US2608829A

US2608829A - Portable marine foundation

Info

Publication number: US2608829A
Application number: US17903A
Authority: US
Inventors: Richard P Knapp
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1948-03-30
Filing date: 1948-03-30
Publication date: 1952-09-02
Anticipated expiration: 1969-09-02

Description

Sept. 2, 1952 R KNAPP 2,608,829

PORTABLE MARINE FOUNDATION Filed March 30, 1948 4 Sheets-Sheet l Richard P Knapp Savant/or Clbbornag P 2, 1952 R. P. KNAPP 2,608,829

PORTABLE MARINE FOUNDATION Filed March 30, 1948 4 Sheets-Sheet 2 Richard P. Knapp {Saverzbor b a W Clbbcr'rzeg Sept. 2, 1952 R. P. KNAPP 2,608,829

PORTABLE MARINE FOUNDATION Filed March 30, 1948 4 Sheecs-Shea-z-t 5 W, lll

Etc/Bard PKHGPP Sax embarsmcltborneg Patented Sept. 2, 1952 mesne assignments, to Standard Oil Development Company, Elizabeth, N. J a corporation of Delaware Application March so, 1948, serial No. 17,903

The present invention is concerned with an improved movable marine foundation. The invention is especially concerned with an apparatus for drilling oil wells in marine locations and submerged lands which will provide a firm, stable base for the drilling operations and which can be readily transported by floating from one location to another. The invention is more particularly directed to marine foundations adapted to be utilized in conjunction with barge drilling operations. In accordance with the present invention the barge containing conventional rig type drilling equipment is stabilized on the ocean floor employing portable marine pontoons which may be separate from the barge itself or which'may actually comprise an integral part of a multiple section barge.

It is known in the art to utilize barges in moving well drilling rigs from location to location for marine drilling operations. However, the use of the present conventional type drilling barge has been limited to operations in water no deeper than the maximum depth of the barge hull. This limitation is caused by the lack of positive stability when the barge is submerged to the deck level. In operations of this character, it is absolutely essential that the barge have the utmost stability in order to avoid loss of the barge and the entire drilling equipment. At the present time there are several factors, among others, which control the extent to which drilling operations can be conducted under water. In the first place, the present barges can only be submerged to a limited extent. This is due to the fact that as the barge is submerged, the stability of the barge is decreased. For safety factors, it is necessary that this barge stability not go below a certain minimum value. In general, it can be stated that the stability of the submersible drilling barge is a function of the water plane area. Thus the stability of a conventional drilling barge completely disappears upon 100% submersion due to the fact that the water plane area becomes 0. That is to say, the stability becomes negative as the deck is submerged and the water plane area disappears.

An improved barge unit which consists of portable sections and which may comprise an integral part of the barge has been discovered. By utilizing the improved barge of the present invention, it is possible to operate in much deeper water than has heretofore been the case. Furthermore, by employing the present invention, greater stability and safety will be secured. By employing the present invention, it is possible to completely submerge the drilling barge and maintain the desired stability by utilizing therewith the pontoon 1 Claim. (01. e -4c) foundation elements. These submersiblepontoon foundation elements provide the necessary water plane area to give the desired safety factor of stability'in the positioning ofthe barge at the location desired. By employing the barge of the present invention, it is possible to positively control the rate of submersion and the rate of floating. 1 e

The invention may be more readily understood by reference to the drawings illustrating various embodiments of the same. Figs. 1, 2, 3, 4, 5, 6

' and"',7 1,illustrate"the invention wherein adjustable floating sections comprise sections of the multiple barge unit.

Referring specificallyto Fig. 1 which illustrates an adaptation of the invention wherein the floating sections comprisean integral part of a multiple barge section, a working platform 20 and rig 2i are extended above the barge deck level 22 at a height determined by the maximum depth of water and wave amplitude at the operating site. The'end

sections

23 and 24 are aflixed to the center section 22 in such a manner that they-can be rotated 90 about an axis perpendicular to the longitudinal, center line of the structure and are of the proper geometrical shape to permit locking in either the horizontal or. vertical position. When the

end sections

23 and 24 are locked in the horizontal position as illustrated in- Fig. 1, the structure is a sea-going vessel and can be-readily towed to any desired deep water location.

Fig. 2 illustrates the operation of the barge unit shown in Fig. 1. Similar numbers are used iFn Filg. 2 to designate the identical elements of Referring specifically to Fig. 2, the

end sections

23 and 24 are, lockedin the vertical positionand the structure is ready for lowering to the'ocean floor. With proper ballasting, the details of which are well known, the submersible hull can be safely submerged to any depth of water that is within the limitsof the vertical height of

theend sections

23 and 24. During the sinking operation stability is provided by'the end sections 23and 24. These sections must have an adequate water plane area to insure positive stability and be of a heightpgreater than the depths of the waterin which the rig is to be positioned. V I

I Fig. 3 is an end view of the barge in position. on the ocean or marine floor. Elements similar to those of Fig. 1 are designated by the same numers.

After the unit is landed on the marine floor, the entire structure is 'leveledby ballasting the end sections; Forexample, in a preferred adaptation of theinvention, this positioning of the within the limits of the safe load carrying capacity of the ocean floor in that area.

Fig. illustrates the operation of the invention in the refloating step. The structure is floated by the proper removal of ballast from

areas

23 and 24 and 22 after that section reaches the surface to produce a uniform positive buoyant force. Jet action is preferably used to help free the end sections by securing earthen material away from the bearing area. After reaching the surface, the

section 22 may be lifted clear of the water if desired to clear a completed well or other surface obstruction. With the center section 22' afloat the

end sections

23 and 24 are rotated as described by ballasting or jacking into the horizontal position and the structure is ready to be moved'to another location. a

A very desirable method of r-efloatingthe unit is to employ jacking elements 30, illustrated i'n Fig. 4. The section 22 is raised at a controlled rate by the action of jacks in

pontoon elements

23 and 24. This is very desirable since in raising the submersible barge, great care must be exercised. In general, it is absolutely necessary that this unit have a neutral or slightly negative buoyancy.

If the unit should at anytime have a positive buoyancy, the barge would rise rapidly and probably would have either a translation or rotation movement or a combination of these. When it is considered that the derrick may be from about 150 to 250 feet above the barge, it is quite evident that this movement would cause the derrick to buckle and rupture. In other words, rotation with a radius of this magnitude will cause transverse forces of great magnitude which a conventional derrick structure can not withstand. Thus, it is absolutely essential that the buoyancy be a controlled buoyancy. 3

Furthermore, by employing a modification of the invention as illustrated inFig. 4, the jack elements 30 can position barge element 22 atany point with respect to

pontoon elements

23 and 24. Thus, the distance between the marine floor bottom and the element 22* can be regulated to a depth so that the working platform is positioned at any predetermined distance above the surface water in order to avoid-wave action and the like.

Figures 5, 6 and '7 illustrate one method of tions may be either attached or be free of the barge main section carrying the working plat- 4 form and the rig. By employing the invention as pointed out heretofore, it is possible to operate the barge section carrying the working platform and the rig at appreciably greater water depth.

When the barge is submerged and resting on the ocean floor, this structure will be subjected to minor forces of wave action as the greatest portion of the buoyancy compartments are located far below the surface with only the platform supports and the upper limits of the end sections in the area of destructive wave action.

. The working platform is installed at a height sumcient to .clear the waves of maximum amplitude.

The platform supports and end sections can have any desired design or geometrical form to reduce wave action. The barge sections will have the necessary proportions in order to keep the center section at a depth below the surface where wave action is small or substantially nonexistent.

The end sections can be made longer for operations in deeper water and the basic structure is so designed for operation in the minimum depth of water anticipated and thus'will permit operation in limited range of depths abovethe minimum.

An additional desired feature ofthe invention is thatun'der certain circumstances it may be possible to float the center section of the barge containing the working platform independent of the end sections providing'it is found that these .en'd sections cannot. be readily broken loose. The center section and the end sections can be manufactured so that this center section can be detached from the end sections. Thus, as the centerfsectio'n is floated, theendsections may serve as guides as the center section rises. Thecenter section can then be removed from the; area and'the end sections broken loose by any desired or suitable means. After the end sections have been freed from the ocean floor these sections can then be reattached to the barge and the entire unit moved to. the desired new location.

Having described the invention, it is claimed: Marine foundation comprising a structure consisting of an adjustably buoyant hull supporting a working platform, a plurality of hollow pontoon, members'pivotally fixed to said structure, meansto maintain said pontoon members in a first non-verticalposition and a second vertical position, said hollow pontoon. members being'characterized by being trapezoidal in ver-' tical cross-section, said pontoon members being further characterized by a length greater than the depth of the water in whichthe marine foundation. is to be .used, whereby on pivoting said members to the vertical position. and on decreasing the buoyancy of the "hull, the "said memberssupport the working platform above the water level. f I

' RICHARD P. KNAPP...

I REFERENCES CITED The following referencesare of record in the fileof this patent:

UNITED STATES PATENTS Number 2,327,118 MacKnight i Aug-l7, 1943