SPE
`
`Society of Petroleum Engineer'S
`
`SPE 18263
`
`Simultaneous Multiple Entry Hydraulic Fracture Treatments of
`Horizontally Drilled Wells
`by C.E. Austin and R.E. Rose, Halliburton Services, and F.J. Schuh, Drilling Technology Inc.
`
`SPE Members
`
`Copyright 1988, Society of Petroleum Engineers
`
`This paper was prepared for presentation at the 63rd Annual Technical Conference and Exhibition of the Society of Petroleum Engineers held in
`Houston, TX, October 2-5, 1988.
`
`This paper was selected for presentation by an SPE Program Committee following review of information contained in an abstract submitted by the
`author(s). Contents of the paper, as presented, have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the
`author(s). The material, as presented, does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Papers
`presented at SPE meetings are subject to publication review by Editorial Committees of the Society of Petroleum Engineers. Permission to copy is
`restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of
`where and by whom the paper is presented. Write Publications Manager, SPE, P.O. Box 833836, Richardson, TX 75083-3836. Telex, 730989 SPEDAL.
`
`II
`
`ABSTRACT
`
`The number of horizontally dri 11 ed we 11 s has
`continued to increase in the past few years. Nearly
`all of
`these we 11 s have
`been
`camp 1 eted
`as
`"drainholes 11 with slotted or perforated liner and
`without a cement sheath. The majority of these have
`been successful in their designed intent.
`
`been
`have
`treatments
`fracturing
`Hydraulic
`performed on a relatively small number of these
`wells.
`To be effectively fracture stimulated, a
`horizontally drilled well must be cased and cemented
`through
`the horizontal producing section of
`the
`well. Casing and cementing the horizontal section
`allows fracture initiation points to be controlled
`in placing multiple fractures.
`
`the
`influence
`greatly
`stresses
`situ
`In
`potential effectiveness of any fracturing treatment
`The one
`factor which most directly
`procedure.
`affects horizontal wellbore fracturing is the least
`principal stress, which is at a right angle to the
`induced fracture. The direction of the hori zonta 1
`segment of the borehole dictates whether or not the
`induced fracture will be parallel or at an angle to
`the borehole.
`
`The use of properly applied controlled entry
`techniques at several
`fracture
`initiation points
`will help allow equal placement of proppant or
`stimulation
`treatment.
`in one
`reactive
`fluids
`Either
`fracturing with
`proppant
`or
`fracture
`acidizing can be used in the stimulation treatment.
`The potential economic benefit to be derived from a
`fracturing
`treatment
`successful multi p 1 e entry
`merits
`strong
`consideration
`be given
`to
`the
`development of fracturing techniques to help obtain
`maximum wellbore drainage.
`
`References and 1 I lustrat1ons at end of paper.
`
`and
`techniques
`explains
`paper
`Subject
`in creating and placing
`methods
`to be used
`prop pant and/ or reactive fluids in each of the
`in a horizontally drilled
`multiple
`fractures
`well.
`Economic
`considerations
`of
`the
`simultaneous stimulation treatment procedure are
`presented and compared to a vertical well under
`similar conditions.
`
`INTRODUCTION
`
`Horizontally drilled wells have been around
`the
`last 50 years.
`Some of
`the early
`for
`attempts were experimenta 1 eff9.r"t conducted in
`the Soviet Union in the 1950's, ' where some 43
`horizontal wells were drilled at considerable
`effort with respect to equipment, measurement,
`and
`theory.
`The conclusion drawn
`from
`this
`effort appears
`to have been
`that horizontally
`drilled wells were
`technically feasible, but
`economically disappointing.
`In the 1950's, wells
`were dri 11 ed from
`the shore in the Long Beach
`California Field
`to penetrate a productive
`offshore horizon. Dri 11 i ng reached a 90 degree
`deviation angle and
`subsequently
`relaxed
`to
`vertical
`to penetrate
`the producing
`zone.
`Because of
`the production obtai ned without
`setting offshore platforms these wells were both
`In
`profitable and environmentally acceptable.
`the 1970's, Mobil, et al. drilled a highly
`into the Pine Island Chalk. The
`deviated well
`well was
`stimulated by hydraulic
`fracturing
`through multiple
`fracture
`initiation points.
`Each of
`the
`initiation points was
`treated
`separately.
`As a
`result of
`the
`technology
`developed for th~ experiment, Mobil was issued a
`though,
`the conclusion
`patent in 1974. Again
`based on Mobi 1 's experience appeared to be that
`horizontal
`or
`highly
`deviated wells were
`technically
`feasible
`but
`economically
`disappointing.
`
`of better directional
`development
`The
`drilling techniques resultinq from experience
`
`811
`
`1 of 15
`
`Ex. 2098
`IPR2016-01517
`
`

`

`2
`
`SIMULTANEOUS MULTIPLE ENTRY HYDRAULIC FRACTURE TREATMENTS OF HORIZONTALLY DRILLED WELLS SPE 18263
`
`gained in the Gu 1 f of Mexico and in the North Sea
`led
`to
`the drilling of more highly deviated
`The· development of
`11measurement while
`wells.
`drilling
`(MWD) 11
`techniques gave more
`steerage
`for
`r the
`contra 1
`directional drilling engineer, giving continuous
`steering control of the bit. At approximately the
`same time downhole positive displacement mud motors
`were being perfected. When used with bent subs
`the capabilities of
`these motors further improved
`the drilling engineer.
`In
`fact, at present,
`drilling technology for horizontal wells
`is more
`advanced than the completion techniques.
`
`COMPLETION CLASSIFICATIONS
`
`At the SPE Forum on Horizontal Wells held in
`Durango, Colorado
`in 1987,
`the participants
`present could account for over 110 horizontal or
`highly deviated wells. Some estimates place the
`current number of hori zonta 1 wells between 300
`and 600 wells. Because a 1 arge number of the
`companies keep all information on a 11 tight hole
`basis 11 a closer determination is not possible.
`The types of production completions performed on
`horizontal wells are
`discussed
`in paragraphs
`below.
`
`DRILLING CLASSIFICATIONS
`
`Open Hole Completion
`
`(Fig. 4)
`
`the highly
`The drilling classification of
`deviated or horizontal wells being drilled at
`present falls into four groups:
`
`Group 1. Long Bend Radius (Fig. 1)
`
`-0 to 5° per 100 ft measured depth
`-Horizontal section in excess of 1000 ft
`-Torque and weight easily applied to bottom
`of hole
`-Conventional drilling equipment can be used
`-Multiple borehole sizes
`-MWD and continuous wireline measurement can be
`used for steerage.
`
`Note:
`
`If continuous wireline measurement
`used, then drill pipe cannot
`be rotated.
`
`Group 2. Medium Bend Radius (Fig. 2)
`
`-5 to 20° per 100 ft measured depth
`-Horizontal section in excess of 1000 ft
`-Torque and weight easily applied to bottom
`of hole
`-Conventional drilling equipment can be used
`-Multiple borehole sizes
`-MWD and continuous wireline measurement can be
`used for steerage.
`
`Note:
`
`If continuous wireline measurement used,
`then drill pipe cannot be rotated.
`
`Group 3. Short Bend Radius (Fig. 3)
`
`-Bend completed in less than 40 ft TVD
`-Horizontal .section usually less than 600 ft
`-Limited size of borehole
`-No continuous steerage at present
`-Limited bottomhole motors at present
`-Most casing tools and stimulation tools
`cannot traverse bend
`
`Group 4. Ultra Short Bend Radius
`
`-Bend completed in less than 2 ft TVD
`-Horizontal section usually less than 200 ft
`-Multi-horizontal section at same level
`radially
`-Specialized comple~ion tools and techniques
`developed
`
`Note: This group will not be discussed in
`this paper.
`
`hole
`open
`an
`allow
`formations
`Some
`completion without hole collapse. Tubing can be
`run
`to bottom
`to displace mud and debris by
`turbulent flow. A reactive fluid such as 15% HCl
`acid
`is sometimes spotted over
`the open hole
`section, then a matrix-type squeeze is applied in
`an attempt to correct near-wellbore damage. This
`type .of completion is used in long, medium, and
`short bend radius drilled wells. Dual straddle
`inflation packers have been used to assist in the
`control of matrix acidizing treatments.
`
`Slotted or Perforated Li~er or Casing Completion
`(Fig. 5)
`
`The liner or casing should be equipped with
`. internal wash pipe so that mud and debris can be
`removed from the annulus. A reactive fluid can
`be placed
`in
`the annulus and a matrix
`type
`treatment performed in attempting to remove near
`wellbore damage. This type of completion can be
`used on
`long, medium, and short bend
`radius
`drilled wells. Casing straddle packers have been
`used in an attempt to remove the mud and debris
`from the annulus with some degree of success.
`
`External Casing Packers with Tubing Operated
`Ported Subs (Fig. 6)
`
`External casing packers isolate sections of
`the horizontal part of the well. Tubing operated
`ported subs are sometimes placed on either siqe
`of the extern a 1 casing packers. This
`type of
`completion gives the operator a large measure of
`removing mud and debris, and
`for
`control
`in
`matrix acidizing. This completion
`is usually
`limited to long and medium bend radius drilled
`wells.
`In one particular well, straddle packers
`with a 400 ft spacing between the packers were
`used. The tool was set 12 times in the process
`of removing mud and debris, performing matrix
`acidizing, and
`testing of the various isolated
`sections in this well.
`
`Cemented Liner (Fig. 7A) or Casing (Fig. 7B)
`
`of
`type
`favorable
`the most
`is
`This
`completion for stimulation by either hydraulic
`fracturing treatments with proppant or fracture
`acidizing. The cement and casing allow fracture
`initiation points
`to be placed
`in the casing,
`thus allowing control of the fracture treatments.
`is used
`in
`long
`This
`type of completion
`and medium
`bend
`radius
`drilled wells.
`
`812
`
`2 of 15
`
`Ex. 2098
`IPR2016-01517
`
`

`

`SPE 18263
`
`C.E. AUSTIN, R.E. ROSEs F.J. SCHUH
`
`3
`
`is also being
`liner completion
`The cemented
`in
`formations containing a gas cap.
`The
`used
`deviated borehole is drilled to the bottom of the
`is
`then drilled upward at a
`producing zone and
`slight angle to the top of the zone. A liner is
`cemented and
`the well completed by perforating
`for
`radial
`flow.
`If
`the well
`is producing an
`excess of gas a p 1 ug can be set in the upper part
`to contra 1 gas flow,
`of the 1 i ner with a choke
`the
`lifting of
`thereby assisting
`the crude
`to
`surface.
`
`offsets, and (6) any other information available
`that may be beneficial to a successful completion.
`
`to
`large enough
`lease area should be
`The
`the desired
`the drilling of
`length of
`allow
`horizontal
`section.
`If
`the
`induced
`fracture
`azimuth is deemed accurate, then the well can be
`planned
`for
`an
`area of
`the
`lease. When
`geological conditions allow, it is preferred that
`the horizontal section be at right angles to the
`induced fracture azimuth.
`
`Pre-Packed Liners (Fig. 8)
`
`This type of completion has been used in the
`North Sea
`in a fie 1 d where the producing zone is
`poorly consolidated. This completion
`is used on
`long and medium bend radius drilled wells. A wash
`string is placed internal to the pre-packed liner to
`remove mud and debris from the annulus. The hole is
`all owed
`to
`collapse onto
`the 1 i ner
`and
`all
`production is through the pre-packed gravel liner.
`
`Screen with External Gravel Packing
`
`At present there are no reports of hori zonta 1
`wells having been completed by gravel packing.
`Several service companies believe that the gravel
`packing completion can be easily performed; however,
`this
`type of completion
`is
`limited
`to
`long and
`medium bend radius drilled .wells. Sand production
`has not been reported to be a problem in two cases
`in which gravel packing might have been anticipated:
`one
`in Alaska with cemented perforated
`liner,
`producing approximately 10,000 bbl/day and one
`in
`Canada producing from a tar sand.
`
`FRACTURE STIMULATION TREATMENTS
`
`This paper is intended to discuss primarily the
`fracture stimulation treatments of horizontal wells.
`Most of the completions to date of horizontal wells
`have been
`completed
`as
`11 drain holes. 11
`These
`horizontal wells are being drilled into producing
`zones
`that are known good producers
`in vertical
`wells.
`Some believe that a producing zone
`that
`requires fracture stimulation
`in a vertical well
`will
`also
`require
`fracture stimulation
`in
`the
`hori zonta 1 well . A 1 so, some of the tighter zones
`that are harder
`to produce and are economically
`questionable at present may be economically feasible
`using
`hydraulically
`fractured,
`horizontal
`completions.
`Theoretically,
`by using multiple
`fractures in the horizontal well, the same amount of
`total production will be recovered at an accelerated
`rate, thus the economical payout of the well will be
`obtained in a shorter time period.
`
`Producing Zone Data Acquisition
`
`For optimum results in fracture stimulation of
`a horizontal well,
`some
`information
`should be
`obtained to help in drilling the well and designing
`the
`stimulation
`treatments.
`Initially,
`a
`pre-drilling survey should be made.
`In this survey
`tops and
`information obtained should
`include (1)
`bottoms of the producing formation in other wells in
`field,
`(2)
`induced
`fracture azimuth,
`(3)
`the
`cumulative and daily production of the wells in the
`field, (4) if drill stem testing has been performed,
`the results of these drill stem tests, ( 5) reports
`treatments performed on the vertical
`of stimulation
`
`the drilling
`in
`be made
`should
`Plans
`prospectus for vertical hole data acquisition.
`This data can be obtained by drilling
`the
`vertical hole through the planned producing zone
`or by making the first 45° of the bend radius and
`by using a tangent section (Fig. 9). Extending
`the tangent section through the producing zone
`will
`allow
`important data
`to
`be obtained,
`including the depths of the top and bottom of the
`producing
`zone.
`Whi 1 e drilling,
`i ndi vi dua 1
`mi crofrac treatments should be performed on the
`zones above and below
`the producing zone
`in
`addition to the target zone itself. An oriented
`core should be obtained from
`the zones above,
`be 1 ow, and within
`the producing zone.
`If the
`hole is vertical, then the fracture direction may
`be determined directly from an oriented core
`which was
`fractured
`during
`the microfrac
`treatment. This has been done in about 70% of
`the
`micr~frac tests
`performed
`in
`vertical
`sections.
`If the tangent section is used then
`the same data can be acquired. ~ring should be
`oriented and strain. relaxation
`also can be
`performed to obtain the induced fracture azimuth.
`A series of wireline open hole logs can then be
`obtained. One of the logs should be
`the rock
`stress presentation of the long space sonic log.
`This
`information, when
`calibrated
`by
`data
`from microfrac
`tests,
`should give
`obtained
`sufficient
`least principal
`stress data
`to
`vertical
`placement
`of
`the
`determine
`the
`information may be
`horizontal
`section. This
`input into a 3D computer model
`to predict the
`geometry of the induced fractures. The depth of
`the top and bottom of the producing zone and the
`vertical position of the horizontal section will
`be used by the directional drilling engineer to
`radius and
`to steer
`the
`the bend
`complete
`borehole into the desired position.
`
`the
`in
`is performed
`If data acquisition
`vertical hole, this hole will be plugged back to
`the kick-off point.
`If the data was acquired in
`the tangent ho 1 e, then the p 1 ug back depth will
`be the kick-off of the second 45° segment of the
`bend (Fig. 9). A planned tangent section between
`the first and second 45° section of the bend
`a 11 ows for corrections in entering the correct
`vertical placement of the horizontal section.
`
`Horizontal Section Drilling and Cementing
`
`Most hori zonta 1 wells ·can be drilled and
`camp 1 eted with the same sizes of casing set at
`the same vertical depths as
`the conventional
`If an intermediate protection
`wells in the area.
`casing is require, the horizontal well can be
`completed with a
`liner.
`If no
`intermediate
`casing is required, the horizontal hole can be
`
`813
`
`3 of 15
`
`Ex. 2098
`IPR2016-01517
`
`

`

`4
`
`SIMULTANEOUS MULTIPLE ENTRY HYDRAULIC FRACTURE TREATMENTS OF HORIZONTALLY DRILLED WELlS
`
`SPE 18263
`
`cased and cemented with a casing string run from
`the surface.
`
`The horizontal section can then be completed as
`planned.
`The mud
`system
`should
`be
`carefully
`controlled and monitored to prevent excess solids
`accumulation and
`to assist
`in
`the
`removal of
`cuttings
`from
`the horizontal
`section. After
`the desired TD,
`the casing or
`liner
`reaching
`should
`be
`run
`and
`cemented.
`Recommended
`cementi ?g practices by Keller et a 1. 6 and Wilson
`et al.
`include a non-settling,
`0%
`free water
`cement.
`If comp 1 eted with a 1 i ner, the 1 i ner top
`should be placed
`in the straight tangent section
`of the bend radius and
`tied into an
`intermediate
`casing. This practice should assist the entry of
`tools into-the liner with a minimum of trouble.
`
`PLANNING STIMULATION TREATMENTS
`
`is
`Whi 1 e the hori zonta 1 section of the well
`being dri 11 ~d, cased and cemented, some decisions
`can be made. Using
`the data obtained from
`the
`producing zone, the following should be determined
`or established:
`(1) maximum
`treating rates
`(2)
`initiation points,{3) fracture design(4)
`fracture
`perforation design, and (5) pre-frac considerations.
`
`Maximum Treating Rates
`
`The size of the long string or the intermediate
`casing and
`liner will determine the maximum rate
`that can be pumped down the casing without causing
`damage.
`If the velocity of the fluid in the tubular
`goods
`is greater
`than 100
`ft/sec
`then
`severe
`erosional damage can occur at the joints and offsets
`of the tubu 1 a rs; when
`the fluid contains proppant
`is magnified.
`the damage
`Erosion a 1 damage
`is
`minimized if velocity is limited to 80 ft/sec. The
`maximum
`recommended rates for different size and
`weights of tubulars are shown in Table 1. The rate
`can be limited by the equipment used to perform the
`stimulation treatment with proppant. For example,
`factor when
`the blender becomes a controlling
`describing the maximum rate in terms of pounds of
`proppant per gallon. This rate is between 50 to 60
`bbl/min at 6 lb/gal of proppant. Thus, it can be
`seen
`that
`if the
`required stimulation
`rate
`is
`approximately 110 bbl/min, then two blenders will be
`needed.
`In designing the tota 1 stimulation rates,
`the service company performing the treatment should
`be contacted to assist and advise the rate, proppant
`concentration, and equipment
`for designing
`the
`stimulation
`treatment,
`based
`on
`equipment
`specifications.
`
`Fracture Initiation Points
`
`be
`can
`initiation points
`number of
`The
`arbitrarily selected or can be determined by a
`computer mode 1. -Figures 10 and 11 show the output
`from a single gPhase, finite difference fractured
`well simulator.
`No fluid is assumed to cross the
`lease boundary and fractures are uniformly spaced
`the hori zonta 1 well bore.
`Fracture
`flow
`a 1 ong
`capacity for each fracture is obtained from fracture
`simulators that are to be used in the stimulation
`design. Figures 10 and 11 indicate that for this
`specific example five to seven fractures will be the
`most effective number in draining the lease. This
`number of initiation points could be modified upward
`if the producing zone contains natural fractures.
`
`the absence of computer models or better
`In
`guidelines
`the
`initiation points are
`generally spaced 250
`to 300 ft apart.
`
`Fracture Design
`
`Parameters of the treatment depend on data
`acquired from
`(1) the production zone, (2) the
`zone directly above, and ( 3)
`the zone directly
`below,
`during
`the
`data
`acquisition
`phase
`discussed in previous paragraphs. Also, the rock
`stress presentation from
`the 1 ong-spaced sonic
`log is calculated for each zone, then this and
`data acquired
`from
`the zones
`are used
`to
`calculate an average least minimum stress for the
`3D
`fracture design
`A fully
`three
`zones.
`simulator can
`then be used
`to determine
`the
`fractl.lre geometry,
`(height, 1 ength, and width)
`for a given treatment, and a 3D simulator can be
`used
`to create data similar to that shown
`in
`Figs. 12-15. Figure 16 shows an ex amp 1 e cross
`section of
`the zones with
`their calculated
`minimum stresses; geometry of the fractures is
`controlled by
`these
`stresses.
`If a water
`producing zone is near the hydrocarbon producing
`interval, then the fracture should be designed so
`that it will not extend into the water producing
`zone. After fracture geometry is determined by
`the
`simulator, additional calculations are made
`for proppant transport and placement. Figure 17
`shows this output.
`
`Perforation Design
`
`the number of initiation points, the
`When
`and
`the
`treatment
`rate
`for each
`geometry,
`fracture have been determined,
`the number and
`diameter of perforations in each initiation point
`must be designed.
`To calculate the parameters
`the perforationssg .a.. process called
`the
`for
`Limited Entry Technique ,ru is used. The formula
`for this calculation is shown in Eq. 1 and the
`formula for the perforation coefficient is shown
`in Eq. 2.
`The perforation coefficient varies
`during
`the
`stimulation
`treatment.
`The
`perforations have a sharp edge which causes the
`fluid flow profile to decr~ase in diameter as it
`flows through the perforation (Fig. 18). Within
`minutes after proppant has been pumped
`through
`the perforation the sharp edge
`is 1 ost and a
`rounded edge appears (Fig. 19).
`Crump11 et a 1. showed that the perforation
`coefficient
`(C ) with
`a
`sharp
`edge
`is
`<P.s
`approximately
`and after proppant
`flows
`through the perforation the erosion rounds out
`the perforation and the perforation coefficient
`approaches 1.0.
`Crump also showed
`that
`the
`diameter of
`the perforation
`increases only
`slightly; the major change is the increase in the
`perforation coefficient. Table 2 shows a table
`of calculations using the Limited Entry Technique
`to determine the number of perforations. Based
`on a rate of 13 bbl/min and a perforating charge
`in 5. 5 in. , 23 1 b/ft casing, the
`of 32 grams
`nominal perforation diameter should be 0.54 in.
`Assuming
`the operator wanted
`the perforations
`horizontal
`in the pipe the design diameter is
`0.55 in.
`(The gun is slightly below the center
`of the casing.) Also, if the gun
`is
`laying
`against the casing, the maximum diameter is 0.57
`in., and if the gun is the farthest possible
`
`814
`
`4 of 15
`
`Ex. 2098
`IPR2016-01517
`
`

`

`SPE 18263
`
`C.E. AUSTIN, R.E. ROSE, F.J. SCHUH
`
`5
`
`the casing the minimum diameter is
`distance from
`0.51 in. Table 2 was calculated using linear gel
`fluid with coefficients of 0.5 and of 0.95. Also
`shown
`is
`the
`perforation
`friction
`for
`the
`different sand concentrations
`for
`the proposed
`sand schedule. A minimum perforation friction of
`at least 250 psi
`is required.
`The use of four
`holes
`for
`this
`size
`gun meets
`the
`design
`requirements. Note
`that before proppant erosion
`the perforation friction
`ranges between 797
`to
`1,243 psi, and after erosion
`the range
`is from
`to 462 psi. These calculations are similar
`221
`to the calculations used in a previous
`in which
`fracture
`stimulation
`treatment
`fractures were stimulated simultaneously.
`
`nine
`
`Ppf = 0.237 FD
`
`(N2 C 2 D 4)
`p
`p
`
`..• (1)
`
`Dv
`Dp . • . • • • . . (2)
`
`Pre-frac Considerations
`
`Before the actual treatment is pumped, each set
`of perforations at each initiation point should be
`broken down and an injection rate established. To
`perform this operation, a straddle packer is used.
`The packer is so designed as to provide a minimal
`amount of friction pressure after the fluid leaves
`the tubing and before it enters the perforations.
`This operation
`is essential for
`the simultaneous
`multiple entry hydraulic fracture treatment. Also,
`the breakdown with a straddle packer creates and
`initiates an individual
`induced fracture. This operation should ensure that
`all initiation points take equal volumes of fluid
`and proppant. During
`the breakdown operation,
`pre-fracture measurements may be obtai ned and the
`designed stimulation
`treatments modified,
`if so
`warranted, from
`the information acquired from t~2
`following prE1_-f.rtwture techniques:
`(1) Shelley15
`(2) minifrac,
`'
`or (3) a combination of these.
`
`A well with 2,000 ft of horizontal section
`fracture stimulated with proppant using
`the
`was
`this paper.
`Surface
`procedures
`presented
`in
`indications (designed rate and
`treating pressure)
`were positive that all nine initiation points were
`fractured and propped simultaneously at a total rate
`of 108 bbl/min with a delayed crosslinked gel
`carrying a maximum proppant concentration of 6
`lb/gal. Each initiation point was treated at a rate
`of 12 bbl/min. A radioactive tracer was used in the
`proppant, and the log performed after the treatment
`indicated
`that all
`initiation points contained
`radioactive proppant.
`
`Cost Effectiveness
`
`The cost of drilling a horizontal well with a
`2000 ft horizontal section has been reported as
`twice
`that of a vertical well.
`The cost may
`actually run several
`times hi_gher on a company• s
`first attempt at a horizontal completion.
`As
`experience
`is gained,
`however,
`the
`cost of
`drilling/completing
`subsequent
`horizontal wells
`shou 1 d drop. The hori zonta 1 wells drilled on the
`North Slope are reported to be costing 1.25 to 1.5
`times that of a conventional directional well. This
`cost has been achieved after more than a dozen wells
`
`were drilled. The first well had a cost factor
`of approximately seven.
`The
`same
`should be
`expected
`in drilling horizontal wells
`for
`fracture stimulation. The early wells will be
`more expensive than 1 a ter we 11 s when experience
`It is expected that the
`will reduce the cost.
`cost for a fracture stimulated well can be less
`than twice that of a vertical well.
`
`If stimulation treatments are performed one
`at a time
`in horizontal well completions, the
`cost is the same as if each treatment was similar
`to a vertical well. One way to reduce cost is to
`perform
`all
`the
`treatments
`by
`using
`the
`simultaneous multiple entry fracture techniques.
`For example, one well has had nine fractures
`created and
`treated at one time. Other wells
`have been planned that will have three sets of
`three
`fractures
`performed
`simultaneously.
`Whenever
`multiple
`simultaneous
`fractvre
`treatments are performed
`the
`total cost of
`stimulating will be less compared to performing
`multiple individual treatments.
`
`Fracture Acidizing vs Fracturing With Proppant
`
`This paper has rna i nly referred to fracture
`stimulation treatment with proppant. This type
`is performed more
`than fracture
`of fracturing
`acidizing since fracture acidizing can only be
`performed on carbonate producing zones, and not
`all carbonates are effectively stimulated by
`fracture acidizing. However, where
`fracture
`acidizing can be used effectively because of the
`the results are
`higher fracture conductivity,
`usually better than obtai ned by fracturing with
`If a producing zone can be stimulated
`proppant.
`by fracture acidizing the same basic steps given
`this paper can be used
`to perform
`the
`in
`treatments by using
`the simultaneous multiple
`entry hydraulic
`fracture
`technique using
`a
`reactive fluid, i.e., acid.
`
`SUMMARY AND OBSERVATIONS
`
`hydraulic
`entry
`Simultaneous multiple
`fracture treatments are presented as a viable and
`economical method
`for
`hydraulic
`fracture
`stimulation of horizontal and highly deviated
`wells.
`
`Many methods of horizontal completion used
`are usually dictated by the reservoir.
`
`Comprehensive reservoir data is a necessity
`designing
`simultaneous multiple
`entry
`for
`hydraulic fracture treatments.
`
`The following observations are supported by
`present horizontal well dri 11 i ng and comp 1 eti on
`trends:
`
`1. The number of horizontal we 11 s dri 11 ed
`will increase as more successes are achieved and
`more
`information
`is made
`available
`to
`the
`industry.
`
`2. The number of completions with slotted
`1 i ners will
`decrease
`and
`other
`types
`of
`completions
`affording more
`control
`for
`the
`different forms of stimulation will increase.
`
`815
`
`5 of 15
`
`Ex. 2098
`IPR2016-01517
`
`

`

`6
`
`SIMULTANEOUS MULTIPLE ENTRY HYDRAULIC FRACTURE TREATMENTS OF HORT70NTAI IV nRTI I Fn WEI IS
`
`SPE 18263
`
`in
`be drilled
`3. Horizontal wells will
`greater numbers with
`the
`intention
`to
`fracture
`stimulate, either with acid or proppant.
`
`4. Simultaneous treatments will increase as an
`economical necessity.
`
`paper
`the
`in
`presented
`techniques
`The
`for completion of a
`comprise only one method
`horizontal well.
`The
`type of
`formation
`and
`experience with horizontal wells
`in a particular
`formation will dictate the most appropriate type
`of completion to be used.
`
`Nomenclature
`
`Perforation Coefficient
`
`Sharp Edge Diameter (in)
`
`Perforation Diameter (in)
`
`FD
`
`N
`
`Fluid Density (lb/gal)
`
`Number of Perforations
`
`Ppf =Perforation Friction (psi)
`
`R
`
`Injection Rate (bbl/min)
`
`Acknowledgements
`
`to thank the management of
`The authors wish
`Drilling Technology Inc. and Halliburton Services
`for
`permission
`to
`publish
`this
`paper,
`and
`acknowledge Bill Ray and Debbie Smart for
`their
`assistance in the preparation of the paper.
`
`References
`
`11 Site Selection
`1. Bosio, J., Reise, L. E.,
`Remains Key
`to Success
`in Horizontal Well
`Operation, 11 Oil & Gas, March 21, 1988, p. 71.
`
`couches
`des
`11 Forage
`A.M.:
`2. Grigorian,
`puits
`horizontaux
`par
`productives
`et
`a
`completion multiple, .. Moscow,
`11 Nedra, 11 1969, p.
`190.
`French
`translation of
`the original
`Russian Text.
`IFP 27746, February 1980.
`
`3. Mobil Patent: Strubhar, M. K., Glenn, E. E.
`Jr.:
`11 Method of Creating a Plurality of
`Features from a Deviated Well, 11 U.S. Patent No.
`3,835,928 (1974).
`
`4. Daneshy, A.A., Slusher, G.L., Chisholm, P.T.,
`and Magee, D. A.:
`In Situ Stress Measurements
`During Drilling,..
`JPT, August 1986, pp.
`891-897.
`-
`
`5.
`
`11 Laboratory
`El Rabaa, A.W.M., Meadows, D.L.:
`and Field Application of the Strain Relaxation
`Method, 11 SPE Paper 15072, presented at the 1986
`California Regional Meeting, Oakland, CA. April
`2-4.
`
`6. Keller, S.R., Crook, R.J., Haunt, R.C.,
`Kulakofsy, D.S.:
`11 Problems Associated with
`Deviated-Well bore Cementing . 11 Paper SPE 11979
`presented at
`the 1983 SPE Annual Technical
`Conference and Exhibition, San Francisco, CA,
`October 5-8.
`
`11A Laboratory
`7. Wilson, M.A., Sabins, F. L.:
`of Cementing Horizontal
`Investigatio~
`Wells, 11 Paper SPE 16928 presented at the
`1987 SPE Annual Technical Conference and
`Exhibition, Dallas, TX, September 27-30.
`
`110n
`8. Soliman, M., Hunt, J., El Rabba, A. W.:
`Fracturing Hori zonta 1 Wells, 11 SPE 18542 to
`be
`presented
`at
`SPE Eastern Regional
`Meeting, Charleston, W. VA, Nov. 1-4, 1988.
`
`9.
`
`11 L imited Entry for Hydraulic Fracturing, 11
`Halliburton Services, Fracturing Technical
`Bulletin, 1988.
`
`11 Better
`J.W.:
`10. Lagrone, K.W., Rasmussen.
`Completion by Controlled Fracture Placement,
`Limited Entry Technique... API Paper No.
`906-7-B, presented at the Spring Meeting of
`the Southwestern District Division
`of
`Production, Odessa, TX, March 21-23, 1962.
`
`11 Effects of
`11. Crump, J.B., Conway, M.W.:
`Perforation Entry on Bottomhole Treating
`analysis, 11 SPE Paper 15474 presented at the
`1986 SPE Annual Conference and Exhibition,
`New Orleans, LA.
`
`11 Pump-in Test
`12. Shelley, R.F .. , McGowen, J.M.:
`Correlation Predicts Proppant Placement, ..
`Paper SPE 15151 presented at the 1986 Rocky
`Mountain Regional Meeting, Billings, MT, May
`19-21.
`
`11 New Method of Minifrac Analysis
`13. Lee, W.S.:
`Offers Greater Accuracy
`and
`Enhanced
`Applicability, .. Paper SPE 15041 presented at
`the 1986 Eastern Regional Meeting, Columbus,
`OH, November 12-14.
`
`J.M., Lee, W.S.,
`14. Tan, H.C., McGowen,
`Soliman, M.Y.:
`11 Field Application
`of
`Improve
`Fracture
`Minifrac Analysis
`to
`Treatment Design, 11 Paper SPE 17463 presented
`at
`the 1988 Regional Meeting held at
`Bakersfield, CA, March 22-25.
`
`15.
`
`COMPUVAN, 11
`the
`11 Pressure Analysis with
`Halliburton Services, Fracturing Technical
`Bulletin, 1988.
`
`Table 1
`
`MAXIMUM RATE
`for Size and Weights
`Of Casing or Tubing
`
`Size W