Downloaded from http://onepetro.org/JPT/article-pdf/44/01/10/2222504/spe-22836-pa.pdf/1 by Robert Durham on 12 August 2022
`
`Results of Stress(cid:173)
`Oriented and Aligned
`Perforating in Fracturing
`Deviated Wells
`
`C.M. Pearson, SPE, A.d. Bond, SPE, M.E. Eck, SPE,
`and d.H. Schmidt, SPE, Arco Alaska Inc.
`
`Introduction
`Perforation design for a well that will be
`hydraulically fractured is usually controlled
`by the requirements to place the stimulation
`treatment. 1 Key parameters are the num(cid:173)
`ber, size, orientation, and phasing of per(cid:173)
`forations. Typically, the objective is either
`to minimize or, in the case of limited-entry
`treatments, to control the amount of perfo(cid:173)
`ration friction during the stimulation treat(cid:173)
`ment. No uniform criteria exist within the
`industry for defining perforation phasing or
`shot density. Different operators use differ(cid:173)
`ent techniques. However, the pumping of
`a fluid stage to break down the well and to
`calculate the perforation friction loss is rou(cid:173)
`tine to verify that sufficient communication
`exists between the wellbore and the forma(cid:173)
`tion to place the fracture treatment. Often,
`a ball out treatment is pumped before the
`main stimulation to force additional perfo(cid:173)
`rations to break down. Although it is gener(cid:173)
`ally acknowledged that the .optimal place(cid:173)
`ment of perforations in a vertical well is
`180° phasing in the fracture plane, which
`is perpendicular to the far-field minimum
`stress, there are, to the best of our knowl(cid:173)
`edge, no reported efforts of routinely prac(cid:173)
`ticing such a technique. Laboratory inves(cid:173)
`tigations into fracture intiation from deviated
`wells showed the importance of perforation
`placement on the length of wellbore inter(cid:173)
`secting the fracture. 2,3
`During the past 7 years, more than 600
`new development wells have been fracture(cid:173)
`stimulated in the Kuparuk River field. The
`large number of treatments has provided the
`opportunity for significant advances in the
`technical and operational aspects of hydrau(cid:173)
`lically fracturing deviated wells that are not
`aligned colinear to a direction of principal
`stress. The success of this stimulation pro(cid:173)
`gram was documented in Refs. 4 and 5.
`Perforation strategy during the initial de(cid:173)
`velopment consisted primarily of perforat(cid:173)
`ing the net pay intervals in the Kuparuk A
`Sand. Depending on the drillsite, this would
`result in the perforating of two or three
`separate zones. Before the wellbore tubu(cid:173)
`lars and completion equipment were run,
`casing guns (41h-in.) were shot with a typi-
`
`Copyright 1992 Society of Petroleum Engineers
`
`cal shot density of 4 shots/ft and a phasing
`of either 90 ° or 120 0. We often used large(cid:173)
`hole shots every fifth hole. Most initial frac(cid:173)
`ture treatments pumped in wells where this
`strategy was used had relatively high per(cid:173)
`foration friction drops ranging from 500 to
`1,500 psi. Post-treatment temperature and
`tracer logging often showed fluid entry into
`a few discreet points along the perforated
`interval, with the lowest zone of the A Sand
`often showing no evidence of fracture stimu(cid:173)
`lation. The poor communication at the well(cid:173)
`bore is thought to have caused many treat(cid:173)
`ment screenouts in the field.
`The first change in perforating strategy
`was to use limited perforating (1 shot/ft) of
`the upper A Sand intervals to divert more
`of the stimulation to the lower, less produc(cid:173)
`tive intervals. This strategy was used in 1986
`at Drillsites 3N and 3K (Fig_ 1). Postfrac(cid:173)
`ture reperforating of the upper A Sand lobes
`provided rate improvements of 0 to 400
`BOPD. The second change occurred in 1987
`and 1988 at Drillsites 3Q, 3M, 3H, and 30.
`In these wells, the perforating interval was
`limited to the net pay interval of the thickest
`sand member (less than 20 ft), typically with
`4 shots/ft at a variety of different phasings
`(0°,45°,90°, or 120°). Postfracture per(cid:173)
`forating of the upper A Sand lobes was then
`carried out for additional rate improvement.
`The completions at Drillsite 2K during
`1989-90 incorporated perforation of a sin(cid:173)
`gle interval up to 40 ft long with the aligned
`and oriented perforating technique for frac(cid:173)
`ture initiation from a deviated well. 6 The
`technique consists of perforating at 180°
`phasing and at a specific orientation so that
`fracture initiation from the individual per(cid:173)
`forations occurs in the tension zone around
`the wellbore and a zipper-type fracture is
`formed from the coalescence of the individu(cid:173)
`al fractures. The required alignment typi(cid:173)
`cally is measured as the counterclockwise
`angle from the top of the well looking down.
`Three types of eccentric casing guns were
`used until a satisfactory system was devel(cid:173)
`oped. This type of system has since become
`the standard perforation technique for
`deviated wells that are to be fracture(cid:173)
`stimulated. It has been used for intervals up
`to 54 ft long in later developments at Drill(cid:173)
`sites lA, 1L, and 3G. Additional postfrac-
`
`January 1992 • JPT
`
`Summary. This paper reports the
`first results of stress-oriented and
`aligned perforating of deviated wells
`at the Kuparuk River field, Alaska.
`Preferred perforation alignment and
`spacing are calculated for each well
`so the fractures from individual per(cid:173)
`forations link to produce a single
`"zipper" fracture plane along the
`deviated wellbore. Results of the first
`application of this technique are
`presented from the 26-well develop(cid:173)
`ment of Drillsite 2K. The results from
`use of three different oriented-casing(cid:173)
`gun systems and pertinent data from
`Drillsite 2K fracture stimulation treat(cid:173)
`ments are discussed. Comparisons
`to drillsites where nonaligned per(cid:173)
`forating strategies were used show a
`significant reduction in perforation
`friction, enabling the placement of
`larger, more productive
`fracture
`treatments. Application of this tech(cid:173)
`nique to deviated and vertical wells
`and its use at Kuparuk on develop(cid:173)
`ments after Drillsite 2K are discussed.
`
`10
`
`IWS EXHIBIT 1048
`
`EX_1048_001
`
`

`

`Downloaded from http://onepetro.org/JPT/article-pdf/44/01/10/2222504/spe-22836-pa.pdf/1 by Robert Durham on 12 August 2022
`
`"The first change In
`perforating strategy
`was to use limited
`perforating ... of the
`upper A Sand intervals
`to divert more of the
`stimulation to the
`lower, less productive
`Intervals."
`
`_
`Developed
`o Undeveloped
`
`Fig. 1-Kuparuk River field.
`
`ture perforating was carried out at Drillsite
`2K in the few wells with additional A Sand
`lobes. In specific cases in later drill site de(cid:173)
`velopments, this practice has been modified
`to include aligned perforating of multiple
`zones before fracturing.
`
`Kuparuk Field Development
`The Kuparuk River field , one of the largest
`oil fields in the U.S. , is located in the
`Alaskan Arctic and covers about 115,000
`acres. Fig. I shows the field location and
`the development drillsite pads from which
`the deviated wells are drilled . Initial devel(cid:173)
`opment is on 160-acre well spacing with
`some 80-acre infililocations. The Kuparuk
`reservoir is a sandstone whose primary pro(cid:173)
`duction mechanism is solution-gas drive.
`Most of the field is under secondary recov(cid:173)
`ery, receiving pressure support through a
`combination of waterflood and water(cid:173)
`alternating-immiscible-gas injection.
`Production occurs from two horizons
`within the Kuparuk sandstone. An upper
`sandstone interval, the C Sand , consists of
`very-coarse to very-fine-grained siderite and
`sandstone. Net pay ranges up to 80 ft with
`an average permeability of 150 md. The
`lower producing zone, the A Sand , is pres(cid:173)
`ent throughout the field. Although the A
`Sand typically averages less than 30 ft thick,
`with permeability ranging from 20 to 80 md,
`it contains 65 % of the total reserves in the
`Kuparuk field . It is a fine- to very-fine(cid:173)
`grained sandstone interbedded with shale
`and varying amounts of ankerite . The B
`Unit, made up of sands, siltstones , and
`shales, ranges in gross thickness from 0 to
`150 ft. This high-shale-content zone pro(cid:173)
`vides an impermeable barrier to flow be(cid:173)
`tween the two producing zones and benefits
`
`JPT • January 1992
`
`oil recovery by allowing the two zones of
`distinctly different producing characteristics
`to be waterflooded separately. In addition,
`it provides the stress barrier to isolate and
`treat the A Sand by hydraulic fracturing.
`Kuparuk wells with departures up to
`10,000 ft are drilled from centrally located
`gravel pads to minimize the environmental
`impact on the arctic tundra. Most wells are
`drilled at an angle through the Kuparuk to
`minimize drilling costs. No attempt is made
`to align the wellbore with the fracture orien(cid:173)
`tation, and the typical hole angle across the
`formation is'35 ° to 65 ° from vertical. A sin(cid:173)
`gle, nonselective completion is used for
`wells with minimal C Sand development,
`and the A Sand is generally stimulated be(cid:173)
`fore the C Sand is perforated.
`The moderate-permeability A Sand has
`low initial rates. Unstimulated, it would be
`uneconomic in the high-cost arctic environ(cid:173)
`ment. Prefracture flow efficiencies average
`55 % (flow efficiency is the ratio of the
`well's actual PI to its PI if it is undamaged
`and unstimulated) . Matrix stimulation treat(cid:173)
`ments are unsuccessful because of the highly
`laminated nature of the A Sand, preventing
`effective communication between the per(cid:173)
`forations and all the sand intervals. Fracture
`treatments are used to overcome the near(cid:173)
`wellbore damage caused by drilling and
`completion operations and to provide high(cid:173)
`flow-capacity conduits to maximize with(cid:173)
`drawals. The hydraulic fracture program al(cid:173)
`lows the successful development of the
`reservoir and significantly expands the ec(cid:173)
`onomic acreage of the Kuparuk River field .
`
`Theory
`The state of stress within the Earth's crust
`usually is such that one of the principal stress
`
`directions is vertical. This guarantees that
`the other two principal stress directions are
`perpendicular to the axis of a vertical well(cid:173)
`bore. As a result, hydraulic fractures initiat(cid:173)
`ed from a vertical well will extend along the
`wellbore axis. On the other hand, in a
`deviated well , the wellbore is not aligned
`with any of the principal in-situ stresses .
`This results in shear stresses at the wellbore
`surface, as shown in Fig. 2. The shear
`stresses cause a fracture to turn as it propa(cid:173)
`gates into the direction mostly perpendicu(cid:173)
`lar to the minimum principal stress . To
`describe the fracture initiation, the in-situ
`stresses are first resolved into the compo(cid:173)
`nents shown in Fig. 3. This transformation
`resolves the stresses to a coordinate system
`relative to the high side the wellbore. It is
`given by 6
`
`=>
`=>
`uij =exip exjq upq ,
`where the coordinate transformation is given
`by
`
`cos(ex)cos(m
`
`sin(ex)cos(m sin(m 1
`
`-sin(ex)
`
`cos(ex) O .
`
`[
`
`- cos( ex )sin(m
`
`-sin(ex)sin(m cos(/3)
`
`Superposing solutions to the infinite cylin(cid:173)
`drical hole in an infinite medium loaded with
`internal pressure, normal stresses (ux' uY'
`uz), and shear stresses (uxy, uyz, uxz ) de(cid:173)
`scribes the state of stress anywhere around
`the deviated wellbore. 7,8 In particular, the
`state of stress is known at the wellbore sur(cid:173)
`face. Therefore, the maximum tensile stress
`
`11
`
`IWS EXHIBIT 1048
`
`EX_1048_002
`
`

`

`Downloaded from http://onepetro.org/JPT/article-pdf/44/01/10/2222504/spe-22836-pa.pdf/1 by Robert Durham on 12 August 2022
`
`~ot'vertical)
`
`3
`
`OJ (OHmin)
`
`-----
`
`The Highest Point
`
`Fig. 2-State of stress around a deviated well.
`
`Fig. 3-Deviated coordinate system.
`
`act. At close spacings, however, the inter(cid:173)
`action between the two fractures causes them
`to link up in the zipper-like fashion shown
`in Fig. 7, as reported previously. 10.11
`In practice, minifractures originate from
`individual perforations. The above criteria
`enable a maximum perforation spacing to be
`calculated for a given in-situ stress field and
`wellbore geometry. Successive minifrac(cid:173)
`tures link to form a single zipper fracture
`along the wellbore surface. As pumping
`continues, the single fracture propagates into
`the rock medium and the fracture tip turns
`under the influence of shear and normal
`stresses. The turning rate of the fracture tip
`is calculated by treating the zipper fracture
`as an elliptic fracture, with a major axis
`equal to the link-up distance along the well(cid:173)
`bore and the perforation length as the minor
`axis. A turning angle is then calculated from
`the criterion of minimum strain energy den(cid:173)
`sity. 12,13 Computed results show that the
`fracture turns within tens of feet, aligning
`itself in a direction mostly perpendicular to
`
`"The second change ...
`the perforated interval
`was limited to the net
`pay Interval of the
`thickest sand
`member ...• "
`
`can be found at the well bore surface as a
`function of (J, the counterclockwise rotation
`from the high side of the wellbore, looking
`top to bottom, and the internal wellbore
`pressure, p. In addition to the maximum ten(cid:173)
`sile stress, the oblique angle that the small
`minifracture makes with the wellbore, "{,
`may also be calculated (Fig. 4).7 With the
`maximum tensile stress as the criterion for
`fracture breakdown, a tensile zone symmet(cid:173)
`ric to the point of maximum tensile stress
`at the wellbore surface is located at (Jo
`(Fig. 4).
`Fig. 5 shows the location of two minifrac(cid:173)
`tures induced at different locations in the ten(cid:173)
`sion zone on the deviated-wellbore surface.
`The propagations of the fracture tips are
`determined by looking at the influence of the
`tail of Fracture 2, A2 , on the head of Frac(cid:173)
`ture 1, B l' and vice versa as a function of
`the fracture spacing, h. 9 The fracture
`growth at Tip A follows Path a, while that
`at Tip B follows Path b (Fig. 6). When h
`is large, the two minifractures do not inter-
`z
`
`v
`
`x
`
`Fig. 4-Deviated openhole minifracture
`orientation.
`
`12
`
`January 1992 • JPT
`
`Fig. 5-Multiple minifractures on an open deviated well bore.
`
`Mini-Fractures
`
`IWS EXHIBIT 1048
`
`EX_1048_003
`
`

`

`Downloaded from http://onepetro.org/JPT/article-pdf/44/01/10/2222504/spe-22836-pa.pdf/1 by Robert Durham on 12 August 2022
`
`Fig. 6-Link-up between two inclined Fig. 7-Perforation link-up.
`minifractures.
`
`_ _ _ _ _ _ _ _ _ _ _ _ _ 0 _ _ _ _ . _ . _ _ _
`
`quired spacing. It is based on fracture initi(cid:173)
`that the radius of curvature is larger with
`the minimum in-situ stress. The top and bot(cid:173)
`ation from a deviated open wellbore, as de(cid:173)
`higher pumping pressures.
`tom fracture edges turn vertically, while the
`scribed above. Previous analyses 6
`that
`The Preferred Orientation Placement Pro(cid:173)
`leading fracture edge remains cocked to the
`investigated the effects of casing and cement
`gram was used.in this study to determine the
`vertical at an angle equal to the wellbore
`found little difference in the location of (10
`perforation orientation and minimum re-
`deviation. Additionally, calculations show
`, - - - - - - - - - _ . _ - - _ . _ . ___ 0 - _ - - - - - - _ . _ - - - - - - - _ _ _ _ . _ _ _ _ _ _ _ _ .. _______ . __ _
`
`N
`
`t
`
`2K-17
`
`2K-23
`
`- ----- ------ --- --- ----------- -- ---
`
`I
`
`2K-25
`
`Fig. 8-Drillsite 2K fault/spider map.
`
`JPT • January 1992
`
`13
`
`IWS EXHIBIT 1048
`
`EX_1048_004
`
`

`

`Downloaded from http://onepetro.org/JPT/article-pdf/44/01/10/2222504/spe-22836-pa.pdf/1 by Robert Durham on 12 August 2022
`
`• • • • • • • • • • : • • • • • • • : • • : :
`
`Swivel Head
`
`Top
`Centralizers
`
`Lock Ring
`
`20' Gun
`4 SPF@180°
`
`Lock Ring
`
`Bottom
`Centralizers
`
`Hole Finder
`
`Fig. 9-0riented perforating gun
`schematic.
`
`TABLE 1-PERFORATION DESIGN INFORMATION
`
`E=2xl0 6 psi, JL = 0.2, fw=3.5 in., (11=500 pSi,
`0' 1 .. 0' Hmin ... - 4,340 pSi, (J 2 ,.. 0' Hmax'" - 5,270 psi, 0'3" (J v .. - 6,200 psi
`
`Breakdown Angular Position
`Pressure, Pb
`of Fracture, (J 0
`(degrees)
`(psi)
`8,498
`90
`9,240
`90
`10,575
`0
`8,415
`57.79
`8,850
`49.9
`9,426
`17.61
`8,260
`27.96
`8,261
`22.56
`8,Q70
`9.59
`8,187
`0
`8,017
`0
`7,552
`0
`8,260
`152.04
`8,261
`157.44
`8,Q70
`170.41
`8,415
`122.21
`8,850
`130.1
`9,426
`162.39
`8,498
`90
`9,240
`90
`10,575
`0
`
`24.95
`16.45·
`16.62
`40.97
`23.78
`17.1S
`
`Maximum
`Fracture Plane
`P~rforatlon
`Deviation Angle, 'Y Spacing, d*
`(in.)
`(degrees)
`7.68
`22.18
`14.08
`lS.1
`0.0
`6.58
`11.5
`10.62
`3.78
`6.34
`' 7.63
`0
`0
`0
`3.73
`6.34
`7.63
`6.58
`11.5
`1Q.62
`ua8
`14.08'
`0
`
`40.97
`23.78
`17.13
`24.95
`16.45
`lS.62
`22.18
`16.1
`
`120
`
`150
`
`160
`
`0
`
`80
`
`60
`
`90
`
`Deviation
`Angles
`(degrees)
`fi.
`cr
`15
`80
`60
`15
`80
`60
`15
`30
`60
`15
`SO
`60
`15
`30
`60
`15
`30
`60
`15
`30
`SO
`
`compared with an openhole analysis. Yew
`et ai. 6 also showed that the effect of in(cid:173)
`dividual perforation tunnels was to change
`the breakdown pressure, not the location of
`()o. Finally, the effects of inertia are ne(cid:173)
`glected because hydraulic fracture growth
`is slow compared with wave speeds in rock.
`
`Drillsite 2K Completions
`Fig. 8 shows a spider map of the Drillsite
`2K development and the principal faults.
`These wells were drilled in the latter half
`of 1989 and early 1990. The completions
`were carried out in two distinct phases be(cid:173)
`cause of space limitations at the drillsite: an
`initial nine wells in late 1989 and the re-
`
`mainder of the wells in early 1990. Table
`1 shows the calculated perforation require(cid:173)
`ments (minimum spacing and orientation)
`for a series of different well orientations and
`deviations at Drillsite 2K. Input data were
`obtained from either laboratory or field
`measurements. The minimum stress direc(cid:173)
`tion had previously been found to be per(cid:173)
`pendicular to the younger set of north-south
`faults (Fig. 8). In practice, actual survey
`data were taken at each well to calculate a
`specific perforation alignment, with a 4-
`shots/ft shot density being typical.
`In the first series of completions, two
`different 4lh-in. casing gun systems were
`used. System A used a bowspring to orient
`
`"A method of preferred
`perforation alignment
`and orientation was
`successfully applied
`for the first time."
`
`TABLE 2-DRILLSITE 2K ORIENTED PERFORATING RESULTS, FALL 1989
`
`Wellbore
`Azimuth
`(degrees)
`
`Wellbore Deviation
`(degrees from vertical)
`
`Designed Perforation
`Orientation, Counterclockwise
`From High Side
`(degrees)
`
`Gun 2
`Gun 1
`Actual
`Average
`Actual
`Orientation Orlen.tatlon Difference
`(degrees)
`(degrees)
`(degrees)
`
`314
`297
`291
`79
`
`332
`44
`287
`201
`126
`
`48
`65
`35
`41
`
`38
`33
`58
`7
`26
`
`148
`168
`112
`48
`
`160
`35
`163
`30
`128
`
`151
`189
`.243
`52
`
`161
`186
`*
`67
`Average Difference
`
`166
`46
`183
`8
`197
`
`176
`62
`192
`19
`151
`Average Difference
`
`8
`23
`131
`12
`31
`
`11
`19
`25
`17
`46
`23
`
`Wen
`System A
`2K·03
`2K-04
`2K-OS
`2K·07
`
`System B
`2K-02
`21(..05
`2K·OB
`2K-l1
`2K·12
`
`'The ori$nling equipm$Ol broke while running downhole and could not be repaired In tim., for the $$(lond gun run.
`
`14
`
`January 1992 • JPT
`
`IWS EXHIBIT 1048
`
`EX_1048_005
`
`

`

`Downloaded from http://onepetro.org/JPT/article-pdf/44/01/10/2222504/spe-22836-pa.pdf/1 by Robert Durham on 12 August 2022
`
`I
`
`TABLE 3-DRILLSITE 2K ORIENTED PERFORATING RESULTS, SPRING 1990
`
`WeUbore
`Azimuth
`(degrees)
`57
`321
`27
`260
`259
`104
`198
`127
`174
`240
`217
`219
`195
`121
`162
`144
`105
`
`Well
`2K·01
`2K·09
`2K-l0
`2K-13
`2K·14
`2K-15
`2K·16
`2K·17
`2K-18
`2K-19
`2K·20
`2K-21
`2K-22
`2K-23
`2K-24
`2K-25
`2K·26
`
`-Navigation t~Jalled.
`
`WeUbore Deviation
`(degrees from vertical)
`37
`21
`2
`49
`38
`42
`37 i
`49
`37
`53
`50
`58
`65
`48
`48
`52
`54
`
`Designed Perforation
`Orien~tion, Counterclockwise
`From High Side
`{degrees}
`45
`137
`26
`35
`54
`124
`12
`154
`171
`25
`17
`12
`4
`147
`171
`164
`'1158
`
`8
`6
`7
`1
`14
`4
`0
`1
`3
`5
`
`168
`35
`17
`12
`2
`150
`177
`163
`~,~
`::;;
`
`Gvo 1
`~n2
`Actual
`Actual
`Orientation Difference Orientation Difference
`(degrees)
`'(degrees)
`(degrees)
`(degrees)
`..
`2
`47
`44
`139
`2
`' 25
`16
`10
`33
`2
`34
`56
`6
`60
`12
`4
`122
`4
`15
`16
`*'
`163
`31
`24
`13
`18
`151
`171
`165
`155
`Average Difference
`
`1
`1
`2
`2
`3
`
`3
`10
`
`2
`3
`6
`1
`8
`3
`
`°
`' ~"" °
`
`the guns to the low side of the wellbore; Sys(cid:173)
`tem B used a weighted half-cylinder attached
`below the gun. In both cases, the actual
`orientation angle was measured by a mag(cid:173)
`netic survey tool attached to the bottom of
`each gun. Results are shown in Table 2,
`which lists the designed orientation angle in
`degrees counterclockwise from the high side
`of the well and the measured angle as
`recorded by the survey tool. The average
`errors were 31 ° and 23 ° for Systems A and
`B, respectively. Neither of these convention(cid:173)
`al orientation systems operated satisfactori(cid:173)
`ly, and both failed to meet the required toler(cid:173)
`ance of a ± 10° maximum error.
`Perforation gun designs considered for the
`second phase of completions at Drillsite 2K
`included the use of a downhole orientation
`motor. However, a nonpowered system was
`selected after design and successful field
`testing of a new bearing-mounted, eccen(cid:173)
`tered system incorporating a real-time sur(cid:173)
`face readout of gun orientation. Fig. 9 shows
`a schematic of the tool. The orientation is
`set with a lock ring on surface, and the gun
`is suspended between two rollers to allow
`the gun body to rotate freely to the low side
`of the well. The surface readout navigation
`package is hard-connected to the guns
`through the top roller assembly to provide
`real-time measurement of gun orientation.
`Table 3 gives the results of the second phase
`of completions, with a total of 17 wells and
`34 separate gun runs with average errors of
`5° and 3° for the two runs made per well.
`
`Stimulation Treatments
`Table 4 shows the stimulation treatment de(cid:173)
`sign for Well 2K -07, a typical treatment for
`most of the Drillsite 2K wells where there
`was only A Sand development. Earlier
`work5 showing the productivity benefit of
`larger, more conductive fractures necessi(cid:173)
`tated significantly larger treatments to be
`placed than in previous developments that
`
`JPT. January 1992
`
`never averaged more than 57,000 Ibm of
`proppant per well.
`Fracturing pressure data from Drillsite 2K
`were analyzed to provide a direct measure(cid:173)
`ment of the aligned and oriented perforat(cid:173)
`ing technique. Any increase in the wellbore(cid:173)
`to-fracture intersection was reasoned to
`reduce the near-wellbore/perforation-fric(cid:173)
`tion loss measured during stimulation treat(cid:173)
`ments. Table 5 gives the perforation friction
`pressure measured from surface pressure
`data and calculated with field-measured tub(cid:173)
`ing friction data. In all cases, the data were
`obtained after pumping of the treatment
`prepad and following displacement of the
`tubing volume with either slick diesel or
`slick water (depending on the ambient tem(cid:173)
`perature at the wellsite). The appropriate
`tubing friction, verified on a number of oc(cid:173)
`casions with downhole pressure gauges, was
`
`subtracted from the difference in the treat(cid:173)
`ing pressure and the instantaneous shut-in
`pressure to obtain the values reported in Ta(cid:173)
`ble 5. An average 292-psi pressure loss was
`measured, although the median was 0 psi.
`High pressures were measured at Wells 2K-
`05 and 2K-13. At We1l2K-05, the stimula(cid:173)
`tion treatment was placed as planned despite
`the high perforation friction attributed to
`poorly gelled diesel that caused high tubing
`friction while flushing and freeze-protecting
`the wellbore. We1l2K-13 was reperforated
`before a fracture treatment could be placed.
`Table 5 also compares perforation friction
`pressures measured at Drillsite 2K and the
`previous three development drillsites (Drill(cid:173)
`sites 3H, 3M, and 30). A variety of non(cid:173)
`oriented techniques had been used, and the
`measured perforation friction was signifi(cid:173)
`cantly higher. Drillsite 2K was the first de-
`
`TABLE 4-GELLED-WATER TREATMENT DESIGN: WELL 2K-07
`
`Description
`Prepad, GW··
`Flush
`Pad, GW
`GW
`GW
`GW
`GW
`GW
`GW
`Flush
`
`Pump
`<, Rate.
`(bbllmin)
`25
`25
`25
`25
`25
`25
`25
`25~
`25
`20
`
`'Clean
`Volume
`(bbl)
`335
`75
`1,100.
`92
`94
`103
`118;
`63
`40
`73
`
`Stage
`.1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`
`Total: GW, bb!
`Slickifiesel, bbl
`Clean diesel, bbl
`
`16/20
`1.6/20
`16/20
`16/20
`12118
`12118
`
`2
`4
`6
`8
`10
`12
`
`7,720
`15,710
`25,910
`39,750
`26,240
`19.780
`
`1.044
`.148
`81
`
`16/20-mesh low density ceramic proppant. Ibm
`12118-mesh low den$ity ceramic proppant, Ibm
`Total low density ceramic proppant, Ibm
`
`89,090
`46,020
`135,110
`
`'Prowant concentration ramped through the Job.
`- "Gelled water (GW}flUids are 40 lbtri/l.ooo gal JiYdt'oxyprOpylguar wmlborat& crdsslinker. 40 JbmIl;ooo gal silICa
`floor'and 6% clean diesel in the pt'I)pad and pad stages only.
`
`15
`
`IWS EXHIBIT 1048
`
`EX_1048_006
`
`

`

`Downloaded from http://onepetro.org/JPT/article-pdf/44/01/10/2222504/spe-22836-pa.pdf/1 by Robert Durham on 12 August 2022
`
`velopment in a number of years to use
`gelled-water fracturing fluids and slick water
`as the prepad flush fluid. Therefore, the tub(cid:173)
`ing friction data used to calculate the per(cid:173)
`foration drop were different from data from
`the previous drill sites where only diesel(cid:173)
`based fluids were used. Table 6 compares
`Drillsite 2K and wells that were refractured
`over the past 2 years with similar gelled(cid:173)
`water fluids. These wells had been produc(cid:173)
`ing oil for a number of years with no water
`production from the A Sand, which would
`enlarge the perforations and reduce the fric(cid:173)
`tion. However, they have an average fric(cid:173)
`tion loss of 492 psi, 200 psi higher than the
`Drillsite 2K wells. Of particular note is that
`19 of these 89 wells had O-psi measured per(cid:173)
`foration friction. These wells typically were
`perforated with either 90 0 or 120 0 phasing.
`Thus, a 1 in 5 random chance of placing a
`line of perforations in the tension zone
`would imply a tension zone arc of 20 0 where
`the perforations should be placed. The data
`from Tables 5 and 6 are plotted in Fig. 10,
`which, for a given friction pressure, shows
`the percentage of wells in each group that
`had a friction pressure lower than the refer(cid:173)
`enced value.
`Fig. 11 plots surface fracture initiation
`pressure vs. wellbore azimuth. The upper
`line illustrates the calculated value of frac(cid:173)
`ture initiation pressure for an unperforated
`wellbore. The perforation breakdown pres(cid:173)
`sures are significantly lower; however, the
`sinusoidal nature of the data is evident from
`the field measurements. The minimum
`breakdown pressure at about 0 0 and 180 0
`validates the previous field measurements
`that the minimum stress plane runs north(cid:173)
`south and parallels the fault structure.
`Postfracture temperature and radioactive
`logging measurements are not routinely car(cid:173)
`ried out on the fractured deviated wells at
`Kuparuk because height growth occurs away
`from the wellbore. However, tracers were
`run at Wells 2K-1O, 2K-ll, and 2K-12. Fig.
`12 is a post-treatment log from We1l2K-12,
`which has the highest deviation of these
`three wells. It shows that proppant was
`placed across the entire 32-ft perforated in(cid:173)
`terval. Successful fracture stimulation of
`Drillsite 2K resulted in an average of more
`
`Iridium
`(GR API)
`
`1/1
`
`C o ;:
`t!
`o
`'t:
`Q)
`Q.
`
`2500
`
`2000
`
`1500
`
`1000
`
`500
`
`"T\
`:II
`(';
`_t
`(5
`Z
`"tJ
`
`:II m en en
`c:
`:II m
`-:0
`~
`
`100
`
`Depth
`6750
`
`6800
`
`TABLE 5-PERFORATION FRICTION (psi) ON DEVELOPMENT DRILL SITES
`
`Drillsite 3H
`514
`0
`314
`1,363
`472
`820
`1,050
`609
`1,268
`190
`510
`524
`15
`506
`260
`928
`761
`1,389
`0
`490
`1.923
`86
`
`Drillsite 3M
`292
`0
`376
`0
`2.335
`670
`139
`72
`270
`0
`158
`2,060
`479
`51
`0
`0
`1,105
`0
`450
`393
`1,473
`665
`
`Drillsite 30
`0
`1,121
`421
`1,167
`125
`0
`316
`154
`435
`1,150
`277
`1.248
`485
`566
`1,348
`0
`384
`795
`
`641
`557
`
`499
`281
`
`589
`,460
`
`' DriUsite 2K
`0
`314
`0
`0
`1,611
`80
`0
`206
`412
`,,: 0
`0
`0
`2,026
`490
`0
`0
`0
`0
`0
`211
`
`736
`498
`660
`0
`0
`
`Well
`1
`2
`3
`4
`5
`(I
`1
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`26
`Average
`Median
`
`-------- DRILL SITE 3H
`
`- - - DRILL SITE 30
`
`- - - REFRAC WELLS
`
`- - DRILL SITE 3M
`
`--+- DRILL SITE 2K
`
`a
`
`20
`
`40
`
`60
`PERCENT OF WELLS WITH A LOWER FRICTION PRESSURE
`
`80
`
`Fig. 10-Comparison of perforation frictions.
`
`calculated Non-perforated
`Breakdown Pressure
`
`~~-~-~--~-~--r_-_r--~-_t
`o
`360
`180
`315
`135
`45
`90
`225
`270
`
`WELLBORE AZIMUTH (DEGREES)
`
`Fig. 11-Drillsite 2K fracture initiation pressures.
`
`Fig. 12-Well 2K-12 post-treatment gamma log.
`
`16
`
`January 1992 • JPT
`
`ll000r-------------------...,
`~ w
`II: ii!9000
`ffi
`II: ...
`Z o
`~7000
`E
`:i!E
`~ ... 5000
`~ II:
`;;;;) '"
`
`,'.----.. .
`\, .. . :'
`
`,."
`
`•• it,_
`
`Field Breakdown
`Pressure
`
`w
`
`•
`
`•
`
`""-~---"
`•
`
`•
`
`IWS EXHIBIT 1048
`
`EX_1048_007
`
`

`

`Downloaded from http://onepetro.org/JPT/article-pdf/44/01/10/2222504/spe-22836-pa.pdf/1 by Robert Durham on 12 August 2022
`
`I
`
`TABLE 6-PERFORATION FRICTION MEASURED ON GELLED-WATER REFRACTURED WELLS
`
`Well
`Date
`20·13 May 31,1989
`June 13, 1989
`00·13
`June ~4, 1989
`00·15
`June 28, 1989
`2X·15
`2U..Q9
`July 4~ 1989
`July la, 1989
`2(3·08
`3A-12
`July 19, 1989
`July 30, 1989
`2F·l0
`Aug.3,1989
`2F·11
`3N..Q7 Aug. 11, 1989
`2T-oa Aug. 15, 1989
`2T..Q3
`Aug. 18, 1989
`2F..Q7
`Sept. 14, 1989
`2F-oa Sept. 17, 1989
`3K·10 Sept. 22, 1989
`2H..Q5 Sept. 25, 1989
`2H..Q7 Sept. 29, 1989
`2G..Q4 Oct. 13, 1989
`2G·l1 Oct. 28, 1989
`2W-OS Nov. 6, 1989
`2B·03 Nov. 11, 1989
`2H·l1 April 8, 1990
`30·11 May 1,1990
`2W·15 May 3,1~90
`28-02 May 8, 1990
`3F-11 May 11, 1990
`SC-03 May 16,1990
`lG-08 May 19,1990
`2X·10 May 21,1990
`2X·11 May 23,1990
`2H-a9 May 27,1990
`2V-12 May 30.1990
`2V..Q9
`June 3,1990
`June 8,1990
`3A-07
`June 15, 1990
`2C.09
`2W-03 June 23, 1990
`July 1. 1990
`2A·14
`2A-15
`July 1,1990
`; July 10, 1990
`2C·13
`July 17,19,90
`2C·15
`i July 18. 1990
`20-03
`July 25, 1990
`2U·15
`1A..Q3
`July 29, 1990
`2U-13
`July 29, 1990
`2G..Q9
`. Aug. 8, 1990
`
`Wellbore Wellbore Perforation
`Friction
`AZimuth Deviation
`(degrees)
`(psi)
`(degrees)
`45
`202
`430
`203
`39
`0
`46
`1,240 :
`224
`44
`1,086
`122
`265
`650
`48
`844
`49
`76
`71
`35
`0
`44
`105
`510
`132
`45
`0
`400
`324
`42
`63
`40
`330
`42
`870
`329
`1,201
`80
`47
`43
`19
`227
`1,066
`280
`35
`68
`1,090
`40
`46
`111
`1,235
`334
`39
`360
`129
`0
`45
`38
`1,149
`194
`50
`187
`0
`216
`33
`872
`217
`31
`774
`55
`44
`0
`198
`32
`130
`46
`219
`834
`42
`746
`301
`324
`42
`237
`198
`35
`148
`281
`24
`622
`51
`330
`357
`148
`49
`739
`54
`40
`0
`138
`39
`68
`39
`42
`0
`123
`43
`348
`:101
`36
`764
`142
`40
`1,160
`211
`29
`908
`38
`0
`333
`357
`43
`0
`80
`33
`62
`33
`'800
`48
`44
`39
`643
`40
`104
`345
`
`Well
`Date
`2T·14 Aug. 8. 1990
`2T-17 Aug. 8, 1990
`2U·13 Aug. 11, 1990
`30-13 Aug. 21. 1990
`2W..Ql Aug. 25, 1990
`2W·13 Aug. 29, 1990
`31..Q9
`Sept. 2, 1990
`2T-14 ' Sept. 5, 1990
`lA-OS Sept. 10, 1990
`2W·11 Sept. 10, 1990
`2C-16 ' Sept. 12, 1990
`3A-13 Sept. 19, 1990
`2H·12 Sept. 25, 1990
`W-30, Sept. 27, 1990
`lA·tO Oct. 3, 1990
`3B-14 Oct. 6, 1990
`2A·l0' Oct. 7, 1990
`3H-14 Oct. 9,1990
`3B·11 Oct. 10, 1990
`2A·09 Oct. 16, 1990
`2A-10 Oct. 16, 1990
`2B-13 Oct. 17, 1990
`2U-Ot Oct. 31, 1990
`3N·16 ' Nov.3,199O
`2U·12 Nov. 14, 1990
`lR..Ql Nov. 16, 1990.
`3A·Ol Nov. 18, 1990
`1A-08 Nov. 23, 1990
`iF-07 Oec.4,199O
`1F·12 i March 3, 1991
`2U·02 April 16, 1991
`.2U-08 April 21, 1991
`1E·11
`April 30, 1991
`2T·10 April 30, 1991
`W-16 May 3, 1991
`31-01
`May 4, 1991
`2T·13 May 7. 1991
`3K-06 May 15,1991
`SJ-03 May 18,1991
`2T·12 May 21, 1991
`SJ·14 May 22,1991
`30-11 May 25, 1991
`2U·06 May 28, 1991
`30-15 May 29,1991
`
`Wellbore Wellbore Perforation
`Friction
`AZimuth Deviation
`(degrees)
`(degrees)
`(psi)
`44
`204
`326
`1,439
`124
`37
`44
`39
`648
`170
`35
`93
`85
`45
`290
`49
`455
`40
`54
`317
`380
`44
`199
`0
`43
`170
`505
`338
`60
`0
`340
`545
`41
`352
`733
`35
`1
`44
`121
`323
`43
`0
`228
`1,113
`39
`236
`7
`479
`38
`212
`702
`1,111
`40
`45
`144
`38
`261
`198
`48
`1,021
`212
`925
`38
`SO
`344