`
`SocEmgufFemwflannEmjmfiws
`
`SPE 18255
`
`insights into Hydraulic Fracturing 01‘ a Horizontai Wei! in a
`Naturaiéy Fractured Ffirmafien
`by AW. Layne, v.3, 30E, and H.J. Shiwardane, West Virginia U.
`SP5 Membem
`
`
`
`2
`I'hls yaw! wag prwfiwd is: grissc-mau’on a: the 63rd Annuai Tenhnicai Canismnna and Exhibman oi the Sociaiy ar Pauuiaum Engineers new in
`Haufiém, 7X, acme: 53%; 11353.
`
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`SFESfiL
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`«paper;3: was»: 2128:; Wrrze 5‘22
`
`to be necassary'in farma— BfiCKGROUND
`Horizantal wells are thought
`
`{inns with law«permeability such as the Bevonian shales
`Recent investigatians at the 3.3. Departmant of
`ta increase natural gas recavery and tn reduce the
`risk of drilling a dry hole.
`In a horizontal well3
`Energy’s Horgautewa Energy Technalagy Center have
`the haze hale crasses multiple natural fracturas ia,the addressed the yntantial hf horizontal wells :0
`reservair. Stimulation data Exam 3 2,000 ft (éegaé m)
`increase the gas recavary from inwapermeability
`harizontal well'drillgd intn the Devnnian xhales in
`formations
`A 2000 ft (699. 6 m) borizental well was
`Wayné Cnunty, West Virginia, was used in this study;
`driliefi inta the Bevonian shala formatian in Wayne
`
`Amwym»...mwummmi
`.3.MWM..NW”W,¢“”.
`
`Inflatable packers aufl easing port collars were used
`
`50 that indivifluzl zones squid be tested or stimulacefi
`along tha wellbnren
`
`360unty, Wes: Virgi.nia, he a measured length of 6,620 ft
`
`(1 835 m) and up :0 a true Vertical depth of 3 403 ft
`(1 03? m)
`
` 1
`
`5--.m_vwvw—-.--
`-‘-'~7W'l"-r<r‘
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`Hm--W..M»r_1....(.~1.¢.ww<hw,
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`
`This paper focuses on an analyéis 6f hyfiraulic fratture:A schematic 8f ta: well coafiguratian is Shawn in Fig"
`design and geometry pradictions for the above harizonr gaze I.
`The fracture spacing and lacatians of casing
`tal wall. Current hydraulic fracture modeling thenzies‘packété wera determined with a dawnhele video camera
`address failure mechanisms and the yropagation of a
`Eand geaphysical well logs.
`Seven zones were iswlated
`single crack frdm a vertical wellbareq These theazies
`along the horizantal'aection with external casing
`have been adapted to grgdict the pressure, flaw rgte,
`:pL3nars and part :nliars as part fif Chg cafiing stz'ifig.
`anfi induced fracture gemmetry for each natural fracture Tnc part callaxs and packers were used to isolate
`intersected by the hydraulic fracturing fluifi in the
`estimulatien intervalg with existing perforations.
`harizontal wellbore.
`A tubing/annulus flow model was
`gFraccuting fluids weta injectefi thraugh tha part calm
`cvuyled with a hyfiraulic fracture model that pradicts
`lars into the wellbare tubing and annulug ta pressurize
`the threevdimeusional geometry of multiple natural
`the natural fracture system” Stimulatious were Perm
`fractaras propagating from a horizontal well” Addi“
`iarmad in Zane I (see Figure 2) with nitrogen, cafibon
`Eianally, a clased—form solution was devalapad to 9:3“ dicxida, and sandnladen nitrcgen {aam ta determine
`dict thé pres$ure and flew rate distributien slang the
`{kc mast effective fracturing fluifi Eat
`the shale
`lateral extent of the wallhoreA
`‘
`fazmation.
`
`1.3% $32 ’Im'fCTZ'071'
`
`Prefiieted results wera compared with in situ fracture
`diagnostics from gas (nitrogen and C02} and foam stimum
`latiou treatments. Radiaactive—tracax with spectr81~
`333mma—tay logging coafirmeé that bath fluid pressuré
`§and attess perpefiéicular ta the fracture affect the
`ginjeatian flaw rate distributiaa alang the wallborea
`EBoth cf these factors were used as governing machanisms
`§far fracture geometry preflictinns in the simulation
`Emofielu Preditvicus basad on these mo&als and traccx
`Elags canfirm that the Singla crack theory fut fracture
`{propagation is not agplicsble far stimulations that
`are initiated along an isolatad part of a horizantal
`borehola.
`
`Tfla abjective 0f this study an a horizcntal wellbore
`was he determine the recovery sffectiveness cf the
`natural fractura system and the impact af stimulating
`:fie wall by hyflraulic fracturing. Fiva stimulatiuns
`
`h, V-Z‘ been perfumed. Multiple fractures were greys!"
`gataé simultanecufily during these stimulatian treat“
`Gents.
`Tha well was drilled in the direction 0f the
`
`flifiimflm grincipal stress and arthogonal to the mafia:
`recture systgm in the resarvoir,
`Six natural fracture
`firéqatatigns were iflentified with the downhcle viaeo
`amara and gaaphysiaal well lags.i Figura 2 deyicts
`3& natural fracture pattern and orientaticns in
`
`when highmpressure fluid was pumped flew: the
` gay-37: ,
`References and illustrations at and a
`
`
`an» 3?HalKR uf the we1 aagyrquv ~11vr3’
`
`§ 3E 5 EEs
`
` i
`
`1 of 12
`1 of 12
`
`DEFINV00008252
`
`Ex. 2076
`EX. 2076
`IPR2017-00247
`IPR2017-00247
`
`

`

`
`
`mmmW—W-W-m-
`2
`INSIGHTS TO HYDRfifiLlC FRACTERING OF A EORTZONTAL WELL IN A NATURALLY FRACTURED FORMATIGN
`
`SYE 18255
`
`(11.53 cm) casing with an annulus of 2.2uio (5459 cm)
`tubing.
`
`During the injection at 12 barrels per minute {bpm}
`(1.§2 mzym), 10dinew131 isotope tracer was included
`while Scandium~46 isotope tracer was included during
`the higher injection rate of 20 hpm (3.29 mgpm).
`The
`maximum surface pressure was 2,642 psi (18,216 kPa),
`when the iajection rate reached 20,? bpm (3.31 m3pm).
`The first 290 bbl
`(31.79 m3) of liquid carbon dioxide
`were injected at 12 bpm [1.92 mgym), while the last
`400 bhl (63.5? ms} were injected at a rate of 20 bgm
`(3.2 mspm).
`The well was opened to flow back 5 hours
`after the job wafi completed.
`The recorded treatment
`rate: and bettummhnle pressuzes for Stimulation I are
`Shawn in Figures 3 and 4.
`
`Stimulation Treatment II
`
`
`
`a care
`Stimulation :1 consisted of a hybrid treatment:
`hon dioxide pad followed by a Saud~laden, afivquality,
`nitrogen team treatment whexe the liquid phase canw
`sisteé of 7¢5 pexcemt methanol and water. The hybrié
`treatment was selectefi since results of previous stimu‘
`latices indicated that carbon dioxide is the preferred
`base fluid for this shale formatiou.
`Since information
`an the sand Carrying characteristics of carbofi dioxide
`foam is sparse, nitrogen foam was used as the Proppant
`transport fluié.
`The injectien rates aué computed
`bottam"hole preséure for Stimulation II are ghowu
`in Figures 5 and 6. Phase I consisted of 11% bbi
`(450.5 2) 0f a carbon fiicxide prayed that was pumped
`at a rate 9f 3 bpm {Akg m3pm).
`Phase II cofisisted of
`7,00G gal
`(Zfi,498 i) of an 85-quality nitrogen foam
`§pad iejected at 10 bpm (1.6 mzpm}; aufi Fhaee III ecuw
`sisted 3f four stages of Efiuquality nitregen foam
`laden with %.5 to 2.0 lblgel {.95 Kg/E to .Zé Kg/fi)
`20f ZGIQG mesh gand.
`The well started taking finifi at
`770 psi (5,309 kPa) and the suzfate pressure increasefi
`
`slawly to a maximum of 1,839 psi (12,755 kPa)!
`Twn
`radioactive tracers were used. AntimonywlZé was injec“
`ted into the foam pad and Iridiumulgz pellets were
`injected into the preppznt.
`A spectral gamma ray teol
`‘was pumped down with nitrogen in the airvfilled batin
`zontal wellbare ta measure the tracer distribution
`‘along the casing annulus.
`
`
`§§§r§cteristics of Eatural Eractureg
`
`'Four primary sets of data are zequired to predict the
`:geometry of a single, planar, hydraulic fracture in a
`vertical well:
`(13 fluid type, injectien volume, and
`rate; {2) rock mechaflical properties; {3} prappant
`characteristics and treatment schedule; and (&) reser“
`voir gtuperties. Additimnal flute sets are necessary to
`predict the fracture geometry £3 a horizontal well:
`(1) the number of natural fractures ascepting fluid;
`and {2} natural fracture characteristics such as orien—
`tatifin, extent, spacing, and vertical displacement
`‘between each fracture. Mechanical and farmetion flow
`properties need in the present prefiictiou are given in
`Table l.
`The formation properties were measured from
`well ante samples,1 asd the mechanical properties of
`the shale are typical measured values for flevouian
`‘shales.
`The fluifl rheolagical properties were taken
`free available literature‘2’3
`
`n..
`
`iFracture characteristics required to prefiiet the geome~
`tries are depicted in Figure 2 and listed 13 Table 2.
`fracture spacing is iedicateé as the measured distance
`between gruuys of natural fractures, Vertical dis~
`placement, which ie indicated as eh, is the change in
`wellbore depth between fiiserete fractures,
`The range
`in otientatien of fractures for this well is N22°E
`to wasaw with N52°E being the directiou of maximum
`principal horizontal stress in the reservoir, or the
`preferred orientation for an induced vertical hydro“
`fracture.
`In Zone 1,
`the primary groups of fractures
`iconsisted of N5?°E end K6?°E orientations. These two
`sets have the lawest values of direct normal stresses
`compared to other orientatiane in the zone, and these
`
`
`sets acceptefi most of the fluid duriag both.Stimula~
`ticns l and II.
`The direct normal stressea were calm
`
`Foeumentatiua of the stimulatious of this horizontal
`culated for each fracture orientation and are shuwu in
`yell can be found in Reference 4‘
`A total ef three
`
`Table 2. These values were calculated with data from
`etimulatioe treatments were perfarmed in Zone 1.
`Two
`
`a minifzacture treatment perfnrmeé 0E Zone 6‘ During
`pf these utilized carbon dioxifie while one used only
`
`this miniftac,
`two distinct closure or minimum stress
`bitrogen gas without a propping agent.
`?redictions for
`
`measurements were obsetveé from pressure decline
`toe of the stimulations are preseated in this paper.
`
`fiti elation I censistod of 126 tons (108,862 kg) 0f
`curves. Theie values were 1,050 and 800 psi (7,239as
`
`and 5,515.8 kPa).
`The two fieminaut fracture systems in
`iliguid carbon dioxide injected down tbe A.5~iaWWW“
`
`
`725
`
`2 of 12
`2 of 12
`
`DEFINV00008253
`
`Ex. 2076
`EX. 2076
`IPR2017-00247
`IPR2017-00247
`
`;ftactuzes were enlargedd Actual breakdown of the shale
`Emay not have eccucred: but fluid leek~off and euhee~
`gquent expansien of the existing fracture system took
`Eplace.
`The objectives of the treatments were (1) to
`their anther and location,
`(3) ta identify the mast
`effective treatment desigfi, and (4)
`to investigate th
`influence of propping agents on fracture efficiency in
`a low stress area.
`
`iinducpmultiplehydraulicfractures, {2)
`
`todetermine
`
`Field experiments éetermiaed the effects of fluid type,
`injection rate, fluid volume, and bottomehole treating
`pressure on stimulatien performance. Several stimu1a~
`tion issues were investigated:
`(1} the number of
`natural fractures that can be propagated simultane-
`ously,
`(Z)
`the need for a proppant to sustain high con“
`ductivity aiter stimulation,
`(3) the impact of fracture
`“characteristics on fluid interaction aué propagation,
`and (d) the selection of the best fracture diagnostic
`system to detect fluifi 1055 along the wellbore Casing.
`
`% 2
`
`gThe field experiments inflicated that the most effective
`ifracture oesign consisted of a hybrid treatment with a
`'carhcn dioxide pad and a high quality nitrogen foam as
`the fiend transport fluid. This prevented screenout and
`jformatiufl fiamage while maiutzieing pust~stimulation
`ifracture conductivity.
` _This
`paper focuses on the prediction of multiple fies“
`geometries with two hydraulic iraeture models that
`Etute
`been adapted far a horizental well. Measured data
`{have
`Efrem two of the stimulations performed in Zane l were
`Eused to compute fluifi flow and pressure distributifine
`Ealoug the wellhore. Fracture geometries wexe predicted
`Ewith these boundary cauditions at the wellborei Ehese
`Epredictione provifie insight into the performance of a
`Ehydraulic fracturing treatment in a horizontal well,
`Eand these prefiictious could be used in future stimulaw
`itiou designs.
`
`Egfiewififzalefiiea
`
`

`

`SPE 18255
`
`A.
`
`W. LAYEE ARE
`
`H; J. SIRIWAEDANE
`\
`
`Ethis znne are N67°E and a probable intersectinn of
`:N45°w frmm Zone 7 A direct stress 0f 1,050 psi
`:(1, 213?. 5 kPa) was asrumeé for N44aw, and 800 psi
`5(5 515$ kPa) was assumed for N67°E.
`A stress trans”
`iformation was usad to back calcuiare the maximum and
`Eminimum griucipal atresaes and direct uarmai attesses
`for other arieutations,
`
`IEEE“ Log Results
`
`Spectral gamma ray legging was used to qualitatively
`measure the amunnts of tracer—laden fluids and proppaut
`injected iata galactad fractures al.0ng the we11.bore *
`The tracer leg from Stimulation l is shown in Figure 1.
`Tracer logs iufiicated that during the first phase 0f
`the stimulation, fluids propagated into Fracture Sys~
`tam I (Figure 23 and enterad the fault system that
`intersects Zone 4.
`A Lracer was detected in Zone A
`fram this phase of pumping. Fluids peuetratsd Fracture
`System II (Figura 2) during Phase II when {ha injection
`§rate and pressures were increased.
`The tracer log
`‘indicated that 51 af the 69 fractures presant in Zone 1
`
`accented fluid during Stimulat.ion I fiLring Qhase II,
`
`fluids penatrated FrJCtur- ;§;5tem IT and travgled back
`to the. wellbore as aifleacgd "is the svadim that war
`detectad in Zune 2. This inditates that a highly couu
`nected fracture systam exists in the reservair, amfi
`this system promotes multiple paths sf axpandeé natural
`fracturas from a single stimulatian treatmentq
`
`The tracer leg from Stimulatiun II appears ta be simi—
`lar to that from Stimulatinn I Eva1.uation 9f the lag
`:indicatés that 43 old fractures that accepteé fluid
`during Stimulation I were re cgened sud prayped.
`Six
`of the 43 reteivcd the majority of the praypant.
`
`
`
`Ifii
`pressure and flow rates at each fracture location
`the first methad
`the frac.Cure injection rate, fracture-
`pressure, and flaw rate downstream af each fracture
`were camgutad numerically ufiiug an iterative schemeo
`qu the seccnd methcd,
`the problem was simplified and a
`icloged~form goiutien was obtaiueda Results Exam bath
`Tmathods were then campared with available field
`: “BEES I! remnants .
` Btive Scheme
`5W
`
`(P3D) fractura madelS was
`‘A pseudo three-dimensional
`‘used in the iterative scheme far Camputing fracture
`fiprassures and injecticn rates.
`The ralationship
`‘herween frasture injection rate and wellbore pressures
`”fur a P3D agyroximation can be written as
`
`
`
`h
`
`3
`2+
`'
`mm =1 {(33% " ~53 3 dy
`~h
`
`,
`
`<1)
`
`where:
`
`16
`1
`g : gm k'
`
`n n’+1
`(2 + r}
`(2) '
`
`r i 1/u’
`
`,
`
`h E Kali frgtture height,
`33 : Fracture pressure gradient,
`nf = Fluid behavior inflex, ané
`
`r
`
`3
`1
`
`E
`5
`g
`
`k” : Fluid ccusistency index”
`
`‘
`
`§§ is tha pressure gradient in the rudirectiom, and
`:w is the fracture width The value Q2(x, t) is the
`Efluid injection rate inta the natural fracture 10\area
`at éistance x from the part callar (Figure 83.
`The
`governing equacion fcr,the three-dimenaiausi fracture
`Iflew modala can he exprassed as
`
`__
`—~
`Q2 —
`
`a
`
`.-
`
`n
`
`a 1 2m + 1
`an
`E1
`
`W
`
`g2 u
`{(62
`
`‘2
`f1;
`
`(2)
`
`
`,
`
`E
`E
`
`E E
`
`iThesa 1335 were used as fracture diagnostics to iden-
`BLify the relative amgunx of fluid that entered each
`fracture,
`Two forms of fluié entrance ware identified
`on tha basis at tracar legs:
`{1) annulus leak—off, and
`i€23
`large iujection flow inta éiscrete fractures”
`iLeaknaff is defiued as a small amount of fluid thaL
`ideas not Peufitrate or significantly Jefsrm the fmrman
`:tion;
`Large injectian flow is defi.ned as a significant
`irate 95 fluid penetration that is capable of carrying
`Ea praypaut and inflating existing fractures to enhance
`ireservair permaability
`The large injecticn fractures
`iidentified in Figure 7 currespond L0 the peaks an the
`gtracer 1935.
`The intermefliate low lava} peaks located
`3ngtwnfin the high yeaks are considerefl to be leak~off
`luca'ions. This flow inta the fermatiun is flat con-
`
`1 significant when usmpared with the large
`‘
`iuta discrete fracturea.
`The large injec~
`iinjeetiaas
`Lion flaws
`were camguted aufi used t0 predict induced
`fracture geamatrie..
`
`GOVERNING EQUATIDNS
`
`3
`+ (723 ~ r2321
`
`(1 m m}
`2m
`
`,
`
`+
`
`where‘
`
`i
`u = a (2m + 1}
`0
`m
`
`m
`
`2m
`
`1
`
`y
`
`w = fractura Width,
`
`A
`1
`.
`.
`3L i
`_
`w pressure gradiant 1n r~diracLiun,
`3X1
`
`.
`.
`,
`r
`3£_ _
`_
`a pressure gradient in y~diraction,
`3X2
`
`
`«raw-«Wavi-ea,
`
`i1‘n“.
`
`v.yin—mi.
`.--v-w<v»<.v,~w-7;;
`
`
`
`A schematic of tha wellhare and fracture geametry is
`shown in Figure 8. During the hydraulic fracturing
`gracess,
`treatment fluids are pumyed dowu the tubing
`nd into tha wellhore casing annulus through the port
`rollar. This exyoses the natural fractures to the
`ighrpressure fluid, which initiates the progagatiou of
`uhe fluid front éowu the fracturasq Bacausa 0f pres“
`urizatian in the annulus,
`the fractures subsequently
`Xpand {fracture growth occurs}. >Usually,
`the pressure
`an& the flow rate at tha port callars are knuwu.
`How~
`:ver,
`the flaw rate (injection rate) and preséure at
`:ach discreta fracture is not knawnd These values are
`The fluid friction loss is comguted assuming turbulent
`‘fiuw in a ucllbarc annulus with the Crittendun hydrau—
`equirad to predict the geometry of inducefi'fracturfis.
`These
`
`in this investigation,
`two methods were used ta ccfipute ’lic diameter and Serghides friction factor.
`~..w_w«_w,.ii..___mi
`,
`.
`n
`i
`_
`N
`n
`?27
`
`a m
`
`n : fluid consistency indexD
`
`m fluid behavior index, and
`
`f : gravitational body farce:
`
`3 of 12
`30f12
`
`DEFINVO
`
`0008254
`
`Ex. 2076
`EX. 2076
`IPR2017-00247
`IPR2017-00247
`
`

`

`4
`
`,,
`
`.
`.. "Wyn—A.
`INSIGHTS T0 HYDRAULLCLFlmCLURING U} A HORI.ZQNTAL WELL IN A NATURALLY FEACTZIREDVFGRMATIGN ,
`i
`
` .‘LJ‘
`SFE iL'
`
`3.313133.
`3;, he 915:4; h;51— c‘nrralaf33mg fgr Bing-313m {313:5
` flxittendoa hyéraulic diameter can be writ&&n as
`aanular flaid f10w.7
`fine frJCtiofl lugs and tha
`
`
`
`as :: 9.5-:ng — 31¢ _ {3:04 , (312)3/2wwdinl”
`
`+ 0.5 [defi- - £3,321“?
`
`tzon 1:3
`
`ThePSexghides frictiofl factor and pressura drop equa-
`
`H:
`
`--fp~ v~1./25 :3 de
`
`,
`
`(a)
`
`% a l
`
`the pressuré
`By considaring the canservatina of energy,
`distributian algng the wellboxa annulus can b2 expressm
`as
`
`P
`
`f
`
`.
`
`F
`
`v2
`
`-32;
`
`v.2
`
`here:
`
`?
`
`: ?tessure,
`
`a : Fluid éensity,
`
`V = fluid velatity,
`
`& W211 bore elevatinu at a given yeiflt,
`z
`g = Graviatinnal constant,
`Pi = Pige frictian loss, and
`fl
`: Eydraulic fiiameter 0f the wellbore.
`
`}
`
`s w
`
`i E
`
`g
`g
`g
`3
`
`The cantinuity equation far fluid flaw within a dis~
`crate fracture Can be written a5
`
`Q1=Q2 4‘Q3
`
`3
`
`(6)1
`
`ghis equation can be writtan for each fracture tn
`
`btain the relatianship betweau the flaw rate uystream
`o downstraam flaw rate in a discreLe fractuzan
`The
`3:0ta1 fiuid entarjng tha systam must be equal t0 the
`laid less and the tutal amfinnt Qf fluid taken 33 by
`11 discrate fractures, This can be written a5
`
`g
`
`
`
`Wx-qu-lnnn"nu-nu“.w.punmuuuuufu
`
`is
`
`E Es El
`
`3
`i
`
`
`
`An acceptable solutiau t0 the problem must satisfy all
`of the above equanions.
`The accegtable solutian in
`this case was abtzinaé by using the trial and arts:
`scheme described below:
`
`*
`
`Iwo hydraulic fracture madels were used to predict
`the fracturé geometry from Stimulation 1,
`.
`Phase II ané Stimulaticn E1:
`the P39 and the
`é
`3D medals pzovided the franture presgure anfl
`Enjacti on raLe relationships given bv EquatiOfis 1g
`and 2
`
`a The models utilize fluid pressure and total iujac%
`tion rate at the part collar to compute downstream
`pressures ané injectinn rates at selected fran
`Lures with a high flow rate. Filtratian leaknoff
`along the anuulus was computed usifig the iiltra~
`t3an 1e3k~ off formulatisn presenteé by Reward and
`Fafit.3
`
`9 The hydraulic diameter”af tha aanulus wag assumad
`:9 be the slot width;
`the length of the yiye
`between fractures was assumed :0 be the leak—aff
`distance. These two dimansiaas were useé to com~
`puke the annulus laak-aff area aafi volumea
`
`fi Y?re5 sure was talcalatefl at th& fi
`‘1 snlactad
`
`
`
`
`surfl Q38 t at mai3had
`Czezm elfthe gari t
`3: using Equa—
`"
`
`
`v
`'
`wy f.h& 831%.1.J& its?.w
`yvarying th_g flew rate whii3 X¢2gim
`
`'15t$ cagsiamt.
`
`
`
`3:33:13;- cguztiaws were them 33:35:63
`The :333mm: 1;; gm.
`30 comgwfia (low rata ané presgure a: ihg nest
`’fiownstream fracture The pressuxeg’flow rate match—
`ing procedure was continued until iteratiuns Vera
`performed for all selécted fractures"
`
`The total flow rate was then computed by adding
`the leak~of£ aufl fracture flow {Equatian ?) for
`all salacted fractures.
`IE thfi differsnce betweefl
`the actual injection rate aufi tha Camyutad rate
`was not within tha desired talerance, the matching
`praceduxa was reyeated far tha same tima step
`uhtil flow rate convergence (i1 bpm, i .16 mspm)
`was obtained.
`
`0 The 0v&rburdan and underhurden stress magnitudas
`were adjusted aaé equal far all fractures to
`obtain convergence. These values are cansiderefi
`as a ingical chaice when matching flow rates and
`yrassures.
`The proceduxa was xgpeated for each
`salecteé time step aver th& entire treatmant
`geriad.
`
`flatbed 2:
`
`61
`
`
`
`e Solution
`
`E E
`
`
`
`
`
`3
`
`(73
`
`A simplifieé procedure for comyuting pressure aiong the
`wellbare is presauteé‘ This method is based on the
`assumption that the system of discrete fractures can be
`replaced by an gquivalent leakuaff system as degicted
`in Figura g” \The fricti0nal lass over a segment sf dx
`can.§e expressed as
`
`:
`
`.
`53$
`
`:11
`
`,
`
`‘
`y
`393x
`
`,
`
`V
`
`-
`
`(M
`
`
`3
`
`where‘
`-
`-
`'
`
`and
`?23
`
`a
`
`1
`
`a
`
`= 32 E "i,
`s
`,3 313.2
`
`: Finié viscosity,
`
`N...
`.
`1
`2+}ZQ,,
`
`121L= $.iow rate at the yort collar,
`i
`Q: = Flfiid flow into the fuxmation,
`
`$1 3 Fluid taken by “1"th fractura, anfi
`
`N = Total number 0f discrete fractures.
`
`g
`
`E E
`
`4 of 12
`40f12
`
`DEFINV00008255
`
`Ex. 2076
`EX. 2076
`IPR2017-00247
`IPR2017-00247
`
`

`

`
`
`11:
`
`'1.
`
`1
`
`SPE 18253
`
`A. W. LAYNE AND H.
`
`J. SIRIWARDANE
`
` p
`
`= Fluid fiensity, and
`
` - '
`
`ity at paint 1.
`
`VP 3 Pipe flaw veloc
`' he above equation is tho wellknown Hagen-Poiseuille
`
`'equaiioa for laminar f10w.lt can ea.sily be modified
`to account for turbulent f1nw by selacting aa appro~
`priate value for 61‘
`Since the f'uid is lost to
`gnatural fracture along the pipe,
`the velocity VT (2) is
`1a function of the coofdinate x.
`The total fricfianal
`loss up to a distance of x can b& axprassed by inte~
`grating the above equation as
`
`2?.
`
`ix = a1 i VPCX) dx
`
`,
`
`{9)
`
`ih; leak—Off velocity VL (x) is assumeé to Cake the fol-
`1oowing farm.
`
`“WW?
`
`i
`Ewkera
`
`.:
`
`B
`
`A
`
`C
`,
`(Pl—y) a 21—19~11
`"rm—lull 1.
`ECZL¥ “uZL
`
`,
`= (Q; ~ ‘1)
`
`u E
`
`5
`
`z:
`
`P
`2
`,2
`
`---
`4 a
`D-‘Kl
`
`,
`
`w
`am}.
`
`5
`
`I a",
`1104’
`
`1
`(16b);
`
`:
`l
`(15C);
`
`P = Pressure at the end of the pige, which
`is assumad to be slightly higher than
`the in situ stresa
`
`i:
`1I
`
`RESULTS AND DISCUSSIGK
`
`
`s indicated in the Preceding section, pseudo three»
`dimansicnal
`(P3D) and threewdimeusiaual
`(BB) models
`were used to predict the fracture geometzieg of
`selected iractures from Phasa ll of Stimulation I sad
`all phasas of Stimulation 11.
`The horizontal well was
`located 39 ft (9.2 m} above the lower boundary of the
`shala laYcr, and hcaca, a stress barrier was ossumed at
`the level of 30 ft (9.2 m) below tha wallbure‘
`
`7
`XLix)
`
`: C
`3% 1
`
`3
`f
`am) .
`
`and
`
`C;
`
`fl 8? + y
`
`,
`
`«ooze:
`
`fi and Y = constants, and
`
`P # Pressuro at any given yoint.
`
`the continuity equation at any given point can be
`?htn,
`writteg as
`
`17152:) = ‘31:??? {Q} — (“D—~23 QLX
`
`,
`
`(213
`
`wh:.z& Q is the flow rate at the port collar, and Q(x)
`E13 the total fluié loss up to the yoint of intare<t
`EThis can b: exyrassed as
`
`
`
`Basad on recent reservoir studies,9 it has been
`‘reoerted that the equivalent Ceffgctive} thickness of
`§the reservoir was only 59 ft (15.3 m).
`flowever,
`the
`actual thickness of the shale layer was found as 290 ft
`(6115 m). Since the BSD moflels are suitable only for
`elongated fractures,
`the effective thickness of 56 ft
`(15.3 m) was assumed in tha FED model.
`In other words,
`the upyer stress barrier was assumed at 23 it (6.1 m}
`above the wellhore in the case of tho P3D model"
`
`The three~dimensional modal is capable of gradictimg
`the actual geometry oi the fractures, heuca,
`the actual
`Ear yhysical} value was useé for the reservoir thick—
`ness. Therefora,
`tho upyez stress barrier was assumed
`Eat a height of l?fl ft (52.3 m) shove the Wallbura.
`
`(12)
`
`(13)
`
`X
`
`x
`
`QL
`
`O
`= KB I vii?!) Six
`
`1'
`
`‘Tfie fluid yressare, ?{x}, at a distance x can be
`Wriatefl as
`
`Pix} 2 p1 — ix
`
`,
`
`
`
` 1‘Waxe P1 is the pressure at the port collax.
`
`The
`leads to tho
`31133 of Equationg {8) through {13)
`{fillewiag second— order differential equation
`
`$73.2 my»:a: avail—$71 ,
`
`(14)
`
`lying the pressure hounmary conditions at x = fl aud
`L the following soluti.on fur pressure distribuLion
`
`+ Be
`
`
`”C216
`
`+ Y
`
`,
`
`(15)
`
`fiPradicted injection rates, fracture pressures, and
`gequivaleut fractuza winglangths for thxae of the eight
`éselccted fractures {Figure ?? obtaineé from the BSD
`gmodel for Stimulation I &tfi given in Figures 10
`‘
`Ethrough 12.
`The yressures gradicted with the closed—
`Eform solution are presenteé in Figure 11. Figures 13
`ithrcugh 15 Show aimilax rasult$ for Stimulaziom I with
`the 39 modal predictions‘
`
`Results for Stimulation II are prosented in Xiguzes 16
`through 19.
`The bottomnhale pressure was calculated
`in: Stimulation 11 since only sutface yrfissures were
`Measured. Changes in preppant concentrations were
`taksn into account“ Figure 5 indicates that pressures
`continued to rise while infection rates were held can"
`Estant. This is attributed to the in:rease fa proppant
`Sconcemtraiiona Fluid viscosity Correspaadiag to the
`increase in propyaat concentration was increased over
`tima to match the ytessflre profile.
`
`iThe results of the ¥3fl modeling indicate that some
`icoutainment occurred during the treatments, and thig
`jeontai.nment pramot.&d extensive fluid penetration
`gthroughout the fracture network Thus, it is yrohable
`that highly elongated equivalent fracguxes were induced
`EF
`through more than a single natural fractura orientaw
`ticu. An equivalent fracture has thg same fracture
`E
`volume exteuéed into tho reservoir and does not follow 1
`“a single ariéntatian of maximum yrincipal stress‘ For
`E
`129
`
`5 of 12
`50f12
`
`DEFINV00008256
`
`Ex. 2076
`EX. 2076
`IPR2017-00247
`IPR2017-00247
`
`

`

`
`~w.1...mw.um._1wm1u
`INSIGHTS TO HVDRAULiC ERACIJRINC SE A flex1%?“FTAL EELL
`6
`
`thi-
`in Phase {1 9f Stimulation II, it is postu«
`Eexample,
`Flaiea that. 1h: fluid extended £“t intr; the 12servcir
`«1a
`Ethrough F‘ractura System {3 and returned ta the wellhore Wej_
`Ethxough N37DE fractures to Zone 2.
`A highly sinugated
`REFERENCES
`Eequivalent fracture woulé be required for this scenaria
`Eto be feasible.
`The pageatial for induced 316 natural
`Efracxuxes to intersect and for fluid fienetratiqn was
`Eobserved by Blantonlo ia a laberatory experiment with
`Ehydrostone blocks, This is likely to accur,
`than,
`in
`Ea reservoir with numerous fractuxe intersectiane,
`low
`Eangles uf iaduced fracture approach, and low rating of
`Emaximum and minimum horizontal stresses.
`The intexgec~
`Etion and penetratinn uf fluids in a natural fracture
`E 111 head to impefie prcpagatiun in the same orientation
`Eand may flivert the fluid back to the wellhore.
`
`
`
`I? A NAQURALLY EXACTU? B FORMATIGN
`SFE 13255 .
`
`
`i:pproach can he tested 1a daiazmige 1r
`usefulness.
`
`ecfie“ign cf .
`-
`sl.’
`.s ;
`lontal
`
`Overby, W.K., cht, L,E., and East, A.B., II:
`“Analysis of Natural Fractures fibservad by Vifiea
`Camera in a Horizuntal Well,” paper SPE 1776% pre"
`sented at the SP5 Gag Technalagy Symyosium,
`Dallas, Texas, June 1936.
`
`"liguid C02 fer the Stimulatimn 9f
`King, 5.3.:
`Low Permeability Resexvoirs,” paper SEE llélé
`presented at the SEE/DOE Symposium an LOW“
`Permeability, Denver, Coloradc, Match 1983.
`Cawi.ez&.1, K E.:
`”Rheciog1cal ?rapertiea 0f Foam
`Eractnriag Fluids Unficr Dawnhole Canditious,"
`payer SEE 16191 presenied at the SPE Hydrocarhon
`Economics and Evaluation Sympcsium in Ballas,
`Texas, flaxch 198?.
`
`Yost, A,B¢, W.K. Overhy, B.A. Wikins, and
`C.Dk Locke:
`"Hydraulic Fracturiug 0f 3 Horizca~
`ta? Wall in a Naturally Tractured Reservuir:
`Case Study for Multiple Fracture Resign," page:
`SEE 1?759 presented at the SPE Gas Technology
`Sympusium, £31135, Texas, June 1933,
`
`“Development of a
`Advaui, S.K., and Lee, 31K,:
`Generalized Hydraulic Fracture Model," Annual
`Report to BGEIMETC by Ghia State University under
`mum-mt Ho. Mummmasmzoasa (October MEAL
`Advaui, S.H., and Lee, J.Y.:
`“Bevelupmeut of a
`Generalized Hydraulic Fracture Model,“ ?roceediags
`cf the finconventionsl flag Recovery Cuntractor‘e
`Review Meeting, Contract No. DE—ACZIEEBECZUSBE
`(July 1987}.
`
`“Analysis of Fricw
`Jensefi, T2, and Sharma, M.P~:
`:ian Factor and Equivaleat Diameter Correlatibns
`for Annular Flaw of Drilling Fluids,“ presented
`at zhe Tenth Annual Energynsgurcas Technolagy
`Caniereace aaé Exhibition, Dallas, Texas, Febru'
`ary 15~18, 19$7.
`
`"flptimum Fluid
`Howard, 9.0., anfi Fast, 8.3.:
`Characterifitic for Fracvure Extensiun," Qgilliug
`Egghfirnduction Practices AFI (195?) 251.
`Mercer, J,D., Pratt, 3.3., III, and cht,
`A.B., 11:
`"131111 Drilling Us ing Horizon:31
`Wells:
`A 13aEu Bevelayment Stzntegy £9! T1gbt
`Fracturefi Formatiens," payer STE 1772? presented
`at SEE Gas Technolagy Symposium, Dallas, Texas,
`June 1988.
`
`E
`
`
`
`E
`
`
`E
`
`"Tropagatien cf Eiydraulically and
`Blantuu, T.L.:
`Dynamically Inducefi Fractures ifi Nanurally ExaC°
`turefi Reservoirs," payer SEE 1526! presented at
`SEE Uncnuventigaal Gas Techuelagy Symposium
`
`TA 1 deaseEy
`fine creatioa- cf sig-
`fza::.~s*d reaarvsiz,
`¢3firsat ugh
`CKSEL s giace £.s am: agggreat veaause $5
`ifiw reazatamce gWChs available fiur flui.
`khe flauitiple
`\g
`a~L£at.i0n‘
`It mam Beau bflsetved.1hat Lilfi {inifis
`
`‘
`£1531ur£ ai‘Lentat"fi‘ ana retutfi
`a the welusre a
`$2avel aloeg
`iatarseztefi $383211 fiattnras,
`
`
`‘10.
`
`Th1 gcvatning aquaaians and the methfiéalagy asefi hexeia
`
`pgea: Le riyruauca the trace: log 3238113, 2.2;
`
`
`
`’11; i.crmulaa;ov ma~ 1:21 Yfifizfifl‘ a the 61212
`
`ujeciian catss for eve1v-case,1t fias be-en success-
`“alt." apulied 15 Lb.e th et1m113r1913 presnntefl
`As
`fdé?£19133 és::a become ava1lable,1¢e eggiiaabilit3 cf
`am
`
`PA ,6-13w :fa;
`
`?3§
`
`Lauisville, Kentucky, May 1986.I
`
`6 of 12
`60f12
`
`DEFINV00008257
`
`Ex. 2076
`EX. 2076
`IPR2017-00247
`IPR2017-00247
`
` E
`
`I.
`
`
`
`Effie 3% modeling results indicate that much higher,
`Eshorte: fractures were induced than predicted with the
`gran model.
`If the formatian is 206 ft (fi0,96 m)
`thick
`Eand Stress barriers are a: the unfiexburden and over-
`:iburden locations,
`the fractures would not be contaified
`'and wculé rapidly grow 11 the vertical direction. This
`:is a prabable scemario if the locatlan 0f fracture
`lutersection are close is Zone 1 and fluids did act
`Ehave ta travel a large distance in 3:61: ta ante:
`EZones 2 and A. This scenaria was described in the
`Ediscussion of the tracer logs.
`{See flethdology,
`éTracer Leg Results.)
`
`2 3
`
`EIE5E
`
`Elm bath cases, the majority of the preéicted fluid
`épenetratiun was near the part cellar where the fluid
`Epressures were the highest. As axpefitflfl, fluifi
`-Einjectiou rates fizopped as the éisteuce away from the
`E'yort collar 1mzsxeased The numerical values of paramaw
`: tars rel°ted t9 Lhe simplifieé apyrnach are showu 11
`ETable 1.
`
`the simplified model predicted flow rates intw E
`mowever,
`Efractures that were nab cansistent with this observa»
`E
`Etinn, althnugh the model y1eléed pressure distributioas E
`Ethat compared very wall with Chase camyuted w1th the
`E
`EFBD model
`The availaale fluid 15 depleted by frac~
`Etuxes near the part cellar ,
`leaving small flow rates
`Efar ficwnstream fracturea‘
`The flnifl pressures appear
`Etc drag monotonically as shown in Figures 10 and 13.
`EThis is becaase 01 bath fluid leases in the fractures
`Eamj ft1ct1on31 3b558§ along the raugh wellbmre surfing.
`33902121113102:
`E
`Ezzdicting the geametry
`Faxizwp.211 uzl.l "s mare
`1dfi‘i3flfl41 flats 8
`
`E6
`
`i
`
`.u
`
`
`'R}
`
`"fixab3.12 fractures in a
`f
`am
`1123 t4“an 11 a Vaztica;
`
`We1%. fratkur¢ rrnsaEF agerties.
`
`E
`
`a In:afleé ta determine the
`e‘1rc1uéing the anmher
`
`
`
`
`

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