US3380520A

US3380520A - Drilling and production platform

Info

Publication number: US3380520A
Application number: US525936A
Authority: US
Inventors: Floyd T Pease
Original assignee: Offshore Co
Current assignee: SONAT OFFSHORE DRILLING Inc
Priority date: 1966-02-08
Filing date: 1966-02-08
Publication date: 1968-04-30
Anticipated expiration: 1985-04-30

Description

April 30, 1968 F. T. PEAgE 3,380,520

DRILLING AND PRODUCTION PLATFORM Filed Feb. 8, 1966 5 Sheets-Sheet 1.

INVENTOR f2 6/17 736465 ATTORNEYS April 30, 1968 F. T. PEASE DRILLING AND PRODUCTION PLATFORM Filed Feb. 8. 1966 5 Sheets-Sheet 2 i I w ////61/{ [/4768 Laws-z.

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a a m M Q I W 1: t W mvmon a U 27am 5455 April 30, 1968 F. T. PEASE DRILLING AND PRODUCTION PLATFORM 5 Sheets-Sheet 5 Filed Feb. 8, 1966 INVENTOR BY W454,

ATTORNEYS April 30, 1968 F. T. PEASE DRILLING AND PRODUCTION PLATFORM 5 Sheets-Sheet 4 Filed Feb. 8, 1966 i II I f l ///lr/r///// n 24/ INVENTOR [Z0127 Z P5455 wwa ma ML, ATTORNEYS April 30, 1968 F. T. PEASE DRILLING AND PRODUCTION PLATFORM 5 Sheets-Sheet 5 Filed Feb. 8, 1966 INVENTOR 455 fZara FF ATTORNEYS United States Patent 3,380,520 DRILLING AND PRODUCTION PLATFORM Floyd T. Pease, Houston, Tex., assignor to The Offshore Company, Houston, Tex., a corporation of Delaware Filed Feb. 8, 1966, Ser. No. 525,936 14 Claims. (Cl. 166--.5)

This invention relates to apparatus and methods for conducting underwater drilling and well completion operations. In particular, it relates to an improved support structure for permanent placement on a submerged bottom and to methods for employing the structure as an aid in drilling and constructing underwater wells and in controlling a submerged well from a remote location.

It has been suggested in the prior art to provide rigid, wholly submerged support structures which are employed to elevate a wellhead structure of a submerged well above the bottom and to stabilize well casings during drilling and wellhead construction. Structures of this kind are constructed in the form of a vertically elongated framework which is permanently secured at its lower end to a submerged bottom at a location where a well is to be drilled. Generally the framework includes a plurality of longitudinal tubular members which are embedded in the submerged bottom to anchor the entire structure. Well forming operations are then carried out from the surface of the water, through a long conductor pipe or the like which is placed so as to extend from the top of the support structure into the submerged bottom, the support structure being employed to stabilize the conductor pipe and the wellhead which is subsequently constructed on top of the'conductor pipe.

It is one object of the present invention to provide an improved submerged support structure for use in well forming operations, the support structure performing a variety of guiding and support functions during use. Broadly, the apparatus includes a vertically elongated open framework which is adapted to be anchored at its lower end in a submerged bottom and which carries at least one guide sleeve assembly. In use of the apparatus, after it has been anchored to the bottom, a drive pipe or the like is lowered from the surface through the sleeve assembly and set into the bottom, following which a well is drilled through the drive pipe from the surface. The upper end of the drive pipe terminates within the sleeve assembly, and in a preferred construction the upper end of the latter is of enlarged diameter to serve as a protector for a wellhead which is constructed at the top of the drive pipe.

It is a further object to provide apparatus of the above type with a sleeve assembly whose upper end is adapted to receive the lower end of a removable access tube through which men and equipment may be lowered to the location of the wellhead.

It is a further object to provide apparatus of the above type adapted for use with a plurality of closely spaced wells having separate submerged wellheads, the apparatus including a single, permanent control (as opposed to the removable tube) access tube extending to the surface for carrying wellhead control lines and the like. This arrangement has particular utility where control of the well is to be maintained in a location of severe surface activity. In particular, it is advantageous in cold locations where ice formation and ice movement would prevent the use of a floating service platform or a large bottomanchored service platform. According to the present invention, the wellheads will be disposed below the ice and below wave action, and the relatively small, permanent access tube will be constructed to withstand the action of ice around its upper portions. At the same time, the elevation of the wellheads above the submerged bottom avoids the abrasive action of glacial flow which moves through certain arctic and subarctic regions.

Another object of this invention is to provide means for establishing a control connection between individual wellheads carried by the template structure and the central access tube. The connecting means may be coupled between the wellheads and the access tube by using divers to make the necessary connection so that well operations can be carried on remotely from the above-surface station. However, a further embodiment of this invention provides for the placement and coupling of a connecting means by a remotely controlled mechanism so that divers will not have to be used to complete the control connections for a producing well.

The method of this invention provides for the anchoring of the template structure at a selected underwater drilling site so that the structure may act as a fixed drilling guide and become a platform for a producing well at the underwater site. The method includes the steps of installing the template structure, providing for a guiding of well drilling apparatus through the structure, and establishing well head means and associated control devices at an underwater level for producing the well. Further steps provide for removing guiding tubes and other above-water structures so that the entire Well-producing unit is positioned below the surface of the water with the exception of the central access tube.

These and other features of this invention will become apparent in the more detailed discussion which follows. In the detailed discussion, reference will be made to the accompanying drawings in which:

FIGURE 1 is an elevational view of the template structure in an underwater position as related to a drilling bar-ge which is shown as connected to the template for the purpose of conducting drilling operations from above water;

FIGURE 2 is an elevational view, on an enlarged scale, of the template structure showing details of the guiding means and wellhead protector means associated with that structure;

FIGURE 3 is a horizontal cross-sectional view of the template structure taken at line 3-3 of FIGURE 2;

FIGURE 4 is an elevational view showing details of wellhead protector means associated with the template structure;

FIGURE 5 is a cross-sectional view showing connecting means which can be used between a control line access tube and a wellhead protector casing; and

FIGURE 6 is a cross-sectional view showing another connecting means which can be remotely controlled to make a connection between a control line access tube and a wellhead protector.

Referring to FIGURE 1, there is shown an underwater template structure 10 which can be towed or otherwise carried to an offshore drilling site by a drilling barge 12. The drilling barge 12 is of any conventional construction and includes float means and means for raising the barge above the surface of a body of water. The latter means include piles which can be driven into the underwater floor for fixing the position of the barge, and then the barge is jacked to an above-water level so that it will be unaffected by wave action during the drilling operations.

The template structure 10 may be preassembled in its initial form on shore and then carried to the drilling site, or it may be assembled at the offshore drilling site and then lowered to the ocean floor. The drilling barge is floated to the drilling site, the template structure is lowered to its desired position on the underwater floor, and then the drilling barge is raised out of the water by interior jacking devices which feed a plurality of support columns 14 down to the ocean floor for stabilizing and lifting the drilling barge above the surface of the water.

As shown in FIGURES 2 and 3, the template structure is generally in the form of a frame made up of tubular elements interconnected to form the framework shown. The template frame includes marginal upright hollow columns 16 which define the outer dimensions of the upright structure and which provide an anchoring of the structure into an underwater floor. In addition, various cross members 18 provide a lattice of reinforcing structure between the marginal upright columns so that the template structure is rigid and can withstand the forces encountered in an underwater environment.

The template structure of this invention is intended to provide a twofold function. The structure can be placed and anchored at a below-water level so as to guide the initial drilling of underwater wells at the location of the template. Once the wells are completed, the template structure provides a platform means for supporting wellhead means and other devices associated with taking products from the established well. In its final form, the template structure supports wellheads at a below-water level where there is no likelihood of damage from surface ice or storms which normally affect above-water apparatus. The template structure also maintains wellhead means in positions off the ocean fioor so as to avoid the wave action and erosion which is encountered at the floor level of a body of water. By establishing and supporting all of the operating functions of a well at a below-water level, the well can be operated in all weather conditions and for all climatic changes.

For its initial function as a drilling guide, the template structure 10 includes the framework, already discussed, and guiding means at its upper and lower levels for positioning drive pipes through which well forming operations are carried out. The lower guide means include lower guide sleeves 20 which are spaced from one another on a horizontal plane at a lower level of the template structure. In the preferred form of this invention, there are four lower guide sleeves placed at the bottom level of the template, as shown in FIGURE 3, so as to accommodate four separate wells. Upper guide means include upper guide sleeves 22 which are spaced from one another on a horizontal plane at an upper level of the template structure. The upper guide sleeves 22 are positioned to be in vertical axial alignment with the lower guide sleeves 20 so as to provide a perfectly vertical guide. Both the upper and lower guide sleeves are of sufficient diameters to receive drive pipes between them for guiding a drilling string. The drive pipes 24 are of a sutficient size to permit drilling operations to be conducted therethrough and a typical diameter for such drive pipes is approximately 30 inches. As shown in FIGURE 5, the upper guide sleeves 22 include flared top portions 23 which are fitted into the lower ends of wellhead protector casings 26. Alternatively, the elements shown as 22, 23 and 26 can be formed as a single unitary structure. The flared top portions 23 of the upper guide sleeves assist in guiding drive pipes downwardly through the guide sleeves so as to center the drive pipes in the sleeves. The lower guide sleeves are also provided with flared top portions to assist in guiding a drive pipe therethrough. As shown in the enlarged views of FIGURES 5 and 6, the upper guide sleeves are fixed, as by welding, in position at the lower ends of the wellhead protector casings 26. Then the drive pipes 24 are lowered and guided through the upper sleeves 22 and through the lower sleeves 20 to establish a path through the template structure for lowering drilling equipment. The drive pipes 24 may then be welded by sending a person down a removable access tube 38 which can be fitted over the easing 26 for communication with the surface. The drive pipes 24 are welded, or otherwise sealed, to the upper guide sleeves for preventing the entrance of water into the lower end of the Wellhead casing 26. The wellhead casing members 26 are in the form of elongated sleeves,

and provide protection for installed wellheads of producing wells. The wellhead protectors 26 are rigidly affixed to the framework of the template structure, and initially assist in the guiding function of the template structure during drilling operations.

When it is desired to establish underwater wells at a particular site, the template structure 10 is lowered to the underwater floor and permitted to rest in its normal upright position on that floor. The marginal upright columns 16 of the template structure are hollow so that lower leg portions 28 of each marginal upright column can be driven into the underwater floor for anchoring in that floor. The anchoring of the template structure may be in any conventional way, but it has been found in granular formations that a rapid anchoring can be accomplished by jetting a fluid pressure through the upright columns 16 so as to embed the lower legs 28 of each column into the underwater floor. After the initial embedment of each leg into the floor, a corner tube pile 30 can be driven or jetted through each of the hollow marginal columns 16 and a cement material can then be pumped into the column to fix the pile in an anchored position within the column and in the underwater floor. Alternatively, the leg portions 28 and the corner piles 30 may be drilled into posi.ion depending on the hardness of supporting formations.

After the template structure has been anchored, and the positions of the template structure and the abovewater drilling barge 12 have been fixed relative to each other, one or more drive pipes 24 may be lowered through the wellhead protector sleeves 26 so as to form a communication between the upper guide sleeves 22 and the lower guide sleeves 20. The drive pipes 24 are then driven to a desired penetration into the underwater floor, and the pipes may then be welded to the upper sleeves, thus establishing a rigid and sealed communication from the upper sleeves 22 to the ocean floor.

With the lower guide tubes 24 fixed in their proper positions between the upper and

lower guide sleeves

22 and 20, the template structure is ready for the addition of a temporary wellhead access tube to any one of the four wellhead protector sleeves so as to complete the guide communication between the well bore and the above-surface drilling apparatus. A wellhead access tube 38 is lowered to a coupling position over a wellhead protector sleeve 26 through which a well is to be drilled. Normally only one well at a time is drilled by the abovewater drilling apparatus, and therefore, only one well access tube 38 is required at any one time. The well access tube 38 has an enlarged terminal end which may be lowered over the wellhead protector member 26. The enlarged end of the access drill guide tube is releasably sealed to the top of the Wellhead protector in any suitable manner, and water contained within the temporary access tube 38 and the drive pipe 24 is pumped out at the surface. Thus, there is established a sealed guiding tube means from the point of the underwater well to above the surface of the water so that item 24 may be welded to item 26 and drilling operations may be carried out in a noncorrosive environment contained within the guide tube means. Further, there is provided an easy access for non-diving personnel to be lowered down to the level of a wellhead, thereby eliminating the usual expense and delay in using divers for wellhead work.

The drilling operation is carried on in any conventional manner and the particular drilling apparatus utilized forms no part of this invention. Normally a string of drilling elements are lowered to the drilling site and caused to penetrate the earth to the desired level for obtaining petroleum products or other products from the earth. When the drilling has been completed, and casing strings run in and cemented, a Wellhead 40 can be lowered into the wellhead protector 26 for coupling to the drill tubes which are established in the well. The wellhead is attached in any known way, to seal the top of the Well and to provide a controlled removal of products from the well. The wellhead 40 includes the usual Christmas tree attachments, and these attachments provide valving and pressure control means to control the release of fluids from the well. As mentioned above, a substantial benefit is obtained in being able to lower non-diving personnel through the temporary access tube 38 for carrying out all of the work functions in setting up a well head within the underwater casing 26. A production line 42 is shown in the drawings as passing through the wall of the wellhead protector 26, and this production line may be continued along the ocean floor to a receiving station on shore, or the line may be extended to the surface of the water for conveying products to a barge or other reservoir device near the surface. Of course, in a winter climate where a substantial ice cap is formed over the surface of the water, the production line must stay below the ice cap and will most likely be run along the ocean floor to a suitable receiving point. The production line 42 is connected to the wellhead in a conventional manner to receive products fro-m the well, and a plurality of flow lines 42 from a plurality of wellheads may be connected to a single flow line serving the entire platform production.

After a wellhead is positioned within the wellhead protector 26 and the well has been brought into an operational status, the well access tube 38 is removed from the upper end of the wellhead protector 26. Prior to removing the well access tube 3-8, a sealing plate may be lowered into the top of the wellhead protector so as to seal the protector from the entry of water when the upper guide tube is removed. Such methods for sealing underwater wellhead casings are well known in the art, and do not form a part of this invention. Upon removal of the temporary access tube 38, the drilling rig may then be brought into position for drilling a subsequent well through any of the other positions, as determined by the remaining guide sleeves within the template structure. The temporary wellhead access tube 38 may be lowered over another wellhead protector sleeve 26, and the drilling operation is resumed at the new location, as described above. Drillings may be continued until a plurality of wells are established through a single template structure, and each template structure provides a platform upon which a plurality of wellheads are positioned and protected for carrying oil the products of a producing well. When the desired number of wellheads are established in a particular template unit, control line connecting means are coupled between the various wellheads and a central control line access tube 32 which is permanently positioned in the template structure so that control functions may be carried on from above the surface of the water. A surface station 44 is installed at the above-water end of the control line access tube 32 after all drilling operations have been completed and the drill barge is ready for moving to another drilling site. The control station 44 includes suitable electrical or hydraulic control devices for actuating the various valves and other accessories associated with each of the below-water wellheads. The control lines pass downwardly through the central access tube 32 and are connected to coupling members 46 at the below-water level of each wellhead by coupling means which will be described later with reference to FIGURES 5 and 6.

As mentioned above, the control line access tube 32 is normally placed in the template structure only after it is determined that at least one Well will be successful. After establishing a first successful well, the control line access tube 3-2 may be immediately installed, and then subsequent wells may be drilled at a later time. The control line access tube is lowered from the drilling barge down to the template structure and through a central guide portion of the template. The control line access tube 32 provides for a centrally located tube through which control lines may be connected from a surface station to each underwater wellhead contained within the wellhead protectors '26. The control line access tube 32 is guided through the template structure by upper and

lower guide sleeves

34 and 36 respectively. These latter sleeves are rigidly aflixed in axial alignment with each other in the center of the template structure so as to guide the central access tube 32 through the vertical center of the template structure. The central access tube is lowered until it contacts the ocean floor, and fluid pressure is then applied through the center of the hollow tube to jet material away from the lower end. The tube is thus embedded downwardly into the ocean floor. Alternatively, the tube 32 may be drilled into position if the ocean floor formation is too hard for a fluid jetting action. The penetration of the central access tube 32 may be limited to approximately 20 feet or whatever length is necessary to aid in stabilizing the tube and the template structure relative to each other. Initially, the central access tube 32 has no control station at its upper end, and that end merely projects out of the water, as shown in FIGURE 1, during the drilling operations. The upper portion of the control line access tube 32 is constructed of material having sufiicient strength to withstand the crushing forces of ice which may be encountered in the particular offshore drilling site. It has been found that acceptable dimensions for the access tube include a three-foot diameter at its upper extremity which tapers outwardly to a large diameter of approximately six feet at its lower end. These dimensions, however, are only by way of example and any other suitable dimensions may be used.

As shown in detail in FIGURES 5 and 6, coupling members are provided on the casings of each wellhead protector 26 so as to be in alignment with the coupling members 46 in the casing of the control line access tube 32. In the FIGURE 5 embodiment, a connection is made between the wellhead 40 and the surface station 44 by the jumper line 48. The jumper line includes male coupling members at both of its terminal ends which can be received in the female couplers 46 positioned on each of the casings to be connected. The female couplers on the Wellhead and central access tube include lock members 50 which may be brought into locking engagement with the male members of the jumper line 48. In this embodiment it is necessary for a diver to go to the underwater level of the wellhead in order to make the actual connection between respective wellheads and the central access tube 32.

In the FIGURE 6 embodiment, a remotely actuated coupling means is provided for making the connection of a jumper line 48 between the wellhead protector 26 and the control line access tube 32. The coupling means is in the form of a sled 52 mounted on a track 54 which is rigidly carried by the control line access tube 32. The sled and track are positioned at a level on the control line access tube which will place a jumper line 48 in alignment for connection to a coupler on the wellhead protector 26. The sled may be hydraulically actuated by means of the hydraulic cylinder 56, and control lines 58 may lead to the surface for providing an actuation of the hydraulic cylinder 56. The remotely actuated coupling means includes guidance prongs 60 which may be two in number and which are afiixed to outer surface of the wellhead protector 26 so as to receive a sleeve member 62 carried by the sled 52. The guidance prongs and the sleeves serve to align the male plug member 64 into correct position relative to the female coupler 66 so that a precise and positive coupling can be made by the remotely actuated control device. An alternate to the system shown in FIG- URES 5 and 6 would consist of installing a flanged and bolted personnel and equipment access tube between the tube 32 and the casing 26.

In the enlarged cross-sectional views of the wellhead protectors 26, as shown in FIGURES 5 and 6, the wellhead can be seen in its position within the protector casing. Each wellhead includes a plurality of valves 68 which control separate producing levels of the well. The wellhead is fitted at its lower end into the hanger member 70 which provides for a better positioning and sealing of the wellhead within the wellhead protector 26. The hanger 70 is installed in a wellhead protector 26 after a drive pipe has been installed through that protector and its associated guide sleeve 22. The wellheads are shown in schematic form and it is to be understood that each wellhead includes additional accessories and connections, as are well known in the art.

Although this invention has been described with reference to a single embodiment, it will be appreciated that many variations are possible which are within the scope of the invention. For example, the template structure may be placed on an underwater floor without being anchored to the floor, if the underwater conditions permit such usage. Additionally, it is contemplated that a greater or lesser number of guide means may be incorporated in a single template structure, and four guide means have been shown by way of example only. The template could also consist of a submerged barge type structure utilizing the drill pipes 24 as anchors for the submerged device. The control devices associated with individual producing wellheads may be actuated electrically or hydraulically from the surface control station. It is further contemplated that where hydraulic control means are utilized between the surface station and the individual wellheads, the hydraulic system may be adapted to carry control fluid down to the wellhead and to carry fluid products back to the surface. An electrical system would necessarily be limited to control functions only. Also, it is apparent that the central access tube 32 may be used for drilling a well, if conditions warrant such a use. These and other variations will become apparent to those skilled in the art and are intended to be covered by the scope of this invention.

What is claimed is:

1. A template structure for use in underwater well drilling operations and for supporting submerged devices associated with a producing well comprising:

a guide and support frame structure for anchoring to an underwater floor at a drilling site, guide sleeve means connected to said frame for guiding drive pipe means into the drilling site from a drilling rig located above the surface of the water,

wellhead protector means carried by said frame for encasing and supporting wellhead means of a completed producing well, and

a rigid control line access tube carried by said frame and communicating between the frame and the surface of the water, whereby control lines may be connected between the wellhead means and a surface station for remotely controlling well operations.

2. The template structure of claim 1 wherein said wellhead protector means are carried by said frame at a level above the underwater floor and below the water surface.

3. The template structure of claim 1 and including connecting means for connecting control lines within said control line access tube to actuate devices associated with said wellhead means.

4. The template structure of claim 1 and including access tube means which can be temporarily connected between said wellhead protector means and the surface of the water for providing a passageway for nondiving personnel to a wellhead for servicing the same.

5. The template structure of claim 4 wherein a single rigid control line access tube services a plurality of wellheads carried by said template structure and wherein said control line access tube is carried by said frame in a centralized position relative to the plurality of wellheads.

6. An underwater well apparatus for guiding underwater drilling operations and for supporting submerged devices associated with a producing well comprising:

a template structure for placement on an underwater floor at a drilling site, drive pipe means connectable to said template structure for guiding drilling means to the drilling site,

access tube means which can be temporarily connected between the surface of the water and said drive pipe means for providing a passageway for nondivin personnel into said access tube means and said drive pipe means for establishing and servicing a wellhead at an underwater level, and

a control line access tube carried by said template structure for forming a communication path between said template structure and the surface of the water, whereby control lines may be connected between the wellhead means and a surface station so that well operations may be remotely controlled from the surface station.

7. The template structure of claim 6 and including connecting means for connecting control lines within said control line access tube to control devices associated with said wellhead means.

8. The underwater Well apparatus of claim 7 wherein a single control line access tube services a plurality of wellheads placed within said plurality of wellhead protector means, said control line access tube being carried by said frame structure in a centralized position relative to the plurality of wellheads.

9. An underwater well apparatus for guiding underwater drilling operations and for supporting submerged devices associated with at producing well, comprising:

a template structure for placement on an underwater floor at a drilling site, said template structure having:

a frame structure having a base portion and an upper portion,

guide sleeve means positioned in said base portion for receiving drilling apparatus, and wellhead protector means carried by the upper portion of said frame for encasing and supporting wellhead means of a completed well, said wellhead protect-or means being positioned in axial alignment with said guide sleeve means, drive pipe means connectable to said template structure for guiding drilling means to the drilling site,

access tube means which can be temporarily connected between the surface of the water and said drive pipe means for providing a passageway for non-diving personnel into said access tube means and said drive pipe means for establishing and servicing a wellhead at an underwater level. 10. The underwater well apparatus of claim 9 wherein said frame structure includes a plurality of said guide sleeve means positioned in spaced relationship about the base portion of the frame structure for receiving drilling apparatus at a plurality of drilling positions, and a plurality of wellhead protector means corresponding to the number of said plurality of guide means with each of said wellhead protector means being in axial alignment with a guide means, whereby a plurality of drive pipe means and access tube means can be arranged in alignment with said plurality of guide sleeve means so that a plurality of wells can be drilled and established for production within a single template structure.

11. A method for drilling an underwater well and for installing operational underwater wellheads which can be controlled remotely from above the surface of the water, comprising the steps of:

placing a template structure at the underwater drilling site for locating at least one drilling position, guiding a drive pipe and a wellhead access tube through said template to establish a communication between the surface of the water and the underwater floor,

passing drilling means through said drive pipe and wellhead access tube for drilling a well into the underwater floor at the drilling position,

placing a wellhead within a wellhead protector casing located at an intermediate level between the surface of the water and the underwater floor,

connecting remotely actuated control devices to said wellhead for controlling production of the well, removing the wellhead access tube after the well has been made operational, and

placing a control line access tube in said template for providing a communication between control devices of the wellhead and the surface, whereby said control devices may be actuated remotely from a position above water.

12. The method of claim 11 wherein a plurality of wellheads and well positions are established through the template structure and including the step of placing each of the plurality of wells in communication with a single access tube to the surface, for actuating all control devices through the single access tube.

13. A method for drilling an underwater well and for installing operational underwater wellheads which can be controlled remotely from above the surface of the water, comprising the steps of:

floating a barge to an offshore drilling site,

lowering a template structure from the barge into the water and down to the drilling site, establishing a drive pipe and a wellhead access tube through said template structure and to the surface of the water to form a rigid communication between the surface of the water and the underwater floor,

dewatering the combined drive pipe and wellhead access tube,

passin drilling means through said combined pipe and tube for drilling a well into the underwater fioor,

placing a wellhead within a wellhead protector casing at an intermediate level between the surface of the water and the underwater floor, and

removing the wellhead access tube above the position of the wellhead, after the well has been made operational, so that no part of the wellhead access tube will protrude up to the surface level of the water.

14. The method of claim 13 and including the step of:

placing a control line access tube between the template structure and the surface of the water for providing a communication between wellhead control devices and a surface control station.

References Cited UNITED STATES PATENTS 1,900,163 3/1933 Dana et a1. 1759 2,684,575 7/1954 Pryor et a1 175-8 X 2,854,215 9/1958 Cox et al 166.5 X 2,965,174 12/1960 Haeber 175-8 2,970,646 2/1961 Knapp et al 166-.5 2,938,144 6/1961 Conrad 166.5 3,004,612 10/1961 Kofahl 166-.5 X 3,196,958 7/1965 Travers et al. 166-.5 X 3,202,216 8/1965 Watts ct al 166.6

CHARLES E. OCONNELL, Primary Examiner.

30 R. E. FAVREAU, Assistant Examiner.

Claims

1. A TEMPLATE STRUCTURE FOR USE IN UNDERWATER WELL DRILLING OPERATIONS AND FOR SUPPORTING SUBMERGED DEVICES ASSOCIATED WITH A PRODUCING WELL COMPRISING: A GUIDE AND SUPPORT FRAME STRUCTURE FOR ANCHORING TO AN UNDERWATER FLOOR AT A DRILLING SITE, GUIDE SLEEVE MEANS CONNECTED TO SAID FRAME FOR GUIDING DRIVE PIPE MEANS INTO THE DRILLING SITE FROM A DRILLING RIG LOCATED ABOVE THE SURFACE OF THE WATER. WELLHEAD PROTECTOR MEANS CARRIED BY SAID FRAME FOR ENCASING AND SUPPORTING WELLHEAD MEANS OF A COMPLETED PRODUCING WELL, AND A RIGID CONTROL LINE ACCESS TUBE CARRIED BY SAID FRAME AND COMMUNICATING BETWEEN THE FRAME AND THE SURFACE OF THE WATER, WHEREBY CONTROL LINES MAY BE CONNECTED BETWEEN THE WELLHEAD MEANS AND A SURFACE STATION FOR REMOTELY CONTROLLING WELL OPERATIONS.