially set in the extended position of FIG. 27B by placing pin 150 behind spring 151 upper end 154 as shown in FIG. 27B. Spring 151 thus holds the pin 150 in a generally vertical position by rotating shaft 148 so that arm 149 extends into flow bore 51.

[0077] In FIG. 28, upper valve 112 is shown supporting a first dart 145. Lower valve 113 is shown supporting a second dart 146. Operation is the same as was described with respect to FIGS. 1-26. Lower valve 113, is rotated to an open position as shown in FIG. 29 by rotating the valve 113 through about ninety degrees. Dart 146 then drops as indicated by arrow 164 in FIG. 29. As the dart 146 travels downwardly, leaving valve 113 and moving toward lower end portion 138 of tool body 136, the dart 146 engages lever arm 149. The dart 146 continues to move downwardly, pushing the arm 149 to the retracted position of FIG. 29 as illustrated by arrow 165 in FIG. 29. In this position, the pin 150 deflects spring 151 until pin 150 assumes the position shown in phantom lines in FIG. 32.

[0078] The spring 151 upper end portion 154 prevents the pin 150 from returning to the position of FIG. 28, as the pin is now being held in the position shown in FIG. 29. Arrow 152 in FIG. 32 illustrates the travel of arm 149 from the extended position to the retracted position. An operator can then reset the indicator 147 by rotating the pin 150 to the position shown in FIG. 30 as illustrated by arrow 153 in FIG. 30. This procedure can then be repeated for the upper and second dart 145 as illustrated in FIGS. 30 and 31. In FIG. 31, the upper valve 112 is moved to an open position. A working fluid is pumped into tool body 136 at upper end 137. Flow moves downwardly in the tool body 136 as illustrated by arrows 166. Flow travels through openings 143 in cap 141 as illustrated by arrows 167 in FIG. 31. This downward flow moves the darts 145, 146 downwardly.

[0079] Indicator 147 can be attached to tool body 136 as shown in FIG. 33. A pair of recesses 155, 156 on tool body 136 enable attachment of shaft 148. The shaft 148 can be held in position using fasteners such as bolts, for example. Spring 151 can then be attached to tool body 136 at recess 156 using fasteners 158 such as bolts. Curved arrow 157 in FIG. 33 illustrates rotation of shaft 148 for moving arm 149 and pin 150 between the extended position of FIG. 30 and the retracted position of FIG. 31. Arm 149 extends through slot 159 in the extended position of FIGS. 30, 32, 33.

[0080] FIGS. 27C and 32 illustrate placement of insert/sleeves 160, 163. The sleeve 160 provides an upper end portion that is conically shaped or tapered. This tapered section 161 is placed just below lower valve 113 and aids in the efficient flow of fluid downwardly in the tool body 136 eliminating unnecessary accumulation of material such as cement. Annular shoulder 162 on tool body 136 enables support of lower insert 163 which is placed below upper insert 160 as shown in FIGS. 27B and 27C.

[0081] The following is a list of parts and materials suitable for use in the present invention.

[0082]

PARTS LIST
Part Number	Description
10	oil well drilling structure
11	platform
12	derrick
13	top drive unit
14	flow line
15	ball/plug dropping head
16	string
17	sea bed/mud line
18	body of water
19	water surface
20	platform deck
21	lifting device
22	tubular member
23	well bore
24	surface casing
25	cement/concrete
26	formation
27	casing shoe
28	float valve
29	passageway
30	passageway
31	upper end
32	liner/production casing
33	lower end portion
34	tool body
35	section
36	section
37	section
38	section
39	section
40	larger diameter ball
41	dart
42	smaller diameter ball
43	first valving member
44	second valving member
45	third valving member
46	threaded connection
47	threaded connection
48	threaded connection
49	threaded connection
50	threaded portion
51	flow bore
52	sleeve
53	channel
54	stem
55	stem
56	sleeve
57	sleeve
58	plug
59	plug
60	o-ring
61	opening position
62	opening position
63	opening position
64	opening position
65	opening position
66	opening position
67	spacer
68	outer curved surface
69	flat surface
70	flat surface
71	central flow channel
72	outer flow channel
73	fin
74	tool
75	arrow
76	upper plug
77	lower plug
78	arrows
79	flow passage
80	cement
81	flow passage
82	arrow
83	fluid
84	opening
85	opening
86	smaller diameter section
87	arrow - fluid flow path
88	fastener
89	internally threaded opening
90	opening
91	fastener
92	bushing
93	external threads
94	sleeve
95	passageway/bore
96	fastener
97	internally threaded opening
98	opening
99	pin
100	arrows
101	space
102	frac-ball
110	ball/plug dropping head
111	sleeve
112	valving member
113	valving member
114	valve opening
115	flat surface
116	curved surface
117	flat surface
118	internal surface
119	stem
120	stem
121	arrow
122	reference line
123	beveled edge
124	arrow
125	arrow
126	arrow
127	arrow
128	spacer
129	smaller gap
130	arrow sleeve movement
131	annular groove
132	opening
133	internally threaded opening
134	arrow
135	larger gap
136	tool body
137	upper end portion
138	lower end portion
139	section
140	sleeve
141	cap
142	threaded connection
143	opening
144	tool receptive socket
145	dart
146	dart
147	indicator
148	shaft
149	lever arm
150	pin
151	spring
152	arrow
153	arrow
154	spring upper end
155	recess
156	recess
157	curved arrow
158	fastener
159	slot
160	insert/sleeve
161	conical/tapered section
162	annular shoulder
163	insert/sleeve
164	arrow
165	arrow
166	arrow
167	arrow

[0083] All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. All materials used or intended to be used in a human being are biocompatible, unless indicated otherwise.

[0084] The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.