US3602302A - Oil production system - Google Patents

Abstract

An elongated floating vessel in the form of a large fluid capacity barge has a swivel near the forward end thereof which passes down through the vessel and is securely moored to the water bottom so that the barge may weathervane about the swivel. The barge carries oil production equipment for processing well fluid. A plurality of flexible flow lines extend down through the swivel to connect with a plurality of individual wellheads, or with one or more central manifolds on the water bottom. Servicing of the individual wells is made possible by apparatus on the swivel which allows for selective well testing and selective well access for a full range of pump down tool techniques.

Description

United States Patent [72] Inventor Charles S. Khith Baltimore, Md. [21] Appl. No. 875,350 [22] Filed Nov. 10, 1969 [45] Patented Aug. 31,1971 [73] Assignee Westinghouse Electric Corporation Pittsburgh, Pa.

54 on. PRODUCTION SYSTEM 13 Claims, 12 Drawing Figs.

[52] U.S. Cl 166/.5, 1 14/5 [51] lnt.Cl E21b43/01 [50] Field oiSearch 175/5,7,8;

[56] References Cited UNITED STATES PATENTS 2,699,321 1/1955 Nelson 175/8 3,111,692 11/1963 Cox 175/8 X 3,279,404 10/1966 Richardson 1 14/5 3,335,690 8/1967 Busking 114/230 Primary ExaminerStephen J. Novosad' Assistant Examiner-Richard E. Favreau Attorneys-F. H. Henson, E. P. Klipfel and D. Schron ABSTRACT: An elongated floating vessel in the form of a large fluid capacity barge has a swivel near the forward end thereof which passes down through the vessel and is securely moored to the water bottom so that the barge may weathervane about the swivel.

The barge carries oil production equipment for processing well fluid. A plurality of flexible flow lines extend down through the swivel to connect with a plurality of individual wellheads, or with one or more central manifolds on the water bottom.

Servicing of the individual wells is made possible by apparatus on the swivel which allows for selective well testing and selective well access for a full range of pump down too] techniques.

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011. PRODUCTION SYSTEM BACKGROUND OF THEINVENTION 1. Field of the Invention Offshore floating oil production systems.

2. Description of the Prior Art A major problem in producing oil from underwater fields which lie in deep water is the cost of the bottom supported surface-piercing fixed platforms employed to support the control and treating equipment. Additionally the possibility of earthquakes is a major factor in increased platform costs.

Another major problem in producing oil from underwater fields is that they are sometimes located so far from land that the cost of moving the oil ashore is very high or even prohibitive. The capital and operating costs of any given size of pipeline are direct functions of its length and it is obvious that the length can exceed economic feasibility.

One proposal for eliminating the pipelines contemplates utilization of a floating semisubmersible platform such as in U.S. Pat. No. 3,111,692, having well production and storage facilities and which will be able to stay on station without severely being affected by wave action, due to its unique configuration. An undesirable factor however is that such semisubmersibles are very sensitive to the amount and location of load and are inherently inefficient in their ability to support and enclose a large amount of oil.

It is therefore a primary object of the present invention to provide an economical means of producing oil in remote deep water locations or in near shore areas where it is not desirable to bring the production directly ashore by pipeline.

Storage barges for offshore oil wells have been described which utilize a ship form facility in conjunction with a swivel so that the facility may weathervane to reduce the effect of wave action. U.S. Pat. Nos. 3,335,690 and 3,407,768 describe such structures. In 3,335,690 the swivel is located forwardly of the vessel and presents a dangerous condition for personnel who may have to work on the swivel, particularly in adverse weather conditions. In addition, the very limited workspace provided makes necessary operations to be carried out on the various wells extremely difficult. In 3,407,768 the swivel extends down to a point above the water surface and the structure presents an overhang which in heavy weather is a serious hazard to the ship. The shock and vibration experienced by the vessel in such weather would subject it to severe stresses which might result in catastrophic failure.

The patents illustrate a single hose extending below the surface of the water but the necessary equipment for achieving the aforestated object of the present invention is not disclosed.

A protected swivel is the subject of U.S. Pat. No. 3,279,404, however the swivel is midship and the vessel willnot of itself maintain its head into wind and sea.

U.S. Pat. No. 2,699,321 and page 99 of the July 1968 issue of World Oil each show a craft which has a large diameter spindle extending through the craft with a rigid connection to the bottom such rigid connection being a plurality of tubular metal pilings in the patent, and a 3 or 4 foot diameter steel tube in the article. Such rigid connection, although providing for weathervaning action of the vessel (yaw) and rise and fall of its (heave), permits little or no freedom in pitch, roll, surge, or sway. Since the great mass and waterplane area of the vessel make it virtually impossible completely to restrain these motions, such rigid connection must necessarily be in grave jeopardy when large seas are acting upon the vessel.

None of the related prior art existing or proposed-systems disclose the necessary means for practicing another feature of the present invention. which is the provision interrelationship of various equipment for performing maintenance and test operations on the wells.

SUMMARY OF THE INVENTION An elongated vessel having a swivel near the bow thereof carries oil production equipment and storage tanks for storing large quantities of processed oil. A plurality of flexible fluid lines extend through the swivel and connect with underwater oil wells and at the vessel flow control means are provided for selectively connecting the lines with a testing separator and metering station for testing wells, and a pumping station for delivering and retaining tool strings inserted into selected lines.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a slide elevational view, with portions broken away, of an offshore floating oil production system in accordance with one embodiment of the present invention;

FIG. 2 is a cross-sectional view of the swivel shown in FIG. 1;

FIG. 3 is a top view of the swivel illustrated in FIG. 2;

FIG. 4 is a perspective view of a portion of the swivel illustrated in FIG. 2;

FIG. 5 is a plan view of the apparatus illustrated in FIG. 1;

FIG. 6 is a diagrammatic flow diagram of the apparatus shown in FIG. 1;

FIG. 7 illustrates the arrangement of apparatus for performing certain operations;

FIGS. 7A and 7B are flow diagrams of the apparatus of FIG. -7 in two different modes of operation;

FIG. 8 illustrates another embodiment of the present inventron;

FIG. 9 illustrates the switching network of FIG. 8 in somewhat more detail; and

FIG. 9A is a table of various valve openings for FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 there is illustrated anelongated vessel 10 on station above thewater bottom 12. Thevessel 10 may be in the form of an elongated barge and includes a full compliment of production equipment 14 such as high and low-pressure separators, free-water knockouts, treaters etc. situated on the open deck, and additionally includes a plurality ofstorage tanks 16 connected to receive the output from the production equipment 14'for storing treated crude oil.

Positioned nearthebow 18 and within the boundaries of the vessel is a well 20 extending from thedeck 21 to the bottom 22 ofvessel 10. Positioned within the well 20 is a swivel means in the form ofmooring swivel 24 extending from the deck to below the water surface and held in position by mooring means in the form of a plurality of anchor chains 26 (only two are shown) firmly secured to the water bottom 12 so that the vesselwill weathervane about theswivel 24 to maintain the bow portion headed into the waves and wind. For those conditions where wind and sea are not in agreement, thrustunits 28 are provided at the stern of thevessel 10 and are operable to maintain the vessel on the most favorable heading.

It is preferable that crews living quarters 29 be established forward of theswivel 24 since the vessel always weathervanes into'the wind and the bow may serve as the place of last refuge for the crew in the event of fire.

Flexible hose assemblies 32aid 33 fromunderwater wells 36 and 37 extend up through theswivel 24 to certain apparatus on the swivel. Acrane 40 is provided forward of theswivel 24 to aid in the handling of various pieces of equipment such aslubricator 42, as will be explained.

A more detailed, cross-sectional view of the swivel and part of the vessel, is illustrated in FIG. 2.

Theswivel 24 has alarge diameter tube 25 situated within the well 20 and an upper flange portion forming aswivel platform 47.

Theswivel 24 is rotatably supported by a plurality ofroller units 50 extending from the bottom ofswivel platform 47 to acircular track 51 on thedeck 21. Theswivel 24 is additionally restrained laterally by a set of upper roller units 53 extending between thetube 25 andtrack 54, and a plurality oflower roller'units 57 extending between thetube 25 andtrack 58.

Eachanchor chain 26 extends up through aflange 60 at the bottom of theswivel 24, through theswivel platform 47 and secured thereto at respective securing points 62.

Thehose assembly 32 includes at least a pair of fluid carrying lines in the form ofproduction line 65 andcirculation line 66. Athird line 67 is a control line andmay include power conveying means for actuating valves at the underwater well such means being, for example, hydraulic pneumatic or electrical. Alternatively thecontrol line 67 may be eliminated and the valves controlled automatically in response to coded acoustic signals transmitted through the water medium. Thelines 65, 66 and 67 are held together as a unit by means of aspacer 69 such spacers-being distributed along the length of the assembly.Bouyant materials 70, also disposed along the length of the assembly prevent the assembly from possibly dragging on the water bottom.

The threelines 65, 66 and 67 pass up through a relatively small diametervertical tube 73 within theswivel 24, and are disconnectable by means of ahose assembly connector 75.Production line 65 andcirculation line 66 pass up through asupport 77 positioned on theswivel platform 47.

Hose assembly 33 connected to well 37 is identical tohose assembly 32 in that it contains a plurality of flexible fluid conveying lines such asproduction line 84,circulation line 85 and acontrol line 86, passing up throughvertical tube 88 and being disconnectable by means ofhose assembly connector 90. Thehose assembly 33 includes thespacer 92 andbuoyant material 93 to prevent it from dragging on the water bottom and the assembly passes up throughsupport 95 at the top of theswivel platform 47.

In operation when the wells are producing, and only two are shown for clarity, well fluid, for example from well 36 passes up theproduction line 65 through a first ormaster valve 100, into connecting pipe 102, through a second orwing valve 104 and into a centrally locatedvertical header 107, a header being a tube, chamber or similar structure to which a bank or series of tubes or other connections are joined to permit fluid flow. Suitable flow control units such as chokes may be included but are not shown herein.

Well fluid from well 37 passes up theproduction line 84 to themaster valve 110, through connectingpipe 112 andwing valve 114 into theheader 107, In a similar fashion well fluid from all of the other wells in the field flow intoheader 107 and the comingled well fluid iscarried to the production equipment byproduction hose 116 connected to theheader 107 by means of a rotary pipe joint 1 19,

In order to efficiently produce an oilfield it is necessary to have information about how much oil and gas and water each individual well is producing and at what pressures. On the vessel there is provided a test and metering station which includes a metering separator where the components of the well fluid are separated and individually metered. Accordingly means are provided for selectively controlling fluid flow in individual ones of the fluid lines to place individual wells on test. This means, in the embodiment of FIG. 2, includes anannual header 122 concentrically disposed aboutheader 107, and a plurality of valves for connecting the production line from each well to the annular header. Since theannular header 122 is utilized in test operations it will herein be termed the test header. With respect to well 36 there is providedvalve 124 which when open will divert the flow from connecting pipe 102 into connectingpipe 126 andtest header 122. During suchoperation wing valve 104 would normally be closed.

With respect to well 37, fluid fromproduction line 84 may be diverted from connectingpipe 112 by openingvalve 129 so that produced fluid may enter thetest header 122 by way of connectingpipe 130.Wing valve 114 would normally be closed while the remaining wing valves from the other assemblies would be open such that during testing operations well fluid from only one well is diverted into thetest header 122.

Thetest header 122 communicates with a testing station in a manner to be hereinafter described.

There are many maintenance operations which an oil well may require during its life, such as cleaning paraffin out of the flow line and tubing string in the well, bailing sand, changing various chokes in the system, bottom hole pressure surveys and the installation and removal of production control and safety devices, to name a few. There has been developed a technique for performing these operations by means of various tools which are pumped down through the flow line and returned after accomplishing the desired operation. The present invention provides for the full utilization of this technique by the provision of means for selectively inserting a tool string of one or more units into individual one of the fluid lines, in conjunction with'means for delivering and returning the tool string from the sell. For this purpose, and in the embodiment of FIG. 2, there is provided a plurality of valves on the swivel platform for individually controlling fluid flow in the circulation lines. By way of example and with respect to well 36, thecirculation line 66 includes a first ormaster valve 134, and a second orwing valve 136. When both of these valves are open, and a third or swabbingvalve 138 is closed, fluid communication is established betweencirculation line 66 and a second annular header l40'herein termed the circula tion header and concentrically disposed about theheader 107.

With respect to well 37, fluid flow in circulation line is controlled by afirst valve 142 and asecond valve 144 both of which are operable when open to communicate fluid with thecirculation header 140.

Since the valves at the underwater well may be controlled in a number of different ways including acoustic means, for clarity no particular connections are illustrated for thecontrol lines 67 and 86.

Insertion of a pump down tool string into a fluid line such asproduction line 65 may be accomplished with the provision of alubricator 42. The tool string is inserted into thelubricator 42 which is connected to the production line such as byflange connection 146. Pressure is then applied at the top of the lubricator while swabbingvalve 148 and master valve are open to send the tool string out of the lubricator and past the level ofwing valve 104. If the tool string to be inserted is very long, the valving means at the underwater wellhead can be closed and the entire length of flow line used as a lubricator. By proper connection and selective operation of swabbingvalves 138, 148, 150 and 151, tool strings may be inserted intorespective fluid lines 66, 65, 84 and 85.

Means, including guide or track extending around the periphery of theswivel platform 47, are provided for connecting thetest header 122 andcirculation header 140 to certain equipment on the vessel. Such connections are better illustrated in FIG. 3 which is a plan view of theswivel platform 47 of FIG. 2 with the valves and certain other equipment omitted for clarity. Positioned on the periphery ofswivel platform 47 is a first connecting means such as a rotary pipe joint 159 and a second connecting means such as rotary pipe joint 161.Test header 122 is connected to the rotary pipe joint 159 by means of fluid conveyingconduit 163 andcirculation header 140 is connected to rotary pipe joint 161 by means offluid convening conduit 164.

First and second reels and 171 on the vessel deck haveflexible hoses 173 and 174 coiled thereon and connected respectively to rotary pipe joints 159 and 161. The other end ofhose 173 is connected through a rotary pipe joint tofluid conduit 176 and the other end offlexible hose 174 is connected through a rotary pipe joint tofluid conduit 177. As the vessel pivots about the swivel, for example in FIG. 3 ifswivel platform 47 relatively moves counterclockwise,hoses 173 and 174 will be pulled from their respective reels I70 and 171 and will be placed in the track means 155. Another view of this operation is illustrated in FIG. 5. When theswivel platform 47 relatively moves in aclockwise direction reels 170 and 171 will take up the slack of thehoses 173 and 174. This arrangement provides fluid communication, and prevents entanglement as the vessel rotates about the swivel. The relative rotation may be for a full turn or more depending upon the length ofhose 173 or 174.

Alternatively, and as illustrated in the plan view of FIG. 5,

additional counterpart equipment may be provided on the,

bow side of theswivel platform 47. The additional system components are shown in dotted line and have primed reference numerals. As a typical operation let it be assumed that rotary pipe joint 159 is connected to reel 170 and rotary pipe joint 161 is connected to reel 171. Should the swivel rotate a half turn, the rotary pipe joints 159 and 161 may be connected up torespective reels 170 and 171' by means of suitable valving and connection means not illustrated. Thereafter another half turn in the same direction will bring the rotary pipe joints 159 and 161 into a position to be again connected toreels 170 and 171.

In FIG. 6 there is illustrated a flow diagram for theunderwater well 36, Those components previously described in other figures have been given the same reference numeral. At the upper portion of the figure are the components illustrated in FIG. 2 for selective control of theunderwater well 36. At the lower portion of the figure there is illustrated apile structure 188 secured to thewater bottom 12 and which supports a hose assembly connector 190. Theproduction line 65 extending from the connector 190 over to the well 36 may be in the fonn of steeltubing having curvatures 192 of sufficient radius, for example 5 feet, to enable passage of long tool trains and would lie on the bottom 12.

Thecirculation line 66 on the bottom may similarly be of steel tubing withcurvatures 193 to enable tool train passage.

Theunderwater well 36 includes aChristmas tree 193 with theproduction line 65 being connected with theproduction string 195 by means ofwing valve 197 andmaster valve 198.Circulation line 66 is connected to thecirculation string 200 by means ofwing valve 202 andmaster valve 203.

During operation of the well it may be necessary to perform a certain operation such as the removal of avalve 106 in the production string. The apparatus of the present invention allows such maintenance operation to be performed by the use of conventional pump down tool techniques and to this end reference is now made to FIG. 7.

FIG. 7 illustrates a flow diagram and components already described have been given the same reference numeral.

Onboard apparatus for testing and servicing the various wells includes a test separator andmetering station 210 and a pump andmetering station 212 in conjunction with a plurality ofvalves 214 through 217.

If it is desired to test the well fluid ofunderwater well 36,valves 124 and 214 are open. Well fluid then proceeds fromproduction string 195 toproduction line 65, throughvalve 124 into thetest header 122, out of the test header and intofluid line 176 by way of the rotary pipe joint 159 andflexible hose 173 wound onreel 170. Fromfluid conduit 176 the fluid passes throughvalve 214 and into the test separator andmetering station 210. The well fluid as it emerges from the well is at very high pressures, for example thousands of p.s.i. and the test separator atstation 210 reduces the pressure to atmospheric. After suitable testing the quiescent crude is provided to atank 16 and if it is desired to test other wells,valve 124 may be closed and a similar wing valve associated with another well may be opened to deliver that wells fluid to station 210.

If it is desired to test the well throughcirculation line 66,valves 136 and 217 may be opened to establish fluid flow from thecirculation line 66 intocirculation header 140 through rotary pipe joint 161 andflexible hose 174 to thereel 171 andfluid conduit 177 and into thetest station 210 throughvalve 217.

For maintenance operation where it is required to send a tool string down into theproduction string 195, the arrangement of FIG. 7 may be utilized as shown in FIG. 7A, which for clarity, shows only those conduits and valves involved in the operation.

Lubricator 42 containing a tool string is connected as previously described andvalves 148 and 124 are opened. By suitable means connected to the lubricator the tool string is sent pastvalve 148 which is thereafter closed.Pumping station 212 pumps quiescent crude fromtank 16, throughvalve 215 and intoproduction line 65 behind the tool string, by the path includingfluid conduit 176,flexible hose 173, rotary pipe joint 159,header 122 andvalve 124. A return for the fluid displaced ahead of the tool string is provided by the path includingcirculation line 66,valve 136,circulation header 140, rotary pipe joint 161,flexible hose 174,fluid conduit 177,valve 217, and into thetest station 210 where it is returned to thetank 16.

After performance of the necessary operation, the tool string is returned as illustrated in FIG. 7B.Pumping station 212 pumps the quiescent crude down thecirculation line 66 by thepath including valve 216,fluid conduit 177,flexible hose 174, rotary pipe joint l6l', circulation header andvalve 136. Fluid displaced ahead of the tool string inproduction line 65 is returned to thetesting station 210 by thepath including valve 124,test header 122, rotary pipe joint 159,flexible hose 173,fluid conduit 176 andvalve 214.

The pumpingstation 212 includes metering means for determining the approximate position of the tool in theline 65, since there is a direct relationship between its position and the quantity of quiescent crude pumped.

In addition to test and tool service, the circulatingline 66 could also be used to provide gas to the wells for artificial lift for which purpose there is illustrated a gas lift system 220.

Unloading of thevessel 10 can be accomplished by having a tanker come alongside, special fendering and mooring winches being provided aboard thevessel 10 to prevent metalto-metal contact between the hulls and to maintain good control over the tanker. Alternatively, the tanker could approach from astern and tie to a single mooring line from the stern of thevessel 10 the oil being transferred fromstorage tanks 16 through a floating hose; if the tanker were to go astern slowly on its engine the two hulls need never come in contact. However, for reason of the security of the loading hoses, some shipmasters might prefer the former method which provides for the tanker to be well secured alongside thevessel 10. For those cases where proper handling of the tanker requires that it have ballast water in some of its tanks, pollution of the sea can be avoided by discharging this dirty ballast into special tanks on thevessel 10, which could take the time between unloadingsto treat this water for discharge into the sea. It should be noted that thrustunits 28 would be available for assistance in the mooring operation.

Atypical vessel 10 may have a length in the order of 600 feet with a beam or width of 80 feet and a depth from top deck to the bottom of the vessel of 50 feet. The storage capacity of such vessel may be 300,000 barrels and approximately 16 wells may be serviced by means of the arrangement described. Larger vessels and swivels may accommodate a larger number of wells however there is a point at which practical limitations on the size of the swivel will limit the number of wells which can be accommodated within it. For a greater number of wells, the arrangement of FIG. 8 may be utilized.

In FIG. 8 there is illustrated theswivel 24 within thevessel 10 at the surface and depending from theswivel 24 and extending toward thewater bottom 12 is a plurality of flexiblefluid conveying conduits 224, 225 and 226 with theflexible conduit 224 being a production line,flexible conduit 225 being a test and tool line, andflexible conduit 226 being the circulation line. These flexible conduits are held in spaced relationship by means ofspacers 228 withbuoyant material 229 as previously described.

Positioned on thewater bottom 12 is agathering station 236 which includes alanding base 238 concreted in position within apile 240 in the water bottom.

Mating with thelanding base 238 and being detachably secured thereto is a manifold means 242 which includes acarrier unit 244 having aguide pipe 245 for guiding the unit into its position on thelanding base 238. The manifold means 242 is connected to thelanding base 238 by a plurality ofdetachable connectors 248.

The manifold means 242 includesheader 252 in addition to a plurality of test andtool lines 225a to 225n havingrespective valves 254a to 254n. Eachline 225a to 225;: is connected with theheader 252 by means ofrespective branch lines 2580 to 258n having respective valves 459a to 259n. The test andtool lines 225a to 225n are selectively connectable to test andtool line 225 through aswitching network 261. The manifold means also includes a plurality ofcirculation lines 226a to 226a havingrespective valves 260a to 260n which connect the lines 2260 to 226n with thecirculation line 226.

When thecarrier unit 244 is in mating engagement with thelanding base 238, connections are provided betweenlines 225a to 2251 andrespective lines 225a to 225n' which carry the well fluid from respective wells of which two, 264 and 265, are illustrated. Connection is also made betweenlines 226a to 226:: andlines 226a to 226n' which constitute the circulation lines for the individual wells. The fluid lines extending from the base 238 are suitably valved to allow for detachment of the manifold means 242.

Thecomingled production lines 224, the test andtool line 225 and thecirculation line 226 extend from the manifold means 242 up through theswivel 24 in thevessel 10 and at theswivel platform 47 rotary pipe joint 268 connected to thecomingled production line 224 connects the well production with the vessel-carried production equipment by way of thehose 270. Means are provided for connecting the test andtool line 225 andcirculation line 226 with the pumping and the test stations as previously described. The means may include respective pipe connections to the periphery of theswivel platform 47 and thereafter to a hose and reel arrangement as previously described. Alternatively, suitable valving means may be supplied to these lines at theswivel platform 47 and thereafter the lines may be directly connected with a pumping and test station for those situations where relatively little swivel action takes place or for those instances where some degree of twisting of lines may be tolerated.

Assuming that means are provided for control of the valves illustrated at thegathering station 236, a typical operation will now be described.Valves 254a to 254n in the test and tool lines andvalves 260a to 26011 in the circulation line are closed; all other valves are open. Well fluid from the various wells flow up therespective lines 225a to 225n' and into theheader 252 through respective valved branch lines 258a to 258n. The comingled fluids then travel up theflexible line 224, through the swivel and to the production equipment. If it is now desired to test a certain well, for example well 264, valve 259a in the branch line 258a is closed andvalve 254a inline 225a is opened so that the well fluid from well 264 travels up the test andtool line 225, through theswivel 24 and to a test station as described previously with respect to FIG. 7. Subsequent to the test, valve 259a is again opened andvalve 254a is closed.

If a maintenance operation is to be performed at one of the wells, for example well 265, and such operation requires the use of a tool string, such tool string may be inserted in thetest line 225 at theswivel platform 47. Valve 259k in branch line 258b is closed and valve 254b inline 225b as well as valve 26Gb incirculation line 226b is opened. By means of the arrangement illustrated in FIG. 7A (except for the annular headers which would not be needed), the tool string is pumped down the test andtool line 225, enters theswitching network 261 where it is directed-toline 225b and thereafter to thewell 265. Upon completion of the maintenance operation the tool string may be returned'by the method illustrated in FIG. 7B, the'tool string passing up through theswitching network 261 and after its recovery at theswivel platform 47 the valves may be returned to their respectively normally operating conditions.

Theswitching network 261 is operative upon proper command from the surface, such as by hydraulic, pneumatic, electric or acoustically encoded signal activation to switch a tool string intest line 225 from thevessel 10 to any selected one of a number of underwater sells connected to thegathering station 236. A typical switching network may include various branch lines with fluidic switching such as illustrated in FIG. 9 wherein a switching network for controlling nine wells is shown. The switching network of FIG. 9 includes a plurality offluidic switches 280 to 283 each having an input line, three output lines and two control lines. The lines for each fluidic switch are labeled accordingly and operation is such that if a high-pressure fluid is supplied to the first control line, the tool will be forced over to the third output line. If high-pressure fluid is supplied to the second control line the tool will be forced over to the first output line and if high-pressure fluid is supplied to both the first and second control lines (or simultaneously not supplied to both lines) then the tool string will pass straight through to the second output line. In order to supply the high-pressure fluid to the various fluidic switches there is provided acontrol unit 286 which includes a source of high-pressure fluid and which has eight outputs controlled by eight valves designated V1 to V8.

A tool string at the input offluidic switch 280 may be directed to any one of the nine wells by selective opening of one or more of the valves V1 to V8. If the tool string is to be sent to well 1, valves V3 and V8 are opened whereby the tool string atfluidic switch 280 is forced by the high-pressure fluid in the second control line over to the first output line as is the case influidic switch 281. For servicing well 5, all of the valves are closed (or all of the valves may be opened) such that the tool exits fromfluidic'switch 280 at the second output with a similar exit fromfluidic switch 282. The table of FIG. 9A designates the particular valve or valves which are to be opened in order to service the designated wells.

The principle demonstrated in-FIG. 9 may be expanded such that many more than nine wells may be serviced. Fluidic switching may also be accomplished with a fluidic switch having one input and two outputs and two control lines however many more fluidic switches would be required.

For the accommodation of a greater number of wells a plurality of gathering stations may be provided in conjunction with a header arrangement on theswivel 24. The arrangement would include a first header for valved connection with all the comingled production lines, a second header for valved connection with all the circulation lines, and a third header for valved connection with all the test and tool lines. Fluid connection with the pumping test and metering stations would be similar to that previously illustrated.

Although the present invention has been described with a certain degree of particularity it should be understood that the present disclosure has been made by way of example and that modifications and variations of the present invention are made possible in the light of the above teachings.

I claim as my invention:

1. Offshore oil production apparatus comprising a. an elongated vessel having a well extending vertically therethrough to below the vessels waterline;

b. swivel means positioned within said well, and including a swivel platform at the upper portion thereof;

0. means for mooring said swivel means to the bottom of a body of water; oil production equipment carried by said vessel; said vessel including storage tanks for receiving the output of said oil producing equipment, a test separator and metering station, and a pumping station; a plurality of flexible fluid carrying lines for connection to a plurality of underwater oil wells, said flexible fluid carrying lines extending up through said swivel means to said swivel platform; means for inserting tool strings into selected one of said flexible fluid carrying lines; flow control means i. for selectively connecting individual ones of said flexible fluid carrying lines with said test separator and metering station for placing individual ones of said underwater wells on test, and ii. for selectively connecting individual one of said flexible fluid carrying lines with said pumping station for delivering and returning tool strings inserted into selected flexible fluid carrying lines;

I I. first header means for comingling produced well fluid from said underwater oil wells; and

J. first conduit means for carrying said comingled well fluid to said oil production equipment.

2. Apparatus according toclaim 1 wherein:

A. the swivel means includes a relatively large diameter vertical tube depending from the swivel platform; and

B. a plurality of relatively smaller diameter vertical tubes extending vertically within said large diameter tube;

C. at least pairs of flexible fluid carrying lines extending to the swivel platform through respective ones of said smaller diameter tubes.

3. Apparatus according toclaim 1 wherein:

A. for each underwater well there is provided at least two flexible fluid carrying lines, constituting a production line and a circulation line.

2. Apparatus according toclaim 3 wherein:

A. each production line and each circulation line of each underwater well extends up through the swivel means; and which includes B. a test header and a circulation header positioned on the swivel platform;

C. a first plurality of valves respectively connecting each production line with said test header; and

D. a second plurality of valves respectively connecting each circulation line with said circulation header.

5. Apparatus according toclaim 3 which includes:

A. at least one underwater gathering station;

B. valve connections at said gathering station for combining the production lines of a plurality of underwater wells;

C. other valve connections at said gathering station for combining the circulation lines-of a plurality of underwater wells;

D. means connecting the combined production lines with a first one of the flexible fluid carrying lines extending up the swivel means and for connecting the combined circulation lines with a second one of the flexible fluid carrying lines extending up the swivel means.

6. Apparatus according toclaim 5 which includes:

A. a switching matrix at said gathering station for diverting tool strings into a selected one of the production lines.

7. Apparatus according toclaim 5 wherein:

A. the swivel means is located near the bow of the vessel,

and which includes,

B. crews living quarters situated between the swivel means and said bow.

8. Apparatus according toclaim 1 wherein:

A. the first header means is centrally located on the swivel platform, and which includes B. a rotary pipe joint connecting the first conduit means to the first header means.

9. Apparatus according toclaim 8 wherein:

A. the production header and circulation header are concentrically disposed about the first header.

10. Apparatus according toclaim 1 wherein:

A. the pumping station pumps crude oil from one of the storage tanks.

1 1. Apparatus according to claim 10 wherein:

A. the pumping station includes metering means for metering the quantity of the crude oil pumped, for determining the approximate location of a tool string in a selected one of the flexible fluid carrying lines.

12. Apparatus according toclaim 1 which includes:

A. second and third header means;

B. selected ones of said flexible fluid carrying lines being connected to said second header means;

C. other ones of said flexible fluid carrying lines being connected to said third header means;

D. a pair of connection means respectively connected to said second and third header means;

E. a pair of hose reels each operable to wind and unwind carried hose; F. one end of the hoses from said pair of hose reels being connectable with respective ones of said pair of connection means;

G. means for selectively connecting the other end of said hoses to the test separator and metering station and the pumping station.

13. Apparatus according to claim 12 wherein:

A. the pair. of connection means are disposed on the periphery of the swivel platform; and which includes B. a guide on said periphery of the swivel platform for receiving respective hoses from the hose reel when the vessel and swivel means relatively rotate.

Claims (13)

1. Offshore oil production apparatus comprising a. an elongated vessel having a well extending vertically therethrough to below the vessel''s waterline; b. swivel means positioned within said well, and including a swivel platform at the upper portion thereof; c. means for mooring said swivel means to the bottom of a body of water; d. oil production equipment carried by said vessel; e. said vessel including storage tanks for receiving the output of said oil producing equipment, a test separator and metering station, and a pumping station; f. a plurality of flexible fluid carrying lines for connection to a plurality of underwater oil wells, said flexible fluid carrying lines extending up through said swivel means to said swivel platform; g. means for inserting tool strings into selected one of said flexible fluid carrying lines; h. flow control means i. for selectively connecting individual ones of said flexible fluid carrying lines with said test separator and metering station for placing individual ones of said underwater wells on test, and ii. for selectively connecting individual one of said flexible fluid carrying lines with said pumping station for delivering and returning tool strings inserted into selected flexible fluid carrying lines; I. first header means for comingling produced well fluid from said underwater oil wells; and J. first conduit means for carrying said comingled well fluid to said oil production equipment.

2. Apparatus according to claim 3 wherein: A. each production line and each circulation line of each underwater well extends up through the swivel means; and which includes B. a test header and a circulation header positioned on the swivel platform; C. a first plurality of valves respectively connecting each production line with said test header; and D. a second plurality of valves respectively connecting each circulation line with said circulation header.

2. Apparatus according to claim 1 wherein: A. the swivel means includes a relatively large diameter vertical tube depending from the swivel platform; and B. a plurality of relatively smaller diameter vertical tubes extending vertically within said large diameter tube; C. at least pairs of flexible fluid carrying lines extending to the swivel platform through respective ones of said smaller diameter tubes.

3. Apparatus according to claim 1 wherein: A. for each underwater well there is provided at least two flexible fluid carrying lines, constituting a produCtion line and a circulation line.

5. Apparatus according to claim 3 which includes: A. at least one underwater gathering station; B. valve connections at said gathering station for combining the production lines of a plurality of underwater wells; C. other valve connections at said gathering station for combining the circulation lines of a plurality of underwater wells; D. means connecting the combined production lines with a first one of the flexible fluid carrying lines extending up the swivel means and for connecting the combined circulation lines with a second one of the flexible fluid carrying lines extending up the swivel means.

6. Apparatus according to claim 5 which includes: A. a switching matrix at said gathering station for diverting tool strings into a selected one of the production lines.

7. Apparatus according to claim 5 wherein: A. the swivel means is located near the bow of the vessel, and which includes, B. crew''s living quarters situated between the swivel means and said bow.

8. Apparatus according to claim 1 wherein: A. the first header means is centrally located on the swivel platform, and which includes B. a rotary pipe joint connecting the first conduit means to the first header means.

9. Apparatus according to claim 8 wherein: A. the production header and circulation header are concentrically disposed about the first header.

10. Apparatus according to claim 1 wherein: A. the pumping station pumps crude oil from one of the storage tanks.

11. Apparatus according to claim 10 wherein: A. the pumping station includes metering means for metering the quantity of the crude oil pumped, for determining the approximate location of a tool string in a selected one of the flexible fluid carrying lines.

12. Apparatus according to claim 1 which includes: A. second and third header means; B. selected ones of said flexible fluid carrying lines being connected to said second header means; C. other ones of said flexible fluid carrying lines being connected to said third header means; D. a pair of connection means respectively connected to said second and third header means; E. a pair of hose reels each operable to wind and unwind carried hose; F. one end of the hoses from said pair of hose reels being connectable with respective ones of said pair of connection means; G. means for selectively connecting the other end of said hoses to the test separator and metering station and the pumping station.

13. Apparatus according to claim 12 wherein: A. the pair of connection means are disposed on the periphery of the swivel platform; and which includes B. a guide on said periphery of the swivel platform for receiving respective hoses from the hose reel when the vessel and swivel means relatively rotate.

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