Table Of ContentHybrid Enhanced Oil
Recovery using Smart
fl
Water ooding
KUN SANG LEE
Professor
Department of Earth Resources and Environmental Engineering
Hanyang University
Seoul, South Korea
JI HO LEE
Post-Doctoral Researcher
Department of Earth Resources and Environmental Engineering
Hanyang University
Seoul, South Korea
]
HYBRIDENHANCEDOILRECOVERYUSINGSMARTWATERFLOODING ISBN:978-0-12-816776-2
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Preface
Duringrecentyears,systematicefforthasestablishedthe Chapters1e3focusonvariousaspectsoflow-salinity
scientific basis for low-salinity and smart waterflood andsmartwaterflood.Chapter1servesasanintroduc-
technology. Moreover, various enhanced oil recovery tion to the topic by tracing the development of
(EOR) techniques are combined with low-salinity and low-salinity and smart waterflood technologies in the
smartwaterfloodtechnology.Smartwater-basedhybrid laboratory and field. Chapter 2 reviews proposed
EORtechniquesarestillnewanddevelopingtechnolo- mechanisms in sandstone and carbonate reservoirs.
gies.Thoughwidespreadsuccessfulapplicationsremain Chapter 3 discusses modeling methods including
atthelaboratoryandfielduseisgenerallylimitedtopilot empirical modeling and mechanistic modeling using
scale,theadvanceof technology is fosteringtheaccep- geochemistry.
tance of hybrid EOR technologies coupled with smart Chapters4e6focusonvarioushybridEORtechnol-
waterflood through the petroleum community. The ogiescombinedwithlow-salinityandsmartwaterflood.
applicabilityofsmartwater-basedEORtechnologies,its Chapter 4 describes hybrid chemical EOR including
economic feasibility, and indications for future di- polymer flood/gel treatment, surfactant flood, alkaline
rectionshavebecomeessentialelementsofcurrentEOR flood,surfactant-polymerflood,andalkaline-surfactant-
research. polymer flood. Chapter 5 presents hybrid CO EOR
2
The authorsbelieve that more comprehensiverefer- including CO WAG and carbonated waterflood.
2
enceisneededtofacilitatetheexchangeofinformation Chapter 6 explains hybrid thermal recovery including
and a discussion of ideas for the field application and hot water injection and steam injection for heavy oil
future research emphasis. In view of this, the authors recovery.
preparedthisbook,whichreviewsandsummarizesen- Thisbookwouldneverhavebeenpublishedwithout
gineering fundamentals of smart waterflood coupled theableassistanceoftheElsevierstafffortheirpatience
withEORandcurrentprogressinresearchandpractical and excellent editing job. We shall appreciate any
applications. The intent of this book is to provide a commentsandsuggestions.
rather in-depth review and to be a guide to the engi-
neering aspects of smart waterflood-based EOR KunSangLee
technologies. Seoul,Korea
v
Contents
1 History of Low-Salinity and Smart 5 Hybrid CO EOR Using Low-Salinity
2
Waterflood,1 and Smart Waterflood,111
2 Mechanisms of Low-Salinity and Smart 6 Hybrid Thermal Recovery Using
Waterflood,27 Low-Salinity and Smart Waterflood,129
3 Modeling of Low-Salinity and Smart
Waterflood,39 ABBREVIATIONS, 137
SYMBOLS, 139
4 HybridChemicalEORUsingLow-Salinity INDEX, 141
and Smart Waterflood,65
vii
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CHAPTER 1
History of Low-Salinity and
Smart Waterflood
ABSTRACT LABORATORYEXPERIMENTS
Historically,thesignificantinvestigationsregardingthe Thissectionfocusesonexplainingexperimentalobserva-
reservoir wettability develop the technology of low- tionsinsandstoneandcarbonaterocks.Thedescription
salinity and smart waterflood. Because of the different ofcarbonaterocksfollowsthatofsandstone.
conditionsandthedifficultconsistencyofexperiments,
Sandstone
many laboratories show a variety of responses of the
low-salinity waterflood (LSWF). Especially, the totally Extensive studies of waterflood have interested in the
differentconditionsbetweenthesandstoneandcarbon- effects of salinity on oilrecovery from sandstones and
ate rocks hardly draw the universal and consistent developed the LSWF to improve oil production.
resultsofLSWFinsandstoneandcarbonatereservoirs. Bernard (1967) flooded freshwater and brines into
In addition, the increasing oil recovery from LSWF synthetic and natural water-sensitive cores containing
experiments hardly guarantees the successful field clays and investigated the relative effectiveness of
deploymentsofLSWF.Despitethevariousobservations salinity on oil recovery. The study assumed that the
anduncertainty,extensiveresearchstudieshaveclearly freshbrinecausestheclayhydration,whichcontributes
observed the enhanced oil production of LSWF in to the oil production of freshwater injection. The clay
some conditions and agreed the potential of LSWF bearing synthetic and natural cores are subjects to the
as enhanced oil recovery technology. Therefore, this experimentalstudy.Thesyntheticcoreshave2%mont-
chapter reviews the important laboratory and field morillonite, which has extremely high surface activity,
studies, up to date, to summarize the evidences and swelling potential, and exchange capacity. The natural
experimentalconditionsofLSWF. cores are provided from Berea sandstone and outcrop
nearWyoming.TheBereasandstonecorehasrelatively
Morethan50yearsago,theobservationsofthesalinity less clay concentration of 0.1%, but it exhibits high
effectonwaterfloodrecoveryinitiatetoinvestigatethe
water sensitivity. Another core from Wyoming has
potential of low-salinity waterflood (LSWF) in sand-
expandable clays of 1.2%. The brines are made by
stone. In addition, the unexpected higher oil recovery controlling NaCl concentration (0.1%, 0.5%, 10%,
of seawater injection in the carbonate field leads and15%).Whilethebrinesandfreshwaterareflooded
totheinvestigationsofioniccompositiononthewetta-
into the cores and oil recovery, residual oil saturation
bilityofcarbonatesandtriggerstheresearchstudiesof
and pressure gradient are measured. The experiments
LSWF or smart waterflood in carbonates. Up to date, observe that the injection of freshwater results in less
the many researchers and industries have explored
residual oil saturation as well as higher pressure
anddevelopedthenoveltechnologiesofLSWForsmart
gradient compared with the injection of brines
waterflood, which are known as LoSal, SmartWater, (Fig.1.1).Thestudyproposedthetwomechanismsto
Desinger Waterflood, and Advanced Ion Management
explain the observations. Further experiments of
(AIM). Hereafter, the terminology of LSWF is used
constantinjectionrateorconstantdifferentialpressure
as a representative. This chapter illustrates the history are carried out to demonstrate the suggested mecha-
of LSWF and describes the important observations of
nisms and validated the previous observations of
experiments and field applications in sandstone and
increasing oil recovery and pressure drop. In the
carbonaterocks,respectively.
experiments, the freshwater injection at constant rate
HybridEnhancedOilRecoveryusingSmartWaterflooding.https://doi.org/10.1016/B978-0-12-816776-2.00001-5
Copyright©2019ElsevierInc.Allrightsreserved. 1
2 HybridEnhancedOilRecoveryusingSmartWaterflooding
60 6 1
50 5
% 0.8
Residual oil saturation, 23410000 1234 Pressure gradientacross core, psi/ in I Wettability indexw-o00..46 High calciLuomw bcrainlceium brine
Brine Swi
0.2 Symbol
0 0 NaCI CaCI2 TA=26°CTA=50°CTA=80°C
0 5 10 15 4 0.2 26.428.424.625.027.125.8
% NaCI 24.7
4 1.0 24 28
26.3
FIG.1.1 Effectsofsalinityontheresidualoilsaturationand 0
0 20 40 60 80 100
pressuregradient.(Credit:FromBernard,G.G.(1967).Effect
offloodwatersalinityonrecoveryofoilfromcorescontaining TA Aging temperature °C
clays.PaperpresentedattheSPECaliforniaRegional FIG. 1.2 Effects of salinity and aging temperature on
Meeting,LosAngeles,California,USA,26e27October. wettabilityindex.(Credit:FromJadhunandan,P.P.,&
https://doi.org/10.2118/1725-MS.) Morrow,N.R.(1995).Effectofwettabilityonwaterflood
recoveryforcrude-oil/brine/rocksystems.SPEReservoir
increasestheoilrecoveryandpressuredropacrosscore. Engineering,10(1),40e46.https://doi.org/10.2118/22597-PA.)
Another fresh water injection at the same pressure
differential produces no additional oil. The study
concludedthatoilrecoveryincreaseshouldbeaccompa- spontaneous imbibition experiment. The spontaneous
nied with the additional pressure drop, and the imbibitionexperimentsusingthecrudeoilsarecarried
proposedmechanismscouldexplaintheseobservations. out by controlling initial water saturation, aging
Extensive research studies have investigated the temperature,andsalinity.Resultsoftheseexperiments
relationship between oil recovery and low salinity in indicate that wettability index increases when initial
terms of wettability. The reservoir wettability is a water saturation increases and aging temperature
complex property to determine multiphase flow in decreases.AnotherexperimentalresultsusingtheMou-
porous media and oil recovery of waterflood. Morrow traycrudeoil,notST-86,reportthatbrinecomposition
(1990) investigated the wettability of crude oil/brine/ and aging temperature change the wettability index
rock (COBR) system and its effect on oil recovery of (Fig.1.2).Inaddition,morethan50corefloodingtests
waterflood. Because the accurate understanding and describethattheclose-to-neutralwettabilitymaximizes
duplicating wettabilityof reservoir rocks areofimpor- oilproductionofwaterflood.Fromtheseobservations,
tance for numerical simulation and experiment of wettability is shown to be sensitive to crude oil type,
waterflood,aseriesofresearchstudiesbyMorrowand brine composition, aging temperature, and initial
coworkers have tried to quantify the parameters to saturation. However, this experimental study hardly
control the wettability and oil production of water- reported the effect of brine composition on the wetta-
flood. Jadhunandan and Morrow (1995) reported bility and waterflood recovery. Yildiz and Morrow
dominant parameters relating to the wettability of (1996)investigatedthepotentialofbrinecomposition
COBR system through experiments. The experiments toaffectcrudeoilrecoveryincorefloodingandsponta-
includewettabilityindexmeasurementsandcoreflood- neousimbibitiontests.Ittestedthesamecrudeoilfrom
ing tests of waterflood. Various brines are formulated Moutrayandtwodifferentbrines.TheBrine1ismade
with NaCl and CaCl2 and tested in the experiments. up of 4% NaCl and 0.5% CaCl2 and Brine 2 had
ThebrineshaveNaClfrom4%to6%andCaCl2from only 2% CaCl2. The experiments investigate various
0.2% to 2%. Crude oils from West Texas (Moutray) combinationsforinitialformationandinjectingbrines
andST-86,andBereasandstonesareusedintheexper- using the two types of brine (Brine 1 and Brine 2)
iments.ThewettabilityindexoftheBereacoresamples and examine the secondary or tertiary recoveries of
is determined by a modified Amott method and brine injections. The results of secondary recovery
