OIL PRODUCTION SYSTEM
United States Patent 3602302
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.
US Patent References:
Deepwater oil drilling and storage craft
Nelson - January 1955 - 2699321
Floating production platform
Cox - November 1963 - 3111692
Floating mooring system
Richardson - October 1966 - 3279404
Floating storage unit for a fluid
Busking - August 1967 - 3335690
Offshore storage, mooring and loading facility
Graham - October 1968 - 3407768
Deepwater oil drilling and storage craft
Nelson - January 1955 - 2699321
Floating production platform
Cox - November 1963 - 3111692
Floating mooring system
Richardson - October 1966 - 3279404
Floating storage unit for a fluid
Busking - August 1967 - 3335690
Offshore storage, mooring and loading facility
Graham - October 1968 - 3407768
Application Number:
04/875350
Publication Date:
08/31/1971
Filing Date:
11/10/1969
View Patent Images:
Export Citation:
Assignee:
Westinghouse Electric Corporation (Pittsburgh, PA)
Primary Class:
Other Classes:
114/264, 114/256, 166/357, 166/352, 166/366
International Classes:
E21B23/12; E21B33/076; E21B43/017; E21B23/00; E21B33/03; E21B43/00; E21B43/01
Field of Search:
175/5,7,8 166/.5,.6 61/46 114/.5T,.5D,230
US Patent References:
Primary Examiner:
Novosad, Stephen J.
Assistant Examiner:
Favreau, Richard E.
Claims:
I claim as my invention
1. Offshore oil production apparatus comprising
2. Apparatus according to claim 1 wherein:
3. Apparatus according to claim 1 wherein:
1. Offshore oil production apparatus comprising
2. Apparatus according to claim 1 wherein:
3. Apparatus according to claim 1 wherein:
Description:
BACKGROUND OF THE INVENTION
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 will not 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 invention;
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 an elongated vessel 10 on station above the water bottom 12. The vessel 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 of storage tanks 16 connected to receive the output from the production equipment 14 for storing treated crude oil.
Positioned near the bow 18 and within the boundaries of the vessel is a well 20 extending from the deck 21 to the bottom 22 of vessel 10. Positioned within the well 20 is a swivel means in the form of mooring 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 vessel will weathervane about the swivel 24 to maintain the bow portion headed into the waves and wind. For those conditions where wind and sea are not in agreement, thrust units 28 are provided at the stern of the vessel 10 and are operable to maintain the vessel on the most favorable heading.
It is preferable that crew's living quarters 29 be established forward of the swivel 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 32 and 33 from underwater wells 36 and 37 extend up through the swivel 24 to certain apparatus on the swivel. A crane 40 is provided forward of the swivel 24 to aid in the handling of various pieces of equipment such as lubricator 42, as will be explained.
A more detailed, cross-sectional view of the swivel and part of the vessel, is illustrated in FIG. 2.
The swivel 24 has a large diameter tube 25 situated within the well 20 and an upper flange portion forming a swivel platform 47.
The swivel 24 is rotatably supported by a plurality of roller units 50 extending from the bottom of swivel platform 47 to a circular track 51 on the deck 21. The swivel 24 is additionally restrained laterally by a set of upper roller units 53 extending between the tube 25 and track 54, and a plurality of lower roller units 57 extending between the tube 25 and track 58.
Each anchor chain 26 extends up through a flange 60 at the bottom of the swivel 24, through the swivel platform 47 and secured thereto at respective securing points 62.
The hose assembly 32 includes at least a pair of fluid carrying lines in the form of production line 65 and circulation line 66. A third line 67 is a control line and may include power conveying means for actuating valves at the underwater well such means being, for example, hydraulic pneumatic or electrical. Alternatively the control line 67 may be eliminated and the valves controlled automatically in response to coded acoustic signals transmitted through the water medium. The lines 65, 66 and 67 are held together as a unit by means of a spacer 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 three lines 65, 66 and 67 pass up through a relatively small diameter vertical tube 73 within the swivel 24, and are disconnectable by means of a hose assembly connector 75. Production line 65 and circulation line 66 pass up through a support 77 positioned on the swivel platform 47.
Hose assembly 33 connected to well 37 is identical to hose assembly 32 in that it contains a plurality of flexible fluid conveying lines such as production line 84, circulation line 85 and a control line 86, passing up through vertical tube 88 and being disconnectable by means of hose assembly connector 90. The hose assembly 33 includes the spacer 92 and buoyant material 93 to prevent it from dragging on the water bottom and the assembly passes up through support 95 at the top of the swivel 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 the production line 65 through a first or master valve 100, into connecting pipe 102, through a second or wing valve 104 and into a centrally located vertical 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 the production line 84 to the master valve 110, through connecting pipe 112 and wing valve 114 into the header 107. In a similar fashion well fluid from all of the other wells in the field flow into header 107 and the comingled well fluid is carried to the production equipment by production hose 116 connected to the header 107 by means of a rotary pipe joint 119,
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 10 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 an annual header 122 concentrically disposed about header 107, and a plurality of valves for connecting the production line from each well to the annular header. Since the annular header 122 is utilized in test operations it will herein be termed the test header. With respect to well 36 there is provided valve 124 which when open will divert the flow from connecting pipe 102 into connecting pipe 126 and test header 122. During such operation wing valve 104 would normally be closed.
With respect to well 37, fluid from production line 84 may be diverted from connecting pipe 112 by opening valve 129 so that produced fluid may enter the test header 122 by way of connecting pipe 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 the test header 122.
The test 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, the circulation line 66 includes a first or master valve 134, and a second or wing valve 136. When both of these valves are open, and a third or swabbing valve 138 is closed, fluid communication is established between circulation line 66 and a second annular header 140 herein termed the circulation header and concentrically disposed about the header 107.
With respect to well 37, fluid flow in circulation line 85 is controlled by a first valve 142 and a second valve 144 both of which are operable when open to communicate fluid with the circulation 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 the control lines 67 and 86.
Insertion of a pump down tool string into a fluid line such as production line 65 may be accomplished with the provision of a lubricator 42. The tool string is inserted into the lubricator 42 which is connected to the production line such as by flange connection 146. Pressure is then applied at the top of the lubricator while swabbing valve 148 and master valve 100 are open to send the tool string out of the lubricator and past the level of wing 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 swabbing valves 138, 148, 150 and 151, tool strings may be inserted into respective fluid lines 66, 65, 84 and 85.
Means, including guide or track 155 extending around the periphery of the swivel platform 47, are provided for connecting the test header 122 and circulation header 140 to certain equipment on the vessel. Such connections are better illustrated in FIG. 3 which is a plan view of the swivel platform 47 of FIG. 2 with the valves and certain other equipment omitted for clarity. Positioned on the periphery of swivel 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 conveying conduit 163 and circulation header 140 is connected to rotary pipe joint 161 by means of fluid convening conduit 164.
First and second reels 170 and 171 on the vessel deck have flexible hoses 173 and 174 coiled thereon and connected respectively to rotary pipe joints 159 and 161. The other end of hose 173 is connected through a rotary pipe joint to fluid conduit 176 and the other end of flexible hose 174 is connected through a rotary pipe joint to fluid conduit 177. As the vessel pivots about the swivel, for example in FIG. 3 if swivel platform 47 relatively moves counterclockwise, hoses 173 and 174 will be pulled from their respective reels 170 and 171 and will be placed in the track means 155. Another view of this operation is illustrated in FIG. 5. When the swivel platform 47 relatively moves in a clockwise direction reels 170 and 171 will take up the slack of the hoses 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 of hose 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 the swivel 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 to respective 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 to reels 170 and 171.
In FIG. 6 there is illustrated a flow diagram for the underwater 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 the underwater well 36. At the lower portion of the figure there is illustrated a pile structure 188 secured to the water bottom 12 and which supports a hose assembly connector 190. The production line 65 extending from the connector 190 over to the well 36 may be in the form of steel tubing having curvatures 192 of sufficient radius, for example 5 feet, to enable passage of long tool trains and would lie on the bottom 12.
The circulation line 66 on the bottom may similarly be of steel tubing with curvatures 193 to enable tool train passage.
The underwater well 36 includes a Christmas tree 193 with the production line 65 being connected with the production string 195 by means of wing valve 197 and master valve 198. Circulation line 66 is connected to the circulation string 200 by means of wing valve 202 and master valve 203.
During operation of the well it may be necessary to perform a certain operation such as the removal of a valve 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 and metering station 210 and a pump and metering station 212 in conjunction with a plurality of valves 214 through 217.
If it is desired to test the well fluid of underwater well 36, valves 124 and 214 are open. Well fluid then proceeds from production string 195 to production line 65, through valve 124 into the test header 122, out of the test header and into fluid line 176 by way of the rotary pipe joint 159 and flexible hose 173 wound on reel 170. From fluid conduit 176 the fluid passes through valve 214 and into the test separator and metering 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 at station 210 reduces the pressure to atmospheric. After suitable testing the quiescent crude is provided to a tank 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 well's fluid to station 210.
If it is desired to test the well through circulation line 66, valves 136 and 217 may be opened to establish fluid flow from the circulation line 66 into circulation header 140 through rotary pipe joint 161 and flexible hose 174 to the reel 171 and fluid conduit 177 and into the test station 210 through valve 217.
For maintenance operation where it is required to send a tool string down into the production 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 and valves 148 and 124 are opened. By suitable means connected to the lubricator the tool string is sent past valve 148 which is thereafter closed. Pumping station 212 pumps quiescent crude from tank 16, through valve 215 and into production line 65 behind the tool string, by the path including fluid conduit 176, flexible hose 173, rotary pipe joint 159, header 122 and valve 124. A return for the fluid displaced ahead of the tool string is provided by the path including circulation line 66, valve 136, circulation header 140, rotary pipe joint 161, flexible hose 174, fluid conduit 177, valve 217, and into the test station 210 where it is returned to the tank 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 the circulation line 66 by the path including valve 216, fluid conduit 177, flexible hose 174, rotary pipe joint 161, circulation header 140 and valve 136. Fluid displaced ahead of the tool string in production line 65 is returned to the testing station 210 by the path including valve 124, test header 122, rotary pipe joint 159, flexible hose 173, fluid conduit 176 and valve 214.
The pumping station 212 includes metering means for determining the approximate position of the tool in the line 65, 195 since there is a direct relationship between its position and the quantity of quiescent crude pumped.
In addition to test and tool service, the circulating line 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 the vessel 10 can be accomplished by having a tanker come alongside, special fendering and mooring winches being provided aboard the vessel 10 to prevent metal-to-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 the vessel 10 the oil being transferred from storage 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 the vessel 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 the vessel 10, which could take the time between unloadings to treat this water for discharge into the sea. It should be noted that thrust units 28 would be available for assistance in the mooring operation.
A typical 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 the swivel 24 within the vessel 10 at the surface and depending from the swivel 24 and extending toward the water bottom 12 is a plurality of flexible fluid conveying conduits 224, 225 and 226 with the flexible conduit 224 being a production line, flexible conduit 225 being a test and tool line, and flexible conduit 226 being the circulation line. These flexible conduits are held in spaced relationship by means of spacers 228 with buoyant material 229 as previously described.
Positioned on the water bottom 12 is a gathering station 236 which includes a landing base 238 concreted in position within a pile 240 in the water bottom.
Mating with the landing base 238 and being detachably secured thereto is a manifold means 242 which includes a carrier unit 244 having a guide pipe 245 for guiding the unit into its position on the landing base 238. The manifold means 242 is connected to the landing base 238 by a plurality of detachable connectors 248.
The manifold means 242 includes header 252 in addition to a plurality of test and tool lines 225a to 225n having respective valves 254a to 254n. Each line 225a to 225n is connected with the header 252 by means of respective branch lines 258a to 258n having respective valves 459a to 259n. The test and tool lines 225a to 225n are selectively connectable to test and tool line 225 through a switching network 261. The manifold means also includes a plurality of circulation lines 226a to 226n having respective valves 260a to 260n which connect the lines 226a to 226n with the circulation line 226.
When the carrier unit 244 is in mating engagement with the landing base 238, connections are provided between lines 225a to 225n and respective lines 225a' to 225n' which carry the well fluid from respective wells of which two, 264 and 265, are illustrated. Connection is also made between lines 226a to 226n and lines 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.
The comingled production lines 224, the test and tool line 225 and the circulation line 226 extend from the manifold means 242 up through the swivel 24 in the vessel 10 and at the swivel platform 47 rotary pipe joint 268 connected to the comingled production line 224 connects the well production with the vessel-carried production equipment by way of the hose 270. Means are provided for connecting the test and tool line 225 and circulation line 226 with the pumping and the test stations as previously described. The means may include respective pipe connections to the periphery of the swivel platform 47 and thereafter to a hose and reel arrangement as previously described. Alternatively, suitable valving means may be supplied to these lines at the swivel 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 the gathering station 236, a typical operation will now be described. Valves 254a to 254n in the test and tool lines and valves 260a to 260n in the circulation line are closed; all other valves are open. Well fluid from the various wells flow up the respective lines 225a' to 225n' and into the header 252 through respective valved branch lines 258a to 258n. The comingled fluids then travel up the flexible 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 and valve 254a in line 225a is opened so that the well fluid from well 264 travels up the test and tool line 225, through the swivel 24 and to a test station as described previously with respect to FIG. 7. Subsequent to the test, valve 259a is again opened and valve 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 the test line 225 at the swivel platform 47. Valve 259b in branch line 258b is closed and valve 254b in line 225b as well as valve 260b in circulation 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 and tool line 225, enters the switching network 261 where it is directed to line 225b and thereafter to the well 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 the switching network 261 and after its recovery at the swivel platform 47 the valves may be returned to their respectively normally operating conditions.
The switching 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 in test line 225 from the vessel 10 to any selected one of a number of underwater sells connected to the gathering 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 of fluidic 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 a control 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 of fluidic 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 at fluidic switch 280 is forced by the high-pressure fluid in the second control line over to the first output line as is the case in fluidic 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 from fluidic switch 280 at the second output with a similar exit from fluidic 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 the swivel 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.
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 will not 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 invention;
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 an elongated vessel 10 on station above the water bottom 12. The vessel 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 of storage tanks 16 connected to receive the output from the production equipment 14 for storing treated crude oil.
Positioned near the bow 18 and within the boundaries of the vessel is a well 20 extending from the deck 21 to the bottom 22 of vessel 10. Positioned within the well 20 is a swivel means in the form of mooring 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 vessel will weathervane about the swivel 24 to maintain the bow portion headed into the waves and wind. For those conditions where wind and sea are not in agreement, thrust units 28 are provided at the stern of the vessel 10 and are operable to maintain the vessel on the most favorable heading.
It is preferable that crew's living quarters 29 be established forward of the swivel 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 32 and 33 from underwater wells 36 and 37 extend up through the swivel 24 to certain apparatus on the swivel. A crane 40 is provided forward of the swivel 24 to aid in the handling of various pieces of equipment such as lubricator 42, as will be explained.
A more detailed, cross-sectional view of the swivel and part of the vessel, is illustrated in FIG. 2.
The swivel 24 has a large diameter tube 25 situated within the well 20 and an upper flange portion forming a swivel platform 47.
The swivel 24 is rotatably supported by a plurality of roller units 50 extending from the bottom of swivel platform 47 to a circular track 51 on the deck 21. The swivel 24 is additionally restrained laterally by a set of upper roller units 53 extending between the tube 25 and track 54, and a plurality of lower roller units 57 extending between the tube 25 and track 58.
Each anchor chain 26 extends up through a flange 60 at the bottom of the swivel 24, through the swivel platform 47 and secured thereto at respective securing points 62.
The hose assembly 32 includes at least a pair of fluid carrying lines in the form of production line 65 and circulation line 66. A third line 67 is a control line and may include power conveying means for actuating valves at the underwater well such means being, for example, hydraulic pneumatic or electrical. Alternatively the control line 67 may be eliminated and the valves controlled automatically in response to coded acoustic signals transmitted through the water medium. The lines 65, 66 and 67 are held together as a unit by means of a spacer 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 three lines 65, 66 and 67 pass up through a relatively small diameter vertical tube 73 within the swivel 24, and are disconnectable by means of a hose assembly connector 75. Production line 65 and circulation line 66 pass up through a support 77 positioned on the swivel platform 47.
Hose assembly 33 connected to well 37 is identical to hose assembly 32 in that it contains a plurality of flexible fluid conveying lines such as production line 84, circulation line 85 and a control line 86, passing up through vertical tube 88 and being disconnectable by means of hose assembly connector 90. The hose assembly 33 includes the spacer 92 and buoyant material 93 to prevent it from dragging on the water bottom and the assembly passes up through support 95 at the top of the swivel 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 the production line 65 through a first or master valve 100, into connecting pipe 102, through a second or wing valve 104 and into a centrally located vertical 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 the production line 84 to the master valve 110, through connecting pipe 112 and wing valve 114 into the header 107. In a similar fashion well fluid from all of the other wells in the field flow into header 107 and the comingled well fluid is carried to the production equipment by production hose 116 connected to the header 107 by means of a rotary pipe joint 119,
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 10 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 an annual header 122 concentrically disposed about header 107, and a plurality of valves for connecting the production line from each well to the annular header. Since the annular header 122 is utilized in test operations it will herein be termed the test header. With respect to well 36 there is provided valve 124 which when open will divert the flow from connecting pipe 102 into connecting pipe 126 and test header 122. During such operation wing valve 104 would normally be closed.
With respect to well 37, fluid from production line 84 may be diverted from connecting pipe 112 by opening valve 129 so that produced fluid may enter the test header 122 by way of connecting pipe 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 the test header 122.
The test 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, the circulation line 66 includes a first or master valve 134, and a second or wing valve 136. When both of these valves are open, and a third or swabbing valve 138 is closed, fluid communication is established between circulation line 66 and a second annular header 140 herein termed the circulation header and concentrically disposed about the header 107.
With respect to well 37, fluid flow in circulation line 85 is controlled by a first valve 142 and a second valve 144 both of which are operable when open to communicate fluid with the circulation 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 the control lines 67 and 86.
Insertion of a pump down tool string into a fluid line such as production line 65 may be accomplished with the provision of a lubricator 42. The tool string is inserted into the lubricator 42 which is connected to the production line such as by flange connection 146. Pressure is then applied at the top of the lubricator while swabbing valve 148 and master valve 100 are open to send the tool string out of the lubricator and past the level of wing 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 swabbing valves 138, 148, 150 and 151, tool strings may be inserted into respective fluid lines 66, 65, 84 and 85.
Means, including guide or track 155 extending around the periphery of the swivel platform 47, are provided for connecting the test header 122 and circulation header 140 to certain equipment on the vessel. Such connections are better illustrated in FIG. 3 which is a plan view of the swivel platform 47 of FIG. 2 with the valves and certain other equipment omitted for clarity. Positioned on the periphery of swivel 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 conveying conduit 163 and circulation header 140 is connected to rotary pipe joint 161 by means of fluid convening conduit 164.
First and second reels 170 and 171 on the vessel deck have flexible hoses 173 and 174 coiled thereon and connected respectively to rotary pipe joints 159 and 161. The other end of hose 173 is connected through a rotary pipe joint to fluid conduit 176 and the other end of flexible hose 174 is connected through a rotary pipe joint to fluid conduit 177. As the vessel pivots about the swivel, for example in FIG. 3 if swivel platform 47 relatively moves counterclockwise, hoses 173 and 174 will be pulled from their respective reels 170 and 171 and will be placed in the track means 155. Another view of this operation is illustrated in FIG. 5. When the swivel platform 47 relatively moves in a clockwise direction reels 170 and 171 will take up the slack of the hoses 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 of hose 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 the swivel 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 to respective 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 to reels 170 and 171.
In FIG. 6 there is illustrated a flow diagram for the underwater 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 the underwater well 36. At the lower portion of the figure there is illustrated a pile structure 188 secured to the water bottom 12 and which supports a hose assembly connector 190. The production line 65 extending from the connector 190 over to the well 36 may be in the form of steel tubing having curvatures 192 of sufficient radius, for example 5 feet, to enable passage of long tool trains and would lie on the bottom 12.
The circulation line 66 on the bottom may similarly be of steel tubing with curvatures 193 to enable tool train passage.
The underwater well 36 includes a Christmas tree 193 with the production line 65 being connected with the production string 195 by means of wing valve 197 and master valve 198. Circulation line 66 is connected to the circulation string 200 by means of wing valve 202 and master valve 203.
During operation of the well it may be necessary to perform a certain operation such as the removal of a valve 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 and metering station 210 and a pump and metering station 212 in conjunction with a plurality of valves 214 through 217.
If it is desired to test the well fluid of underwater well 36, valves 124 and 214 are open. Well fluid then proceeds from production string 195 to production line 65, through valve 124 into the test header 122, out of the test header and into fluid line 176 by way of the rotary pipe joint 159 and flexible hose 173 wound on reel 170. From fluid conduit 176 the fluid passes through valve 214 and into the test separator and metering 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 at station 210 reduces the pressure to atmospheric. After suitable testing the quiescent crude is provided to a tank 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 well's fluid to station 210.
If it is desired to test the well through circulation line 66, valves 136 and 217 may be opened to establish fluid flow from the circulation line 66 into circulation header 140 through rotary pipe joint 161 and flexible hose 174 to the reel 171 and fluid conduit 177 and into the test station 210 through valve 217.
For maintenance operation where it is required to send a tool string down into the production 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 and valves 148 and 124 are opened. By suitable means connected to the lubricator the tool string is sent past valve 148 which is thereafter closed. Pumping station 212 pumps quiescent crude from tank 16, through valve 215 and into production line 65 behind the tool string, by the path including fluid conduit 176, flexible hose 173, rotary pipe joint 159, header 122 and valve 124. A return for the fluid displaced ahead of the tool string is provided by the path including circulation line 66, valve 136, circulation header 140, rotary pipe joint 161, flexible hose 174, fluid conduit 177, valve 217, and into the test station 210 where it is returned to the tank 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 the circulation line 66 by the path including valve 216, fluid conduit 177, flexible hose 174, rotary pipe joint 161, circulation header 140 and valve 136. Fluid displaced ahead of the tool string in production line 65 is returned to the testing station 210 by the path including valve 124, test header 122, rotary pipe joint 159, flexible hose 173, fluid conduit 176 and valve 214.
The pumping station 212 includes metering means for determining the approximate position of the tool in the line 65, 195 since there is a direct relationship between its position and the quantity of quiescent crude pumped.
In addition to test and tool service, the circulating line 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 the vessel 10 can be accomplished by having a tanker come alongside, special fendering and mooring winches being provided aboard the vessel 10 to prevent metal-to-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 the vessel 10 the oil being transferred from storage 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 the vessel 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 the vessel 10, which could take the time between unloadings to treat this water for discharge into the sea. It should be noted that thrust units 28 would be available for assistance in the mooring operation.
A typical 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 the swivel 24 within the vessel 10 at the surface and depending from the swivel 24 and extending toward the water bottom 12 is a plurality of flexible fluid conveying conduits 224, 225 and 226 with the flexible conduit 224 being a production line, flexible conduit 225 being a test and tool line, and flexible conduit 226 being the circulation line. These flexible conduits are held in spaced relationship by means of spacers 228 with buoyant material 229 as previously described.
Positioned on the water bottom 12 is a gathering station 236 which includes a landing base 238 concreted in position within a pile 240 in the water bottom.
Mating with the landing base 238 and being detachably secured thereto is a manifold means 242 which includes a carrier unit 244 having a guide pipe 245 for guiding the unit into its position on the landing base 238. The manifold means 242 is connected to the landing base 238 by a plurality of detachable connectors 248.
The manifold means 242 includes header 252 in addition to a plurality of test and tool lines 225a to 225n having respective valves 254a to 254n. Each line 225a to 225n is connected with the header 252 by means of respective branch lines 258a to 258n having respective valves 459a to 259n. The test and tool lines 225a to 225n are selectively connectable to test and tool line 225 through a switching network 261. The manifold means also includes a plurality of circulation lines 226a to 226n having respective valves 260a to 260n which connect the lines 226a to 226n with the circulation line 226.
When the carrier unit 244 is in mating engagement with the landing base 238, connections are provided between lines 225a to 225n and respective lines 225a' to 225n' which carry the well fluid from respective wells of which two, 264 and 265, are illustrated. Connection is also made between lines 226a to 226n and lines 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.
The comingled production lines 224, the test and tool line 225 and the circulation line 226 extend from the manifold means 242 up through the swivel 24 in the vessel 10 and at the swivel platform 47 rotary pipe joint 268 connected to the comingled production line 224 connects the well production with the vessel-carried production equipment by way of the hose 270. Means are provided for connecting the test and tool line 225 and circulation line 226 with the pumping and the test stations as previously described. The means may include respective pipe connections to the periphery of the swivel platform 47 and thereafter to a hose and reel arrangement as previously described. Alternatively, suitable valving means may be supplied to these lines at the swivel 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 the gathering station 236, a typical operation will now be described. Valves 254a to 254n in the test and tool lines and valves 260a to 260n in the circulation line are closed; all other valves are open. Well fluid from the various wells flow up the respective lines 225a' to 225n' and into the header 252 through respective valved branch lines 258a to 258n. The comingled fluids then travel up the flexible 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 and valve 254a in line 225a is opened so that the well fluid from well 264 travels up the test and tool line 225, through the swivel 24 and to a test station as described previously with respect to FIG. 7. Subsequent to the test, valve 259a is again opened and valve 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 the test line 225 at the swivel platform 47. Valve 259b in branch line 258b is closed and valve 254b in line 225b as well as valve 260b in circulation 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 and tool line 225, enters the switching network 261 where it is directed to line 225b and thereafter to the well 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 the switching network 261 and after its recovery at the swivel platform 47 the valves may be returned to their respectively normally operating conditions.
The switching 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 in test line 225 from the vessel 10 to any selected one of a number of underwater sells connected to the gathering 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 of fluidic 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 a control 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 of fluidic 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 at fluidic switch 280 is forced by the high-pressure fluid in the second control line over to the first output line as is the case in fluidic 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 from fluidic switch 280 at the second output with a similar exit from fluidic 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 the swivel 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.