US3366173A - Subsea production system - Google Patents

Description

Jan. 30, 1968 D. F. J. MCINTOSH 3,366,173

SUBSEA PRODUCTION SYSTEM Filed Sept. 29, 1965 4 Sheets-Sheet 1 SATELLlTE CASING CONTAINING a {g WELL- SATELLITE LINES SUBMERGED INVENTOR.

DONALD F. J. MEINTOSH Jan. 30, 1968 D. F. J. M INTOSH SUBSEA PRODUCTION SYSTEM 4 Sheets-Sheet 2 Filed Sept. 29, 1965 EOPPOQ mm @N A on o m P2 On MEDJIE 29w mmtsok oz zzOo wmz] mm:

INVENTOR.

DONALD F. J. MQINTOSH BY a e/W Jan. 30, 1968 D. F. J. M INTOSH 3,356,173

SUBSEA PRODUCTION SYSTEM Filed Sept. 29, 1965 4 Sheets-Sheet 5 H2 SUMP OVERFLOW I841 WET GAS OILQ 61. GAS

86 INTEGATING GAS M TER INVENTOR DONALD E J. MEINTOSH BY M D. F. J. M INTOSH SUBSEA PRODUCTION SYSTEM Jan. 30, 1968 4 Sheets-Sheet 4 Filed Sept. 29, 1965 mi i INVENTOR DONALD F.J. MEINTOSH By 0J0 flpwf I mmnmmmaa 7 NM muqumzm O... xudFm mm United States Patent 3,366,173 SUBSEA PRQDUCTION SYSTEM Donald F. J. McIntosh, Ventura County, Calif., assignor to Mobil Oil Corporation, a corporation of New York Filed Sept. 29, 1965, Ser. No. 491,265 29 Claims. (Cl. 166-.5)

ABSTRACT OF THE DISCLOSURE This specification discloses a subsea production system having spaced submerged wellheads, and a central submerged satellite supported by and rigidly fixed in the marine bottom. A conning tower is shown for permitting a man to reach the satellite from above the surface. The satellite contains production equipment such as grouptest separator apparatus through which the fluid products from subaqueous wells flow from the submerged wellheads. The well control valves on the various submerged wellheads are controlled from the satellite in response to the flow of fluid products through the respective wellheads.

The invention relates to the production of subaqueous fluid minerals through a subsea production system, having a central satellite anchored beneath the surface of a body of water at a site of a plurality of subaqueous wells. Particularly, the invention relates to a production satellite to be located beneath the surface of a body of water, and having a conning tower extending between the surface and the submerged satellite.

Present developments in the offshore industries indicate that production elforts for the recovery of subaqueous deposits of fluid minerals, such as oil and gas, will be extended to underwater areas where bottom-supported permanent surface installations are neither as economically nor technologically feasible as they are in the Gulf of Mexico where most of the experience with offshore completion has previously been obtained. One of these areas is the Arctic, particularly Cook Inlet, Alaska, where a bottom-supported permanent surface installation must be built to withstand the tremendous loading of ice that forms on any above-surface structure most of the year. While any, at least partially, above-surface production platform is subject to the mercy of the winds and waves, particularly to hurricanes and other violent storms, in areas such as Cook Inlet, these stresses are compounded by the ice loading. The problem is further compounded by the fact that the tides are extremely high in the northern latitudes and the force of the water, tending to lift the ice formed on the legs of the platform, could conceivably tear the anchoring means therefor completely out of the sea bottom. Even when such adverse conditions are not present it usually is advisable to shelter as much of the production equipment as possible beneath the surface of the sea. The term sea is used here to denote the body of water in which the satellite system is used; it is meant to encompass any open ocean, coastal, or inland submerged land area. If economically feasible, such design would be used even in sheltered bay and large lakes, such as Lake Maracaibo in Venezuela.

The reason that the production equipment is not sheltered on the bottom more often is that there are certain problems associated with servicing production equipment beneath the surf-ace, where a man cannot Work efliciently, if he must be encumbered by a diving suit. Robotic and remote control TFL (through flowline) tools have been developed for handling maintenance problems in these situations, but these maintenance and servicing devices, at this point, can only handle simple chores and the cost of maintaining these devices, themselves, is also quite high. In particularly muddied waters, television for a robot cannot even function, and therefore the necessary 3,366,173 Patented Jan. 30, 1968 maintenance of the equipment is even more restricted. Furthermore, if the equipment is left open under water, the abundant marine life will quickly cover it and possibly cause damage while the corrosive salt water environment is also not conducive to long equipment life.

Accordingly, it is an object of this invention to provide a subsea system for handling the production of a number of subaqueous wells through a submerged satellite at an offshore site.

It is another object of the invention to provide a submerged satellite which may be serviced without a diver.

It is a further object of this invention to provide a submerged satellite having a conning tower for transporting personnel between the surface and the interior of the satellite.

Other objects and advantages of this invention will become readily apparent from the following description when taken in conjunction with the accompanying drawings and illustrated useful embodiments in accordance with this invention:

FIGURE 1 is a plan view of the subsea system of the present invention showing a circular configuration of subaqueous wells and their interconnection with a central submerged satellite;

FIGURE 2 is an elevational view of the subsea system illustrating the working over of a well through the submerged satellite;

FIGURE 3 is a diagrammatic plan view of the interior of the submerged satellite showing the placement of the production apparatus therein; and

FIGURE 4 is a cross-sectional elevational view through the submerged satellite, and one of the wellheads, illustrating in particular the interconnections therebetween.

The satellite, of the present invention, is a watertight pressure-resistant vessel installed beneath the surface of the sea. It consists of a fabricated shell of the shape and design adequate to withstand the hydrostatic head of the water depth which is intended to be installed. Although other shapes could prove adequate under particular conditions, a spherical satellite shell and a cylindrical conning tower are illustrated in the drawings.

The submerged satellite is situated at approximately the center of a ring of subaqueous wells which have been completed at the sea bottom with their wellheads spaced several feet above the mudline. Production lines, workover circulation lines, gas lift lines, and hydraulic control lines for actuating valves on the wellhead connect the satellite with each of the wells. The spherical body of the satellite lies beneath the turbulent area near the surface of the body of water, mounted on a submerged bottomsupported platform base consisting of a number of elongated, substantially vertical, legs interconnected by an open network of bracing. (The minimum depth of the satellite may also be determined by Coast Guard Regulations.) Each of the legs is locked, by a two-way releasable slip, within a tubular piling anchored in the sea bottom. The conning tower, large enough in diameter for a man to gain access to the satellite therethr-ough, extends from the upper end of the satellite to a point above the surface of the water.

The main functions of the conning tower are to transport personnel and provide a means of extending certain flowlines to a point above the surface of the water, e.g., workover circulating line, air intake and discharge lines, line for waste fluids, and stack line for gas separator relief valves. As a safety feature, the conning tower would include a section designed to fail first should it be severely encumbered by external forces. This section would be located at a point above a pressure hatch into the spherical satellite shell. This design feature would simply provide a fail-safe measure to save the satellite equipment should the conning tower be rammed by a ship. In severe weather areas such as Cook Inlet, it is conceivable that a detachable conning tower could be designed to meet local conditions which could be removed during periods when ice flow would cause damage. The normal conning tower design would include sections of flexible pressure hose for all flowlines affixed thereto in the region of the fail section to avoid dislocations to permanent piping below this point, should failure occur.

The satellite is installed by first setting a piling tem plate on the bottom at the point directly beneath where the satellite will be positioned. Hollow tubular pilings are placed in drilled holes through a circular configuration in the template and the piling is anchored in place by cementing the piling at a point below the overburden using conventional oil field techniques similar to that used for drilling in and cementing oil well surface pipe, or anchor holes drilled for anchoring drilling barges. The satellite is then towed to the site, suspended from a floating crane barge and lowered with its legs vertically oriented so they may be inserted into the hollow piles and be locked in place by releasable slips aflixed to each leg. Individual setting mechanisms for actuating the slips are accomplished by a rotating shaft extending upward within the tubular legs to a point within the satellite. The actuating mechanisms can be either manually operated or power assisted.

The circular configuration of Wells is drilled directionally to group the wellheads therefor closely around the satellite, while allowing subaqueous fluid minerals to be produced from widely designated areas of subaqueous mineral-bearing formations therebeneath. Particularly in connection with underwater operations, it is advantageous to use directional drilling, to downwardly diverge the subaqueous wells, and group the wellheads close together to avoid the additional cost of laying long subsea lines between the satellite and the individual wells. The term fluid minerals, for purposes of this discussion, is to be construed broadly and is intended to encompass minerals in slurries and any other similar states of matter that may be transported up through a production passage of a well and/or through flowlines. The vulnerability of the flow and well control lines also dictates that they should be as short as possible. An added advantage is then, when drilling from a bottom-supported structure, the additional cost of drilling directional wells would be less than that of moving the platform. Grouping the submerged wellheads will also reduce future well maintenance and workover costs.

The interior of the satellite is fitted with equipment to perform the normal production functions, such as periodically gauging production of the individual wells, separating produced gas and oil, boosting the pressure of the produced oil so that it can be transported from the satellite to central production facilities for storage, distributing artificial lifting energy from the central production facilities to the individual wells, supplying gas or water for injection into the reservoir, and the remotely controlling, as Well as adjusting of, and performing minor repair operations on the individual wells. Most of the equipment installed to perform these various functions will be similar to that used in conventional onshore operations, with necessary modifications, miniaturization, and automation to adapt the system to the limited confines and unattended operation of the submerged satellite. The satellite is connected, by the necessary pipelines, power lines, and communication cables, to the central production facilities to ship the produced oil and gas, and transmitting control and information data to the central production facilities, and for receiving from the central production facilities the necessary control information, electrical power, and artificial lift energy, when necessary.

More particularly, the satellite of the present invention is designed to carry out most of the functions that would require a diver in conventional completions. All the pertinent wellhead valves are controlled from within the satellite shell so that they may be opened or closed by personnel therewithin. A permanently connected circulation return line from each well annulus is one of the special features of this system. This device together with the permanently installed BOP (blowout preventer) on the wellhead, will greatly facilitate the speed, economy, and safety at which workovers may be performed. Most wells, in the early part of their life, require blowout control when worked on. The proposed facility would greatly reduce high cost boat and crew time that would otherwise be spent installing the required equipment temporarily.

For working over a well, once a service or workover boat is anchored over the well and contact made with the well by guide-lines installed during the original drilling of the well, the production of the well is shut olf at the tubing, the gas lift, if any, is shut off at the annulus, and the workover circulation return line is opened, all by the operator within the satellite. The well cover is lifted up by the workover boat and the drill-tubing string is stabbed in and made up to a connection on top of the production tubing to establish circulation. The upper end of the workover return line, at the upper end of the conning tower, is connected to the mud tanks on the boat so that circulation can be established and the circulated material can be re-used. All this may be accomplished without a diver and without unflanging any part of the wellhead which might be highly risky on a medium or high pressure well.

A waste collection vessel could also be anchored nearby to remove the accumulation of waste oil wax, well water, and other waste materials that might from time to time be collected in the sump of the satellite. The waste material is pumped to the surface through a.connection with the return circulation line or a separate line.

Looking at FIGURE 1, a submerged production satellite, generally designated 10, is centered within a plurality of subaqueous wells 14. The wells 14 extend in a circular pattern around the satellite and are connected therewith by casings 16 each carrying the necessary lines for controlling the wells 14 and removing the produced products therefrom. Shipping lines 18 are connected between the satellite 10 and production storage facilities (not shown) some distance away.

As shown in FIGURE 2, the satellite 10 is supported above the bottom on a platform base 20 consisting of four tubular columns 22 and an open network of triangulated trusses 24. The lower end of each of the columns 22 is held within a piling 26 anchored in the sea bottom and forms an integral of a piling template 27. The columns are prevented from dropping too far into the pilings 26 by stop rings 29 welded around the lower ends of each of the columns 22 and are held in the piles 26 by means of releasable slips 28. Actuating rods 30 for releasing the slips 28 are located inside of the columns 22 and extend upward into the interior of the satellite.

A cylindrical tubular element or conning tower 32 is vertically mounted atop the spherical satellite 10 and is braced by four substantially triangular gussets 34. A landing facility, comprising a doughnut-shaped lightweight cork landing base 36, encircles the upper end of the conning tower, floating on the surface of the water to facilitate entry from a boat or helicopter. A ladder 38, mounted on the side of the conning tower 32, extends from the lowest point at which the cork landing base 36 will float to a hatch 40 at the upper end of the conning tower. An emergency hatch 41 (see FIGURE 4) at the base of the conning tower (see FIGURE 4) can be sealed to resist the full pressure of the water at the depth at which the satellite is anchored.

Each of the subaqueous wells 14 has a submerged wellhead 44 and a wellhead cover 45 aflixed thereto adjacent the sea bottom. A locating or marking buoy 46 floats above each well 14, during production (FIGURE 2, the right side), and is moored by guidelines 48 connected at their lower ends to a well base structure 47 lying on the bottom beneath the wellhead 44. When a workover boat 58 is located over a well 14 (FIGURE 2, at the left side), the guidelines are connected through a Working well 59 of the boat 58 to guide a workover drill-tubing 60 and releasable left-hand tubing connector 61 into the wellhead 44 after the wellhead cover is removed.

The inner end of'each of the tubular casings 16, connecting the wellheads 44 of the wells 14 with the satllite 10, is supported on the legs of the platform base 20 so as to reach the satellite, some of the lines in each casing 16 entering by a watertight connection midway up the sphere. A workover return circulation line 50 contained within the casing 16 does not enter the shell of the satellite 10, but instead connects to a manifold 51 encircling the upper end thereof. A main workover return line 52 is connected to the workover manifold 51 and is supported along its vertical path, to a point above the surface of the water, by the conning tower 32 terminating in a shut-off valve 53 above the landing base 36. When the well 14' is worked over, the main workover line 52 is connected to the workover boat 58, anchored over the wellhead 44' of the well 14', by means of a floating line 54 carried on the surface of the water by buoys 56.

FIGURES 3 and 4 show the interior of the satellite, diagrammatically illustrating the placement of the production apparatus therewithin. As shown in FIGURE 3, each of the wells is tied into a test manifold 62 and a group manifold 64 by a three-way, two-position valve 66, which, in a first position, connects the production line 68 from the particular well 14 to a group separator 70 through the group manifold 64 and a group separator input line 72. In a second position of the three-way valve 66, a test separator 74 is operatively connected to the production line 68 through the test manifold 62 and a test separator input line 76. A gas lift line 78 extends from the production facility to the interior of the satellite where it is connected by a manifold 80 and individual gas lift lnes 82 to supply gas lift to the annuli of any of the wells 14 in which it is needed.

The test and group separators 74 and 70, respectively, each has gas and oil output lines. The production output gas line 83 of the test separator 74 is connected to a gas shipping line 84 through an integrating gas meter 86 and a regulator 88. The production output gas line 90 from the group separator 70 is also connected to the gas shipping line 84 through a regulator 92. The oil output line 94 from the test separator 74, containing an integrating oil meter 96, and the oil output line 98, from the group separator 70, are connected to a main oil output line 100. A pair of oil output pumps 102 are connected between the main oil output line 100 and the oil shipping line 104 to boost the output oil pressure, if it becomes necessary. Manually operated lines 106 extend from the bottom of each of the separators 70 and 74 to drain accumulated wastes into a sump 108 beneath the production equipment. A pump 110 in the sump 108 has a waste shipping line 112 extending therefrom to the surface to be connected to a waste collection vessel. The sump 108 is large enough for emergency drainage problems and for overhauling equipment. A fluid pressure accumulator 114, kept at the required pressure by an accompanying electric pump 115, an electric power panel 116, and an electronic programming and data storage panel 118 are also contained within the shell of the satellite 10. A ladder 120 (see FIGURE 3) extends down into the center of the satellite 10 from the conning tower 32.

As seen in FIGURE 4, the conning tower 32 has functions beyond that of being a means for protecting personnel in transit between the satellite 10 and the landing base 36. A stack 122, connected to the outlet of a safety relief valve 124 atop the test separator 74, is attached to the outside of the conning tower 32 and rises to the surface to relieve excess pressures to the atmosphere outside the satellite 10. The group separator 70 (not shown in this View) is also connected to the stack 122 through a pressure relief valve at its upper end. High velocity air conditioning units consisting of an air input unit 126 and an exhaust unit 128 are connected into the satellite. The air pickup for the unit 126 is attached to the outside of the conning tower 32 and discharges fresh air out through duct 130 at the deck level. The exhaust unit 128 has an air pickup 132 near the ceiling of the shell of the spherical satellite 10 and exhausts through a duct 134 extending up and attached to the outside of the conning tower 32. The ladder 120 (FIGURE 3), within the conning tower 32 depends to a working deck 135 just below the midpoint of the shell of the satellite 10. The working deck 135 is the upper face of a concrete ballast section 137 filling the lower end of the shell. The sump 108 is formed in the ballast section 137 from the deck 135.

The remote controls for one well 14 are shown in schematic form in FIGURE 4. Mounted on the wellhead 44, beneath the removable wellhead cover 45, is a fluid-pressure actuated BOP 136 connected by a hydraulic pressure line 138 to the pressure accumulator 114 and controlled by an actuator valve 140 therefor in the line within the satellite shell. The Well production line 68, connected from the inlet side of the three-way valve 66 to the interior of the production tubing 142 of a well 14, has a control valve 144 on the Wellhead, the control valve 144 being actuated through another hydraulic pressure line 146 also connected to the pressure accumulator 114. The gas lift line 82 connected between the gas lift manifold 80 within the satellite and the annulus of the well 14, within the wellhead 44 thereof, has a control valve 148 therefor on the wellhead 44, being actuated also by a hydraulic pressure line 150 also connected to the pressure accumulator 114. The workover return circulation line 50 is connected to the annulus of the well 14 through a valve 152 on the wellhead, this valve also being controlled by a hydraulic pressure line 154 from the accumulator 114.

A power conduit 156 from the production storage facility connects to the electrical panel and electric transformers 116 within the satellite. From the panel 116 power is distributed to the electronic programming and data storage unit 118 and the various electric motors used for actuating the oil boost pumps 102, the sump pump 110, and the fluid pressure accumulator 114, as well as the air conditioning unit and all other auxiliary electrical equipment. Readout lines 158 and 160 are connected between the integrating gas meter 86 and the oil meter 96, respectively, in the output lines of the test separator 74, and the electronic programming and data storage unit 118. The electronic programming and data storage unit 118 is also connected by output signal control lines 162 to each of the three-way valves 66 and control lines 164 and 166 to adjustable bean valves 168 and 170, respectively, in the gas lift line 82 and the production line 68, respectively, within the shell of the satellite 10. The BOP shut-off valve 140 is connected to the unit 118 by electric signal control line 172. A communication line 174 also interconnects the electronic programming and data storage unit and the production storage facility.

Utilizing the satellite 10 as a central gathering station, the production of all of the subaqueous wells 14 connected thereto is ordinarily directed through the respective production lines 68 into the satellite 10 and from there through the group manifold or header 64. The electronic programming and storage unit controls the three-way, two-position valve 66 in each of the production lines 68 so that each well 14 is singly and sequentially connected to the test separator 74. Therefore, the gas and oil outputs of each of the individual wells are measured, one at a time, by the gas and oil meters 86 and 96, respectively. The flow rates are transmitted through the readout lines 158 and 160 to the electronic programming and data storage unit 118 where the gas-oil ratio is determined and the bean valves 168 and 170 on the gas lift line 82 and the production line 68, respectively, of the well being tested are adjusted to provide a better oil-gas ratio or for other purposes.

When it is desired to work over one of the subaqueous wells, as indicated by the information sent back to the production storage facilities by the electronic programming and data storage unit 118 through the communication line 174, a workover boat 58 is brought over the particular well 14' (as shown in FIGURE 2 at the left), the well being located by means of the buoy 46 and the guidelines 48. With the boat 58 positioned over the well 14, pressure from the accumulator 11.4 is directed by personnel within the satellite 10, through the control lines 150, 146, and 172, to actuate the wellhead valves 148, 144, and the shut-off valve 140, respectively, to cut off the gas lift line 82 and the production line 68, respectively, as well as close the BOP 136. The wellhead cover 45 is removed by a tool suspended from the boat 53 and the tubing string 60 is lowered into the well and made up to the production tubing 142 by the remote left-hand connector 61.

The well 14' can then be controlled by circulating drilling fluids. The circulating fluids are pumped down through the tubing 60 and the production tubing 142, and are returned to the workover boat 58 for reprocessing or disposal by the workover return circulation line 50, manifold 51, the main return line 52 (the valve 53 being open), and the floating line 54. If chokes are to be set or removed, and/or through flowline (TFL) tools are to be inserted into the production tubing, the return lines can serve as reverse pressure lines and fluid pressure can be applied therethrough to drive the choke or tool back out through the tubing 69.

Although in the embodiment shown, the satellite It) is mounted on a platform base 20, this is to illustrate a specific utilization of the system in deep water. For example, in one hundred feet of water a twenty-foot sphere would be mounted fifty-five feet from the bottom so that the conning tower, the weakest portion of the structure, must rise only thirty-five feet to the surface. This thirtyfive feet, in one hundred feet of water, is generally considered to be the zone of greatest turbulence, being most affected by surface wave actions. In one hundred feet of water it would be desirable to use 24-inch or larger anchoring piles extending thirty to forty feet into the bottom. In deeper or shallower water, the turbulent Zones would be of different depths and the conning towers heights, and the positioning of the spherical satellites would vary accordingly. In shallower water, the satellite could rest directly on the bottom. It is a good design practice to hold the length of the conning tower to the depth of the turbulent zone to minimize the cantilever stresses thereon, and provide a fail-safe feature in the conning tower design to protect the main body of the satellite.

Although the present invention has been described in connection with details of the specific embodiments thereof, it is to be understood that such details are not intended to limit the scope of the invention. The terms and expressions employed are used in a descriptive and not a limiting sense and there is no intention of excluding such equivalents in the invention described, as follow in the scope of the claims. Now having described the apparatus herein disclosed, reference should be had to the claims which follow.

What is claimed is:

1. A subsea system for producing fluid minerals from subaqueous deposits through wells provided with submerged wellheads comprising: a production satellite having a watertight pressure-resistant shell with production equipment therewithin, means rigidly fixing said satellite beneath the surface of a body of water, means for providing substantially atmospheric conditions within said satellite shell, a plurality of subaqueous wells whose submerged wellheads at least partially suround said satellite, and means for connecting at least one production passage of each of said submerged wellheads to said production equipment within said satellite shell whereby production process steps may be accomplished simultaneously on the combined production of said wells.

2. The subsea system of claim 1 wherein said means for connecting said production passages of said wellhcads to said production equipment in said satellite comprises tubular lines extending along said bottom of said body of water from said submerged wcllheads to said satellite.

3. The subsea system of claim 1 wherein said wells diverge downwardly to produce said fluid minerals from a large area of a subterranean field beneath said bottom of said body of water.

t. The subsea system of claim 1 wherein said means for providing substantially atmospheric conditions within said shell of said satellite is a conning tower extending substantially vertically from the point of connection with said satellite to a point above said surface of said body of water whereby personnel may enter said satellite without a diving suit.

5. The subsea system of claim 4 in which said satellite is adapted for use in deep water wherein said satellite is rigidly fixed atop a platform structure anchored in said bottom whereby said conning tower can extend to said point above said surface without being so long that it is subject to high cantilever stresses.

6. The subsea system of claim 4 wherein there is a personnel landing facility adjacent said conning tower at the surface of said body of water to assist personnel in entering said satellite from a. boat or helicopter.

7. The subsea system of claim 6 wherein said landing facility comprises a landing base having a central aperture through which the conning tower extends whereby the landing base is always at the surface of the water adjacent said conning tower, facilitating the transfer of personnel to and from said satellite.

8. The subsea system of claim 1 wherein there is means to facilitate circulating fluids through an individual well comprising: a return circulation line connected to the annulus of each well through said wellhead thereof, means for selectively shutting off any fluid flow through said line from said well, means controlled from within said satellite shell for actuating said shut-off means, and conduit means for connecting each of said return circulation lines from the wells in said satellite system with a point above said surface of said body of water whereby a fluid being injected into one of said wellheads from a surface boat can be continuously circulated into the well through the production passage, and out through said annulus and the return circulation line to the mud tank of said boat for re-use.

9. The subsea system of claim 8 wherein said conduit means includes a manifold connected to each of said return circulation lines and an output line, said output line being supported on said satellite shell and said conning tower to transport said fluid gathered in said manifold to a single point above said surface of said body of water.

it). The subsea system of claim 1 wherein said means for connecting said production passage of each of said submerged wellheads to said production equipment within said satellite shell includes a well production shut-off means located at each of said wcllheads for selectively controlling production fiuid flow through the respective one of said wells to said production equipment within said satellite shell, and means controlled from within said satellite shell for actuating said shut-off means.

11. The subsea system of claim it wherein said well production shut-off means is a fluid-pressure actuated device, a continuous source of fluid pressure within said satellite shell, means forming a fluid path between said source of fluid pressure and said fluid-pressure actuated device 011 each of said wellheads, and means within said satellite shell for selectively controlling the application of fluid pressure to said actuating devices at said wellheads through said means forming a fluid path.

12. The subsea system of claim wherein the annuli of each of said wells extending into said respective wellheads are connected to a source of fluid pressure, valve means at said wellhead to vary said fluid pressure, and means controlled from within said satellite shell for selectively actuating said annulus fluid-pressure varying valve means.

13. The subsea system of claim 12 wherein there is a source of fluid pressure within said satelilte, said annulus pressure varying valve means being fluid-pressure actuated, said valve actuating means including a conduit forming a fluid path between said source and each of said annulus pressure varying valve means, means within said satelilte shell for selectively controlling the fluid pressure in said conduit applied to said annulus pressure varying valve means.

14. The subsea system of claim 1 wherein a permanent blowout preventer is mounted on the upper end of said wellhead above said production passage shut-off means, and means controlled from within said satellite shell for actuating said blowout preventer.

15. The subsea system of claim 14 wherein there is a source of continuous fluid pressure located within said satellite shell, said blowout preventer being fluid-pressure actuated, and means Within said satellite shell for selectively controlling said fluid pressure applied to said blowout preventer.

16. The subsea system of claim 1 wherein said production equipment within said satellite shell includes a group separator and a test separator for separating gas, oil, and water outputs of said wells, manifolding for combining, at said satellite, the fluid flow of said wellto-satellite connecting means of said plurality of wells and directing said flow to the inlet of said group separator, means for selectively directing the flow from each of said wells to said test separator, and means for automatically and sequentially actuating said selective directing means for directing the flow from one of said wells at a time to said test separator.

17. The subsea system of claim 16 wherein there are separate shipping lines extending from said satellite for connecting said gas and oil outputs of said separators with at least one facility at a distance from said satellite, and means for combining the oil outputs of said group and test separators and directing said combined oil output into said oil shipping line and for combining the gas outputs of said group and test separators and directing said gas output into said gas shipping line.

18. The subsea system of claim 17 wherein there are means for measuring the separate gas and oil outputs of said test separator and means responsive, at least in part, to said measuring means for regulating the gas-oil ratio and rate of flow of each of said wells.

19. A method of installing the subsea system recited in claim 1 including the following steps:

(a) anchoring said satellite in position beneath said surface of said body of water;

(b) directionally drilling said wells close by said satellite whereby a large subterranean area of a fluid mineral bearing formation can be produced through said satellite without the need for long interconnecting lines between the satellite and said wellheads;

(c) completing said wells beneath the surface of said body of water with said wellheads therefor being near said bottom of said body of water; and

(d) connecting said production passages of each of said wells, within said wellhead thereof, to the production equipment within said satellite and connecting the output of said production equipment within said satellite to storage facilities removed therefrom whereby said produced fluid is processed through said subsea satellite.

20. A subsea system for producing fluid minerals from subaqueous deposits through wells having wellheads located beneath the surface of a body of water comprising a production satellite having a watertight, pressureresistant shell with production equipment therewithin; means for rigidly fixing said satellite shell beneath the surface of a body of water; a wellhead of at least one of said suhaqueous wells located in the body of water outside said satellite shell; and means for connecting at least one production passage of said one of said subaqueous wells, through said wellhead thereof, directly to said production equipment within said satellite shell whereby the produced fluid minerals are first processed within said satellite shell.

21. A subsea system for producing fluid minerals from subaqueous deposits through wells having wellheads located beneath the surface of a body of water as recited in claim 20 wherein there is a plurality of subaqueous wells, each having a wellhead located beneath the surface of the body of water outside of said satellite shell, means for connecting production passages of said plurality of subaqueous wells through the wellheads thereof, respectively, to said production equipment within said satellite shell, a means within said satellite shell for combining one of said minerals produced through said means for connecting production passages of a plurality of subaqueous wells whereby the combined production of said one of said minerals from said plurality of subaqueous wells is processed within said satellite shell.

22. A subsea system for producing fluid minerals from subaqueous deposits through wells having wellheads located beneath the surface of a body of water comprising a production satellite having a watertight, pressureresistant shell with production equipment therewithin; means for rigidly fixing said satellite shell beneath the surface of a body of water; means for connecting at least one production passage of a subaqueous well, through the wellhead thereof, located in the body of water outside of said satellite shell, to said production equipment within said satellite shell to process the produced fluid minerals within said satellite shell; a means including pump means for shipping the processed produced fluids out of said satellite shell.

23. A subsea system for producing fluid minerals from subaqueous deposits through wells having wellheads located beneath the surface of a body of water as recited in claim 22 wherein there is means for connecting production passages of a plurality of a subaqueous wells through the wellheads thereof, respectively, to said production equipment within said satellite shell; means with in said satellite shell for combining the fluid minerals produced through said means for connecting production passages of a plurality of subaqueous wells whereby the combined production of said plurality of subaqueous wells is processed within said satellite shell.

24. A subsea system for producing fluid minerals from subaqueous deposits through wells having wellheads located beneath the surface of a body of water as recited in claim 22 wherein there is a means for providing a lifesustaining atmosphere within said satellite shell.

25. A subsea system for producing fluid minerals from subaqueous deposits through wells provided with wellheads located beneath the surface of a body of water as recited in claim 24 wherein said means for providing substantially atmospheric conditions Within said satellite shell comprises a permanent connection between the interior of said shell and a point above the surface of a body of water.

26. A subsea system for producing fluid minerals from subaqueous deposits through wells provided with wellheads located beneath the surface of a body of water as recited in claim 24 wherein said means for providing substantially atmospheric conditions within said satellite shell comprises a rigid tubular element anchored with respect to the marine bottom and extending vertically upward toward the surface of the overlying body of water.

27. A subsea system for producing fluid minerals from subaqueous deposits through Wells having wellheads located beneath the surface of a body of Water comprising a production satellite having a Watertight, pressureresistant shell with production equipment therewithin said production equipment comprising means for separating said produced fluid minerals into component fluids; means for rigidly fixing said satellite shell beneath the surface of a body of water; and means for connecting at least one production passage of a subaqueous well, through the wellhead thereof, to said production equipment Within said satellite shell whereby the produced fluid minerals are processed within said satellite shell.

28. A subsea system for producing fluid minerals from subaqueous deposits through wells having wellheads located beneath the surface of a body of water as recited in claim 27 wherein said separator comprises means for removing aqueous components from said produced fluid minerals.

29. A subsea system for producing fluid minerals from subaqueous deposits through wells having well- 12 heads located beneath the surface of a body of water as recited in claim 27 wherein said separator comprises means for dividing into separate flow paths liquid and gaseous components of said produced fluid minerals.

References Cited UNITED STATES PATENTS 1,900,163 3/1933 Dana et a1. 1759 2,503,516 4/ 1950 Shrewsbury 175--8 X 2,614,803 10/1952 Wiggins 166.5 2,937,006 5/1960 Thayer 175-8 X 2,965,174 12/1960 Haeber 1758 X 3,004,612 10/1961 Kofahl 175--7 3,064,735 11/1962 Bauer et a1 1666 3,099,316 7/1962 Johnson 166.6 3,111,692 12/1963 Cox 166.5 X 3,221,816 12/1965 Shatto 166.5 3,261,398 7/1966 Haeber 166- 5 20 CHARLES E. OCONNELL, Primary Examiner.

R. E. FAVREAU, Assistant Examiner.

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