US3191695A - Method of drilling and locating an underwater well - Google Patents

Description

June 29, 1965 w BATEs ETAL 3,191,695

METHOD OF DRILLING AND LOCATING AN UNDERWATER WELL Filed Sept. 28, 1962 3 Sheets-Sheet 1 umwa I NVENTORS:

W. F. BATES R. A. MALOTT BY 9 H, Q

THEIR AGENT June 29, 1965 w. F. BATES ETAL 3,191,695

METHOD OF DRILLING AND LOCATING AN UNDERWATER WELL Filed Sept. 28, 1962 3 Sheets-Sheet 2 F|GI4 FIG.5 FIG.6

INVENTORS W. F. BATES R. A. MALOTT fi, QCCQ%,

THEIR AGENT June 29, 1965 w. F. BATES ETAL 3,191,695

METHOD OF DRILLING AND LOCATING AN UNDERWATER WELL Filed Sept. 28, 1962 3 Sheets-Sheet 3 FIG.? FIG. 8

INVENTORS:

W. F. BATES R. A. MALOTT Hm QMEZ THEIR AG ENT United States Patent "ice 3,191,695 RETHOD 6F DRILLENG AND LOCATKNG AN UNDERWATER WELL William F. Bates, Arcadia, and Raymond A. Maiott,

Fullerton, Caiifi, assignors to Shell Oil Company, New

York, N.Y., a corporation of Delaware Filed Sept. 28, 1962, Ser. No. 226,880 9 Claims. (Cl. 175- This invention is related to the underwater drilling of oil and gas wells and pertains more particularly to methods for establishing contact with a hole drilled in the ocean floor and for subsequently installing a foundation pipe string in the hole and/or continuing drilling operations.

During recent years, the continued search for oil has resulted in developing methods and apparatus for drilling underwater wells 'at locations where the water may range from 100 to 1500 feet or more in depth. In these locations it is customary to position the wellhead at a considerable distance below the surface of the water, preferably on the ocean floor, so that it is not a hazard to the navigation of ships in the area. One method of drilling and completing wells in this manner is described in copending patent application, Serial No. 830,538, filed July 30, 1959, and entitled Underwater Well Completion Method.

One of the most important operations in the drilling of an underwater well is that of starting the well and installing the conductor or foundation pipe in the ocean floor. This operation may be carried out in any one of several ways, one of which is described in US. Patent 2,929,610 which issued March 20, 1960 to H. Stratton. In the described method of the patent, a drill bit drills a hole in the ocean floor slightly larger in diameter than the diameter of the well conductor or foundation pipe which is subsequently slipped down along the drill pipe and into the hole during which time drilling fluid is pumped down the drill pipe and up the outside of the foundation pipe.

This method is limited somewhat in its application in that in order to slip a foundation pipe down over a drill string and bit into a holt drilled in the ocean floor, the drill bit must be smaller than the internal diameter of the foundation pipe so that the pipe can he slipped over it. However, the drill bit must be capable of drilling a hole larger than the outside diameter of the foundation pipe in order for the foundation pipe to enter the hole in the ocean floor. Thus, it is essential that the drill bit be of the collapsible or retractable type or that a second drill bit be mounted on the drill string of this type. The second bit in its expanded position would be wide enough to drill a hole in the ocean floor large enough to insert the foundation pipe therein. Prior to inserting the foundation pipe, the second bit would be collapsed or the extended cutting arms retracted so that the foundation pipe could be slipped over it. Stripping operations involve considerable delay in running casing which may cause it to stick.

Collapsible drill bits or drill bits having retractable cutting elements are inherently weaker and less rigid than ordinary drag or rock bits due to their complicated design. Hence, upon being subjected to abnormal drilling forces while drilling into some formations, a greater 3,191,695 Patented June 29, 196

amount of bit failure. has been experienced. In addition, large drill collars and stabilizers cannot be run which can lead to crooked hole. In addition it will speed up and provide greater safety in running casing.

A further object of the present invention is to provide a method for drilling a hole in the ocean floor or formation underlying the ocean, withdrawing the drill mechanism therefrom, and subsequently regaining contact with the hole in the ocean floor for installing a foundation pipe therein or for reinstalling a drill mechanism.

A further object of the present invention is to provide a method whereby an elongated pipe string may be suspended from a vessel floating on the surface of the ocean and be manipulated so that its lower end is adapted to be moved over the ocean floor and reestablish contact with a Well or hole previously drilled in the ocean floor.

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

FIGURES 1 through 3 are diagrammatic views taken in longitudinal projection illustrating a floating vessel positioned over a drilling location during the sequential steps of starting to drill a well, re-establishing contact with the well by the pipe string after having removed the drill string, and inserting a foundation pipe into the well by guiding it along the pipe string.

FIGURES 4 through 6 are diagrammatic views taken in longitudinal projection illustrating a floating vessel in FIGURES 4 and 6 positioned over a drilling location during the sequential steps of establishing contact be tween the vessel and a previously drilled hole in the ocean floor by means of a pipe string having a foundation pipe at the lower end thereof, positioning the foundation pipe in the well, and subsequently continuing driling operations through the foundation pipe.

FIGURES 7 and 8 are longitudinal views, taken partially in cross section, of the lower end of a drill string, with a plug being removed from the drill string in FIGURE 8.

Referring to FIGURE 1 of the drawing, a drilling vessel, barge or platform 11, of any suitable floating or floatable type, .is illustrated as floating on the surface of a body of water 12 while being substantially fixedly positioned over a preselected well location by suitable vesselpositioning means well known to the art, or by being anchored to the ocean floor 13 by anchor lines 14 and 15 running to the anchors (not shown). Equipment of this type may be used when carrying on'well drilling operations or well work-over operations in water varying from about feet to 1500 feet or more in depth. The drilling vessel 11 is equipped with a suitable derrick 16 containing a fall line system 17 which includes a suitable hoist (not shown), traveling block 18 and suitable hook and swivel or other connector means 19 adapted to be connected to the top of a drill pipe 21 during well drilling operations and being adapted to circulate a drilling fluid therethrough in a manner well known to the art. The vessel 11 is also provided with other auxiliary equipment needed during well drilling operations, such, for example, as a rotary table 22 positioned on the operating deck of the vessel, a hinged slip and spider assembly, etc. The derrick 16 is positioned over a drilling slot or well 23 which extends vertically through the barge in a conventional manner. When using equipment of the present 3 invention, a slot 23 in the vessel 11 may either be centrally located or extend in from one edge. Alternatively, drilling operations may be carried out over the side of the vessel without the use of a slot. For example, the drilling vessel may be provided with a deck portion which overhangs the hull of the vessel.

When drilling wells in accordance'with the method of the present invention, a drilling vessel is positioned at a selected offshore location and a drill string having a, bit secured to the lower end thereof is lowered through the body of water int contact with the formation or ocean floor and a well is drilled therein by rotating the drill string from the vessel. The drill string is then withdrawn from the hole and no attempt is made to maintain contact between the hole and the vessel. On the vessel a pipe string is made up and closed at its lower end. By providing the lower end f the pipe string with a horizontally-directed unidirectional fiuid discharge port, fluid may be pumped down the pipe string and jetted out the port. Prior to or subsequent to lowering the drill pipe so that its lower end assumes a position near the ocean floor, a well-finding or locating unit, such, for example, as a television camera, is removably positioned near the lower end of the pipe string. Thus, by moving the lower end of the pipe string horizontally relative to the formation,

the previously drilled hole in the ocean floor is located and the lower end of the pipe string is positioned thereabove to be subsequently lowered into the well while the observation unit is returned to the vessel. If desired, the pipe string may be employed as guide means to guide a well foundation pipe into the hole. In the event that the lower end of the pipe string is provided with a drill bit, continued drilling of the hole may take place.

The drill string 21 (FIGURE 1) preferably includes a conventional telescoping joint 24 in its length to compensate for the rise and fall of the vessel 11 relative to the drill string 21. Drill string 21 also includes a drill bit 25 at its lower end as well as drill collars (not shown) thereabove, if desired. In FIGURE 1 the drill string 21 is shown as having drilled a hole or well 26 in the ocean floor 13. After drilling the hole 26 to the desired depth, the drill string 21 is pulled back to the vessel 11 in order to change a bit, or to be replaced by a running or guiding pipe string 27 (FIGURE 2). Although the running and guiding pipe string 27 (FIGURE 2) and the drill string 21 (FIGURE 1) are shown as continuous lengths of pipe, it is to be understood that a drill string or other pipe string extending from the vessel 11 to the ocean floor 13 is normally made up of a plurality of short sections of pipe, say 30 feet long, connected together in a suitable manner, as by screw threads.

The running or guiding pipe string 27 (FIGURE 2) is closed at or near its lower end, as by a jet sub or plug 28 being provided in the side wall thereof with a horizontally-directed unidirectional fluid discharge port 29. The lower end of the pipe string 27 is: preferably provided with suitable stop means, such, for example, as the shoulder 30 formed by the upper end of the jet sub or plug 28. The shoulder 30' forms stop means for limiting the downward movement of a cylindrical frame 31 which is slidably mounted for axial movement on the pipe string 27 between the vessel 11 and the lower end of the pipe string 27; The frame 31 is preferably provided with centralizer springs 32.

The frame 31 serves as a television camera carriage or means for releasably securing a television camera 33 to the guide pipe string 27 near the lower end thereof.- The television camera 33 or the carriage frame 31 is provided with lights 34 for illuminating the area in the vicinity of the television camera 33. The television camera 33 may also be mounted to the carrier frame 31 by means of a remotely-controlled swivel pan and tilt apparatus 35 whereby the television camera may be turned in any direction to scan the ocean floor 13. Alternatively, the.

television camera 33 may be removably secured to the carrier frame 31 in a fixed substantially downwardlydirected manner together with downwardly directed lights 34. Preferably, the television camera 33 is positioned adjacent to the guide pipe string 27 on the opposite side from the jet port Zfi in the jet sub 23, however this is not essential. The television camera is provided with an electrical transmission cable 36 for supplying current to the television camera 33 and lights 34 while returning television signals upwardly to a receiver and viewing screen 37 positioned on the vessel 11. The transmission cable 36 may run along a weight-supporting hoist cable 38 secured at its lower end to the television carriage 31 and extending upwardly to a hoist 39 on the vessel 11.

Thus, as shown in FIGURE 2, the carriage 31 and television camera 33 may be secured to the lower end of the pipe string 27 at the vessel 11 and lowered through the water to the ocean floor 13 as the pipe string is made up. Alternatively, the entire pipe string 27 may be made up and extended to the ocean floor before mounting the carriage 31 at the top thereof and sliding it down along the pipe to its position above the jet sub or plug 28. If it is desired to orient the television camera 33 relative to the jetting port 2g and the jet sub 23, any suitable orienting means well known to the art may be employed. For exampie, as shown in FIGURE 8, the lower end of the pipe string 27 may be provided with an orienting shoulder 46 along which a pin 41, carried by the frame 31, may slide to rotate the frame until the television camera 33 is opposite the jet port 29.

With the pipe string 27 being suspended from the drilling vessel 11 with its lower end above the ocean floor 13, as shown in FIGURE 2, suitable holding slips 42, well known t the art, are inserted around the pipe string 27 at the rotary table 22 while the upper end of the pipe string 27 is connected to a suitable source of fluid pressure, such, for example, as a pump 43 mounted on the vessel 11. Alternatively, the drilling mud circulation system and the power swivel used in the drilling of the well (FIGURE 1) could be employed.

When fluid is being pumped down the pipe string 27 the fluid stream being jetted from the discharge port 29 at the lower end thereof provides sufficient reaction force to move the lower end of the pipe string substantially horizontally over the ocean floor in a direction radially and outwardly away from its normal vertical suspended position. Since the elongated pipe string 27, which may be several hundred feet long, has considerable flexibility, 1t 18 quite apparent that a jetting fluid supplied by the high pressure mud pumps carried by the drilling vessel 11 can cause the lower end of the pipe 27 to move considerable distances away from its normal vertical posi tron. By varying the pump pressure at the vessel, the etting force at the lower end of the pipe 27 can be regulatedso as to vary the distance that the lower end of the pipe is moved. As the pipe moves, the operator on the vessel observes the picture of the ocean floor in the television receiver screen 37. In this manner he is able to relocate the hole or well 2-6 previously drilled in the ocean floor 13.

Since the upper end of the pipe string 27 is wedged in the rotary table 22 or suspended from the hook (unlocked) on the vessel 11, the drill string 27 may be rotated slowly from its upper end by slowly rotating the rotary table or with tongs on casing through short arcs or full circles while the television camera at the lower end of the pipe string 27 sweeps the ocean floor 13 so that the operator on the vessel 11 can locate the previously drilled hole or well 26. By increasing the pump pressures at the vessel, the lower end of the pipe string 27 and its television camera 33 may be caused to sweep through larger and larger concentric circles. After the well or hole 26 in the ocean floor has been located, the pipe string is lowered into the hole to the position shown in FIGURE 3 while the television camera 33 in its car-- riage frame 31 is returned to the vessel 11 by pulling up on the hoist line 38.

Although the television camera 33 (FIGURE 2) is illustrated as being secured to the pipe string 27 by means of a cylindrical carriage frame 31 that is slidably mounted on the pipe string 27, it is to be understood that the television camera 33 or other types of well-finding devices may be movably mounted or detachably mounted at the lower end of the pipe string 27 in any suitable manner well known to the art. Thus, for example, the television camera and light 34, and if desired a portion of frame 31, may be detachably secured to the lower end of the 'pipe string 27 as by spring clips, remotely actuated arms, electromagnets supplied by current through cable 36, etc. After the television camera 33 and its carriage 31 are removed from the pipe string 27, the pipe string 27 being positioned in the hole 26 as illustrated in FIGURE 3, a well conductor or foundation pipe 45 may be made up at the vessel 11 and lowered down over the pipe 27 by slipping or stripping it down. If desired, the foundation pipe 45 may be provided with a base support member 46 adapted to rest on the ocean floor 13.

The foundation pipe 45 may be lowered in any suitable manner, as by a running pipe string, or by wire lines 47 and 48 secured at their lower end to the base support member 46 of the foundation pipe and extending upwardly to winches 49 and 59 on the vessel 11. If desired, these wire lines may provide guide lines for subsequently lowering other well equipment down to the top of the well. In the event that they are to be used as guide lines, the winches 49 and 50 are preferably replaced by means for providing a constant tension to the lines 47 and 4-8, as by constant-tension hoists.

A modification of the method of the present invention of establishing contact with a hole previously drilled in the ocean floor and installing a foundation pipe therein, without the use of the guide pipe 27 as described hereinabove, is illustrated in FIGURE 4. After the hole or well 26 has been drilled in the ocean floor 13, a running pipe string 51 is detachably secured at its lower end 52 in any suitable manner, as by screw threads or a J-slot latch device 53 to the upper end of a Well foundation pipe 54 which is provided with a base member 55 and is closed at its lower end by means of a cap or jet sub 56. The jet sub 56 is similar to that described hereinabove with regard to FIGURE 2 and is provided with a jet port 57. However, the jet sub 56 is preferably made of a drillable material such as an aluminum alloy or cast iron which can be readily drilled through by a drill bit as will be described hereinbelow. A television camera 33 is provided together with lights 34 and a pan and tilt connection 35. The camera 33 is secured temporarily to the outer surface of the well foundation pipe 54 by suit able means, as by electromagnets 58 which are energized by current received through a current-transmitting and weight-supporting cable 59. The cable 59 is adapted to retrieve the television camera 33 to the surface after the electromagnets 58 have been de-energized remotely from the vessel 11.

The operation of the apparatus in FIGURE 4 is similar to that described hereinabove with regard to the apparatus in FIGURE 2. Thus, by suspending the running string 51 from the rotary table or hook 22 and supplying fluid pressure from pump 43, fluid may be jetted out port 57 in the jet sub in the bottom of the pipe string to cause the foundation pipe 54 to be moved outwardly from its normal vertically-suspended position. At the same time the upper end of the pipe string 51 can be rotated in the rotary table 22 to cause the displaced lower end of the pipe string and foundation pipe to sweep sufficient areas of the ocean floor so as to relocate the well or hole 26 drilled therein.

After finding the hole or well 26 in the ocean floor and positioning the foundation pipe 54 thereabove, the

running pipe string 51 and foundation pipe 54 are lowered preferably until at least the lower end of the foundation pipe is in the hole 26 at which time the television camera is released from the foundation pipe 54 and the latter is then dropped into the hole 26 until the base member 55 rests on the ocean floor. If it is desired to cement the foundation pipe in the well, the upper end of the running pipe string may be connected to a cement pump so that the cement slurry can be pumped down the pipe string 51 through the foundation pipe 54 and its jet port 57 to fill the annular space outside the foundation pipe 54 as shown in FIGURE 5. After the cementing operation the running pipe string would be disconnected from the top of the foundation pipe 54 and retrieved to the vessel. Subsequently, drilling operations could be continued by lowering the pipe string from the vessel by methods described with regard to FIGURES 2 and 4 hereinabove and drilling operations could be continued as shown in FIGURE 6 with the drill pipe drilling through the bottom of the cap at the bottom of the foundation pipe 54. In continuing the drilling operations the drill bit 25a would be smaller than the inner diameter of the foundation pipe 54. j

As shown in FIGURES 7 and 8, if it is desired to lower the drill string 21 (FIGURE 6) into register with the foundation pipe 54 by using the observation means described with regard to FIGURES 2 and 4, the drill string 21 (FIGURE 7) is preferably provided with a fluid discharge port 64) in the outer wall thereof above the bit 25a. Within the pipe string 21, a sleeve valve 61 is provided for normally closing the port 60. A compression spring 62 is provided for normally urging the valve 61 against a stop shoulder 63. As shown in FIGURE 8, when the drill string 21 is originally run down from the vessel 11 (FIGURE 6) to find the well in the ocean floor, a retrievable plug 64 is preferably positioned on the valve 61 so that when fluid pressure is applied from above the plug 64 will prevent fluid from normally being discharged down the bore of the drill string 21 and out the normal jet ports in the bit 250,. With the bore 65 of the drill string 21 closed by the plug 64, the fluid will be discharged out the port 60 in the wall of the pipe 21 so as to give a jetting action which willmove the lower end of the drill pipe in a manner described hereinabove with regard to pipe string 27 (FIGURE 2). The top of the plug 64 is provided with a fishing neck 66 so that after the drill bit has been positioned in the well, a fishing tool 67 of any suitable well-known type can be lowered down through the drill pipe 21 to engage the fishing head 66 so that the plug 64 can be withdrawn from the bore 64 of the drill pipe 21. With the plug 64 removed, the spring 62 would return the sleeve valve 61 to its normal position closing jet port 69 and any drilling fluid being pumped down the drill pipe 21 would be discharged out the jet ports (not shown) in the drill bit 25a.

While it is preferred to employ observation means such as a television unit to observe the ocean floor in locating a hole or well previously drilled therein in order to reestablish a connection between the well and the vessel on the surface of the water, it has been found that connection can be re-esta'blished between a vessel and the Well in the ocean floor by using the method of moving the lower end of a pipe string relative to the ocean floor by the method of the present invention without the use of a television camera. Thus, since a drilling vessel 11 is normally fairly well anchored in a predetermined position over a drilling location, if connection is lost between the vessel and a hole drilled in the ocean floor, it is possible to re-establish connection by slowly moving the lower end of a pipe string relative to the ocean floor in a manner described hereinabove while periodically stabbing the pipe string downwardly into the ocean floor until the hole is located. This might be accomplished with the wave movement of vessel. At that time the pipe would be run down into the hole and a foundation pipe 7 could be stripped down using the pipe string' as guide means to guide the foundation pipe into the hole.

If an observation unit is employed as described hereinabove and the well is Within the observed range before the pipe is moved or rotated, the lower end of the pipe may be moved suficiently merely by moving the upper end laterally within the vessel slot 23, which may be 30 feet wide. By use of a pan and tilt unit on the television camera, considerable area of the ocean floor can be scanned without moving the depending pipe or rotating it, If desired and/ or necessary, the pipe may merely be rotated on a vertical axis.

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 method comprising (a) positioning a drilling vessel at a selected offshore location,

(b) lowering from the vessel into contact with the formation beneath the body of water a drill string including a bit at the lower end thereof,

(c) forming a hole in said formation with said drill string,

(d) withdrawing said drill string to said vessel,

(e) making up at the vessel a pipe string closed near its lower end,

(f) providing said pipe string with horizontally-directed unidirectional fluid discharge means above the closed lower end,

(g) lowering said pipe string from said vessel to a position near the formation beneath said body of water,

(h) positioning an observation unit on and near the lower end of said pipe string with a visual receiving unit on the vessel,

(i) moving at least the lower end of said pipe string and said observation unit relative to the formation to find the hole drilled in said formation and position the lower end of said pipe string in' register thereabove, said moving step comprising the steps of pumping fluid down the pipe string and jetting it substantially horizontally out said fluid discharge means to displace the lower end of the pipe string outwardly from its normal vertical position and scanning with the observation unit the formation traversed,

(j) lowering said pipe string until at least the lower end thereof is in the hole, and

(k) withdrawing said observation unit back to the vessel by sliding it upwardly along said pipe string to said vessel.

2. A method of inserting a pipe in an underwater well from a vessel on the surface of a body of water, said method comprising (a) making up at the vessel a pipe string adapted to be closed near its lower end,

(b) closing the lower end of said pipe string,

(c) providing said pipe string with horizontally-directed unidirectional fluid discharge means above the closed lower end,

(d) lowering said pipe string from said vessel to a position near the formation beneath said body of Water,

(e) positioning a well-finding unit near the lower end of said pipe string with an indicating unit on the vessel,

(f) moving at least the lower end of said pipe string and said well-finding unit relative to the formation to find the hole drilled in said formation and position the lower end of said pipe string in register thereabove, said moving step comprising the steps of pumping fluid down the pipe string and jetting it substantially horizontally out said fluid discharge means to displace the lower end of the pipe string outwrdly from its normal vertical position and g. scanning with the observation unit the formation traversed, and

(g) lowering said pipe string until at least the lower end thereof is in the hole.

3. The method of claim 2 including the additional step of withdrawing the well-finding unit back to the vessel after the lower end of the pipe string is in the hole.

4-. The method of claim 2 including the additional step of varying the pumping fluid pressure to vary the displacement and position of lower end of the pipe string.

5. The method of claim 2 including the additional step of at least partially rotating the upper. end of the pipe string to sweep the displaced lower end of said pipe string horizontally over the underwater formation.

6. A method of installing a foundation pipe in an underwater well from a vessel on the surface of a body of water, said method comprising (a) making up at the vessel a foundation pipe closed at its lower end,

(0) providing said foundation pipe with horizontallydirected unidirectional fluid discharge means above the closed lower end,

(c) detachably securing said foundation pipe to the lower end of a pipe string,

(d) lowering said foundation pipe by said pipe string from said vessel to a position near the formation beneath said body of water,

(e) positioning an observation unit near the lower-end of said foundation pipe with a projection unit on the vessel,

(f) moving at least the foundation pipe at the lower end of said pipe string and said observation unit relative to the formation to find the hole drilled in said formation and position the lower end of said foundation pipe in register thereabove, said moving step comprising the steps of pumping fluid down the pipe string and jetting it substantially horizontally out said fluid discharge means to displace the lower end f the pipe string outwardly from its normal vertical position and scanning with the observation unit the formation traversed, and

(g) lowering said foundation pipe until at least the lower end thereof is in the hole.

7, The method of claim 6 including the steps of (h) withdrawing said observation unit back to the vessel,

(i) seating the foundation pipe in the hole in the formation,

(j) disconnecting the lower end of the pipe string from the foundation pipe, and

(k) withdrawing the pipe string back to the vessel.

d. The method of claim 7 including the steps of (l) lowering a drill string into the foundation pipe,

and

(m) drilling through the substantially closed lower end of said foundation pipe and into the formation therebelow.

9. A methodof drilling an underwater well from a vessel on the surface of a body of water, said method comprising (a) making up at the vessel a pipe string adapted to be closed near its lower end and having a drill bit on the lower end,

(b) providing said pipe string with horizontallydirected unidirectional fluid discharge means above the lower end,

(c) closing the bore of said pipe string below the fluid discharge means, lowering said pipe string from said vessel to a position near the formation beneath said body of water,

(d) positioning an observation unit near the lower end of said pipe string with a projection unit on the vessel,

(e) moving at least the lower end of said pipe string and said observation unit relative to the formation to 'find the hole drilled in said formation and position the lower end of said pipe string in register thereabove, said moving step comprising the steps of pumping fluid down the pipe string and jetting it substantially horizontally out said fluid discharge means to displace the lower end of the pipe string outwardly from its normal vertical position and scanning with the observation unit the formation traversed,

( f) lowering said pipe string until at least the lower end thereof is in the hole,

(g) withdrawing said observation unit back to the vessel,

(h) opening the bore of the pipe string above its lower end and closing the fluid discharge means,

(i) lowering a bit to the bottom of the hole and rotating the bit to drill more hole.

References Cited by the Examiner UNITED STATES PATENTS ORourke 6169.1

Anderson 175268 X Laurie 166-665 X Dwyer 175-231 X Marsee 175267 X Bauer et al 175-7 Reistle 1757 X Ahlstone et a1 16666.5

Great Britain.

15 CHARLES E. OCONNELL, Primary Examiner.

Claims (1)

1. 2. A METHOD OF INSERTING A PIPE IN AN UNDERWATER WELL FROM A VESSEL ON THE SURFACE OF A BODY OF WATER, SAID METHOD COMPRISING (A) MAKING UP AT THE VESSEL A PIPE STRING ADAPTED TO BE CLOSED NEAR ITS LOWER END, (B) CLOSING THE LOWER END OF SAID PIPE STRING, (C) PROVIDING SAID PIPE STRING WITH HORIZONTALLY-DIRECTED UNIDIRECTIONAL FLUID DISCHARGE MEANS ABOVE THE CLOSED LOWER END, (D) LOWERING SAID PIPE STRING FROM SAID VESSEL TO A POSITION NEAR THE FORMATION BENEATH SAID BODY OF WATER, (E) POSITIONING A WELL-FINDING UNIT NEAR THE LOWER END OF SAID PIPE STRING WITH AN INDICATING UNIT ON THE VESSEL, (F) MOVING AT LEAST THE LOWER END OF SAID PIPE STRING AND SAID WELL-FINDING UNIT RELATIVE TO THE FORMATION TO FIND THE HOLE DRILLED IN SAID FORMATION AND POSITION THE LOWER END OF SAID PIPE STRING IN REGISTER THEREABOVE, SAID MOVING STEP COMPRISING THE STEPS OF PUMPING FLUID DOWN THE PIPE STRING AND JETTING IT SUBSTANTIALLY HORIZONTALLY OUT SAID FLUID DISCHARGE

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