US3189105A

US3189105A - Method and apparatus of drilling underwater wells

Info

Publication number: US3189105A
Application number: US197115A
Authority: US
Inventors: William F Bates; Glenn D Johnson; Bruce J Watkins
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1962-05-23
Filing date: 1962-05-23
Publication date: 1965-06-15
Anticipated expiration: 1982-06-15
Also published as: DE1178026B; GB982496A; BE632628A

Description

June 15,1965 w. F. BATES ETAL METHOD AND APPARATUS OF DRILLING UNDERWATER WELLS Filed May 23, 1962 5 Sheets-Sheet l F l G 2 F IG. 3

INVENTORSI FIG.

W. F. BATES G. D. JOHNSON B, J. WATKINS BY: 3 H1 THEIR AGENT I June 15, 1965 w. F. BATES ETAL METHOD AND APPARATUS OF DRILLING UNDERWATER WELLS 5 sheetssheet 2 Filed May 25, 1962 50 U I D ,20

m ..4s- 1; 1' 78 e3 i i 54 64 an H' 12 82 83 43 F F I G 4 INVENTORSI W. F. BATES G. D. JOHNSON I B. J. WATKINS THEIR AGENT June 15, 1965 Filed May 23, 1962 W. F. BATES ETAL METHOD AND APPARATUS OF DRILLING UNDERWATER WELLS 5 Sheets-Sheet 3 O I N h h n v m .'k

m m m 9 9 N 2 a g 3| INVENTORS:

W. F. BATES G. D. JOHNSON B. J. WATKINS H.144

THEIR AGENT FIG .7

FIG.6

June '15, 1965 w. e. BATE IS m 3,189,105

METHOD AND APPARATUS 0F DRILLn g UNDERWATER WELLS Filed May 23, 1962 5 Sheets-Sheet 4 FIG. INVENTORSZ w. F. BATES e. o. JOHNSON B. J. WATKINS THEIR AGENT June 15, 1965 w. F. BATES ETAL 3,189,105

METHOD AND APPARATUS OF DRILLING UNDERWATER WELLS Filed May 23, 1962 r 5 Sheets-Sheet 5 H ACOUSTIC 6 TRANSMITTER MICROPHONE PREAMPLIFIER n2 FILTER n3 lmETEcToR CIRCUIT n5 ||4 us I I OSCILLATOR CRCUIT RELAY BATTERY CODE MODULATOR FIG. l3

INVENTORS:

w. F. BATES e. o. JOHNSON B. J. WATKINS THEIR AGENT United States Patent This invention relates to a method and apparatus for drilling ofishore wells and pertains more particularly to a method and apparatus whereby wells may be drilled from a floating vessel on the surface of the ocean with a wellhead assembly positioned a substantial distance below the surface of the water andprefera'bly on the ocean floor.

In an attempt to locate new oil fields an increasing amount of well drilling has been conducted at offshore locations, suchfor example, as oif the coast of Louisiana, Texas, and- California. As a general rule, the string of casing in a shallow water well together with the tubing string or strings, extend to a pointwell above the surface of the water where they are closed in a conventional manner that is used on land wells, with the conventional wellheadassembly being attached to the top of the casing. Due to the steeply dipping nature of the shore line on the Pacific Coast of the United States, there is a relatively narrow strip of ocean floor under less than 300 feet of'wate'r which might be developed economically from the platforms employing legs which extend down to the ocean floor. The remainder of the offshore land, in water greater than 300 feet in depth, particularly the area off the southernCalifoi-nia coast that includes deep basins potentially as productive as those onshore, can be developed economically only by drilling wells from floating vessels and by utilizing underwater well completion methods and apparatus. 7 p p A recent'clevelopment in oifshore welldrilling operations is the drilling and completion of wells front afloating vesselwhereinthe wellhead assembly is located at a substantial distance below the surface of'the water and preferably on the ocean floor. There are two general methods of drilling wells of this-type and both methods employ a flexible connection between the vessel on'the surface of thebody of water and the wellhead on the 'ocean floor whereby various pieces of the equipment used during drilling. operations and also used in the well oron the well assembly can be guidedfrom the vessel through the water downto the wellhead assembly and be aligned thereon. Onesystem employs aseries of flexible guide lines or cablesextending from the vessel to the subsurface well assembly with-carrier;means provided for slidingup and down the cables andholdingapieceof equipment to guide it into alignment on thewellhead' of the ocean floor. The use of guide lines isnot' entirely satisfactory since after the well" has been completed it-i's necessary to make provision for employing the guide lines again to' enter" the well for workover operations which must be carried out in a'well from time to time: If the guide lines are attached to a buoy on the surface of the'water they become a navigational hazard; If, on" the other hand, the guide lines are dropped to the ocean floor they often become entangled "and aresubje ct to corrosion.

In a second method of providing guide means betweendiameter is both time consuming and cumbersome, hence is not entirely satisfactory.

It is therefore a primary object of the present invention to provide a methodan'd' apparatus for drilling oil and gas wells from a floating vessel in a manner such that the wellhead assembly is positioned on the ocean floor.

A further object of the present invention is to provide a method and apparatus for drilling an offshore well having a wellhead assembly positioned a substantial distance below the surface of the water and preferably on the ocean floor without any guide means extending from the wellhead assembly to' the vessel.-

Another object of the present invention is to provide a method and apparatus for drilling an offshore well from which a drill pipe may be readily withdrawn to change bits, or in an emergency, and subsequently reentered by the drill pipe without the use of elongated flexible guide lines or" guide pipes extending betweenthe vessel and the ocean floor to guide the drill pipe.

Still another object of the present invention is to provide a method and apparatus whereby strings of casing or tubing may be loweredinto a well from a vesselen the surface of the ocean without the use of guide lines.

These and other objects of this invention will beunderstood from the following description taken with reference to the drawing, wherein:

FIGURES 1 2, and 3 are diagrammatic views illustrating a floating vessel positioned over a drilling location during the sequential steps of starting a well, lowering a well pipe and a base member to the ocean floor, and subsequently withdrawing the drill string to the vessel;

FIGURES 4, 5, and 7 are diagrammatic views taken in longitudinal projection illustrating the sequential steps of lowering a drill string from a drilling vessel'on the surface of the ocean and guiding it into axial alignment and subsequently operative position within the wellhead on the ocean floor;

FIGURE 6 is a isometric view illustratingone form of a working base of the wellhead assembly of the present invention; I

FIGURE 8 is -a longitudinal view taken in partial crosssection of a hinge connection employed withthe' apparatus of the present invention;

FIGURE 9 is a bottom view of one form of a pipe manipulator and observation apparatusto be used to positioning pipe in accordance with themethod of the present invention;

FIGURE 10 is a diagrammatic view taken in longitudinal projection of another formof a pipe manipulator of the present invention, having a pipeguide offset to one side thereof;

FIGURE 11 is a plan view diagrammatically representing another form of a pipe manipulator adapted to be positioned concentrically with regard to a pipe string and removed from a pipe string by lateral movement, that'is, movement normal to the axis of the pipe;

, FIGURE 12 is a diagrammatic view taken' in longitm dinal detail and in partial cross section of another form of a pipe manipulator of the present invention;

' FIGURE 13 is a schematic circuit diagram of a sound transmitting device for use on a wellhead assembly on the ocean floor; and 7 FIGURE 14 is a diagrammatic view takenimlongitu dinal cross section of a slip'asser'nbly adapted to be car r'ied by the pipe m anipulator'of the present invention for holdinga string of pipe-therein.

Referring to'FIGURE'I of the drawing, a drilling barge'or vessel 11 0f any suitable float-able type is illustrated as floating on the surface of a body of water 12* while lb eing substantially fixedly positioned over a preselected drilling location as by being anchored to the ocean floor 13 by suitable anchors (not shown) at the o (is ends of the

anchor lines

14 and 15. Equipment of this type may be used on carrying out well drilling, completion, or servicing operations in the water varying from about 100 feet to 1500 feet or more in depth. Alternatively, the vessel 11 may be maintained at a relatively :fixed position on the surface of the ocean 12 by any other type of ship-positioning means, such for example as propulsion units which may be in the form of opposing outboard motors 16 and 17 (FIGURE 2). The drilling vessel 11 is equipped with a suitable derrick 18 provided with a suitable hoist system having a traveling block adapted to be secured in any manner well known to the art to the top of a pipe string or drill string 20. During drilling operations a rotary table 21 is positioned on the operating deck of the vessel beneath the derrick 18 for rotating .the drill string and the bit 22 attached to the lower end thereof. Positioned above .the drill bit 22 is a retractable and laterally extensible hole enlarger or remaining bit 23 of any suitable type which is adapted to assume a vertical position when not in use. The derrick 18 on the drilling vessel 11 is positioned over a drilling slot or well 24 which extends vertically through the barge in a conventional manner. Well operations may also be carried out over the side of some barges without the use of slot.

FIGURE 1 diagrammatically represents the operation of starting to drill a well 25 in the ocean floor 13 by rotating

bits

22 and 23. After suflicient hole has been drilled, a wellhead base member 27 is lowered or stripped down over the top of the drill string 2th from the vessel 11. Secured to the lower end of the wellhead base member 27 is a suitable anchoring device, preferably in the form of a large-diameter casing string, commonly known as a con ductor pipe, which is stripped over the top of the drill string 20 ahead of the wellhead base member. The wellhead base member 27 may be supported from the vessel and subsequently lowered by any suitable means, as by a pair of

cables

28 and 29 running from

hoists

30 and 31. Alternatively, the wellhead base member and its depending conductor pipe 32 may be suspended below the vessel 11 prior to originally lowering the drill string 20 to the ocean floor to start the well as shown in FIGURE 1.

The wellhead base member 27 and its conductor pipe 32 are lowered down over the drill string 20 with acts as a guide member to guide the lower end of the conductor pipe 32 into the well 25. After the wellhead base mem- 'ber 27 has been seated on the ocean floor 13, the conductor pipe 32 is preferably cemented in the well by pumping a cement slurry down the drill string, out the lower end thereof, and up the space between the outside of the conductor pipe 32 and the well wall to form a cement bond 33, as shown in FIGURE 3. The drill pipe 20, after the cementing operation, may be withdrawn to the surface so as to remove the auxiliary bit 23 prior to drilling the well dee er.

Instead of anchoring the wellhead base member to the ocean floor by means of a conductor pipe 32 which is preferably cemented in the well, a wellhead base member anchor of the type shown and described in US. 2,808,230 to McNeill et al. may be employed. As shown in FIGURE 4, the wellhead base assembly 27 may comprise a base plate or platform 34 to which the conductor pipe 32 may be secured, as by welding. The upper end 35 of the conductor pipe 32 may form the casing head for the well from which additional strings of well casing may be hung in a manner well known to the art. Aligning means in the form of an aligning cone are preferably employed at the top of the conductor pipe 32 or its casinghe-ad 35 to facilitate the bringing into register of a drill bit with the top of the conductor pipe 32. The aligning and centering device, which in this case is in the form of a cone 36, is of a shape to receive therein and mate with a cone-shaped extension 37 extending downwardly from a pipe manipulator device, generally represented by numeral 38 (FIGURE 4).

One form of a pipe manipulator device is shown in FIGURE 12 as comprising a housing member 40 having a vertical bore 41 therethrough of a diameter greater than the diameter of a drill bit. In some forms of the apparatus of the present invention the bore 41 may be smaller than the drill bit of a drill extending through the bore 41. The pipe manipulator housing 40 is provided with suitable propulsion means for moving the manipulator device at least laterally through the water. In the arrangement of the present invention the propulsion means take the form of at least a pair of

propeller units

42 and 43 driven by

electric motors

44 and 45 and mounted within

protective cages

46 and 47. Each of the motors is driven selectively and is provided with current through leads 48 which extend to a junction box 49 and thence out of the housing 40 and up an electrical signal-transmitting cable 50, which may also be in the form of a weight-supporting cable, if desired, for emergency purposes. In one form of the present invention the pipe manipulator 38 is provided with vertically-disposed propulsion units in the form of one or

more propeller units

51 and 52 mounted on the .top of the manipulator device housing 4! and causing the housing to move vertically within a body of water. Preferably, the manipulator housing 40 may have portions thereof formed as buoyancy tanks so that the manipulator device can be arranged to have a slightly negative buoyancy so that it will sink readily along with a drill bit and drill string when the latter is being lowered from a vessel to a underwater well.

The pipe manipulator device 38 is provided with one or more downwardly disposed

television cameras

53 and 54 which are swivel mounted in any suitable manner, as by the hinge pins 55 and 56 for movement in one direction [about

rotatable posts

57 and 58. Each post, for example post 57, is provided with suitable gear means 59 atfixed thereto which driven by motor 60 which is powered through electrical leads 61. Lead 62 extends into the post 57 for moving the camera 53 about its hinged point 55, as by a motor-driven worm and worm gear on the pin. The pipe manipulator housing 40 also carries a suitable number of flood lights to illuminate the area in the vicinity of the wellhead. Preferably at least one of the

lights

63 or 64 are carried on the

television cameras

53 and 54, being fixedly secured thereto so as to be moved therewith .and illuminate the area toward which the cameras are directed. The pipe manipulator device 38 may also be provided with signal-transmitting and signalrecei-ving means diagrammatically represented by elements 65 and 66 whereby sound signals may be sent and received from the pipe manipulator device in employing any suitable well locating device, well known to the art, for example as SONAR or another system as will be described hereinbel'ow. It is to be understood that the signals received by elements 65 and/or 66 and the signals transmitted .by the

television cameras

53 and 54 are transmitted (from the housing 40 up the cable 50 to the vessel 11 at the surface, while current to run the various components of the pipe manipulator device is transmitted down the same cable 59 which is in the form of a multiconductor cable.

Every time that the drill string is withdrawn from the well to the vessel in order to change a bit, add drill collars, or for other purposes, the drill bit and drill string are lowered into register with the top of the wellhead again in a manner described with regard to FIGURES 4, 5, and 7 of the drawing. At the vessel, the pipe manipulator device 38 is secured in any suitable manner to the drill string 20 near the lower end thereof. Thus, prior to attaching a new bit 22 to the lower end of the drill string, the lowermost section of the drill string 20 would be inserted through the bore 41. By attaching to the lower end of the drill string 20 a bit 22 having a diameter larger than the bore 41 through the pipe manipulator device 38, a pipe manipulator device of negative buoyancy can be hung on the bit as illustrated in FIGURE 4 and lowered therewith toward the wellhead base member 27.

U The televisioncameras 53 and 54*as well as the lights 63* and- 64' would be aimed downwardly so as to illuminate the area below the hit.

As shownxin FIGURE the pipemanipulator device 38 has been lowered with the drill string into the vicinity of the wellhead base 111611156127 but it. is out' of register with the base member 27. At this time one or more of the propulsion units 42 and 43' are actuated to move the pipe manipulator device 38 and the lower end of the drill stringi20 to a position wherein the drillbit 22is in axial alignment with the upper. end of the conductor pipe 32. If two'propulsion'

units

42 and 43 are disposed on opposite sides of the marine manipulator device, it may be necessary to energize a single propeller or propulsion unit 42 to turn the pipe manipulator device 38 about the drill string. 20? a slight distance. When the two propulsion I1nits42 and 43" are'positioned in a line substantially normal to a radial line extending from the well or conductor pipe 32, both

propulsion units

42 and 43 wouldb'e energized to move thedrill bit 22 over the top of the cone 36. With-the drill bit 22' above the centering and guiding cone 36'of the wellhead base member 27, the drill string and its pipe manipulator device 38 would be lowered to seat the pipe manipulator device on the wellhead base member 27. The drill string 20 and the bit 22 would then be lowered to the bottom of the well anddrilling operations would continue with the drill string 20 being rotated by a rotary table 21 on the operating platform of the vessel 11. Throughout the drilling operations the pipe manipulator device 38 would remain seated on the top of the wellhead base member 27.

In FIGURE 4 the control cable 50 extends from the top of the pipe manipulator device 38' to a cable reel 70' on the vessel which is electrically connected to a control panel 71 for controlling the various components of the pipe manipulator device 38. Additionally, the television signals are transmitted to a television screen 72 on the vessel so that an observer can determine the relative position of the pipe manipulator device 38 and drill bit 22 with regard to the wellhead assembly 27. In FIGURE 5 a separate cable 73 is run from a television receiver 72 on the vessel down along the signal-transmitting cable 59' to the pipe manipulator device 38' at the lower end of the pipe string 20.

r The pipe manipulator device 38' of FIGURE 5 difiers from that of FIGURE 4 in that a removable annular plate or collar- 74' is provided on the lower end of the pipe manipulator device 38-. The collar 74" forms a landing surface adapted to be seated on a cooperating collar of flange 75 which is fixedlysecured to the lower end of the drill string 20 above the bit 22. With this arrangement the weight of the pipe manipulator device 38 need not be carried on the bit 22 when the bit 22 is being pulled up to the vessel. It is to be understood that the collar on flange 75 is of a diameter at least slightly smaller than the diameter of the bit 22. Collar '74 in-essence forms an inwardly extending landing flange which can be constructed in manysizes to fit varying sizes of drill pipes to beused. The flange element 74 may be secured to the housing of. the pipe manipulator device 30 inv an suitable manner, as by bolts. 7

In the arrangement of the pipe manipulator device 38 of'FIGURE 5, the cable is attach'ed'to and passes down alongside of any elongated arm element 76 which is pivoted at 77 and, if desired, may beprovided with a weight Won the other end thereof. The constructioniof the hinge 77-andits housing 79; as shown in FIGURE 8; is a preferred form wherein the upper portion of the housing is sloped, as at 80. slightly off the vertical so that the arm' member 7 6 cannot reach a vertical position, as shown in' FIGURE 5, Thus, when apipe manipulator SS-has been seated'irr'the wellhead base member 27, as shown in FIGURE'7', the arm member 76, which may be of any length say 20 feet ormore, falls to a horizontal lator device 38 may be provided with one ormore television cameras 81 and flood lights 82 and 85 (FIGURE 5) which are downwardly directed and fixedly secured to the outer surface of the housing 40 without being adjustable as to direction. A television camera' arranged in this manner is sufiicient to give a view of the direction in which the pipe manipulator device 38 is being lowered and is suflicient to observe the location of a well;

In the bottom view of one form of a manipulator device" (FIGURE 9), an arrangement of buoyancy tanks 85; S6 87, and. 88', to be included in the pipe manipulator device as, is shown. Instead of the housing 40 of the pipe manipulator device 38 being provided with a centrallydisposed bore 41, as shown in FIGURE 9, in another form of the present invention the housing 40 of the pipe manipulator device 38'is provided with a radially-extending slot9t) of a size at least slightly larger than the drill pipe 20 to be positioned therein so that in an emergency, or at other times as desired, the propulsion units- 42 and 43 could be energized'to move the pipe manipulator device laterally through the water out of the cone and away from the drill string 20 in the well. The pipe manipulator device 38 could be retrieved either by pulling up on the cable 50, FIGURE 5, or by energizing the vertically disposed propulsion units 51 and 52 (FIGURE 12).

In another form of the apparatus of the present invention, the guiding and aligning cone 36 may be located to one side of the casing head 35 'and'the conductor pipe 32 as shown in FIGURE 10. For a wellhead base member of this design, the pipe manipulator device is provided with a pair of outwardly extending

arms

91 and 92 to which is secured a vertically extending sleeve 93 inthe form of a short pipe section having an internal diameter greater than the diameter of the drill string 20 to be rot'ated therein. In carrying out drilling operations with any of the above described types of pipe manipulator; devices, a pipe manipulator device 38 may either be left positioned on the wellhead base assembly 27 throughout the drilling operations or may be raised again to the vessel by sliding it-along the drill pipe 20.

' While the manipulator device of the present invention has been described with regard topropeller type propulsion units 42 (FIGURE 9), it is to be understood that the propulsions may be in the fornr of jets I42 and'1'43 (FIGURES 10 and 11) which are laterally directed and supplied by a gas or fluid under pressure. Thus, a hose" or hoses 150 (FIGURE 10') would rundown from the vessel at the surface to provide jetting fluid" to the

jets

142 and 143 of the manipulator, Atthe'top of themanip ulator the hose 150 may divide into hoses 1'51 and 152' to the individual jets 142 and'143. Alternatively, a multiconductor" hose could be employed with one conduit running to each jet. This would provide an arrangement whereby a pump on the vessel may be hooked up to each conduit. Preferably, the hose 1'54? and the electric cable 50'would be bound together. While the

hoses

151 and 152 are shown as being on the outside of the manipulator,

inactual construction the hoses would be in the'form of pipes preferably positioned within or secured to the outside of the manipulator.

While the wellhead base member 27 .has been described hereinaboveas having: an aligning and centering device 36 in the form of a'cone of sheet metal, the aligning and centering device may take other forms; A'preferred form is shown in FIGURE 6 wherein the aligning and'c'entering device 36 comprises an open framework having'legs 96, 97 and 98'supporting a top seating ring99' with a smaller seating ring 109 suspended therebelow on four metal hanger straps 101, 182, 103, and 104. If desired, the lower ring 100 may also be supported on the top of the casing head 35 although preferably it is suspended thereabove so that other equipment or strings of pipe may be supported from the top of the casing head 35. The use of an open framework as in aligning and centering device over the casing head 35 prevents any cement from being deposited in the aligning cone during cementing operations.

While it has been found that a SONAR system on an underwater manipulator device will readily locate an underwater wellhead structure, it may be advantageous to provide the wellhead base member with one or more acoustic reflectors in the form of gas-filled spheres 196 and 107 (FIGURE 6) which are secured to the base plate 34. Additionally, a transponder 1G3 operated by battery power may be positioned at the wellhead for aiding a receiving system on the pipe manipulator device in finding the wellhead. A sound-locating system for the wellhead on the pipe manipulator device may be employed in addition to, or as a substitute for, a television camera.

A typical transponder circuit is shown in FIGURE 13 as comprising a microphone 116 adapted to pick up an acoustic pulse from the pipe manipulator device as the latter moves through the water toward the wellhead. The signal from the acoustic receiver or microphone is amplified in the preamplifier 111 and passed through a filter 112 which is tuned to interrogate and passes signals of a selected frequency to a detector 114. The detector 114 may be of any suitable type such as for example as a diode rectifier with RC network to detect the signal from the filter and control the gate or relay 114. Thus, on signal from the detector 113, the gate or relay 114 would pass current to the oscillator circuit 115 whose output signal is transmitted from the wellhead through an acoustic transmitter 116. If desired, the circuit may include a code modulator 117 which would apply a time characteristic to the signal retransmitted by the oscillator circuit. The only power used continuously by the transponder would be that small amount of power need to listen for an acoustic signal put out by the pipe line manipulator device 38. Thus, the battery 11% would be adequate for supplying power for this continuous use and for sending a signal back to the vessel or to the pipe manipulator device 38. Whereas a SONAR system transmits short bursts of acoustic energy and then listens for the return of some of the energy reflected back from the wellhead, a transponder picks up a signal, amplifies it and uses it to trigger a return signal from the wellhead.

In practicing the well drilling method of the present invention, the drilling vessel 11 is first positioned in a substantially stationary manner at a selected offshore location and a hole is formed, as by drilling or washing, in the formation of the ocean floor. In fairly loose unconsolidated formations, a drill bit need not be employed in order to wash a hole of a size sufiicient to accommodate a well conductor pipe. With the well conductor pipe and wellhead base member securely anchored to the formation, as shown in FIGURE 3, drilling operations are continued with the drill bit being lowered from the vessel each time and guided into position in the top of the well by observing or otherwise determining the position of the drill bit relative to the well base and lowering the drill bit into the conductor pipe. Since the observation equipment or the well-indicating equipment on the pipe manipulator device will show that the drill bit is generally displaced to one side of the wellhead, it will be necessary to start a propulsion unit on the pipe manipulator device to move the lower end of the pipe laterally through the water to its desired position over the well base. In the event that the pipe manipulator device is slidably rotatable at the lower end of the pipe string, it can be slightly rotated thereon as necessary by either running just one of the propulsion units or by driving them differentially. In the event that the pipe manipulator device is fixed against rotation at the time it is positioned in the lower end of the drill pipe, the pipe manipulator device can be rotated slightly by rotating the top of the drill pipe at the barge.

While the pipe manipulator device 33 has been described hereinabove as preferably having a negative buoyancy so as to rest on the bit or collar at the end of the drill pipe 20 when the bit is being raised to a surface, it is to be understood that the

buoyancy tanks

85, 86, 87, and 88 (FIGURE 9) in the pipe manipulator device may be of size to make the entire unit buoyant at all times. Since a buoyant member or housing 40 of the manipulator device 38 would cause the unit to rise in the water, it would be necessary to provide the manipulator device 48 with suitable latch or hold-down means by which the manipulator device could be temporarily locked near the lower end of the drill pipe as the drill pipe was being run back to the well.

As shown in FIGURE 12 of the drawing, the manipulator device may be provided with one or more laterally-extending latches or pipe-engaging means 120 and 121 which extend into the bore 41 of the manipulator housing a distance sufiicient to engage the drill string 2-3 or an element carried thereby, such for example as the collar 75. The latches 120 and 121 are remotely retractable back into the housing in any suitable manner, as by means of

solenoids

122 and 123 which are remotely controlled from the vessel 11 at the surface. Thus, in running a drill string back into a well from the vessel when using a buoyant pipe manipulator device 38, as shown in FIGURE 12, the latches and 121 would engage the lower surface of the collar '75 and the weight of the drill string would force the pipe manipulator device down to the water to the wellhead where the television cameras would be employed to center and align it thereon. Once the drill bit 22 entered the casinghead 35, a control switch at the surface on the vessel could be closed to energize the solenoids to retract the latches 121; and 121. The buoyancy of the manipulator device would then cause the unit to rise upwardly through the water along the drill string and it could be retrieved at the surface and placed on a vessel until it was necessary to run another drill bit into the well. Although the latches 120 and 121 are shown as contacting the collar 75, it is to be understood that the outer faces of the latches 120 and 121 could be serrated in the manner of pipe slips so as to set and hold against the outer surface of the drill string when set thereagainst. This would eliminate the need for the collar 75 on the lower end of the drill string. The latches of this type could be used to engage the lower end of a pipe string such as a string of well casing which might subsequently be run into the well while using the pipe manipulator de vice to position its lower end within the top of the well.

Instead of holding the upper end of the string of casing by

cables

28 and 29, as shown in FIGURE 2, a running pipe string which is usually a small-diameter pipe string 135 (FIGURE 14) having a large-diameter lower end 136 could be used. Another form of a pipe latch to hold a non-buoyant type of pipe manipulator device on the lower end of a pipe string is shown in FIGURE 14. The pipe-engaging device comprises a series of slips having serrated edges 131 and set in a slip bowl that tapers downwardly and outwardly, as 132. Compression springs 133 below each of these slips tend to urge the slips upwardly against the surface of a pipe 137 positioned in the bore 41. The spacing between the slips 130 would be selected so as to be sufficient to cut into the outer wall of the lower end of the pipe string 137 being lowered into place in the well by the running string which would be J-latched or otherwise connected in a disengageable manner to the top of the pipe string 131. However, the diameter of the running string 135 above its large lower end 136 would be selected small enough so that the running string 135 could be rotated within the slips 130 to be unlatched from'the top 'ofthe'pipe string that it had Since the lower end 136 of the. running run in the well. string 135 would have a larger diameter than the distance between the actuated slips 130, the lower end 136 of the string 135 would engage the slips-130 so as to pick up the manipulator. Thus, the present pipe manipulator apparatus could'be employed to center well" casing and well tubing over a Welland subsequently release it so that it could be run into and hung within a well. Other suitable forms of latches could be used instead of slips 130.

It is to be understood that the'motor 44 of FIGURE 12 could be a hydraulically-operated motor supplied with power fluid from the vessel through a conduit in place of electrical lead 48; or jets could housed in place of the motor. it is quite apparent that the" apparatus of the present invention can locate and position a pipe string or a drill bit at the top of awell in theocean'floor'without the use of a guide cone 36.

We claim as our invention:

1. A method of drilling an' underwater well from a vessel on the surface of a body of water, said underwater well having a well'base positioned a substantial distance below the surface of the water, said method comprising (a) positioning a drilling vessel ata selected oifshore location above said underwater well base,

(b) slidably mounting a submersible self-propelled pipe manipulator and well-indicating device above a bit on a drill string depending from said vessel,

(c) lowering'saiddrill string and device simultaneously through the water into the vicinity of the underwater well base,

(d) determining. the position of the drill bit relative to the well base,

(e) moving at least the bottom of said drill string and bit into alignment with the top of'the well base,

(f) lowering the pipe manipulator and well-indicating device intoa seated position on the topof the well base, and

(g) lowering the drill bit and drill string into the well.

2. The method of claim 1 including the step of rotating the drill string and bit in the well and continuing the drilling of the well with the pipe manipulator and well indicating device positioned on the well base.

3. The method of claim 2 including the step of withdrawing the drill string from the well, engaging the lower end of the drill string with the pipe manipulator and wellindicating device prior to withdrawing the drill string from the well base, and raising the. pipe manipulator and well-indicating device on said drill string through the water to the surface.

4. The method of claim 1 including the step of removing the pipe manipulator and wellindicating device from the well base and raising it to the surface of the body of water, and subsequently resuming drilling of the well.

5. The method of claim 4 wherein the pipe manipulator and well-indicating device is removed from the well base by floating it to the surface of the water while guiding it along the drill pipe.

6. A method of drilling an underwater well from a vessel on the surface of a body of water, said method compris- (a) positioning a drilling vessel at a selected oiishore location,

(b) forming a hole in the formation beneath the body of water with a pipe string while pumping fluid down the pipe string,

(c) attaching a well base to the top of a base-anchoring device,

((1) lowering the base-anchoring device from the vessel down through the body of water while it is slidingly positioned on said pipe string,

(e) lowering at least a supporting length of the lower end of saidbase anchoring deviceiin'the hole with the well base positioned thereabove, (f) anchoring the base arrchoringdevic'e in the. hole and withdrawing the pipe string to the'vessel,

(g) attaching to the lower end: of thepipe strin'gra bit of a size to pass: through the well base and the base anchoring'device,

('h) slidably mounting a submersible" selfprop'e'lled' pipe manipulator and'well-indicating device above the bit on said pipe string depending from said vessel,

(i) lowering said pipe'strir'igand' device simultaneously through the water into'the vicinity of the underwater well base,

(j) determining the position of the drill bittrelativeto the wellbase;

(k) moving at least thebottom of'said pip'e'string and bit into alignment with the top ofthel conductor pipe in the well base,

(1) lowering the pipe manipulator and" well indicating device into a seated position on the top of the well base'a'nd'thedrill bitinto thehole, and i (m) continuingxthe drilling of the hole;

7. A methodiof drilling: aniunderwater well'from a vessel on the surface of a body of water, said methodcomprising- (a) positioning: adrilling'vessel substantially stationary at a selected offshore location,

(b) drillingahole in'the'formation beneath the body: of water with a drill string havinga drill bit at the lowerend thereof,

(c) attachinga well base tothetop of a well conductor (d) lowering the conductor pipe from the vessel down through the body of water while it is concentrically positioned outside'said drill string,

(e) lowering at least a supporting length" of the lower end'of said conductor pipe in the drilled hole with the well base positioned thereabove,

(f) cementing the conductor pipe in the hole and withdrawing the drill string to the vessel,

(g) changing the bit at the end of the drill string,

(h) slidably mounting a submersible self-propelled pipe manipulator and well-indicating device above the bit on said drill string depending from said vessel.

(i) lowering said drill string and device simultaneously through the water into the vicinity of the underwater well base,

(i) observing the position of the drill bit relative to the well base,

(k) moving at least the bottom of said drill string into alignment with the top of the conductor pipe in the well base,

(1) lowering the pipe manipulator and well-indicating device into a seated position on the top of the well base and the drill bit into the hole, and

(m) continuing the drilling of the hole.

8. A method of running a pipe string into an underwater well from a vessel on the surface of a body of water, said method comprising (a) positioning a drilling vessel substantially stationary above a underwater wellhead, at a selected offshore location,

(b) removably mounting in a slidable manner a submersible self-propelled pipe manipulator and wellindicating device above the lower end of a pipe string depending from said vessel,

(c) lowering said pipe string and device simultaneously through the water into the vicinity of the underwater wellhead, 1

(d) determining the position of the lower end of said pipe string relative to the wellhead,

(e) moving at least the bottom of said pipe string into alignment with the top of the wellhead,

(f) lowering the pipe manipulator and well-indicating 1 it device into a seated position on the top of the wellhead, and

(g) lowering the pipe string into the well.

9. Apparatus for use in drilling, completing and servicing underwater wells from a vessel positioned on the surface of a body of water above a well base assembly having aligning means thereon, said apparatus comprising (a) body member means having an opening therethrough for receiving therein an elongated member, said body member being of a size to be freely movable up and down said elongated member,

(b) well-indicating means carried by said body member means,

(c) remotely-controllable propulsion means carried by said body member means for moving said body member through said body of water,

((1) electrical transmission means extending between said vessel at the surface of said body of water and said well-indicating means and said propulsion means, and

(e) aligning means carried by said body member means,

said aligning means being adapted to engage cooperating aligning means on said underwater well base assembly.

10. The apparatus of claim 9 including an elongated pipe string of a diameter to pass through the opening of said body member means.

' 11. The apparatus of claim 10 including means carried near the lower end of said pipe string of a size greater than the opening in the body member means.

12. The apparatus of claim 10 including pipe connector means carried by said body member means and extending into the bore thereof.

13, The apparatus of claim 10 including cooperating connector means having one portion carried by said body member means and the other portion carried near the lower end of said pipe string for securing said body member means on said pipe string against axial movement in one direction.

14. The apparatus of claim 9 including buoyancy tank means carried by said body member means and being of a size to make said body member means buoyant.

15. Apparatus for use in drilling, completing said servicing underwater wells from a vessel positioned on the surface of a body of water above a well base assembly having aligning means thereon, said apparatus comprising (a) a body member having a bore therethrough for slidably receiving therein an elongated tubular member, said body member being of a size to be freely movable up and down said elongated member,

(b) at least one television camera carried by said body member, said camera being normally directed toward a line forming a downward extension of the axis of the bore in said body member,

(c) remotely-controllable propulsion means carried by said body member outwardly thereof for moving said body member through a body of water,

(d) light means carried by said body member for illuminating at least the area to one side of said body member,

(e) electrical transmission means extending between the vessel at the surface of said body of water and said television camera and said propulsion means and said light means, and

(f) aligning means carried by said body member, said aligning means being adapted to engage said cooperating aligning means on said underwater well base assembly.

References Cited by the Examiner UNITED STATES PATENTS 1,785,528 12/30 ORourke 6169.l 2,359,964 10/44 Barnett 61-69 2,984,308 5/61 Bauer et al 175-7 3,032,105 5/62 Reistle 16646 CHARLES E. OCONNELL, Primary Examiner.

Claims

1. A METHOD OF DRILLING AN UNDERWATER WELL FROM A VESSEL ON THE SURFACE OF A BODY OF WATER, SAID UNDERWATER WELL HAVING A WELL BASE POSITIONED A SUBSTANTIAL DISTANCE BELOW THE SURFACE OF THE WATER, SAID METHOD COMPRISING (A) POSITIONING A DRILLING VESSEL AT A SELECTED OFFSHORE LOCATION ABOVE SAID UNDERWATER WELL BASE, (B) SLIDABLY MOUNTING A SUBMERSIBLE SELF-PROPELLED PIPE MANIPULATOR AND WELL-INDICATING DEVICE ABOVE A BIT ON A DRILL STRING DEPENDING FROM SAID VESSEL, (C) LOWERING SAID DRILL STRING AND DEVICE SIMULTANEOUSLY THROUGH THE WATER INTO THE VICINITY OF THE UNDERWATER WELL BASE, (D) TERMINATING THE POSITION OF THE DRILL BIT RELATIVE TO THE WELL BASE, (E) MOVING AT LEAST THE BOTTOM OF SAID DRILL STRING AND BIT INTO ALIGNMENT WITH THE TOP OF THE WELL BASE, (F) LOWERING THE PIPE MANIPULATOR AND WELL-INDICATING DEVICE INTO A SEATED POSITION ON THE TOP OF THE WELL BASE, AND (G) LOWERING THE DRILL BIT AND DRILL STRING INTO THE WELL.