Combined Effect Of Salinity And Ionic Composition Biology Essay
This research work will be based on current field pattern in ASAB field and will implement the combined consequence of tuning both the ionic composing and salt of the injected H2O to determine what has been reported in the literatures.The experiments will dwell of the followers ;X-Ray Diffraction Analysis / Thin subdivision analysis to find the mineralogy of the nucleus sample.X ray Computed Tomography ( CT ) / Scaning Electron Microscopy ( SEM ) Analysis will done pre and station experiment to verify any alteration in pore construction, possibly due to sway disintegration ( Hiorth et al.
, 2008 ) and choosing composite nucleuss from individual nucleuss of the same stone belongingssIFT measuring will be done to measure the influence of the combined consequence on the brine-oil ( Liquid-liquid ) interaction.Wettability monitoring will be used to measure the wettability change caused by the injected fluid.Spontaneous imbibition will look into for the consequence of dilution and functions of Mg2+/SO42- ( Yousef et al.
, 2010 ; Fathi et al. , 2010 )Coreflooding experiments will be done consecutive on both individual and composite nucleuss in order to acquire an optimized seawater composing for improved oil recovery.Ionic composing analysis will look into for the concentration of the possible determining ions and the non-active salts in the wastewater against the concentration in the injected seawater.Zeta potency is the possible difference that exists within the dual bed which is the grade of repulsive force between next, likewise charged atoms. Zeta Potential measurings will measure the consequence of injected seawater on the surface charge of the nucleuss.Surface responsiveness surveies will be done to measure the affinity of each possible finding ion on the surface of the nucleuss.Last, the 1-D simulation will be done utilizing the comparative permeableness curve to fit the experimental informations and accordingly, upscale to field informations.
With all these experiments conducted, an optimized seawater composing will be developed to better oil recovery in our tight carbonate reservoir and besides, add to the literatures on mechanism of smart waterflooding.
Contentss
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..41.0 Introduction.
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51.1 Background… ..
. … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … .51.2 Motivation… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … 71.3 Objectivesaˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦ … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … ..81.4 Significanceaˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦ … … … … … … … … … … … … … … … … … … … … … … … … … … … … ..91.5 Scope of Study… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … 103.0 Methodologyaˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦..aˆ¦aˆ¦aˆ¦ … … … … … … … … … … … … … … … … … … ..123.1 Materials… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … ..123.1.1 Core stoppers… … … … … … … … .aˆ¦aˆ¦aˆ¦.aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦ … … … … … … … … … … … … .123.1.2 Fluid belongingss… … … … … ..aˆ¦.aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦ … … … … … … … … … … … … .123.1.2.1 Seawaters… … … … … aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦ … … … … … … … … … … … … … ..123.1.2.2 Reservoir Oil Samplesaˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦..133.1.2.3 Extra chemicals for dissolver cleansing… … … … … … … … … … … … … … 133.2 Apparatus… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … ..143.2.1 Air minipermeameter… … … … … … … … … … … … … … … … … … … … … … … … … … … … … .143.2.2 Digital tensiometer… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … ..143.2.3 Coreflooding setup… … … … … … … … … … … … … … … … … … … … … … … … … … … … .143.3 Experimental Procedureaˆ¦ … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … ..153.3.1 Core Samples Selection and Preparation… … … … … … … … … … … … … … … … … … … … ..153.3.2 Fluid Preparation… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … ..173.3.3 IFT Measurements… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … ..173.3.4 Wettability monitoring… … … … … … … … … … … … … … … … … … … … … … … … … … … … … ..183.3.5 Spontaneous Imbibition Experiments… … … … … … … … … … … … … … … … … … … … … 193.3.6 Coreflooding Experiments… … … … … … … … … … … … … … … … … … … … … … … … … … ..193.3.7 Ionic composing analysis… … … … … … … … … … … … … … … … … … … … … … … … … … … … 203.3.8 Zeta possible measurings… … … … … … … … … … … … … … … … … … … … … … … … … … … 213.3.9 Chromatographic studies/surface responsiveness… … … … … … … … … … … … … … … … … … … ..213.4 Simulation Studies aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦aˆ¦ … … … … … … … … … … … … … … … … … … 254.0 Project Task and Time Frame… … … … … … … … … … … … … … … … … … … … … … … … … … … … ..26Mentions… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … 27
List OF TABLES
Table 3.1 Geochemical analysis of field formation H2O samples… … … … … … … … … … … … 13Table 3.2 Geochemical analysis and the corresponding chemicals concentrationaˆ¦aˆ¦ … ..22Table 3.3 Composition of seawaters used in the chromatographic trials and zeta studiesaˆ¦aˆ¦24
Introduction
1.0 BACKGROUND
Carbonate reservoirs contain about 60 % of the universe ‘s oil militias and approximately 90 % of these reservoirs are described as impersonal to oil-wet ( Akbar et al. 2001 ) . Yet experts believe that over 60 % of the oil trapped in carbonate stones is non recovered because of factors associating to reservoir heterogeneousness, produced unstable type, drive mechanisms and reservoir direction ( Sun and Sloan, 2003 ) .Reservoir oil recovery is typically executed in three phases throughout the life rhythm of the field. Primary recovery is by utilizing the natural energy of the reservoir ; secondary recovery is by chiefly shooting H2O ( waterflooding ) and gas for force per unit area care ; and third recovery or enhanced oil recovery ( EOR ) is by utilizing an injection ( Yousef et al. 2010 ) . Due to the potency for EOR, different techniques have been applied in order to better oil recovery from carbonate formations. There are five classs of EOR procedures: mobility-control ( polymers, froths ) , chemical ( wetting agents, alkalic agents ) , mixable ( hydrocarbon dissolvers, CO2 ) , thermic ( steam, unmoved burning ) and other procedures, such as microbic EOR, non-miscible CO2 etc. , ( Green and Willhite, 1998 ) . Smart waterflooding ( Low salt ) should possibly be categorized under other procedures. Waterflooding has been the most widely used oil recovery method for many decennaries.Waterflood is dominant among unstable injection methods and has been used since 1865 as a consequence of inadvertent H2O injection in Pithole City, Pennsylvania ( Lewis, 1961 ) . The mark of any waterflood reservoir direction is chiefly to maximise the ultimate oil recovery. Historically, the measure of the H2O was given more consideration instead than the H2O quality. However, people subsequently realized that it was of import to supervise H2O quality every bit good as the measure. Good quality H2O should be free from the solids suspension and organic affairs, compatible with formation H2O and chemically inactive with compounds and elements present in the injection system. It is good known that aquifer H2O and saltwater are the two chief H2O beginnings for waterflooding ( Alotaibi and Nasr-El-Din, 2009 ) .Because waterflooding has been viewed as a physical procedure to keep reservoir force per unit area and drive oil towards the bring forthing Wellss, less attending has been given to the function of the chemical science of the injection H2O and its impact on oil recovery. In recent old ages, extended research has shown that tuning salt and ionic composing of the injected H2O can favourably impact Crude oil/brine/rock ( COBR ) interactions, alter stone wettability, enhance microscopic supplanting efficiency, and finally better waterflood oil recovery chemical science both for sandstone and carbonate reservoirs ( Yousef et al. 2010 ) . However, H2O chemical science is an of import factor that may assist in bettering oil recovery due to the interactions of COBR.The thought of shooting smart H2O into crude oil reservoirs has been addressed since the sixtiess. Researchers ( Martin, 1957 ; Bernard, 1967 ) began shooting fresh H2O into nucleus samples about a half century ago. Bernard observed increased oil recovery in Coreflood experiments when shooting fresh H2O and attributed the betterment to improved microscopic sweep efficiency induced by clay swelling and plugging of pore pharynx by migrating mulcts, nevertheless this work did non capture the attending of the crude oil industry.Considerable involvement in low salt waterflooding was generated in the 90 ‘s by research workers at the University of Wyoming ( Jadhunandan, and Morrow, 1991 ; Yildiz and Morrow, 1996 ; Tang. and Morrow, 1997 ) analyzing the consequence of seawater, rough oil, mineralogy and experimental process on wettability. Tang and Morrow noticed that shooting low salt seawater improved recovery in clay rich nucleus but non in clay free nucleuss. They observed mulcts in the wastewater during successful low salt waterfloods. Extensive research work in sandstone reservoirs ( Jadhunandan and Morrow, 1995 ; Tang and Morrow 1999 ; Tang and Morrow 2002 ; Zhang and Morrow 2006 ; Zhang et al. , 2007 ) has developed this thought into an emerged tendency.Low salt H2O has proved its high potency for bettering oil recovery compared to high salt waterflooding. Laboratory waterflood ( Yildiz and Morrow, 1996 ; Zhang and Morrow, 2006 ; James et Al. 2008 ; Morrow and Buckley, 2011 ) and successful field trials ( Webb et al. 2004 ; McGuire et Al. 2005 ) have showed that low salt waterflooding can better the oil recovery in sandstone reservoirs. However, the low salt consequence has non been exhaustively investigated for carbonates. One statement for why low salt is non expected to work in carbonates is that clay minerals play a cardinal function in the low salt consequence, and clays are missing in most carbonates ( Lager et Al. 2008a ) . RezaeiDoust et Al. ( 2009 ) reported another statement that different chemical mechanism may be responsible for difference in the low salt consequence: it is the rough oil surface assimilation onto positively charged calcite surface and negatively charged quartz surface.Even after few research, ( Austad et al. , 2005 ; Strand et al. , 2008 ; Yousef et al. , 2010 ; Gupta et al. , 2011 ; Yousef et Al. 2011 ; Yousef et al. , 2012 ; Romanuka et al. , 2012 ; Zahid and Shapiro, 2012 ; Winoto et al. , 2012 ) smart waterflooding in carbonates remains rather controversial. Great success in oil recovery was made by injection of saltwater into the extremely fractured mixed-wet Ekofisk chalk field ( Sulak, 1991 ) . Zhang et Al. ( 2006 ) reported the impact of possible finding ions as one of the factor responsible for wettability change. Another study was made by Yousef et Al. ( 2010 ) but a contrary study was given by Zahid and Shapiro ( 2012 ) . The mechanism ( s ) responsible is ill understood, the duplicability of published consequences is doubted and the engineering ‘s scalability to the field is questioned. However, optimisation of waterflooding by pull stringsing H2O salt is non executable due to the deficiency of understanding the primary mechanisms and all factors that might impact the oil recovery.
1.2 Motivation
Previous experiments conducted on chalk show a higher recovery than limestone because chalk is pure biogenic stuff, and it has a much larger surface country compared to limestone ( a‰? 2 m2/g compared to a‰? 0.3 m2/g for limestone ) . Even though the chemical composing of chalk and limestone is similar, CaCO3, the response against the possible determining ions present in saltwater may be different with respect to wettability alteration. Subsequently, similar interactions behaviour ( betterment in oil recovery and decrease in residuary oil impregnation ) have been reported with limestone stones ( Strand et al. , 2008 ) . Many studies have shown extra oil recovery by tuning the salt and ionic composing of the injection H2O. The initial consequences are assuring. While many recovery mechanisms are proposed, still many uncertainnesss remain with regard to the mechanism and the functions of the H2O chemical science. This work will therefore contribute to the apprehensions of impact of possible finding ions on oil recovery by smart waterflooding.However, smart waterflooding is appealing because it could offers considerable recovery benefit, is comparatively low cost and is comparatively simple compared to other chemical EOR techniques. This inquiry arises “ how is injection of saltwater into the Ekofisk chalk such a enormous success in oil recovery, which is now estimated to near 55 % ? ” Ekofisk is assorted moistures, extremely fractured, it has low matrix permeableness, approximately 2 mendeleviums, and the reservoir temperature is high at 130oC. For the ASAB field which has reached the waterflooding adulthood phase, a considerable sum of oil is still left in the formation. Critical scrutiny of the field belongingss with old experiments conducted ( Strand et al. , 2006a ; Zhang and Austad, 2006 ; Zhang et al. , 2006 ; Yousef et al. , 2010 ; Gupta et al. , 2011 ; Yousef et Al. 2011 ; Yousef et al. , 2012 ; Romanuka et al. , 2012 ; Zahid and Shapiro, 2012 ; Winoto et al. , 2012 ) has made smart waterflooding a promising EOR methods for this really tight Carbonate reservoir field.
1.3 Aim
It has been verified by a figure of documents ( Strand et al. , 2006a ; Zhang and Austad, 2006 ; Zhang et al. , 2006 ) that saltwater can move as a “ smart H2O ” to better oil recovery from chalk by wettability change towards more water-wet conditions by both self-generated and forced imbibition and a mechanism has been suggested ( Zhang et al. , 2007 ) . In a really preliminary survey, Strand et Al. ( 2008 ) showed that the surface responsiveness of reservoir limestone cores towards Ca2+ , Mg2+ and SO42- had a similar tendency as that of the chalk surface.This research survey is aimed at measuring the impact of seawater salt and composing to heighten oil recovery. It will besides show a systematic process for analysis of the potency of smart waterflooding so as to reflect the reservoir conditions and current field injection patterns, including reservoir force per unit area, reservoir temperature, salt and ionic content of initial formation H2O and current types of injected H2O.The chief aims of this survey include:Investigate the reported mechanism for oil recovery by tuning the chemical science of injected H2O.Study the surface chemical science of carbonate nucleus and look into the affinity of possible determining ions ( particularly Mg2+ and SO42- ) in injected H2O towards carbonate nucleus at reservoir conditions.Investigate potency of thining injected H2O salt while changing the possible determining ions for bettering oil recovery in carbonate formation ( individual and composite ) by analysing coreflooding consequences, ionic/chromatographic analysis carry oning contact angle and IFT measurings.Construct a mechanistic reservoir simulation theoretical account to entree the possible consequence of H2O chemical science on oil recovery.Correlate the coreflooding experiments with the simulation consequences.
1.4 SIGNIFICANCE OF STUDY
Until really late, EOR by Low Salinity was a phenomenon allocated to sandstone and non observed for carbonates. Yousef and colleagues ( Yousef et al. , 2010 ) increased the oil recovery from composite limestone nucleuss by in turn deluging the nucleuss with Gulf SW and diluted Gulf SW: 2, 10, and 20 times. A important addition in oil recovery was observed as the injected SW was diluted. On the other manus, no consequence was observed when outcrop chalk nucleuss were imbibed or flooded with diluted SW. In fact, the oil recovery was decreased drastically as SW was diluted due to the lessening in active ions ( Fathi et al. , 2010a ) .Several works done on chalk nucleuss by Austad and colleagues have shown enormous addition in oil recovery. One of their observation is that saltwater contains reactive ions SO42- , Ca2+ and Mg2+ towards chalk surface that can move as possible determining ions since they can alter the surface charge of CaCO3 ( Zhang and Austad, 2006 ) . They have besides shown that increasing the SO42- in saltwater can function as a wettability qualifier. Fathi et al. , ( 2010a ) even suggested that consuming saltwater in NaCl concentration should be even smarter H2O than ordinary saltwater. Zhang et Al. ( 2007 ) investigated the consequence of Ca2+ and Mg2+ at the chalk surface and noticed that at high temperature, the affinity of Mg2+ was higher than Ca2+ . It was observed that without Mg2+ nowadays, the solubility of CaSO4 is drastically decreased and will precipitate at a temperature of 100oC which will barricade the porous system.Besides, a set of comprehensive trials done by Zhang and Hemanta ( 2012 ) utilizing UAE carbonate stone to gauge displacement efficiency, assess wettability fluctuation through wettability monitoring and optimise brine composing at changing temperature of 700C, 900C and 1200C showed that take downing H2O salt or increasing sulfate concentration of the injected H2O can take to much higher oil recovery.Sing these studies, this survey will be based on accessing the combined consequence of saltwater and diluted saltwater on oil recovery while tuning the concentration of Mg2+ and SO42- with/without NaCl on a carbonate nucleus at a high temperature, i.e. reservoir temperature. This survey is new and will probably add to literature on the mechanism of oil recovery as observed in the research lab experiments.
1.5 SCOPE OF STUDY
Coreflood Experiments
Core inundation experiments will be performed utilizing reservoir nucleuss and unrecorded petroleum oil under reservoir conditions and current field injection patterns, including reservoir force per unit area, reservoir temperature, representative wettability, salt and ionic content of initial formation H2O and current types of injected H2O. To quantify the degree of oil recovery by H2O deluging utilizing seawaters with different salts and ionic composings, a series of coreflooding experiments will be carried out on both individual and composite nucleuss. Alteration of injection H2O in footings of both salt and ionic composing would be based on gulf H2O. Basically, smart H2O coreflood experiments will be performed in the undermentioned two scenarios:Waterflood with different saltsWaterflood with different ionic composingsThe consequences of these trials will quantify the degree of oil recovery by utilizing different injection H2O and aid specify the most favorable seawater salt and composing for bettering oil recovery. Furthermore these trials will besides bring forth informations for ciphering water/oil comparative permeableness for the above scenarios, which would be used in simulation survey.
Mechanistic survey on LSW survey
In order to better understand relevant mechanisms for smart waterflooding in carbonates, ionic composing analysis, surface charge possible measuring, chromatographic surveies ( surface assimilation analysis ) , contact angle and IFT measurings will be carried out under full reservoir conditions. In these measurings, the combined consequence of seawater salt and ionic composing will be considered as variables.
Simulation survey
By following the Kr informations from 1-D simulation lucifer on Coreflood consequences and reservoir inactive theoretical account, reservoir simulation will be conducted to measure the public presentation of different injection scenarios on research lab graduated table. In add-on, based on mechanistic survey, simulation method could be proposed for LSWF in carbonates.
Methodology
3.1 Materials
3.1.1 Core stoppers
Limestone nucleus stopper will be used in this work. These nucleuss will be collected from a really tight zone ( permeableness scope of 0.01 to 5 mendelevium ) of a UAE carbonate reservoir. All the nucleuss used in this work will be measured and sooner 1.5 inches in diameter and around 2 inches in length will be cut from whole nucleuss and composite nucleuss ( 1.5 inches and 30 centimeters long ) will be arranged.
3.1.2 Fluid Properties
3.1.2.1 Seawaters
Different seawaters will be used in this survey, including formation H2O ( Table 3.1 ) to set up initial or irreducible H2O impregnation ( Swi ) for nucleuss and saltwater, SW, for base injection, and different salt bullets of injection saltwater to displace oil. All seawaters will be prepared from distilled H2O and reagent class chemicals, based on geochemical analysis of field H2O samples. Table 3.2 depicts the geochemical analysis and the corresponding chemicals concentration for each type of seawater. For the experiments described below, saltwater had a salt of about 43,619 ppm, and initial connate H2O is really saline with salt of 252,923ppm by weight.Other dilute versions of saltwater will besides be prepared by blending with different volumes of deionized H2O and addition/removal of salts ( Sulfate and Magnesium ) . This includes:10 times diluted saltwater as DSWSeawater incorporating twice the usual Mg and sulfate ion concentration as SW X 2Mg2+ X 2 SO42-Seawater without NaCl and incorporating four times the usual Mg and sulfate ion concentration as SW X 4Mg2+ X 4 SO42- X 0NaCl10 times diluted saltwater incorporating twice the usual Mg and sulfate ion concentration as DSW X 2Mg2+ X 2 SO42-10 times diluted saltwater without NaCl and incorporating four times the usual sulphate ion concentration as DSW X 4 SO42- X 0NaCl
3.1.2.2 Reservoir Oil Samples
Reservoir oil samples will be used in this survey.
3.1.2.3 Extra chemicals for dissolver cleansing
Toluene: Used for the cleansing of the limestone reservoir nucleuss.Methanol: Used for the remotion of Toluene and H2O in the limestone reservoir nucleuss during the cleansing procedure.Table 3.1: Geochemical analysis of field formation H2O samples
Formation Water
kppm
Mol/L
Ionic Strength
Na+74.9693.2603.2595Ca2+18.9720.4740.2250Mg2+3.4320.1430.5720SO42-0.2670.0030.0111HCO3-0.040.0010.0059Cl-155.2364.3734.3728
4.2232
TDS252.916SO42-/Ca2+0.014SO42-/Mg2+0.078Solubility merchandiseKc0.0013Kd0.0004Entire0.0017
Apparatus
3.2.1 Air Minipermeameter
Air permeableness will be measured utilizing a minipermeameter which measures flow rate and recess force per unit area.
3.2.2 Digital Tensiometer
The chief parts of the instrument are the IFT chamber cell, the manus pump for injection, a quiver free tabular array, needle, temperature control system, lamp, transportation cells, force per unit area transducers with digital show, and a to the full automated imagination system. The imagination system allows a direct digitisation of the bead image with the assistance of a picture frame grabber of a digital camera
3.2.3 Core Flooding Apparatus
The coreflooding setup to be used in this research work is custom designed to execute experiments with both normal and composite nucleus stoppers to measure oil recovery utilizing waterflooding at reservoir conditions. The chief constituents of the setup are oven, nucleus holder, fluid collectors, differential force per unit area transducers, two pumps, back force per unit area regulator ( BPR ) , restricting force per unit area faculty, and three stage centrifuge ( Yousef et al. , 2010 ) .The implosion therapy system is capable of managing temperatures up to 150 A°C, pore force per unit areas up to 9,500 pounds per square inchs, and overburden force per unit areas up to 10,000 pounds per square inchs. Volumes of oil and different salt seawaters are supplied from high-pressure drifting Piston collectors, operated by external high-pressure pumps. Oil and seawater injection will be accomplished through a pump connected by a set of valves in front of the nucleus holder. System force per unit area is maintained by a back force per unit area regulator ( BPR ) at the nucleus mercantile establishment, and measured by absolute and differential force per unit area transducers ; and these informations are registered by a computing machine based informations acquisition and command board. The coreflooding setup is equipped with a three-phase centrifuge, used to mensurate the cured oil during waterflooding. The centrifuge is placed inside the oven in a climb bracket and operates at reservoir force per unit area and temperature. The three stage centrifuge with a two-bore form is chiefly used for stage degree measuring of the oil/water and gas/oil interfaces at trial force per unit area and temperature.Three separate package plans that can be run in a manual, semi-automated or machine-controlled manner, allows the user for full manner control on most facets of the system from the chief screen. This characteristic includes valve toggling, reading force per unit areas and temperatures, command the position of the pumps, and restricting force per unit area pump scenes.
3.3 EXPERIMENTAL PROCEDURE
3.3.1 Core Samples Selection and Preparation
The nucleuss might had some taint during coring and film editing procedures, they will foremost be subjected to solvent cleaning utilizing Dean-Stark extraction and dried at 230 A°F for about 24 hours before transporting out petrophysical measurings and wettability Restoration stairss.Solvent cleansingThe nucleuss will be cleaned by deluging the nucleuss at room temperature with methylbenzene in Dean-Stark setup until the wastewater became colourless ( Thomas et al. , 1993 ) . Thereafter, the nucleuss will be flooded with several PVs of methyl alcohol to take methylbenzene and H2O. Then the nucleus was dried out at 230 A°F to vaporize methyl alcohol.Different research lab trials will be exercised to choose a consistent nucleus complex in footings of petrophysical belongingss every bit good as stone types ; this includes everyday nucleus analysis, XRD analysis ( to look into the mineralogy of the stone ) and X-ray Computerized Tomography ( CT ) scan. Routine nucleus analysis will be foremost conducted to mensurate the dimensions, air permeableness, porousness, and pore volume of nucleus stoppers. The nucleus stopper will so be CT scanned to test out any nucleus with breaks or permeableness barriers.Permeability MeasurementThe absolute permeableness for selected nucleuss is calculated from Darcy ‘s jurisprudence based on the ascertained force per unit area bead across the seawater saturated nucleus after steady-state is achieved by shooting formation H2O through the nucleus sample. The oil permeableness at the initial H2O impregnation will besides be measured. Darcy ‘s jurisprudence ( equation 3.1 ) for single-phase, steady-state, incompressible, horizontal flow in laboratory units of cc/min, mendelevium, cm2, pounds per square inch, cp and centimeter:The comparative permeableness measuring will done utilizing unsteady province waterflooding process. After the measuring of the seawater permeableness, the nucleus will be flooded by the reservoir oil to the connate H2O impregnation and oil permeableness will be measured. At the initial phases of waterflooding before H2O discovery, during the H2O discovery, during the production of oil and H2O and at the terminal of H2O inundation, i.e. residuary oil impregnation, the effectual permeableness to oil and H2O will be measured and their impregnations will be recorded ( equation 3.2 ) .Effective permeabilites for each stage will be normalized to 100 % seawater permeableness for comparative permeableness computations ( equation 3.3 ) .Air permeableness was measured utilizing the minipermeameter described above. Compressed N is injected into the prepared nucleuss at a scope of flowrates. An linear force per unit area dial is used to mensurate force per unit area bead. Air permeableness will be calculated accounting for Klinkenberg consequence.Pore Volume and Initial Water ImpregnationThe pore volume of nucleuss, original oil in topographic point, and initial H2O impregnation of selected nucleus stoppers will be determined utilizing a extractor setup. The dry weight of the nucleus sample will be step. Then the nucleus stopper will be saturated by vacuity for 10 yearss with formation H2O to accomplish ionic equilibrium with the nucleus samples. The wet weight of the sample will be measured. The pore volume will be calculated by weight difference and the denseness of formation H2O at the reservoir temperature. Each nucleus stopper will be centrifuge at 2,000 revolutions per minute to run out the H2O in the pores and set up the connate H2O impregnation. Then weight of centrifuged nucleus sample will be measured to find weight difference of the original oil in the nucleus and the initial H2O impregnation – before and after extractor.Afterwards, impregnation nucleuss with formation H2O will be analyzed to screen some nucleus samples into complexs with similar stone types. Based on a reappraisal of the conventional nucleus analysis & A ; CT scan ( before and after experiment ) , one complex nucleus will be selected for this survey. The purpose of this is to analyze the consequence of different wettability provinces on oil recovery.
3.3.2 Fluid Preparation
SeawaterThe H2O and salts will be mixed in the appropriate proportions. Every seawater sample will be filtered with the utilizing porous media for any unexpected atoms remotion. The impact of salt and ion composing, on the physical belongingss ( denseness and viscousness ) of prepared Waterss will be studied. The denseness and viscousness belongingss will be measured at reservoir temperature of 230 A°F.Crude oilEvery oil sample is filtered with the organic filter paper to take solids and contaminations to cut down any ( asphaltene atoms and mulcts ) experimental troubles during coreflood experiments. The oil analysis informations, viscousness and denseness measuring at reservoir status are taken.
3.3.3 IFT Measurements
IFT measurings will be conducted utilizing reservoir oil and different diluted seawater at reservoir conditions. The experiment is conducted to turn to the consequence of fluid-fluid interaction in wettability change in bettering oil recovery. A high temperature/high-pressure pendant bead instrument ( max 10,000 pounds per square inch and 392oF ) will be used to mensurate IFT values between the petroleum oil and injected seawaters.After thorough cleansing of the setup ( first by hexane, propanone, dry air and in conclusion, deionized H2O ) to take any hint sums of taint which might change the consequence, a standardization trial is first run by puting the chromium steel steel ball inside empty an IFT cell and the image system to be set ready to take a image.The ball will be removed from the IFT cell and the place of the camera fixed. The formation H2O will be injected into the IFT cell while the temperature is set to reservoir value to obtain temperature equilibrium inside the whole cell. More formation H2O is injected into the cell to increase the force per unit area inside the cell to reservoir force per unit area.Reservoir oil will be injected through the bottom acerate leaf to acquire a stable oil bead on the top of the needle inside the cell. Then a digital exposure will be taken and the image bead plan will be run to cipher IFT values. The same process will be done with regular SW, SWX2Mg2+X2SO42- , SWX4Mg2+X4SO42-X0NaCl, DSW, DSWX2Mg2+X2SO42- and DSWX4SO42-X0NaCl.
3.3.4 Wettability monitoring
Contact angle is one of the most various methods to quantify wettability of stone. The purpose is to measure the impact of chemical science of the diluted saltwater on carbonate stone wettability. The general conventional categorization of contact angle is ( Anderson 1986 ) : water-wet, 0A° – 75A° ; intermediate-wet, 75A° – 115A° ; and oil-wet, 115A° – 180A° .To obtain an penetration on the drive mechanisms for extra oil recovery observed in coreflood experiments, it is critical to mensurate contact angle values utilizing the same inundation sequence at which the coreflood experiments is conducted. For the same stone sample, the measurings will be conducted in both remarkable and consecutive manner:FW, SW and DSWFW, SWX2Mg2+X2SO42 and DSWX2Mg2+X2SO42FW, SW, SWX2Mg2+X2SO42- and SWX4Mg2+X4SO42-X0NaClFW, DSW, DSWX2Mg2+X2SO42- and DSWX4SO42-X0NaClThe same process of cleansing of stone samples will be done and to reconstruct stone wettability, nucleus is foremost aged in formation H2O for 1 hebdomad, and so aged in the field oil for more than six hebdomads. Mount the nucleus to the upper acerate leaf utilizing epoxy and topographic point it inside the chamber cell at a suited place to be seen in the image system. Formation H2O will be injected into the contact angle cell. Both the temperature and force per unit area of the cell will be set to reservoir conditions. The bottom acerate leaf will be raised near to the nucleus and an oil droplet will be placed on the surface of the stone home base. Run the plan on contact angle measuring manner and the contact angle between the oil-brine-solid interfaces will be monitored over 7 yearss
3.3.5 Spontaneous Imbibition Experiments
Spontaneous imbibition experiments will be conducted to look into the wettability change potencies of the diluted seawater samples with different H2O chemical science. The Spontaneous imbibition experiments are conducted as follows:After the initial H2O impregnation has been established in the nucleuss. The nucleuss will be aged for 20-30 yearss to reconstruct wettability and so they will be placed in convectional glass Amott cells in an oven at 230oF. The nucleuss will be surrounded by the saltwater and oil production by self-generated imbibition will be recorded as a map of clip. Once the oil production Michigan, the environing saltwater will be replaced with one of the diluted seawaters ( SWX4Mg2+X4SO42-X0NaCl, DSWX4SO42-X0NaCl ) .
3.3.6 Coreflooding Experiments
A coreflooding survey is conducted to look into the impact of tuning the salt and ionic composing of the injection H2O on oil recovery. The experimental parametric quantities and processs will be designed to reflect the initial conditions normally found in carbonate reservoirs, every bit good as the current field injection patterns.Single nucleus implosion therapyThe experimental process followed is described below:All collectors of the coreflooding setup is foremost filled with injected fluids including reservoir oil and seawaters.The three stage centrifuge is checked and calibrated to accurately find the oil production during waterflooding.The nucleus stoppers are loaded into the nucleus holder.Restricting force per unit area of 4,500 pounds per square inch is maintained on the nucleus stopper by make fulling the nucleus holder restricting ring.The pore force per unit area is initiated by puting up the back force per unit area regulator at 200 pounds per square inch.Reservoir oil is flushed through the nucleuss at back force per unit area conditions to displace gas and guarantee complete fluid impregnation.Reservoir oil flushing is maintained until the force per unit area bead across the nucleuss is stabilized. This procedure takes 1-2 hebdomads.The oven is switched on and the temperature is set to the reservoir temperature of 230 A°F.The nucleus is aged at reservoir temperature with perennial reservoir oil flowers. This procedure takes 4weeks and it ends when the force per unit area bead across the nucleus is stabilized.The pore force per unit area of the nucleus is set at reservoir force per unit area through the back force per unit area regulator.Conduct saltwater deluging while supervising the sum of oil produced, the force per unit area bead across the nucleus, pH and the injection rate of the saltwater as a map of clip.Water will be injected at a changeless rate of about 0.1cc/min until no more oil release.The injection rate will be increased to 0.2cc/min, and so to 0.5cc/min to guarantee all nomadic oil is produced and avoids capillary terminal consequence.The diluted H2O will so be injected into the nucleus sample following the same injection process as described above.The same procedure goes for composite coreflooding. The composite must be assembled, wrapped with TeflonA® , placed into a gum elastic arm, and in order to increase the capillary figure, the implosion therapy rate will be increased in stairss.
3.3.7 Ionic composing analysis
Effluent collected at changeless clip intervals will be analyzed. An ion-exchange chromatograph and inductive coupled plasma will be used to analyse the ionic concentrations of Na2+ , Ca2+ , Mg2+ and SO42- .
3.3.8 Zeta possible measurings
The zeta potency indicates the grade of repulsive force between next, likewise charged atoms in scattering. For molecules and atoms that are little plenty, a high zeta potency will confabulate stableness, i.e. , the solution or scattering will defy collection. When the potency is low, attractive force exceeds repulsive force and the scattering will interrupt and flocculateA ( Hanaor, 2012 ) .Sample readying: The stone stuffs will be wet-milled with methyl alcohol utilizing a planetal ball factory and dried at 230 A°F. In order to look into the affinity of possible finding ions towards the stone surface, the aqueous stone pulverization suspension will be prepared by blending representative solution ( 100 % pure NaCl ) with milled stone pulverization. The suspension will so be stirred for 24 hours before usage.Zeta potency: Zeta potency will be measured utilizing a Colloidal Dynamics Acousto Sizer II that worked based on electro-acoustic and supersonic fading measurings.The consequence of divalent ions in the representative solution, ( selectively SO42- and Mg2+ ) at different concentrations on the charge of carbonate surface will be analyzed.For each individual divalent ion, a new batch will be prepared. The carbonate pulverization suspension in a representative solution will be stirred for 24 hours. Then the surface charge will be measured at different molar concentration of each individual divalent ion. For each measuring, the pH will be kept changeless, equal to 8 by seting with little sums of concentrated HCl or NaOH. The carbonate suspensions will be stirred for 15 proceedingss after new chemicals were added in order to accomplish a new equilibrium before the measuring. Then the measuring will be repeated with SW and DSW.
3.3.9 Chromatographic studies/surface responsiveness
A 100 % water-saturated carbonate nucleus will be mounted in a Hassler nucleus holder, with a constraining force per unit area of 4,500 pounds per square inchs. A back force per unit area of 200psi will be used to guarantee changeless pore force per unit area, and to forestall the fluid from boiling at high temperatures. The nucleus will be flooded at changeless rate. Samples of the wastewater will be taken utilizing a fraction aggregator and the ionic composings will be analyzed.Affinity of SO42- : Affinity of SO42- towards the surface of nucleus samples at reservoir temperature will be studied utilizing SW1/2T, saltwater with half equal sums of SCN- and SO42- and DSW1/2T, 10 times diluted saltwater with half equal sums of SCN- and SO42- . This will be done to look into the consequence of sulphate at the saltwater salt and 10 times dilution ( table 3.3 ) . Before the trial, the nucleus will be flooded with at least 5 PV ‘s of saltwater without SCN- and SO42- ( SW0T ) .Substitution of Ca2+ by Mg2+ : Due to the addition in responsiveness of Mg2+ at Temperature above 90 A°C, it has been observed that Mg2+ is able to displace Ca2+ from the carbonate surface lattice, by a permutation reaction. In the presence of SO42- , Mg2+ is besides able to move as a wettability qualifier. Therefore, the permutation of Ca2+ by Mg2+ is believed to be portion of the wettability change procedure ( Zhang et al. , 2007 ) . Different diluted H2O – Southwest, SWX2MgX2SO4 and DSW, DSWX2MgX2SO4 – will be flooded through the nucleuss at a rate of 0.1cc/min and the concentration of Ca2+ , Mg2+ , and SO42-will be plotted versus the PV injected.Table 3.2: Geochemical analysis and the corresponding chemicals concentration
Seawater Water
kppm
Mol/L
Ionic Strength
Diluted Seawater Water
kppm
Mol/L
Ionic Strength
Na+13.70.59570.5957Na+1.370.05960.0596Ca2+0.5210.01300.0002Ca2+0.05210.00131.70E-06Mg2+1.620.06750.2700Mg2+0.1620.00680.0270SO42-3.310.03450.1379SO42-0.3310.00340.0138HCO3-00.00000.0000HCO3-00.00000.0000Cl-24.4680.68920.6892Cl-2.44680.06890.0689
0.8465
0.0846
TDS43.62TDS4.362SO42-/Ca2+6.35SO42-/Ca2+6.353SO42-/Mg2+2.04SO42-/Mg2+2.043Solubility merchandiseSolubility merchandiseKc0.0004Kc4.49E-06Kd0.0023Kd2.33E-05Entire0.0028Entire2.78E-05
SWx2Mgx2SO4
kppm
Mol/L
Ionic Strength
Diluted SWx2Mgx2SO4
Kppm
Mol/L
Ionic Strength
Na+13.70.5960.5957Na+1.370.05960.0596Ca2+0.5210.0130.0002Ca2+0.05210.00131.70E-06Mg2+3.240.1350.5400Mg2+0.3240.01350.0540SO42-6.620.0690.2758SO42-0.6620.00690.0276HCO3-00.0000.0000HCO3-00.00000.0000Cl-24.4680.6890.6892Cl-2.44680.06890.0689
1.0504
0.1050
TDS48.55TDS4.855SO42-/Ca2+12.71SO42-/Ca2+12.706SO42-/Mg2+2.04SO42-/Mg2+2.043Solubility merchandiseSolubility merchandiseKc0.0009Kc8.98E-06Kd0.0093Kd9.31E-05Entire0.0102Entire1.02E-04
SWx4Mgx4SO4x0NaCl
kppm
Mol/L
Ionic Strength
Diluted SWx4SO4x0NaCl
kppm
Mol/L
Ionic Strength
Na+000Na+000Ca2+0.5210.0130.0002Ca2+0.05210.00131.70E-06Mg2+6.480.2701.0800Mg2+0.1620.00682.70E-02SO42-13.240.1380.5517SO42-1.3240.01385.52E-02HCO3-000HCO3-000Cl-000Cl-000
0.8159
0.0411
TDS20.24TDS1.538SO42-/Ca2+25.41SO42-/Ca2+25.413SO42-/Mg2+2.04SO42-/Mg2+8.173Solubility merchandiseSolubility merchandiseKc0.0018Kc1.796E-05Kd0.0372Kd9.309E-05Entire0.0390Entire1.111E-04Table 3.3: Composition of seawaters used in the chromatographic trials and zeta surveies
SWx0T
kppm
Mol/L
Ionic Strength
DSWx0T
kppm
Mol/L
Ionic Strength
Na+13.70.59570.5957Na+1.3700.05960.0596Ca2+0.5210.01300.0002Ca2+0.0520.00131.70E-06Mg2+1.620.06750.2700Mg2+0.1620.00680.0270SO42-00.00000.0000SO42-0.0000.00000.0000HCO3-00.00000.0000HCO3-0.0000.00000.0000Cl-24.4680.68920.6892Cl-2.4470.06890.0689SCN-000.0000SCN-000.0000
A
A
A
0.7775
A
A
A
0.0777
TDS40.309
A
A
TDS4.0309
A
A
SO42-/Ca2+0
A
A
SO42-/Ca2+0
A
A
SO42-/Mg2+0
A
A
SO42-/Mg2+0
A
A
Solubility merchandise
A
A
Solubility merchandise
A
A
A
Kc
A
0
A
Kc
A
0
A
Kd
A
0
A
Kd
A
0
A
Entire
A
0
A
Entire
A
0
A
A
A
A
A
A
A
A
A
SWx1/2T
kppm
Mol/L
Ionic Strength
DSWx1/2T
kppm
Mol/L
Ionic Strength
Na+13.70.59570.5957Na+1.370.05960.0596Ca2+0.5210.01300.0002Ca2+0.05210.00131.70E-06Mg2+1.620.06750.2700Mg2+0.1620.00680.0270SO42-1.6550.01720.0690SO42-0.16550.00170.0069HCO3-00.00000.0000HCO3-00.00000.0000Cl-24.4680.68920.6892Cl-2.44680.06890.0689SCN-1.6550.02850.0285SCN-0.16550.00290.0029
A
A
A
0.8120
A
A
A
0.0812
TDS43.62
A
A
TDS4.362
A
A
SO42-/Ca2+3.18
A
A
SO42-/Ca2+3.177
A
A
SO42-/Mg2+1.02
A
A
SO42-/Mg2+1.022
A
A
Solubility merchandise
A
A
Solubility merchandise
A
A
A
Kc
A
0.0002
A
Kc
A
2.25E-06
A
Kd
A
0.0012
A
Kd
A
1.16E-05
A
Entire
A
0.0014
A
Entire
A
1.39E-05
A
A
A
A
A
A
A
A
A
SWxT
kppm
Mol/L
Ionic Strength
DSWxT
kppm
Mol/L
Ionic Strength
Na+13.70.5960.5957Na+1.3700.05960.0596Ca2+0.5210.0130.0002Ca2+0.0520.00131.70E-06Mg2+1.620.0680.2700Mg2+0.1620.00680.0270SO42-3.310.0340.1379SO42-0.3310.00340.0138HCO3-00.0000.0000HCO3-0.0000.00000.0000Cl-24.4680.6890.6892Cl-2.4470.06890.0689SCN-3.310.0570.0571SCN-0.3310.00570.0057
A
A
A
0.8465
A
A
A
0.0846
TDS46.93
A
A
TDS4.693
A
A
SO42-/Ca2+6.35
A
A
SO42-/Ca2+6.353
A
A
SO42-/Mg2+2.04
A
A
SO42-/Mg2+2.043
A
A
Solubility merchandise
A
A
Solubility merchandise
A
A
A
Kc
A
0.0004
A
Kc
A
4.49E-06
A
Kd
A
0.0023
A
Kd
A
2.33E-05
A
Entire
A
0.0028
A
Entire
A
2.78E-05
A
3.4 SIMULATION STUDIES
Computer patterning group, CMG will be used to pattern the one dimensional simulation solution. The theoretical account ‘s preparation will integrate known mechanisms under reservoir graduated table for imitating smart H2O procedures. Homogeneous theoretical accounts will be required to do usage of the derived research lab informations ( the relation permeableness curve ) and fit the simulation consequences with experimental consequences.
4.0 PROJECT TASK AND TIME FRAME
The whole proposed research is divided into six subtasks as:Undertaking 1: Extensive relevant literature reappraisal and literature reappraisal sum-up ;Undertaking 2: Experimental stuffs aggregation and apparatus readying for experiments ;Undertaking 3: Spontaneous imbibition experiments, Contact angle and IFT measurings utilizing different seawaters for LSW ;Undertaking 4: Coreflood experiments for smart waterflooding ;Undertaking 5: Ionic composing analysis, Zeta potency and Surface responsiveness measurings utilizing different seawaters ;Undertaking 6: Reservoir simulation survey ;The GANTT CHART is shown below.
