- 1. SPE 69582Field Experiences in Evaluation and Productivity
Improvement Using SelectiveHydraulic Fracturing in Deep Directional
Wells. Orocual Field, VenezuelaG.A. Carvajal, SPE, K. Ortiz, PDVSA,
A. Carmona, PDVSA, G. Parra, PDVSACopyright 2001, Society of
Petroleum Engineers Inc. 15 % of the planned volume). The hydraulic
fractures wereThis paper was prepared for presentation at the SPE
Latin American and Caribbean Petroleum designed to be carried out
in stages, in order to improve theEngineering Conference held in
Buenos Aires, Argentina, 2528 March 2001. production profile of the
wells due to the high heterogeneity ofThis paper was selected for
presentation by an SPE Program Committee following review
ofinformation contained in an abstract submitted by the author(s).
Contents of the paper, as the sands combined with a width of 670 ft
in average that didpresented, have not been reviewed by the Society
of Petroleum Engineers and are subject to not allow the best
allocation of the proppant and slug.correction by the author(s).
The material, as presented, does not necessarily reflect
anyposition of the Society of Petroleum Engineers, its officers, or
members. Papers presented atSPE meetings are subject to publication
review by Editorial Committees of the Society ofPetroleum
Engineers. Electronic reproduction, distribution, or storage of any
part of this paper Field Descriptionfor commercial purposes without
the written consent of the Society of Petroleum Engineers is
Orocual Field is operated by Eastern PDVSA EyP through
theprohibited. Permission to reproduce in print is restricted to an
abstract of not more than 300words; illustrations may not be
copied. The abstract must contain conspicuousNorth Unit Management
Team, it is located 20 km West ofacknowledgment of where and by
whom the paper was presented. Write Librarian, SPE, P.O.Box 833836,
Richardson, TX 75083-3836, U.S.A., fax 01-972-952-9435. Maturin at
the North of Monagas State in Venezuela. The San Juan Formation is
part of the deep Orocual reservoirs and it represents around 80%
the North Units total production. TheAbstract San Juan Formations
developed area is divided into fourUntil 1998, eleven vertical
wells had been drilled in Deep reservoirs, these are San Juan-03,
06, 07 and 09, allOrocual Field in Eastern Venezuela for a total of
16 hydraulically separated by sealing faults. The San
Juancompletions to produce light oil and condensate.
Bystratigraphic column has been characterized and defined
ashydraulically fracturing these wells, the productivity
improvedthree different hydraulically connected flow units,
Lower,up to three times compared to the initial rates. The use of
newMiddle and Higher San Juan (see Fig. 1). The
reservoirstechnologies in drilling directional wells allowed the
contained in the San Juan Formation are medium, light
andconstruction of three of these wells wells in the San Juan
condensate producers with variation of the composition of
theFormation. fluids with depth. The average thickness of the
Formation isThis paper resumes the experiences associated to three
650 feet. The OOIP is estimated in 336411 stb. The reservoirswells
in the Orocual Field, the evolution of operational have been
described as volumetric and, to date, only one ofpractices and data
acquisition that had to be implemented in them is subject to
secondary recovery through gas injection.order to, in some cases,
overcome the effect of early stagescreenouts and properly evaluate
the productivity of suchGeology and Tectonism. The structural model
on top of thewells. Additionally said, experiences allowed the
comparison San Juan Formation indicates an asymmetric anticline
with,of the fracturing techniques applied in these case studies,
with slightly steeper dips to the south related to thrusting from
thethe conventional designs used in the past and to establish the
north. The thrust sheet was subsequently cut by one left
lateralbest evaluation and stimulation techniques for the San
Juanshear fault, separating the Orocual Field into two
distinctFormation wells. structures. The depositional environment
was relatively uniform as indicated by a minimal grain size
variation. TheIntroduction appearance of the San Juan Formation is
a continuousThe drilling of new directional wells in Orocual Field
meant a sedimentation in a transgressive system, with the
initialreal challenge in the planning and design of the hydraulic
deposition of clastic material, coarse type at the bottom
andfracturing activities to be performed on these wells. Based on
shale beds occurrences towards the top.an exhaustive study of the
tectonics of the formation, the wells The maximum horizontal stress
is oriented in North East-were drilled with 25 to 42 degrees from
the vertical axis in the South East direction. As a result of the
collision of thedirection of the minimum stress and in the
direction of theCaribbean and South American Plates the Serrana del
Interiormaximum stress, to and against the dip of the
reservoirs.was formed. The maximum stresses have a preferentialThe
initial design of the hydraulic fractures in the first direction of
170. These structural styles make their statementwells was
conventionally planned based on statistical behavior in the main
fault patterns in which a pattern of 50 to 60 ofof the previous
jobs. In some of the wells, the result was andirection is
highlighted, and it corresponds to the direction ofearly screenout
with little proppant entrance (between 10 and
2. 2 K. ORTIZ, G.A. CARVAJAL, A. CARMONA, G. PARRA SPE 69582the
principal structural feature (inverse faults and
anticlines)Perforating Designwith a subordinated direction of 15 to
20 corresponding to The conventional vertical wells were perforated
to obtain thenormal faults.most contribution per foot of perforated
sand, for this reason100% of the net interval was perforated,
including Lower,Drilling and Completion Middle and Higher San Juan
Formation. This led to a non-Since 1990, fourteen wells have been
drilled in the San Juanhomogeneous production profile due to the
non-selectivity ofFormation; seventeen of these are vertical wells
with doublethe fracturing jobs. In these cases, the fracturing
fluid and thecompletions. In the past two years, two directional
wells,proppant were displaced throughout the intervals that
offeredORC-29 and ORC-30, were drilled, in San Juan 06 and San less
horizontal stress and higher permeability, which in allJuan 07
reservoirs, respectively. The most importantcases, was the most
shallow of the intervals and thus the onecharacteristics can be
detailed in Table 1. with the highest GOR and nearest to the
gas-condensate cap.In search of the best fracture and productivity
results, theThis non-effective production profile attempted against
adrilling design was made based upon the highest natural rational
production of the San Juan reserves.vertical fracture distribution
and the direction of the minimum An initial conventional
perforating design was establishedhorizontal stress. A solid-free
drilling fluid was used in 7 andfor the deepest interval (zone 1)
of Lower San Juan in ORC-294-1/2" holes. This fluid provided
excellent drilling conditions well (see Fig. 5). During the first
Fracture treatment, on thissuch as drilling rate, hole stability
and adequate rheologicparticular interval, there was an early stage
screenout,behavior; it also allowed the use of a fluid with density
of 9.5presumably due to the formation of multiple fractures
thatppg, representing 2.5 ppg less than the usual 11.5 ppg used
ininhibited the proppant entrance in the formation. Since thisother
San Juan wells. was the only case in San Juan fracturing history
and one of theThe direction and incline of the wells were
established most deviated wells on the field, the theory of the
formation ofconsidering the dip of the geological structure, the
direction of multiple fractures led to the redesign of the
perforatingthe minimum horizontal stresses and the distribution of
the techniques and methodsformations natural fractures. Due to
numerous operational andproduction problems presented by double
completions and a Shot HolePhas Type Selectionnew characterization
of the reservoir, as three hydraulicallydensityDiameter
ecommunicated flow units, a 4-1/2"monobore completion Conventional
100 % 6 spf 0,25 inch 60design was employed on these new
directional wells. Figure 2Redesign10 feet 12-18 spf 1,1 inches
60shows an example of the direction and incline of the wells.The
perforating of 10 feet of the net pay and the increaseGeomechanical
Model of the Reservoirof the shot density and hole diameter in some
cases propitiatedSan Juans geomechanical model allowed the
description of some control of the mitigation of multiple vertical
fracturesthe stresses and the characterization of natural
fractures. The and high tortuosity effects.existence of natural
fractures in highly consolidatedsandstones (Cf = 6*106 1/psi),
specifically in San Juan, hasHydraulic Fracturing Designbeen
broadly documented in studies and special core analysis, After the
selection of the intervals, it was important toimage logs, and
fluid loss studies. The geomechanical studies consider the elastic
and petrophysical characteristics of thehave proved a variation in
the direction of the horizontalrock. These were measured with
special logs such as Crossed-stresses of the formation and the
nature of the natural Sonic Dipolar and Spectral Gamma Ray. The
following datafractures. The natural fracture analysis and the
regional was obtained from the processing of these logs:tectonics
support a direction of the minimum stress as N35Wwith parallel open
fractures toward this direction and closed Youngs Modulus =
5,4*10-6 psiones in perpendicular direction.Poissons Ratio = 0.2The
formations stress field presents a normal regime Porosity = 6%where
the higher stress is the vertical (v = 1-1,1 psi/ft) and
Permeability = 5 mDthe intermediate and minor stresses correspond
to the Rock Compressibility = 6*10-6 psi-1intermediate horizontal
stress (H =0,68 psi/ft) and minimumInvasion radius = 45
fthorizontal stress (h=0,65 psi/ft). Temperature = 275FThe stress
field map is shown on Figure 3 where the Net Pay = 50 -220
ftdirection and magnitude of the horizontal stresses can be
Vertical Stress = 1-1,28 psi/ftobserved. The directional wells were
drilled toward the Horizontal Stress = 9250 psiminimum stress in
order to reduce the drilling days andoperational costs (see Fig.
4). In order to prevent early screenouts and assure the success
ofthe fracturing job, 10 feet of the net pay were selected;
thechoice was based on the best elastic characteristics such as a
3. FIELD EXPERIENCES IN EVALUATION AND PRODUCTIVITY IMPROVEMENT
USING SELECTIVESPE 69582 HYDRAULIC FRACTURING IN DEEP DIRECTIONAL
WELLS. OROCUAL FIELD, VENEZUELA 3Youngs Modulus between 1.2 and
6.8*106 psi and a Poissons Pore Pressure, psi7500-6300Ratio from
0.1 to 0.25Fracture Gradient, psi/ft 0,43-0,6The vertical and
horizontal stresses were determined by Depth, ft 14000-16000the
following equations:Average bauxite concentration 3,5Total bauxite,
pounds 40.000v = 0,007 * * D Pr .(1)Average Conductivity, mD-ft
30.000 Bauxite size, mesh20/40H = (v Pr ) ...(2) Pumping rate, bpm
201 Max. Pumping pressure, psi10.200Practical Design
Considerations. In very low horizontal Frac. Dimensions (xf, hf,
wf), ft 100, 100, 0,2permeability and very heterogeneous
reservoirs, like San Juan,(Kv = 0.2 mD, Kh = 5 mD) hydraulic
fracturing in stages is Formation Evaluationvery important. This
technique consists in fracturing, fromThe evaluation of the wells
followed the same procedure forbottom to top, each prospective
interval separately, isolating the most detailed and economical
friendly characterization ofthe fractured zones after each
stimulation. Also, for thickSan Juan 07 and San Juan 06. The first
pre-evaluation stepsands, it is recommended to perforate only from
5 to 15 ft ofwas a compilation of the existing information of the
reservoirsthe net pay before the stimulation to have better control
of the that led to a jerarchical organization of the new
informationfracture and then connect the stimulated formation
byrequired for the new wells. Typical evaluation techniques
wereperforating the remaining feet with high penetration shots
(seeused, such as:Figure 6). In deviated wells, it is difficult to
achieve thisBuildup Tests. Layer reservoir parameters, such
asconnection, which makes it hard to perform this
techniquepermeability and formation damage, were obtained
fromsuccessfully. One helpful practice is to locate the
perforations pressure transient analysis of build up tests. These
tests werenear the top op the shale seal in order to induce the
growth ofconducted before and after hydraulic fracturing for both
initialthe hydraulic fracture from bottom to top. characterization
of permeability, skin and reservoir pressureIn naturally fractured
reservoirs like San Juan, avoiding to and the resulting parameters
after hydraulic fracturing; specialperforate in zones with natural
fractures oriented towards the attention was given to formation
damage values in order tomaximum stresses has been noted to help
prevent early stageevaluate the effectiveness of the stimulation
jobs.screenouts during hydraulic fractures. Production Logs.
Production logs were used after eachIn order to obtain a more
homogeneous production profile fracturing treatment to obtain
information of productionand a better fracture the perforated zones
were chosen takingprofiles of the wells after each fracturing
job.in account the zone with the lowest permeability. Also,
usingPVT Sampling. Three PVT samples, one bottomhole andthe Neutron
Density Logs, the high GOR and gas intervals two surface samples
were taken as part of the characterizationwere identified and
avoided to minimize the gas production of both San Juan 06 and
07.and optimize the bottom light oil contribution.The approach used
in these cases was to obtain initialStimulation Treatment. The
dimensional design of the reservoir parameters from pressure
transient analysis that werefractures pursued the following
characteristics: xf = 90 ft ; Hf compared and validated with
previous core, petrophisical and= 10 ft ; = 0,2 inches. The
fracture was designed totransient analysis. The evaluation of the
fracture jobsovercome the invaded and damaged zone, the Geerstma-
performance was achieved through production log tools toDeklerk
equation was used in order to calculate xf.quantify the fluids and
the quality of the production profile after all the stages of the
fractures and perforations were finished.xf = E * w p ...(3) Field
Experiences and ResultsTo achieve a length of 90 ft, the fracturing
pressure design ORC-29 Well. This well was drilled to produce light
oilwas 9200 also from the Geerstsma-Deklerk equation: reserves of
San Juan 06 reservoir. The initial evaluation and stimulation
design consisted in three hydraulic fractures, twop = ( E 3 * f *
qi )1 / 4 / (hf 1 / 4 * xf 1 / 2 ).(4) in Lower San Juan and one in
Higher San Juan Lower San Juan.The conductivity of the fracture was
obtained from equation 5: Zone 1. 43 feet of the deepest sand were
perforated with 6 shot per foot density. The well produced 190
stb/d with a choke of 1/4". The initial build-up test showed a
typical Sankf * Cdf =(5)Juan Formation value of skin and
permeability ranging from 5k * xf to 9 mD and a skin factor of 35.
For this well, it was possible to use bottomhole shutdown to reduce
the effects of wellboreThe general design of the fractures was as
shown:storage for more accurate and reliable results. 4. 4 K.
ORTIZ, G.A. CARVAJAL, A. CARMONA, G. PARRASPE 69582The hydraulic
fracture was made with a pumping rate ofthe fact that in deviated
wells, it is hard to connect the30 bpm with a 3 ppa proppant
concentration. Once the surfacefractured interval with the wellbore
by perforating thepressure reached 10000 psi, the fracture was
suspended due to remaining zones using conventional practices.an
early stage screenout. Only 20 sacks of proppant could beResults
did not show the increase of production that waspumped into the
formation. After this first hydraulic expected by adding one of the
most prospective zones of thefracturing, the well produced 520
stb/d with the same choke well when it is compared with the same
choke diameter. Thisdiameter. can be explained by the known
compositional variation of theAs noted before, on the perforation
design section, it is fluid with depth that caused an increase on
the GOR, mainlypresumed that the early screenout was due to the
formation of in Middle San Juan, when the fracture job and
perforationsmultiple fractures, which inhibited the proppant
entrance incontacted the higher part of the structure.the
formation. This brought a about redesign of the
perforatingtechnique being applied.ORC-30 Well. This well was
drilled to produce gasZone 2: Only 10 out of a total of 47 feet of
sandstone were condensate (46 API) reserves of reservoir San Juan
07. Theperforated with a shot density of 12 spf. The
previousoriginal evaluation design consisted in hydraulically
fracturingfractured zone (zone 1) was isolated with a gravel plug.
Zone three zones, one in Lower San Juan and two in Middle San2 was
fractured with a pumping rate of 18 bpm. 1272 barrels Juan.of
fracture fluid were pumped with 342 sacks of proppantLower San
Juan. For this case only 5 feet of a total of 7920/40 at a maximum
surface pressure of 7400 psi.of Lower San Juan Formation was
perforated for the fracturingZone 3: Considering the success of the
previous job, zone job. Initially it produced 300 stb/d with a
choke of 1/4" and1 and 2 were isolated and 10 of the 43 remaining
feet ofthere were no representative measures of permeability
andLower San Juan were perforated. The surface pressure raised skin
due to operational problems during the bottomhole shutto 10660 psi
and premature screenout occurred rapidly at thedown of the well.
For the fracture, 410 sacks of 20/40beginning of the fracturing
job; only 22 sacks of proppantproppant were placed in the fracture
reaching a surfacewere pumped into the formation. This second
failure of thepressure of 9200 psi. Due to the poor rock quality of
the zonefracturing job is presumed to have been motivated by a high
(5.6 mD and 5.8 % porosity), the small height of theconcentration
of natural fractures located exactly on the ten perforated
interval, and the small diameter of holes; theselected feet. These
fractures were oriented towards thepumping of the fracturing fluid
was qualified as risky becausedirection of the minimum stress,
generating excessive of the high pressures reached during the
fracture. This led totortuosity. the search of new or different
technologies to diminish theseFor production profile
characterization, two sets ofeffects.production logs were run, one
to quantify the contribution of The total production of the well,
after the fracturing job,Lower San Juan by itself, and the other
after adding thewas 450 stb/d.Middle San Juan Layers. Lower San
Juan alone, achievedMiddle San Juan.1203 stb/d with a highest choke
diameter of 3/8". The Zone 1. Based on the experience on previous
intervals andProduction log showed a production profile with very
lowwell ORC-29, a high pressure and high penetration type
ofcontribution from zone 1 and zone 3. It is interesting to
noteperforation was used on six feet of a total of 108 feet ofhow
zone 1, after having produced alone 520 stb/d postMiddle San Juan
Formation. During the fracturing job, onlyhydraulic fracture, ended
up having almost zero production159 of the 400 planned sacks of
bauxite 20/40 were placed at aafter activating the well with all of
Lower San Juan. The entiremaximum rate of 20 bpm and a maximum
surface pressure ofproduction of the well came from zone 2 and four
added10600 psi. Screenout occurred an it is presumed that
theintervals above and below this zone.creation of multiple
fractures caused the screenouts due to theMiddle San Juan. Only the
lowest interval of Middle San high deviation angle of the well
(42).Juan was fractured at this stage in order to avoid contacting
After this second stimulation and the perforation of 102 fthigher
GOR zones or a gas cap. From the interpretation of the of Middle
San Juan, the production of the well rised to 730sonic dipolar and
image logs, 10 feet in a zone with lowstb/d.natural fracture
density and near the top of a shale seal wereZone 2. Changing in
this occasion all the procedures usedchosen. The result was a
maximum surface pressure during thein previous jobs, 34 ft were
perforated with a shot density offracture of 7200 psi and a
placement of 297 sacks of proppant 18 spf. The fracture job was
done at a pumping rate of 30into the fracture. Afterwards, 95
remaining feet were bpm and a maximum surface pressure of 8500 psi.
Once thisperforated to complete the whole Middle San Juan
interval.pressure was reached, screenout occurred achieving to
placeThe final production log profile was run with different only
235 of a total of 400 sacks of proppant into the fracturechoke
diameters, from 3/8" to 3/4", obtaining a total After the addition
of the remaining intervals in Middle Sanproduction of 4000 stb/d
with a fairly homogeneousJuan, the well reached a total production
of 860 stb/dproduction profile. It is important to highlight that
very littleproduction was obtained from the added perforated
intervalsthat were not directly stimulated by the fractures. This
proves 5. FIELD EXPERIENCES IN EVALUATION AND PRODUCTIVITY
IMPROVEMENT USING SELECTIVESPE 69582HYDRAULIC FRACTURING IN DEEP
DIRECTIONAL WELLS. OROCUAL FIELD, VENEZUELA5Conclusions 30428,
presented at the 1995 Annual Technical1. In low permeability and
very heterogeneous Conference and Exhibition, Dallas, U.S.A.,
October 22-reservoirs, hydraulically fracturing in stages is
25.recommended as a common procedure. 4.Kogsboll, H.H., Pitts,
M.J., and Owens, K.A. "Effects of2. In naturally fractured
reservoirs like San Juan,Tortuosity in Fracture Stimulation of
Horizontal Wells -avoiding the perforations in zones with high A
case Study of the Dan Field". Presented at meetingconcentration of
natural fractures has been noted to held at Offshore Europe held in
Aberdeen, Scottland,help prevent early stage screenouts during
hydraulic September 7-10 1993.fractures. 5.Strubhar, M. K, Fitch,
J. L. , Glenn, E.E.. "Multiple,3. The selection of the zones to
perforate prior to theVertical Fractures from an Inclined Wellbore
- A Fieldfractures has to be made taking in account the zones
Experiment". Presented at the SPE-AIME 49th Annualwith the lowest
permeability an nearest to the top ofFall Meeting, Houston, October
6-9.shally barriers.4. In deviated wells, little production
increase is obtainedfrom added perforated intervals that are not
directlystimulated by hydraulic fractures.Nomenclature = oil
density gravity H =maximun horizontal stresses, psia h =minimum
horizontal stresses, psia v =maximun vertical stresses, psia
D=depth, ft Pr=pore pressure, lpc v=poissons ratio P=maximun pump
pressure, psia Xf= fracture half-length, ft E=Youngs elastic
module, psi w=fracture width, ft f=fluid fracture viscosity, cp
qi=fluid pumped rate, bpm hf= fracture thickness,ft
Cdf=adimensiotal fracture conductivityKf= fracture permeability,mD
k= reservoir permeability,mDAcknowledgmentsThis paper reflects the
work of a large number of people whohave contributed to the
accomplishment of the initialevaluation of the new San Juan wells.
The authors would liketo thank the management of the North
Exploitation Unit,PDVSA for their support on the decisions made
throughoutthe completion and evaluation process of the
wells.References1. Economides, M., Hill, A. D, Ehling-Economides,
C.Petroleum Production Systems. Prentice Hall, Inc.EnglewoodCliffs,
New Jersey. 1994.2. Hagist, P., Harry, J., Abass, H., Hunt, J. And
Besler, M..:"A case History of Completing and Fracture Stimulatinga
Horizontal Well" SPE 29443, presented at the 1995Western Regional
Meeting. Bakersfield, U.S.A, March8-10.3. Hainey, B.W., Weng, X.,
and Stoisits, R.F.: "Mitigation of Multiple Fractures from Deviated
Wellbores" SPE 6. 6K. ORTIZ, G.A. CARVAJAL, A. CARMONA, G. PARRA
SPE 69582 Table 1: Drilling and Completion Characteristics of wells
ORC-29 and ORC-30 Casing WellMudDepthDeviationAzimut Completion
Design20, Aceite 13-3/8, 9- 14898-ORC-29vassa 9,2 20 277,8
Monobore5/8,15161ppg 4-1/220, Aceite 13-3/8, 9- 16448-ORC-30vassa
9,2 42 115 Monobore5/8,15156ppg 7Table 2: Fracturing an Production
ResultsORC-29ORC-30zone 1zone 2zone 3 zone 4zone 1 zone 2zone 3
Pumping Rate, bpm301818 20252020 Total Saks 21 34222 297 410 159
235 Early Screenout YES NOYES NONO YES YES Oil Rate before190NA NA
NA300 NANAStimulation, stb/d Oil Rate after 52012001350 1600 450
730 830Stimulation, stb/d Stimulation Radius, ft 139520 110 120
3789 Maximum Pumping 10600 7400103007200920010600 8500Pressure, psi
Closing Pressure, psi 10000 35007900 6500650064508500Perforated
Interval 431010 105634length, ftShot Density, spf61212 18181818 7.
FIELD EXPERIENCES IN EVALUATION AND PRODUCTIVITY IMPROVEMENT USING
SELECTIVESPE 69582 HYDRAULIC FRACTURING IN DEEP DIRECTIONAL WELLS.
OROCUAL FIELD, VENEZUELA 7EDAD FO RM AC IONPLEIS TO CEN O M ES
AFORMACION SAN JUAN PLIOCE NOLASPIEDRAS 3000 SAN JUAN6600 SUPE RIOR
M IOCE NOCAR APIT A10000 SAN JUAN ARE OMED OILOS OLIG OC ENO J AB
ILLOS 12000EO CEN OCAR ATAS13000 PALEOC ENO V IDO O SAN JUAN INFER
ORI CR ET ACICO S AN J UAN14000 Fig. 1: Orocuals Stratigraphic
Column with highlight on San Juan FormationInduced FracturesORC-29
ORC-30NSNatural Fractures ORC-29ORC-30Vertical WellDeviated Well
Fig. 2: Example of the incline and direction of wells Fig. 3:
Seismic line in direction of the dip of the structure 8. 8K. ORTIZ,
G.A. CARVAJAL, A. CARMONA, G. PARRASPE 69582 Fig. 4: Maximun
Stresses Direction from Crossed Sonic Dipolar and Minimus Stresses
where are directioned the breakoutsEFFECTS: Limited
Entry.Tortuosity Effects.1MxMultiple Fractures. HMx Min 100 %
perforated interval Low shot density. Small Holes. 100% perforated
interval.SreenoutFig. 5: Conventional perforating design, resulting
in formayion of multiple verticalfractures and early screenout 9.
FIELD EXPERIENCES IN EVALUATION AND PRODUCTIVITY IMPROVEMENT USING
SELECTIVESPE 69582HYDRAULIC FRACTURING IN DEEP DIRECTIONAL WELLS.
OROCUAL FIELD, VENEZUELA 9 FracturePropagation Selected
IntervalHigh shot density > 18 spfBig Holes >1,2Few
perforated feet Fig. 6: Perforating design used after
redesign.DIFERENCIA DE ENERGA STONELEY SNICO DIPOLAR CRUZADOFig. 7:
Stonely wave and crossed sonico dipolar show fracture density zone
high 10. 10 K. ORTIZ, G.A. CARVAJAL, A. CARMONA, G. PARRA SPE 69582
Fig. 8: Point select in order to perforating, can see the
directions toward maximun stresses of the nature fractures
