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`SPE 18255
`
`insights into Hydraulic Fracturing 01‘ a Horizontai Wei! in a
`Naturaiéy Fractured Ffirmafien
`by AW. Layne, v.3, EDGE, and H.J. Shiwardane, West Virginia U.
`SP5 Membem
`
`
`
`
`A“.WWWMWWWWWWW
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`I'hls yaw! wag wwww is: grsssc-mau’or. a: the 63rd Annuai Team:in Canismnna and Exhibman oi the Sociaiy ar Pauuiaum Engineers new in
`Haufiém, 7X, acme: 53%; 11353.
`
`, M.fiw
`PE RE. 501 $313335:
`
`
`to be necassary'in farma— BfiCKGROUND
`Horizantal wells are thought
`{inns with lmwupermeability such as the Bevonian shales
`Recent investigatians at the 3.3. Departmant of
`ta increase natural gas recavery and tn reduce the
`Energy’s Horgautewa Energy Technalagy Center have
`risk of drilling a dry hole.
`In a horizontal well;
`the haze hale crasses multiple natural fracturfis ia,the addressed the yntantial hf horizontal wells :0
`reservair. Stimulation data Exam 3 2,000 ft (éegaé m)
`increase the gas recavary from lovaermeability
`harizontal well'drillad intn the Devnnian xhales in
`farmatious.
`A 2000 ft (699.6 m) borizental W811 was
`Wayné Cnunty, West Viiginia, was used in this studyu
`udrillefi inta the Bevonian shala formatian in Wayne
`
`Inflatable packers aufl fiasing port collars were used
`
`50 that indivifluzl zones cauld be tested or stimulacefi
`along tha wellbnren
`
`360unty, Wes: Virginia, he a measured length of 6,620 ft
`
`(1,835 m) and up :0 a true Vertical depth of 39403 ft
`(l993? m)(
`
`This paper focuses on an analyéis 6f hyfiraulic fratturfi'é schamatic 8f ta: well coatiguratian 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 Ealong the horizantal'aection, with external casing
`have been 3&3Pt6d t0 PtfidiCt the Presgurea flflw r3tfi,
`:yaakars and part :nllars as part nf thé casing strifig.
`anfi induced fracture gemmetry for each natural fracture'Ths part callaxs and packers were used to isclate
`intersected by the hydraulic fracturing fluifi in the
`éstimulatien intervalg with existing perforations.
`harizontal wellbore.
`A tubing/annulus flow model was
`iFraQCuting fluids wete 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
`fractflras propagating from a horizontal well” Addi“
`iatmad 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.
`
`
`
`Eli‘fi'flfflfils’l’fl'
`
`References
`
`
`
`
`E illustrétions at enéwéEUyayer,
`
`Prefiieted results wera compared with in situ fracture
`diagnostics from gas (nitrogen and C02} and foam stimum
`Tfla abjective 0f this study an a horizcntal wellbore
`latiou treatments. Radiaactive—tracax with spectr81~
`was he determine the recovery sffectiveness cf the
`333mma—tay logging coafirmeé that bath fluid pressuré
`natural fractura system and the impact af stimulating
`land attess perpefiéicular ta the fracture affect the
`wall by hyflraulic fracturing. Fiva stimulatiuns
`linjeatian flaw rate distributiaa alang the wallborea
`been perfurmed. Multiple fractures were groyan
`EBoth cf these factors were used as governing machanisms A
`§far fracture geometry preflictinns in the simulation
`gateé simultanecufily during these stimulatian treat“
`
`Emofielu Preditvicus basad on these mo&als and traccx
`cents.
`Tha wall was drilled in the direction 0f the
`Elags canfirm that the Singla crack theory fut fracture
`gimimum grinciyal stress and tahogonal to the mafia:
`{propagation is not a§plifl3ble far stimulations that
`éracture ayatfim in the resarvoir,
`Six natural fracture
`
`are initiated along an isolatad part of a horizantal
`zrlmqtatigns were iflentified with the downhale viaeo
`iboreholfi.
`' mara and gaaphysiaal well lags.i Figura 2 deyicts
`via natural fracture pattern and orientaticns in
`when highmpressure Eluid was pumyed fiawn the
`
`any? 3374151122; 435 the will,
`-:; Exam ~ “my”
`
`
`
`
`
`Ex. 2076
`
`IPR2016-01496
`
`1 of 12
`1of12
`
`DEFINV00008252
`
`

`

`
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`mmmW—W-W-m-
`2
`INSIGHTS TO HYDRfifiLIC FRACTERING OF A EORTZONTAL WELL IN A NATURALLY FRACTURED FORMATIGN
`
`SYE 18255
`
`gftactuzes were enlargedd Actual breakdown of the shale
`Emay not have cccurred: but fluid 1cok~off and cuhge~
`gquent Expansifln of the existing fracture system took
`Eplace.
`The objectives of the treatments were (1) to
`their nuiher and location,
`(3) ta identify the most
`effective treatment design, 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 bottamchole treating
`pressure on stimulation 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 ané propagation,
`and (d) the selection of the best fracture diagnostic
`system to detect fluifi 1055 along the wellbore Casing.
`
`% 2
`
`(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), 10dine~131 isotope traccr was included
`while Scandium~46 isatmpe tracer was included during
`the higher injection rate of 20 hpm (3.29 mgym).
`The
`maximum surface pressure was 2,642 psi (18,216 kPa),
`when the injection 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.
`Thc recorded treatment
`rate: and battummhnle pressuzes for Stimulation I are
`shown in Figures 3 and 4.
`
`Stimulation Treatment II
`
`a car“
`Stimulation :1 consisted of a hybrid treatment:
`bon dioxide pad followed by a Saud~laden, afivquality,
`nitrogen foam treatment whexc the liquid phase canw
`sistefl of 7¢5 peccemt methanol and water. Thc hybrié
`treatment was selectefi since results of previous stimuwg
`lotions indicated that carbon dioxide is the preferred
`base fluid for this shale formation.
`Since information
`on the sand Carrying characteristics of carbon dioxide
`foam is sparse, nitrogen foam was used as the Proppant
`transport fluié.
`The injcctiun rates aué computed
`bottom"hole presénre for Stimulation II are ghown
`in Figures 5 and 6. Phase I consisted of 11% bbi
`(450.5 2) of a carbon fiicxide prepad that was pumped
`at a rate of 3 bpm {Akg m3pm).
`Phase II cofisisted of
`7,00G gal
`(Zfi,498 i) of an 85-quality nitrogen foam
`ipad icjacted at 10 bpm (1.6 mzpm}; aufi Fhacc III ecuw ‘
`sisted of four stages of Efiuquality nitrogen foam
`3
`laden with %.5 to 2.0 lblgal {.95 Kg/E to .Zé Kg/fi)
`i
`20f ZGIQG mesh oand.
`The wail started taking finifi at
`=
`
`E
`‘
`
`3 i1
`
`‘
`
`770psi (5,309kPa) andthesutfatepressureincreasefi
`
`Tun
`slowly to a maximum of 1,839 psi (12,755 kPa)!
`radioactivc traccrs were used. Antimony~12é was injac“
`ted into the foam pad and Iridiumulgz pellets were
`injected into the prcppznt.
`A spectral gamma ray tool
`:was pumped down with nitrogen in the airvfilled toxin
`zontal welibare ta measure the tracer distribution
`‘along the casing annulus.
`
`
`§§§r§cteristics of Eatural Eracturag
`
`iThe 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 fiamagc while maintaining post~stimuiation
`ifractura conductivity.
` _This
`paper focuses on the prediction of multiple frat“
`geometries with two hydraulic iracture models that
`Etute
`been adapted for a horizontal well. Measured data
`{have
`Efrem two of the stimulations performed in Zone 1 were
`Eused to compute fluifi flow and pressure distributions
`Ealoug the wallbore. Fracture geometries wcxe predicted
`Ewith these boundary conditions at the wellborei
`Ihese
`Epredictiong provifie insight into the performance of a
`Ehydraulic fracturing treatment in a horizontal well,
`Eand these prefiictious could be used in future stimuiaw
`itiou designs.
`
`Egézéiififzalgéiica
`
`'Four primary sets of data are required ta predict the
`:geometry of a single, planar, hydraulic fracture in a
`vertical wall:
`(1) fluid type, injection volume, and
`rate; {2) rock mechanical properties; {3} prappant
`characteristics and treatment schedule; and (&) reser“
`voir gtaperties. Additimnal flata sets are necessary to
`predict the fracture geometry in a horizontal wall:
`(1) the number of natural fractures accepting fluid;
`and {2} natural fracture characteristics such as orien—
`tation, extent, spacing, and vertical displacement
`‘between each fracture. Mechanical and formation flow
`properties ufied in the prescnt prefiictiou are given in
`Table 1.
`The formation properties were measured from
`cell 5028 samples,1 and the mechanical properties of
`the shale are typical measured values for fievouian
`‘shales.
`The fluifl rheological properties were taken
`from available literature‘2’3
`
`iFracture characteristics required to prefiict the geome~
`tries are depicted in Figure 2 and listed ic Tabla 2.
`Eracture spacing is indicateé as the measured distance
`between groups of natural fractures, Vertical dis~
`placement, which io indicatcd as fih, is the change in
`wallbore depth between fiiscrete fractures,
`The range
`in orientation 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
`ficonsisted of N5?°E cud K6?°E orientations. These two
`sets havc the lowest values of direct normal stresses
`compared to other orientations in the zone, and these
`
`sets acceptefi most of the fluid during both.Stimu1a~
`tions 1 and II.
`The direct normal stressea were calm
`Focumentotiua of the stimulatioas of this horizontal
`culaced for each fracture orientation and are shuwu in
`gel} can be fcund in Rafexcncc 4‘
`A total of three
`Table 2. These values were calculatcd with data from
`otimulation treatments were perfarmed in Zone 1.
`Two
`a minifracturc treatment performeé 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 obsctveé from pressure decline
`five of the stimulations are presented in this paper.
`fiti ulatiou I cansistod of 126 tons (108,862 kg) of
`curves. Thais values were 1,050 and 800 psi (7,239as
`and 5,515.8 kPa).
`The two fiominaut fracture systems in
`imam carbon dioxide injected down tbe A.5~ia
`
`
`725
`
`i
`
`31
`
`i 3
`
`
`
`Ex. 2076
`
`IPR2016-01496
`
`2 of 12
`20f12
`
`DEFINV00008253
`
`

`

`>
`
`>
`
`J
`
`A. W. LAYEE ARE H; J. SIRIWAEDANE
`SPE 18255
`u
`rwmw-__nmwmwu_._____.~mg__—u-~4m_u......m ,
`t
`this znne are N67°E and a probable intersectinn of
`5N4$°W‘fzmm Zone 7.
`A direct stress 0f 1,050 psi
`§(?,233.5 kPa) was asgumeé for N44aw, and 800 psi
`(5¢515q8 kPa) was assumed for N67°E.
`A stress trans”
`iformation was usad to back calculate the maximum and
`=minimum grincipal atresaes and direct uarmal attesses
`for other arientations,
`
`E 5
`
`—w
`In
`pressure and flow rates at each fzacture location‘
`the first methad,
`the fraature injection rate, fracture?
`pressure, and flaw rate downstream af each fractute
`é
`3were camgutad numerically ufiing an iterative schemeo
`qu the second methcd,
`the problem was simplified and a;
`icloued~form golutien was obtaineda Results Exam bath g‘2
`Tmathods were then campared with available field
`'measurements.
`
`Igflger Lug Results
`
` stive themg
`5W
`‘A pseudo three-dimensional
`
`(P3D) fractura madelS was
`
`Spectral gamma ray legging was used to qualitatively
`measure the amnunts of tracer—laden fluids and proppaut
`‘used in the iterative scheme far Camputiug fracture
`injected iuta galactad fractures aleng the wellbors.*
`pressures and injecticn rates.
`The ralatiouship
`The trace: leg from Stimulation I is shown in Figure ?.§
`Tracer logs iufiicated that during the first phase 0f
`‘heuween {rasture injection rate and wellbore pressures
`the stimulation, fluids propagated into Fracture Sys~
`‘fnr a P3D agyroximation can be written as
`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 fl
`System II (Figura 2) during Phase II when {ha injection i
`§xate and pressures were increased.
`The tracer log
`3
`‘iudicated that 51 af the 69 fractures presant in Zone 13‘
`1
`accatted fluid during Stimulation I"
`fiuting Qhase II
`
`
`fluid; penatrated Fractuz- System 11 gnu truvuled baci Where"
`to ihé wellbore as avifleacfid by the scaadium that wag
`E
`detectad in Zane 2. This inflitates that a highly can"
`:
`nected fracture systam exists in the reservair, amfi
`this system premates multiple paths sf axpaudeé natural E
`fracturas from a single stimulatiuu treatment,
`E
`
`
`
`
`
`h
`u
`‘
`Q2(X’L) " {h [(Ej
`
`x
`
`w
`
`2+2
`
`3» r.
`5i) 3 dy
`
`’
`
`I _ 1g
`g m §fi k
`
`,
`
`vn’
`A ,
`(4 + r)
`
`{2)
`
`n’+1
`
`r i 1/“
`
`,
`
`’
`
`h : Kali frgtture height,
`
`§
`
`‘
`i
`(1)]
`1
`;
`§
`i‘
`‘
`
`a
`g2 : Fracture pressuze gradient,
`X
`nf = Fluid behavior inflex, ané
`
`k” : Fluid ccusistency index”
`
`1
`~ ~
`m w
`
`fig : an
`
`
`
`{(82 u f1;
`
`T
`
`where:
`
`u“ = m (~——‘—~"}
`
`2
`
`,
`
`w = fractura Width,
`
`g2” : pressure gradiant in i~ditaction,
`
`§E_
`3x;
`
`pressure gradient in y~diractiou,
`
`n
`
`fluid consistency indexD
`
`m m fluid behavior index, and
`H
`
`gravitational body farce:
`
`f
`
`(2)
`
`'
`
`E
`
`
`
`;
`
`E
`i
`E
`E
`§
`Q
`?
`i
`i
`
`é
`i
`
`%
`
`
`
`u«mm-wwmviw,
`
`naan“.
`
`v.yin—mi.
`.--v-w<v»<.v,~w-W;
`
`The tracer leg from Stimulatiun II appears ta be simi—
`lar to that from Stimulatinn IA Evaluation of the lag i
`iinditatés that 43 old fractures that accepteé fluid
`
`during Stimulation I were rewcyeued sud prayped.
`Six
`§% is tha pressure gradient in the xndirectiom, and
`of the 43 reteivcd the majority of the grappant.
`ihkis the fzacture width.
`The value Q2(x,t) is the
`Efluid injection rate iuta the natural fracture inflated
`'at éistance x from the part callar (Figure 83.
`The
`iThesa 1335 were used as fracture diagnostics to iden-
`governing equation fcr,the three-dimenaiausl fracture
`Btify the relative amuunt of fluid that entered each
`fracture,
`Two forms of fluié entrance ware identified :flaw model8 can he exprassed as
`on tha basis at tracar legs:
`{1) annulus leak—off, and
`i€23
`large iajection flow intu éiscrete fractures”
`ELeaknaff is defiued as a small amount of fluid that
`ideas not Peuétrate or significantly fiefurm the fmrman
`.tion; Large injectian flow is defined as a significant
`irate 95 fluid penetration that is capable of carrying
`Ea pzaypaut and inflating existing fractures to enhance
`ireservuir permaability.
`The large injecticn fractures
`iideutified in Figure 7 currespond t0 the peaks an the
`itracer 1933.
`The inteimefliate 10w lava} peaks located
`3hgtwaun the high yeaks are ccusiderefl to be leak~off
`luca'ions. This flow inta the fermatiun is flat con-
`; v;ered as signifiicaut when nompared with the large
`iinjeetiaus iuta discrete fracturea.
`The large injec~
`tion flaws were cumguted aufi used t0 predict induced
`fracture geamatrie..
`
`
`
`GOVERNING EQUATIDNS
`
`A schematic of tha wellhare and fracture geametry is
`shown in Figure 8. During the hydraulic fracturing
`grocess,
`treatment fluids are pumped down the tubing
`nd into tha wellhore casing annulus through the port
`tollar. This exyoses the natural fractures to the
`ighrpressure fluid, which initiates the progagatiou of
`the 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 distreta fracture is not knuwnd These valucs are
`
`equirad to predict the geometry of inducefi'fractnzfis.
`
`
`%n this invastigatiou,
`
`two methods were used ta chfipgte ilic diameter and Serghides friction factor. These
`
`The fluid friction loss is comyuted assuming turbulent
`‘fluw in a wellbarc annulus with the Crittendan hydrau—
`
`
`‘22":
`
`Ex. 2076
`
`IPR2016-01496
`
`3 of 12
`3of12
`
`DEFINV00008254
`
`

`

`
`5‘33
`SPENl
`
`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 arms:
`scheme described below:
`
`*
`
`lwo hydraulic fracture madels were used to predict
`the fracturé geometry from Stimulation T*1-
`Phase II, ané Stimulaticn E1:
`I
`the BSD and the
`g
`BE medals provided the fracture yresgure anfl
`injfiction rata relatiofiships given by EquatiOfis 1%
`and 2.
`'
`
`The models utilize fluid pressure and total iujac%
`tion rate at the part collar to compute downstream
`pressures ané injectinn rates at selected fracw
`taxes with a high flow rate. Filtratian leaknoff
`along the anuulus was computed usifig the filtra~
`tian le3k~off formulatisn presenteé by Reward and
`Fafit.3
`.
`
`E E
`
`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 volume;
`
`l i
`
`g
`
`
`
`Wx-qu-lnnn"nu-nu“.w.».wmuulwfu
`
`
`
`% a l
`
`as g 9.5-gg04 — §i¢ _ {$04 I d1233/2(a¢/di)31’4
`
`+ 0»5 [dag _.
`
`1/?
`
`tion is
`
`The Sexghides frictiofl factor and pressura drop equa-
`
`H:
`
`P
`
`= f p VQL/25.2 de
`
`,
`
`(a)
`
`the pressuré
`By consldaring the canservatina of energy,
`distributian algng the wellboxa annulus can b2 expressm
`as
`
`4 INSIGHTS1
`T0 HYDRAULLC FRACTURING OF A HORIZQNTAL WELL IE A NATURALLY FEACTUREDVFGRMATIGN
`detezw
`equations hava been statistically analyzed and
`1 rl‘
`mifieé tr be tha beat corralatimnfi fag Binghsm E a:
` flxittendoa hyéraulic diameter can be writ&&n as
`aanular fluid flow.7
`132 friction lugs and tha
`
`
`
`calatefl at th& fi
`?ressure was he}
`‘L snlfictaé
`[‘3
`Fract="
`‘
`Cream cf
`3: using Equa—
`sutfl wag t ea maich‘d
`(5..
`
`'
`by {ha axia.L4g
`ow rate whii& Ra
`
`
`
`
`
`6bNi‘(4 Hm
`
`§ingr
`
`
`
`3
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`v
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`§
`g
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`{\
`i
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`£1,314...
`p
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`1 2
`n.2,.”
`+ 22
`
`P
`i
`+ $2 + p
`
`2
`
`:5:
`p
`
`6 a;
`
`: ?tessure,
`?
`p : Fluid density,
`V = fluid velatity,
`
`'
`
`3
`
`& Well bore elevatinu at a given yeiflt,
`
`= Graviatinnal constant,
`g
`Pi = Pige frictian loss, and
`$6 : Eydraulic fiiameter 0f the wellbore.
`
`z
`f,
`i
`gwhere:
`
`3 §
`
`i
`g
`z
`g
`
`The cantinulty equation far fluid flaw within a dis~
`crate fracture Can be written a5
`
`Q1
`
`Q2 + Q3
`
`3
`
`(63‘
`
`
`
`Lg
`
`Fluid less and Ehe tutal amfinnt Qf fluifl taken 33 by
`HM%i
`
`cap-“22+
`
`fi
`11,.
`
`ll
`
`here:
`
`3
`
`Elev rate at the yort collar,
`Q?
`Qg = Flfiid flow into thé fuxmation,
`$1 : Fluid taken by “i“th fracture, and
`N = Total‘nufibér 0f discrete fractures.
`
`his equation can be writtan for each fracture tn
`btain the relatianship betweau the flaw rate uystream
`o flownstraam flaw rate in a discrete fractuzan
`The
`%otal fluid entaring tha systam must be equal t0 the
`11 discrate fractures, This can he written as
`
`§<
`
`cguztiam were them sm‘eé
`The canainmiy gm.
`fiD comgufia (low {aka ané presgure a: thfi may:
`’fiownstream fracture. The pressuxefflow 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 selacted 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.
`
`The avfirburdan and underhurden stress magnitudas
`were adjusted aaé equal far all fractures to
`obtain convergence. These values are cansiderefi
`as a lngical 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 §2l§£i92
`
`(7:
`
`A simplifieé procedure for comyuting pressure along the
`This method is based on the
`wellbare is presauteé‘
`assumption that the system of discrete fractures can be
`replaced by an gquivalent leakuaff system as degicted
`in Figura ?. \The fricti0nal lass over a segment sf dx
`can.§e expressed as
`
`dfx : a1 * vpdg
`where:
`a1 a 32 E "fig
`p 33
`
`
`1
`
`,
`
`5
`
`(8}3
`
`V
`I
`>
`3
`L~———"*V~"""-——*"*fl**—-—*~“““““““——'*‘~““~““'
`
`and
`?26
`
`
`r»
`’7
`y
`: Fluié viscosity,
`f'”*”””
`'"u
`*“‘——“--"-*“*f”
`
`Ex. 2076
`
`IPR2016-01496
`
`4 of 12
`4of12
`
`DEFINV00008255
`
`

`

`
`SPE 18253
`A. W. LAYNE AND H. J. SIRIWARDANE
`w,ij ,,
`E
`;wher£:
`‘
`‘
`‘
`
`C
`e: ZL—(PL—‘fl
`(Pl—y)
`x "~*—~~Fui~w;~~i~m~
`2‘2 "e “2
`
`z (E; n y)
`
`u E
`
`a
`
`B
`
`A
`
`p = Fluid aensity, and
`VP 3 Pipe flaw velocity at paint I.
`
`: he above equation is thc wellwknown Hagen-Paiseuille
`Sequatioa for laminar flow.
`It can aasily be modified
`to accaunt for turbulent flaw by selacting aa appro~
`priate value for 61‘
`Since the fluid is lost ta
`Enatural fracture alang the pipe,
`the veiocity VT(2) is
`1a function of the caofdinate x.
`The total fricfianal
`loss up to a distance of x can b& axprassed by inte~
`grating the abcve equation as
`
`
`
`57
`
`{16%)
`
`(16h)E
`E
`i
`(lécfi
`
`3
`E
`
`{E
`$.
`
`E.
`
`E
`
`EgE
`
`EE
`
`E
`
`E{an
`leak—Off velocity VL(x} is assumeé ta Cake the fol-
`Afl;
`lawing icrmi
`
`P
`VLix) = j% ,
`
`and
`
`Tflese:
`
`C
`
`x
`
`P + “
`’
`i
`8
`1
`fl and Y = constants, and
`
`P # Pressur& at any given yoint.
`
`the cantiuuity equatian at any given point can be
`?htn,
`writtEfi as
`
`s indicated in the Preceding section, pseuda three»
`dimansicnal
`(P3D) and threewdimeusiaual
`(BB) models
`were used to predict the fracture geametzieg of
`selected fractures fram Phasa ll of Stimulation I sad
`all phasas of Stimulation 11.
`The horiznntal well was
`{10) Elocatad 39 ft (9.2 m} above the lower bbundary of the
`stain layer, and hcaca, a stress barrier was &ssumed at
`the level of 30 ft (9.2 m) below tha wallbure‘
`,
`_
`,
`Basad on recent resatv01r studies,9 it has been
`Eregerted that the equivalent (effgctivej thickness af
`§zhe reserveir was only 56 ft (15.3 m).
`flowever,
`the
`actual thickness of the shale layer was fauna as 290 it
`(61‘s m). Since the BSD moflels are suitable only for
`elongated fractures,
`the effective thickness cf 56 ft
`(15.3 m) was assumed in tha FED madel.
`In athet words,
`the upyer stress barrier was assumed at 23 it (6.1 m}
`abave the wellhore in the case of tha P3D model"
`
`m _
`'m , A
`X
`inx) " KEEE) {Q}
`
`,
`,-4
`‘55?) qu ’
`
`E§E4E 3s
`
`r
`x r
`r
`_
`— an i Vlix} dx
`
`x
`
`QL
`
`i
`
`E E
`
`‘Tfie finid yressare, ?{x}, at a distance x can be
`Wriatefl as
`
`m
`E
`‘wbexg Q is the flow rate at the port collar, aha Q(x)
`‘13 the total fluié 1033 up ta the yuint af intaresth
`EThis can ha expressed as
`
`.
`(213 The three~dimensional modal is capable sf gradictimg
`the actual geametry afi the fractures, heuca,
`the actual
`Car yhysical} value was useé for the reservoir thick—
`Hess. Therefore,
`the upyez stress barrier was assumed
`Eat a height mi 1?9 ft (52.3 m) shove the wellbura.
`g
`_
`fiPradicted injection rates, fracture pressures, and
`gequivaleut fractuza winglangths for thxae cf the eight
`éselccted fractures {Figure ?? abtaineé from the BSD
`immdel for Stimulation I ara given in Figures 10
`Ethrough 12.
`The yressures gradicted with the clased—
`Eform solution are presenteé in Figure 11. Figures 13
`ithrcugh 15 Show aimilax rasult$ for Stimulaziam I with
`the 39 modal predictions‘
`
`(12)
`
`Pix} 2 p1 — ix
`
`,
`
`
` gfifire P1 is the pressure at the port collax.
`
`The
`leads to tha
`31133 at Equationg {8) threugh {13)
`'
`Esl«¢wi&g seccnd—ardet differential equation
`
`(13)
`
`Results far Stimulation II are prasented in Xiguzes 16
`thrsugh 19.
`The bottomnhale pressure was calculated
`in: Stimulation 11 since iny sutface yrfissures were
`Measured. Changes in preppant concentrations were
`taksn into account“ Figure 5 indicates that pressures
`continued :0 rise while injection rates were held can"
`Estant. This is attributed ta the increase fa proppant
`éuoncemtrationa Fluid viscesity Carrespaadiag to the
`increase in propyaat caneentratisn was increased ever
`
`2
`V
`v
`4
`is}; me: ~ 37551 max) = $1. ,
`tima t0 match the ytessflre prnfile.
`The results af the ¥3fl madeling indicate that some
`icautainment acturxed during the treatments, and thig
`,
`aygiying the pressure honnfiary conditions at x = fl amd Econtainment pramoted extensive fluid penetration
`:V 3 L,
`the fellas:ng solution fur pressure distribution Ethxomghnut the fracture: network. Thus, it isyrahable
`that highly elengated equivalent fracguxes were induced
`thzaugh more than a single natural fractura orientaw
`ticu. An equivalent fracture has thg same fracture
`volume axteuéfid inta tha reservoir and daes fiat follow
`“a single ariéntatian 0f maximum yrincipal stress‘ Fur
`729
`
`‘E
`
`(14)
`
`(15)
`
`"C2X'
`Pix) 3 $8
`+ 33
`
`
`V
`
`+ Y
`
`,
`
`Ex. 2076
`
`IPR2016-01496
`
`5 of 12
`50f12
`
`DEFINV00008256
`
`4 a
`fi7zl , and
`‘
`
`2
`C2 =
`
`m H
`
`Pressure at the end cf the pige, which
`is assumad to be slightly higher than
`the in situ streSS.
`
`x
`ix = al I V (x) dx
`o
`P
`
`,
`
`{9)
`
`1:
`EI
`
`RESULTS AND DISCUSSIGK
`
`
`
`
`
`

`

`
`
`
`SFF. 13255
`
`uggfulnggs
`genial
`
`
`6
`INSIGHTS TO HYDRAULiC FBAC’IBRING (P)? A, HORIZONTAL WELL II“? A NATURALLY EXACTLY? I} FORK‘MTEC-E‘l
`Pw,___wmwm_m_mwwll
`H,
`n r
`77
`v”
`.
`r
`r
`
`in Phasc ll 9f Stimulation II, it is posLu«
`iexample,
`this approach can ha tested
`Elaied that ch: fluid sxtandcd gut late the rcscrvoir
`,ia 523 figgign 9f ‘
`Ethrough Fracture System 11 and returned ta tbs wellhorc Wells
`A highly elnugated
`Ethrough N373E fractures to Zone 2.
`Eequivaleat fracture woulé be required for this scanaria JREEERENCES
`The pagantial for induced afid natural
`its be feasibla.
`Efraccuxes to intersect and for fluid fienetratiqn was
`I,
`everby, w_K., fast, L”E,’ and Yeats A.B., I};
`“Analysis of Natural Fractures fibscrvcd by Vifica
`lobserved by Blantonlo ia a laburatory experiment with
`ihydrostone blocks, This is likely to accur,
`than,
`in
`Camera in a Horizuntal Well,” paper SPE l77éfi pie"
`Ea reservoir with numerous fractuxe intersectianfi,
`low
`santed at the SP5 Gag lechnalagy Symyosium,
`Dallas, Texas, June 1936.
`gangles uf induced fracture approach, and low rating of
`gmaximum and minimum horizontal stresses.
`The intchec~
`§tion and penetratinn uf fluids in a natural fracture
`
`} ill tend to impefie prcpagatiun in thc same orientation
`gand may flivsrt the fluid back to the wellhore.
`3
`Effie 3% modeling results indicate that much higher,
`Eshurte: fractures were induced than predicted with the
`:93!) model. M:
`the. formatiau
`206 it ($0,596 as)
`thick
`Eand Stress barriers are a: the unfiexburden and over-
`iburden locations,
`the fractures would not be contaified
`iand wculé rapidly grow ifl the vertical direction. This
`515 a prabable scenario if the locatian 0f fracture
`lintersection are close is Zone 1 and fluids did act
`Ehavc ta travel a large distance in axdcr ta ante:
`Elones 2 and A. This scanaria was describcd in the
`fdiscussion of the traccr logs.
`{See flezhcdology,
`fiTracer Leg Rcsults.)
`
`‘IElE
`
`Elm bath cases, the majority of the praéictcd fluid
`épanatratiun was near tbs pert cellar where the fluid
`épressures were the highest. As axpefitflfl, fluifi
`éinjectiou rates fizopped as the éistauce away from the
`Eyort collar increased.
`The unmarical values of paramaw
`Etcrs related :9 the simplifieé apyragch era showc £5
`Elable 1.
`
`the simplified modal predicted flow rates intw g
`mowever,
`Efractures that were nab cansistent with this observa»
`E
`Etinn, althnugh the model yieléed pressure distributioas E
`gthat compared very well with Chase camyuted with the
`§
`model.
`The available fluid is dapleted by frat?
`gtutfifi flag: the Part $011332 leaVing small £10“ {@133
`gfar ficwnstream fractureal
`The flnifl pragsures appear
`gto drag monotonically as shown in Figures 10 and 13.
`gThis is because of bath fluid lasses in the fracturcs
`gand ftictional lbasefi along the raugh wellbmre surface.
`
`7,
`
`“finalysis (sf FriC-
`fiuP‘A3
`Jensefi’ T6, and Shanna,
`clan Factor and Equivaleat Diametat Correlatibns
`for Annalar Flaw of Bxilligg rjuids,“ praseated
`a: ghe Tenth fignaal EnergynSQurces Techmalagy
`Qanferaagg and Exhibition, gallag, Texas, februm
`ary 15mm’ 1937,
`
`6
`
`i
`
`}
`%
`r
`%F
`‘E
`
`8. Howard, 9.c., and Fast, (2.3.: "apth 3mm
`Characterifitic for Fracvurc Extensiun," Qgilliug
`and Prnduction Practices AFI (195?) 251.
`
`9
`
`4 Mercer, J‘D., Pratt, 3.3., III, and cht,
`A.B., ll:
`"lafill Drilling Using Horizontal
`Wells:
`A Fialfi Bcvelaymcnt Stzntcgy far Tight
`Fractureé Formatiens," payer Sffi 1772? presented
`at SEE Gas Technolagy Symposium, Dallas, Texas,
`Jun& 1988.
`
`"$ropagatian cf Hydraulically and
`. Blantuu, T.L.:
`Dynamically Inducefi Fracturas ifi Naturally ExaC°
`turefi Reservoirs," payer SEE 15261 prasanted at
`SEE Uncnuventicaal Gas lechuelagy Symposium
`Lauisville, Kentuckyg May 1986.
`
`‘10
`
`,E E
`
`36015612113102!
`i
`
`
`Ezadiating the gecmetry af uxfiraalic fractures in a
`
`flaxizmntfii wall is mwrfi cmmglcx than la a Verticalc
`fidéitianfil flats cre naafieé ta datcrmins the
`hell.
`Elia
`lati¢n4 ificluéing the Bumhg;
`
`hf -
`laid, aataxal fraczure charac~
`%c
`rack pragertics.
`%n a densely
`
`ificaat flew
`Q
`hhe multiglc
`yflactratlvn.
`gravel aloag
`tn aha wcllhsre a
`
`i
`regarvsiz, aha creatioa cf sig-
`fzaflaa.e
`a 3
`g
`trsth u
`ace £3 39: agggraqt beaausa cf
`11
`{gr fluid
`law rec ataaca yeah; available
`baa Beafi uksetvefi that thc {inifis
`
`icaciurfi arientat"fi' ané Icfiurfi
`iatarseztafi fiatazal fzactnrcsl
`
`
`
`asefi hexeia
`‘ Th3 .evatnin a angina; and the methfiéala:
`.
`S
`8
`8?
`
`siehcugh
`)ygea: t6 rfigruduca 3kg txacc: log 3238133,
`
`15$ cf
`’Liz farmulaaivn may a»:
`tayzufl¢ a the éistx
`E
`
`
`
`it fias been succass-
`‘ujcciiafi takes for avary case
`‘all? apylied $5 the twc stimulsiicfis prescated,
`As
`E
`Jdéitiafisl é&t& become availabl
`l 1&3 eggliaability cf
`2
`g
`=
`E
`EA56-13u3342c;33
`
`
`
`Ex. 2076
`
`IPR2016-01496
`
`6 of 12
`60f12
`
`DEFINV00008257
`
` i
`
`
`
`
`fgr the Stimglatign Qf
`"Liguid €32
`2, King? s_R’:
`Low yermeability Resngoirs," paper SEE 1161§
`Presented at the SEE/DOE Symposium an Low_
`Permeability, Denver, Coloradc, Match 1983.
`
`3‘
`
`”Rh&glagical ?gaPextieg 9f yoam
`fiawieze}, K’E,;
`Fracturing Fluidfi Unficr Dawnholc Canditious,"
`payer SEE 16191 presenfied 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 Lockc:
`"Hydraulic Fracturiug 0f 3 Horizca~
`ta? Wall in a Naturally ?ractured Reservuir:
`Casa Study for Multiple Fracture Resign," page:
`SEE 1?759 presentad at the SPE Gas Technology
`Sympusium, £31135, Texas, June lgfifiq
`
`“Development of a
`Advaui, S.K., and Lee, 31K‘:
`Generalized Hydraulic Fracture Model," Annual
`Report to BGEIMETC by Ghia State University under
`Cnntxact Ho. DE“A321~83M320333 {October 1984);
`
`“Eevclupmeut of a
`, Advaui, S.H., and Lee, J.Y.:
`Generalized Hydraulic Fracture Model,“ ?roceediags
`cf the finconventionsl flag Recovery Cuntractor‘g
`Review Meeting, Contract No. DE—ACZIEEBECZUSBE
`(July 1987}.
`
`

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