WEATHERFORD INTERNATIONAL, LLC, et al.
`EXHIBIT 1005
`
`PACKERS PLUS ENERGY SERVICES, INC.
`
`WEATHERFORD INTERNATIONAL, LLC, et al.
`V
`
`DECLARATION OF REBEKAH STACHA OF THE SOCIETY OF
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`PETROLUEM ENGINEERS
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`1.
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`My name is Rebekah Stacha.
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`I am over the age of twenty—one years, of
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`sound mind, and capable of making the statements set forth in this Declaration.
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`competent to testify about the matters set forth herein. All the facts and statements
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`contained herein are Within my personal knowledge and/or Within my field of
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`I have been employed by the Society of Petroleum Engineers (“SPE”)
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`4.
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`SPE Paper SPE—5 l l77—PA, a true and correct copy of which is attached
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`as Exhibit A to this Declaration, is an SPE Paper entitled, Design and Installation ofa
`
`Cost—Efi’ective Completion System for Horizontal Chalk Wells Where Multiple Zones
`
`Require Acid Stimulation, that was received for publication on March 23, 1998 and
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`Was peer approved for publication on June 15, 1998. The article was subsequently
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`published in the September 1998 issue of SPE Drilling & Completion at pages l5l—
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`l56. SPE Drilling & Completion has had both individual and institutional subscribers
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`including numerous libraries since 1993. The September 1998 issue would have been
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`distributed to subscribers at least by October 1998. Since its publication in September
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`1998, SPE-51177—PA was also publicly available to anyone interested in purchasing a
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`copy of the paper through the online sources provided by SPE discussed above.
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`5.
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`SPE Paper SPE-37482-MS, a true and correct copy of which is attached
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`as Exhibit B to this Declaration, is an SPE paper entitled, Design and Installation ofa
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`Cost Eflective Completion System for Horizontal Chalk Wells Where Multiple Zones
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`Require Acid Stimulation, presented at the SPE Production Operations Symposium on
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`March 9-11, 1997 in Oklahoma City, Oklahoma. SPE is a sponsor of the SPE
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`Production Operations Symposium. Since that conference on March 9-11, 1997, SPE
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`Paper SPE-37482-MS has been publicly available to anyone interested in purchasing
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`a copy of the paper through the online sources provided by SPE discussed above.
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`6.
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`SPE Paper SPE—19090—MS, a true and correct copy of which is attached
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`as Exhibit C to this Declaration, is an SPE paper entitled, Production and Stimulation
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`Analysis ofMultizyle Hydraulic Fracturing ofa 2, 000—ft Horizontal Well, presented at
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`the SPE Gas Technology Symposium on June 7-9, 1989 in Dallas, Texas. SPE is a
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`sponsor of the SPE Gas Technology Symposium. Since that conference on June 7-9,
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`1989, SPE Paper SPE-19090-MS has been publicly available to anyone interested in
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`purchasing a copy of the paper through SPE directly and later through the online
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`sources provided by SPE discussed above.
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`I declare under penalty of perjury of the laws of the United States that the
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`forgoing information is true and correct of my own personal knowledge.
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`Executed on July 11, 2016, in Richardson (city), Texas (state)
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`
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`Print: Rebekah Stacha
`
`Title: Senior Mana er Technical Publications
`
`

`
`Design and Installation of a Cost-Effective
`Completion System for Horizontal Chalk
`Wells Where Multiple Zones Require Acid
`Stimulation
`
`D.W. Thomson, SPE, Halliburton Manufacturing and Services Ltd., and M.F. NClZl'O0,
`Phillips Petroleum Co. Norway
`
`Summary
`
`An innovative completion design that allows multiple acid fractures
`to be performed in horizontal subsea chalk formation wells with a
`single trip into the wellbore has recently been codeveloped by a
`major North Sea operator and an oilfield engineering/manufactun
`ing/service company. The project was begun to develop a system
`that would allow multiple acid stimulations to be efficiently per-
`formed in the shortest possible time in the North Sea Joanne field.
`The system ultimately developed allows acid stimulation of up to
`10 different zones in a single trip with no through-tubing inter-
`vention. The first well in which this new technique was used had
`seven zones, and three additional wells with l0 zones each were
`later completed. This paper presents the development of this sys-
`tem and case histories of the first four subsea wells requiring
`stimulation.
`
`The key element of the system is a multistage acid fracture
`(MSAF) tool that is similar to a sliding sleeve circulating device and
`is run in the closed position. Up to nine MSAF tools can be run in
`the completion with isolation of each zone being achieved by
`hydraulic-set retrievable packers that are positioned on each side of
`an MSAF tool. Each sleeve contains a threaded ball seat with the
`smallest ball seat in the lowest sleeve and the largest ball seat in the
`highest sleeve. With this system, stimulation of 10 separate zones
`is accomplished in 12 to 18 hours. A unique procedure that
`lubricates various sized, low specific gravity (SG) balls into the
`tubing and, then, pumps them to a mating seat in the appropriate
`MSAF tool to seal off the stimulated zone is used. This allows
`stimulation of the next zone, which is made accessible by opening
`the sleeve.
`
`This technique provided a substantial reduction in the operation
`time normally required to stimulate multiple zones and allowed the
`stimulations to be precisely targeted within the reservoir. The case
`history data provides comparisons in operation times between
`traditional stimulations and this new method, as well as the sig-
`nificant enhancements to cost efficiency that resulted from its use.
`Additionally, this completion method allowed the stimulations to
`be designed and matched to the requirements of each reservoir
`zone, which provided the most cost—efficient treatments possible.
`
`Introduction
`
`The Judy/Joanne fields are located in the central North Sea on
`Block 30/7a (commonly known as the J-Block of the UK. North
`Sea), 280 lcm southeast of Aberdeen. The water depth is approx-
`imately 80 m.
`The complete field development consists of a 24-slot platform for
`Judy and a 12-slot subsea template for Joanne. Production from the
`Joanne subsea manifold is transported through two 12-in. pipelines,
`5 lcrn in length, to the Judy platform.
`To date, five Joanne subsea wells have been drilled and com-
`pleted, four of which were in chalk formations, and thus, compre-
`hensive acid stimulation programs were required for their comple-
`
`Copyright 1998 Offshore Technology Conference
`This paper (SPE 51177) was revised for publication from paper SPE 39150, first
`presented at the 1997 Offshore Technology Conference held in Houston, 5-8 May.
`Original manuscript received for review 50 May 1997. Revised manuscript received
`23 March 1998. Paper peer approved 15 June 1998.
`
`SPE Drilling & Completion, September l998
`
`tions. Fig. 1 is a map showing the location of the J-Block Judyl
`Joanne fields.
`
`Well Design
`
`Phillips’ original plan had been to drill 60° wells in these fields;
`however, because drilling horizontal wells would reduce the num-
`ber of well slots, which would subsequently reduce overall drilling
`costs, the decision was made to complete horizontally. Addition-
`ally, it was believed that stimulation programs would be required
`to achieve the necessary production potentials. The new wells were
`designed to intersect the most productive reservoir layers twice to
`further maximize production. Ideally, each reservoir layer was to be
`stimulated by means of a design developed for its specific needs.
`Thus,
`it would be necessary to perform multiple stimulations
`targeted at the reservoir layers. Fig. 2 shows how the well path
`would intersect the individual reservoir layers.
`A review of similar completions carried out by Phillips and other
`operators indicated that each zone would require between 3 and 4
`days to stimulate. This would have meant a minimum of 30 days
`per well to complete the stimulation procedures. It was clear from
`the initial review that the project could not support such greatly
`increased costs, so an alternative method was needed. The resulting
`completion design was based on earlier completions performed by
`Phillips on the Hewett field in the southern part of the North Sea
`(see Fig. 1). During these completions, the initial development
`phase of the MSAF tool had taken place. This tool was instrumental
`in the success of the design and is described in more detail in the
`following section.
`The primary difference in the completion designs concerned the
`number of zones stimulated. The Hewett field completions typi-
`cally used only two MSAF tools that resulted in three stimulated
`zones, whereas the first Joanne completion (Well M1) used six
`MSAF tools, and the completions for Wells M3, M4, and M5 used
`nine MSAF tools. Fig 3 is a schematic of a typical Joanne
`completion.
`
`Typical Joanne Completion Design
`l. Tubing Hanger, 51/s-in. Horizontal (lateral) subsea trees were
`used to allow the completions to be run through them. The final
`operation before leaving the wells was the installation of wireline—
`set, metal-to-metal-sealing wellhead plugs in the tubing hangers.
`2. Tubing-Retrievable Safety Valve (TRSV), 5'/2—in. A non-
`equalizing TRSV with metal-to-metal seals was used to ensure
`reliability.
`3. Side Pocket Mandrel, 4'/2-in. X ll/2-in. These were run with
`blanked off annulus ports to enable electronic memory gauges with
`the same envelope dimensions as a standard 11/2-in. gas lift valve
`to be installed in the completions during the stimulation without
`compromising full bore access. These gauges were run and re-
`trieved with conventional gas lift kick-over tools and gave valuable
`bottomhole information during the stimulations, cleanup proce-
`dures, and Well tests.
`4. Sliding Sleeve Circulating Devices, 41/2-in. The devices were
`run to enable the upper completion/casing annulus to be circulated
`to inhibited brine.
`
`l5l
`
`

`
`MAUREEN
`
`_, BRITANNIA
`in
`165!
`ARMANDA
`
`I
`
`installation of the completion and for use in future workover
`operations.
`8. MSAF Tool (Multiple), 41/2-in. This tool is the heart of the
`completion system. It is a sliding sleeve device that allows com-
`munication between the tubing and the annulus when the sleeve is
`moved to the open position. A ball seat is threaded on the bore of
`this sleeve, and when the correct size ball lands on the ball seat,
`applied pressure from above moves the sleeve to the down/open
`position. The ball and seat form a seal that prevents pumped fluid
`from entering lower zones, thereby diverting the fluid through the
`tool and into the tubing liner annulus. The MSAF tool is shown in
`both the closed and open positions in Fig 4.
`For 41/2—in. tubing, as many as nine ball/seat configurations can
`be used (Table 1). The smallest inside diameter (ID) seat is run at
`the bottom of the completion, and the largest ID seat is run at the top.
`The sleeve in the MSAF tool was designed with an opening
`profile and a closing profile so that the tool could be selectively
`opened or closed as required during workovers. A hydraulically
`operated shifting tool run on coiled tubing was designed for this
`purpose. Note that in the tool version used on Joanne, the ball seats
`had to be milled out before the shifting tool could be used.
`9. The same comment used for Item 6 is appropriate here.
`10. Pump-Out/Cycle Plug. On M1, a conventional shear-out shoe
`was run. This was replaced on the remaining completions with a
`cycle-type plug, which allowed up to 10 pressure cycles to be
`applied to the tubing before it was expelled. This was carried in a
`shear-out subassembly that could be sheared in the event that the
`cycle plug failed.
`
`Fig. 1—Location of the North Sea J—B|ock development.
`
`Ball Material
`
`5. Polished Bore Receptacle (PBR)/Seal Assembly With Annu-
`lar Pressure Release, 30-ft Stroke. Tubing calculations for opera-
`tional conditions, particularly high—volume acid stimulation and
`well testing, showed that a 30-ft stroke expansion device was
`necessary. Ryton/Teflon/Ryton premium seals were considered the
`most appropriate seals for the operating conditions that would be
`faced. A molded seal was added to the Ryton/Teflon/Ryton pre-
`mium seals to ensure good sealing at
`the lower temperatures
`expected during stimulation.
`A conventional shear—pinned PBR/seal assembly was used on
`Ml, but concerns about induced torque led to the design of a special
`annular pressure release that fit on top of the PBR/seal assembly.
`In the closed (running) position, the PBR and seal assembly were
`clutched together to handle applied or induced torque. As a backup,
`it had a secondary shear—screw release mechanism that was isolated
`from any torque that could be applied or induced.
`6. Retrievable Packer (Multiple), 7—in. Perrnanent/7-in. An im-
`portant requirement for completions with multiple hydraulic-set
`packers is that no mandrel movement in relation to the slips of the
`packer should occur while setting. This enables any number of
`hydraulic-set packers to be set simultaneously without requiring
`expansion devices between the packers to account for mandrel
`movement.
`
`The packer selected for this project was a newly designed
`hydraulic-set retrievable packer that had its first use on the Joanne
`project. The packer was designed such that it could be set up as
`either a permanent or a retrievable packer simply by installing a
`lock ring (the configuration for permanent use) or by installing up
`to 16 shear screws (for retrievable). When configured for a per-
`manent installation, the packer could be retrieved by chemically
`cutting the mandrel.
`This packer had large outside diameter (OD) gauge rings at either
`end, which kept the other components ofthe packer from contacting
`the 7-in. liner. The packer elements and slips had an OD in the
`running position smaller than the adjacent parts. After the first well
`(M1) was completed, the gauge rings were fluted to assist in fluid
`bypass while the completion was installed in the liner.
`7. Selective Landing Nipple. This nipple was run below the top
`packer as a contingency in case there were problems during
`
`I52
`
`Two different ball materials were used: phenolic plastic with a SG
`of 1.3 and coated aluminum with a SG of 2.5. The 1.3-SG phenolic
`plastic ball was the preferred choice except in cases in which the
`expected stimulation pressure necessitated the use of aluminum
`balls.
`
`Testing
`
`Flow testing was carried out to determine the minimum flow rates
`required to return the balls (aluminum and phenolic) to surface,
`flow rates for pumping a ball through a seat with the minimum
`ball/seat clearance, and flow rates for operating the MSAF tools.
`Pressure testing was carried out to determine the pressure rating
`for phenolic ball/seat combinations for which there was no existing
`rating.
`In each case,
`three combinations of phenolic ball/seat
`combination were pressure tested to destruction to establish the
`pressure ratings. Pressure ratings were calculated for the aluminum
`ball/seat combinations. Table 2 shows the results of the destructive
`pressure testing of phenolic balls.
`Table 3 shows the shear strength test results of the aluminum
`balls. Values of 100% were based on 6061 aluminum with an
`ultimate shear strength of 9,000 psi, no safety factor, and the
`assumption that the ball would be the point of failure. All values
`were taken at nominal dimensions with no accounting for tolerance
`or erosion.
`Milling tests also were carried out onshore to determine how
`difficult or feasible it would be to mill out the ball seats with milling
`tools on coiled tubing with a motor. These tests gave favorable
`results with a stepped mill, and the testing indicated that it would
`be possible to mill out all nine seats with two or three coiled tubing
`runs.
`
`When the ball seats are milled out, two hydraulic shifting tools
`could be run in one coiled tubing tool string with one facing upward
`(for closing) and one facing downward (for reopening). This would
`give the option of selectively closing or reopening any sleeve in the
`completion.
`
`Completion Installation
`
`General. Before the completion was run, each well was perforated
`with tubing-conveyed perforating guns. The multiple packers in
`
`SPE Drilling & Completion, September 1998
`
`

`
`3017a-3
`lmmtou
`
`2800
`
`2000
`
`2100
`
`2200
`
`2000
`
`1000
`
`1600
`
`1300
`
`1100
`
`I000
`
`000Q00
`
`400
`
`200
`
`SSW
`3000
`
`Ekofiak 1
`Ekolisk 2
`Ekofisk 3
`Tor 1
`
`ow:
`’ (INII-J)<10.1H
`
`
`
`H’:1'VDu(incl)
`
`-9800
`
`-0700
`
`-9000
`
`40000
`
`-'l0l00
`
`-10200
`
`-1 0300
`
`40100
`
`-1 0500
`
`-l 0600
`
`-1 0700
`
`«10800
`
`Fig. 2—Geological section of Joanne field showing well path intersection of reservoir layers.
`
`Lateral Distance Along Wellpath (meters)
`
`each completion were spaced out to isolate the zones to be
`stimulated.
`The installation plan for all wells was the same. The completion
`was run in one trip to the safety valve, and the packers were set
`simultaneously because the packers had the same setting pressure.
`Then,
`the upper completion was disconnected from the PBR,
`spaced out, and run back in with the TRSV.
`As soon as each completion had been run and the packers had
`been set, spaced out, and hanger landed, special high-pressure,
`large-bore (4-in. ID) equipment was rigged up on top of the 5-in.
`I'D flowhead for launching and catching of the balls. After all
`surface equipment had been rigged up and tested, the stimulation
`operation was started by expelling the pump-out/cycle plug and
`then stimulating the zone below the bottom packer. When this zone
`had been stimulated, the smallest ball was lubricated into the
`completion and pumped on to its mating seat in the lowest MSAF.
`When the ball landed on seat, overpressure sheared the preset shear
`pins and allowed the sleeve to move to the open position, allowing
`stimulation of the zone through the MSAF tool and preventing
`pumped fluids from going to any lower zones already stimulated.
`The process was then repeated by pumping increasingly larger balls
`until all zones had been stimulated. All balls were then flowed to
`the surface and caught in the ball catcher.
`For Ml, which had seven zones, one stimulation vessel was able
`to carry enough acid to complete the stimulation program. How-
`ever, two stimulation vessels were required for each of the wells
`with 10 zones (M3, M4, and M5) because of the volume of acid that
`was needed for the increased number of zones.
`
`M1. Seven packers and six MSAF tools (all in the closed position)
`were run (see Table 4 for the six different ball/seat configurations).
`For this well, the expansion device (PBR/seal assembly) was a
`conventional type, straight—pull (shear-screw) release. At the last
`
`SPE Drilling & Completion, September 1998
`
`minute, it was decided not to run the full completion in one trip
`because of concerns ofprematurely shearing the shear screws in the
`PBR/seal assembly, which could be caused by back torque during
`installation into the horizontal section of the liner.
`As a result, it was decided to run the lower half (PBR downward)
`of the completion on a 95/s—in. liner hanger—setting sleeve and hang
`off on the 7~in. liner top. When the lower half ofthe completion was
`at the appropriate depth, pressure was applied down the tubing
`against the pump-out plug (conventional shear-screw release) to set
`all seven packers simultaneously. The upper half of the completion
`was then spaced out and connected to the PBR. The pump-out plug
`failed during the packer-setting procedure (luckily just after the
`packers were set), which resulted in problems in pressure testing of
`the completion and tubing hanger.
`When all testing had been completed, stimulation of the lowest
`zone (below the bottom packer) was carried out. A well test was
`then run on this zone. The upper six zones were then stimulated
`individually by pumping down increasingly larger balls to land
`on/seal their mating seats in each MSAF tool. During this operation,
`pumping operations were continuous. The pump rate was reduced
`to 5 bbl/min to lubricate each ball into the wellbore. The pump rate
`was then increased to 20 to 25 bbl/min to transport each ball to
`within 500 ft of its mating seat and then was again reduced to 5
`bbl/min to pump each ball onto its mating seat.
`When each ball found its seat, the pressure was increased until
`the shear screws sheared, allowing the sleeve to move down to the
`open position. This allowed stimulation ofthe new zone through the
`sleeve. Afier stimulation, all six balls were circulated back to
`surface and caught in a ball catcher during the cleanup flow.
`
`M3, M4, and M5. After the successful installation of the seven-
`packer completion in M1, it was decided to attempt maximization
`of the number of zones for the next three wells. Afier ball/seat-
`
`153
`
`

`
`TABLE 1—BALL/SEAT COMBINATIONS FOR 10-ZONE
`SYSTEM
`
`
`
`Ball Clearance
`(In.)
`
`
`
`Bearing_ Diameter
`Seat ID
`Ball OD
`
`(In-)
`(in.)
`(In.)
`
`0.14
`0.14
`0.14
`0.14
`0.14
`0.14
`0.14
`0.14
`0.13
`
`—
`
`0.11
`0.11
`0.11
`0.11
`0.11
`0.11
`0.11
`0.12
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`1.50
`1.75
`2.00
`2.25
`2.50
`2.75
`3.00
`3.25
`3.50
`
`1.36
`1.61
`1.86
`2.11
`2.36
`2.61
`2.86
`3.11
`3.37
`
`subassembly. This change was made as a result of the problems
`experienced during Ml completion.
`In these three wells, a mixture of phenolic plastic and coated
`aluminum balls were used. The choice of phenolic plastic or
`aluminum balls depended on the anticipated fracture gradient ofthe
`zone being treated. When all 10 zones had been individually
`stimulated, all nine balls were circulated back to surface, where
`they were caught in a special ball catcher.
`In the first two wells with 10 packers and nine MSAF tools, M5
`and M4, the completions were completed without incident. How-
`ever, things did not progress as smoothly on M3, and a potentially
`disastrous situation occurred.
`After the M3 completion had been run, the packers set, the
`hanger landed, and the tubing tested, the cycle plug could not be
`expelled. To make matters worse, the secondary pump—out shear
`ring also refused to shear. This was a serious problem because,
`without a pumping path for the fluid to follow, it would have been
`impossible to get the balls down to their mating seats.
`After numerous pressure cycles at the maximum allowable
`surface pressure, a leak developed in the completion below the
`upper packer. At the time, it was impossible to determine where the
`leak was, except that it was below the top packer. However, the fact
`that there was now a flow path meant the balls could be pumped.
`As it turned out, the smallest ball (1 ‘/5 in.) never found its seat,
`but the next ball (1% in.) found its seat and operated its MSAF tool,
`and the upper eight zones were stimulated as planned. Because the
`smallest ball did not reach its seat and the next ball did, the leak that
`had developed was between the two lowest MSAF tools. Thus,
`eight of the original 10 zones were stimulated, and the well was
`salvaged. The total time taken to install the completions and carry
`out the stimulations and well tests is shown in Table 5.
`
`5 -1/2‘TUB|NG HANGER
`
`5 -112' T.R.S.C.S.S.V.
`
`4 -1/2‘): 1~‘lI2” S.P.M
`(VALVE : BLANK)
`
`-1 ~1I2'x1-1I2'S.P.M
`(VALVE : BLANK)
`
`4 -1/2‘ RD SLIDING SLEEVE
`
`5' P.B.H. SEAL ASSEMBLY
`WITH ANN. PRESS. RELEASE
`
`
`
`3.588‘ ‘R’ NlF‘F'LE
`
`7' RETFIIEVABLE PACKER
`(1 neoran zone)
`
`7‘ PERMANENT
`PACKER
`
`4-1/2' MSAF TOOL
`(1 REQPEH zous)
`
`4-I/2' CYCLE
`PLUG/SHEAR OUT SUB
`
`(T.Fl.S.C.
`Fig.3—Schematic of a typical Joanne completion.
`S.S.V., tubing retrievable surface controlled subsurface safety
`valve; S.P.M., side pocket mandrel.)
`
`bearing areas and ball/seat clearances were carefully considered, it
`was decided to complete 10 individual zones (nine ball/seat con-
`figurations plus the zone below the lower packer).
`It was also decided to fit annular pressure release assemblies to
`the PBR/seal assemblies so that the main completion could be run
`in one trip without fear of premature release of the PER/seal
`assembly. Flutes were machined in the gauge rings of the packers
`to increase the flow rate past the OD of the packers while running
`in the hole.
`The most significant change for the next three wells (apart from
`the additional three zones in each) was the replacement of the
`simple pump—out plug with a cycle plug carried in a shear—out
`
` E ~ez~9I?«
`
`
`Open Position
`
`Fig. 4 -—MSAF tool in the closed and open positions.
`
`154
`
`SPE Drilling & Completion, September l998
`
`

`
`TABLE 2—DESTRUCTlVE PRESSURE TESTING OF PHENOLIC BALLS
`
`Part
`Number
`
`Seat ID
`(in.)
`'
`
`Part
`Number
`
`Test 1
`
`Pressure to Failure
`(psi)
`
`Test 2
`
`Test 3
`
`Quantity
`Tested
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Ball OD
`
`(in.)
`3
`—
`—
`8,200
`8,300*
`8,500‘
`1.50
`495.60209
`1.36
`641 A8
`
`3
`—
`—
`8,000*
`8,300
`8,000*
`1.75
`495.60202
`1.61
`641A12
`
`3
`—
`—
`8,000
`8,000
`8,000
`2.00
`495.60208
`1.86
`641A10
`
`3
`—
`—
`7,000
`8,000
`7,100
`2.25
`495.603
`2.11
`641A13
`
`3
`—
`—
`5,000
`7,000
`6,200
`2.50
`495.604
`2.36
`641A11
`
`3
`—
`——
`6,000
`6,000
`6,100
`2.75
`495.606
`2.61
`641A14
`
`
`4**
`4,000
`4,000
`4,000
`6,000
`2,500”
`3.00
`495.607
`2.86
`641A15
`3
`—
`—
`5,200
`5,500
`6,500
`3.25
`495.608
`3.11
`641A16
`
`
`3
`—
`—
`4,000
`4,000
`4,000
`3.50
`495.6081
`3.37
`913.01352
`
`* Indicates that ball did not fail.
`" This ball was found to be least pressure tolerant.
`
`
`
`
`
`
`
`TABLE 3—SHEAR STRENGTH OF ALUMINUM BALLS
`
`
`
`
`
`
`
`
`
`
`
`
`
`Ball on
`(in-)
`
`Seat ID
`(in-)
`
`1.50
`1.75
`2.00
`2.25
`2.50
`2.75
`3.00
`3.25
`3.50
`
`1.36
`1.61
`1.86
`2.11
`2.36
`2.61
`2.86
`3.11
`3.37
`
`100%
`(psi)
`
`16,755
`15,340
`14,225
`13,325
`12,585
`11,945
`11,400
`10,925
`10.095
`
`
`
`80%
`(psi)
`
`75%
`(psi)
`
`13,404
`12,272
`11,380
`10,660
`10,068
`9,556
`9,120
`8,740
`8,076
`
`12,566
`
`11,505
`
`10,669
`
`9,994
`
`9,439
`
`8,959
`
`8,550
`
`8,194
`
`7,571
`
`SYSTEM
`
` TABLE 4—BALL/SEAT GOMBINATIONS FOR SEVEN-ZONE
`
`
`Ball Clearance
`Seat ID
`Ball OD
`Bearing Diameter
`(in.)
`(in.)
`(in.)
`(in.)
`
`0.25
`0.25
`1.75
`1.50
`
`
`2.25
`2.00
`0.25
`0.125
`2.625
`2.375
`0.25
`0.125
`
`
`2.94
`2.75
`0.19
`0.11
`3.25
`3.05
`0.20
`0.12
`
`
`
`0.13
`3.50
`3.37
`
`
`
`Through-Tubing Intervention/Remedial Action
`The MSAF tool was designed as a single-shot device to be run in the
`closed position. It is operated to the open position by pumping a ball
`and remains in the open position. However, profiles have been de-
`signed into the inner sleeves of the MSAF tools that enable closingl
`reopening of the tools alter the initial ball-operated fiinction. A hy-
`draulic shifiing tool, which is run on coiled tubing, has been designed
`and built for this purpose. Unfortunately, this hydraulic shitting tool
`cannot be used until the ball seats (which are threaded into the inner
`sleeves) are milled out to give a large enough [D through the inner
`sleeve to allow passage of the hydraulic shitting tool.
`
`O MSAF Tools. The use of lightweight balls to operate downhole
`tools in a horizontal completion eliminated the need for coiled
`tubing intervention.
`0 Hydraulic Set Packers With No Mandrel Movement. The use
`of these packers enabled any number of packers to be run in a
`one—trip completion without having to run travel joints between
`them to ensure that all packers would be set at the same time. The
`number ofpackers that could be run was limited only by the number
`of ball/seat configurations that could be fitted into a 41/2—in.
`completion.
`0 Annular Pressure Release With Clutch Joint. The use of this
`equipment enabled heavy tailpipe to be run without concern of
`reliability of shear screws, especially when subjected to applied or
`induced torque during installation into long horizontal
`liners.
`Clutch coupling in the closed position allows rotation while running
`in the wellbore.
`
`O Multiple—Pressure Cycle Plug.
`O The use of this equipment as a plugging device in the tailpipe
`allowed various operations, such as setting of packers and com-
`pletion pressure tests, to be performed without concern of reliability
`of shear screws that could be weakened with every pressure cycle.
`
`important Points To Consider for Future
`Completions
`
`O Thorough preplanning of the overall completion program is
`essential so that contingency can be planned into the program to
`address difficulties that could occur.
`0 Onshore testing needs to be carried out on any operation that
`has not been successfully performed offshore in the past (e.g., flow
`testing of balls).
`0 The well, in general, and liner, in particular, need to be properly
`cleaned and conditioned. This is essential for running 10 packers
`in a horizontal liner.
`0 Because the cycle/pump-out plug in the tailpipe is the one area
`in which problems did occur, further development is indicated.
`Although it appears to be the least important part of the completion
`system, it is actually one of the most crucial. If the plug expends
`early, the packers cannot be set, and the completion cannot be
`tested. If it does not expend, there is no flow path to enable the balls
`to be pumped to their mating seat.
`ORetrievable seats make well workovers less costly and less
`risky.
`
`Future Developments Planned
`
`Summary of Completion Results
`
`Following are key elements that contributed to these successful
`installations.
`
`Work is currently being carried out to further improve the com-
`pletion system with the following four main areas identified as
`candidates for improvement.
`
`SPE Drilling & Completion, September 1998
`
`155
`
`

`
`TABLE 5—TOTAL TIME TO INSTALL COMPLETIONS AND CARRY OUT THE
`SIMULATIONS AND WELL TESTS
`
`True Vertical
`Depth
`(ft)
`
`Well
`
`MD
`(ft)
`
`Run Completion
`(hours)
`
`Rig Up and Test
`(hours)
`
`Stimulate
`(hours)
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`M1
`M5
`M4
`M3
`
`10,370
`15,584
`97*
`209”
`8
`
`10,272
`15,582
`65
`45
`24
`
`—
`15,765
`58
`65
`15
`
`
`
`
`
`11 10,605 15,472 51 55
`‘ Packers’ fracture tools run and set on drillpipe.
`*‘ 19 hours lost because of failure of pump—out plug.
`
`
`
`T 132 hours lost because of failure of iubricator valve and plug swagecl into nipple.
`
`
`
`0 Retrievable Seats. Although this will necessitate through-
`tubing intervention after completion of the fracture job to recover
`the seats, this disadvantage is offset by the fact that an unrestricted
`wellbore is ultimately achieved.
`0 Ball Material. Until now, both phenolic plastic at 1.3 SG and
`aluminum at 2.6 SG have been successfiilly used. However, a
`planned completion for Phillips Petroleum Co. in Norway will use
`balls made from a magnesium alloy at 1.8 SG. This material will
`thus give the high strength associated with aluminum with a density
`midway between the phenolic material and aluminum.
`0 Pressure Rating. Completion systems run to date have been
`rated at 7,500 psi. The planned Phillips Petroleum completion in
`Norway will use a system rated at 10,000 psi.
`0 Cycle/Pump-Out Plug. New technology such as disappearing
`plugs are now on the market from a number of suppliers. These may
`form the basis for a more reliable and cost-effective solution to the
`tailpipe plug.
`
`Conclusions
`
`The successful installation of four multiple packer/MSAF co1nple—
`tions in chalk formation in the North Sea proved that the system was
`not only feasible but highly efficient, both from an operational
`standpoint and from a reservoir treatment stan