NATIONAL CONFERENCE ON HYDROCARBON RESERVOIR ENGINEERING, SCIENCE AND RELATED INDUSTRIES | Year:2014 | دوره:3 |Papers Count:14

THE UPSTREAM OF THE PETROLEUM INDUSTRY INVOLVES ITSELF IN THE BUSINESS OF OIL AND GAS EXPLORATION AND PRODUCTION (E & P) ACTIVITIES. WHILE THE EXPLORATION ACTIVITIES FIND OIL AND GAS RESERVES, THE PRODUCTION ACTIVITIES DELIVER OIL AND GAS TO THE DOWNSTREAM OF THE INDUSTRY. THE PETROLEUM PRODUCTION IS DEFINITELY THE HEART OF THE PETROLEUM INDUSTRY. PETROLEUM PRODUCTION ENGINEERING IS THAT PART OF PETROLEUM ENGINEERING THAT ATTEMPTS TO MAXIMIZE OIL AND GAS PRODUCTION IN A COST-EFFECTIVE MANNER. TO ACHIEVE THIS OBJECTIVE, PRODUCTION ENGINEERS NEED TO HAVE A THOROUGH UNDERSTANDING OF THE PETROLEUM PRODUCTION SYSTEMS WITH WHICH THEY WORK. THE PURPOSE OF THIS PAPER IS TO IDENTIFY THE MOST IMPORTANT ADVANCES IN PETROLEUM PRODUCTION ENGINEERING IN THE PAST DECADE. OF COURSE, A REVIEW PAPER IN THE ALLOTTED SPACE SIMPLY CANNOT DO JUSTICE TO ALL NEW TECHNOLOGIES, ESPECIALLY THOSE THAT ARE ADVANCES TO ESTABLISHED TECHNIQUES. WE THEN EXPOUND UPON TWO TECHNOLOGIES THAT WE FEEL HAVE MADE ALREADY OR HAVE THE CAPACITY OF QUANTUM IMPACT ON THE PETROLEUM INDUSTRY. THESE ARE HIGH-PERMEABILITY FRACTURING (OFTEN REFERRED TO IN THE VERNACULAR AS FRAC-PACK AND VARIANTS) AND COMPLEX WELL ARCHITECTURE WHICH DEALS WITH WELLS WITH A MAIN OR MOTHER BORE FROM WHICH BRANCHES ARE DRILLED.

IN THIS ARTICLE IN ORDER TO ESTIMATE THE VISCOSITY OF CRUDE OIL, A NUMERICAL METHOD HAS BEEN USED. WE USE THIS METHOD TO MEASURE THE CRUDE OIL’S VISCOSITY FOR 3 STATES: SATURATED OIL’S VISCOSITY, VISCISITY ABOVE THE BUBBLE POINT AND VISCOSITY UNDER THE SATURATION PRESSURE. THEN THE CRUDE OIL’S VISCOSITY IS ESTIMATED BY USING KHAN MODEL AND ROLLER BALL METHOD. AFTER THAT USING THESE DATA THAT INCLUDE EFFICIENT CONDITIONS IN MEASURING VISCOSITY, THE ESTIMATED VISCOSITY BY THE PRESENTED METHOD, A RADIAL BASED NEURAL METHOD, IS TAUGHT. THIS NETWORK IS A KIND OF TWO LAYERED ARTIFICIAL NEURAL NETWORK THAT ITS STIMULATION FUNCTION OF HIDDEN LAYER IS GAUSSIAN FUNCTION AND TEACHING ALGORITHMS ARE USED TO TEACH THEM. AFTER TEACHING RADIAL BASED NEURAL NETWORK, RESULTS OF EXPERIMENTAL METHOD AND ARTIFICIAL INTELLIGENCE ARE COMPARED ALL TOGETHER. TEACHING THIS NETWORK, WE ARE ABLE TO ESTIMATE CRUDE OIL' VISCOSITY WITHOUT USIG KHAN MODEL AND EXPERIMENTAL CONDITIONS AND UNDER ANY OTHER CONDITION WITH ACCEPTABLE ACCURACY. RESULTS SHOW THAT RADIAL NEURAL NETWORK HAS HIGH CAPABILITY OF ESTIMATING CRUDE OIL. SAVING IN TIME AND COST IS ANOTHER ADVANTAGE OF THIS INVESTIGATION.

UNITISATION OCCURS WHEN LICENSES OF OIL AND/OR GAS RESERVES POOL THEIR INDIVIDUAL INTERESTS IN RETURN FOR AN INTEREST IN OVERALL UNIT. IT IS THEN OPERATED BY A SINGLE COMPANY ON BEHALF OF GROUP. THIS HAPPENS WHEN A FIELD LIES UNDER DIFFERENT LICENSES WITH DIFFERING EQUITY INTERESTS. THIS IS THE LEGAL DEFINITION OF UNITISATION, HOWEVER, THE VERY BASIS OF THE LEGAL CONCEPT OF THE JOINT DEVELOPMENT RESTS ON THE FLUID NATURE OF PETROLEUM OR NATURAL GAS. IF A DEPOSIT LIES ACROSS THE BOUNDARY LINE OF TWO OR MORE NEIGHBORING OWNERS, A SINGLE OWNER EXTRACTION DAMAGES THE POTENTIAL SHARE OF THE OTHER OWNER OR OWNERS. IT IS DESIRABLE, THEREFORE, TO AVOID SUCH EVENTUALITY ON THE BASIS ON SOME FORM OF COOPERATION BETWEEN THEM IN THE EXPLOITATION OF THE SOURCES. THUS, THE IDEA OF UNITISATION AROSE WHEREBY THE DEPOSIT OF FLUID PETROLEUM OR NATURAL GAS SHOULD BE TREATED AS A SINGLE DEPOSIT IF IT LIES ACROSS THE BOUNDARY LINE AND STRADDLES DIFFERENT JURISDICTIONS. THIS CONCEPT LATER LED TO ON A NUMBER OF INTERNATIONAL AGREEMENTS ON UNITISATION IN 1960S AND 1970S. ALTHOUGH AS THERE ARE ABOUT OVER THAN TWENTY JOINT OIL AND GAS FIELDS BETWEEN IRAN AND ITS NEIGHBORING COUNTRIES, FOR VARIOUS REASONS, MOST OF THEM ARE BEING EXPLOITED UNILATERALLY, WHICH IS NOT COMPATIBLE WITH THE ECONOMIC INTERESTS OF IRAN, SO UNITISATION PROCESS AND ITS ROLE IN AGREEMENTS, PARTICULARLY THOSE OF OIL AND GAS RESERVOIRS AND SUMMARIZING THE COMMON-POOL PROBLEM FACED IN CARBOHYDRATE PRODUCTIONS UNDER THE RULE OF CAPTURE IS REMARKABLE. IT DEFINES UNITISATION AS A SOLUTION TO THE PROBLEM AND THEN DESCRIBES THE ISSUES INVOLVED IN ARRIVING AT AN UNITISATION AGREEMENT.

OIL SANDS MUST BE MINED OR RECOVERED IN-SITU. DEPOSITS CLOSE TO THE SURFACE ARE MINED WHILE RESOURCES WHICH ARE VERY DEEP REQUIRE IN-SITU RECOVERY. STEAM ASSISTED GRAVITY DRAINAGE PROCESS (SAGD) THAT IS AN IN-SITU RECOVERY METHOD THAT HAS BEEN TESTED EXTENSIVELY IN THE HEAVY OIL AND BITUMEN RESERVOIRS. STEAM ASSISTED GRAVITY DRAINAGE PROCESS USES ONE OR MORE HORIZONTAL PRODUCTION WELL LOCATED NEAR TO THE BOTTOM OF THE RESERVOIR WITH STEAM INJECTION ABOVE FROM SEPARATE INJECTION WELLS. THIS CONFIGURATION WILL END IN GOOD PRODUCTION RATES WITH GOOD RECOVERY AND REASONABLY LOW SOR (STEAM-OIL RATIO).USE OF STEAM ASSISTED GRAVITY DRAINAGE HAS BEEN DEMONSTRATED TO BE A PROMISING WAY OF PRODUCING HEAVY OIL AND TAR SANDS WHICH ARE NOT RECOVERABLE IN NORMAL OPERATION IN FIELDS. IN THE CASE OF IRANIAN NATURALLY FRACTURED RESERVOIRS, WHATEVER HAS INFLUENCED THE HEAVY OIL PRODUCTION IN OTHER PARTS OF THE WORLD CAN CERTAINLY HELP US FOR FUTURE PRODUCTIONS AND DEVELOPMENTS WHICH CAN BE ACHIEVED EFFICIENTLY BY USE OF HORIZONTAL AND MULTILATERAL DRILLING TECHNIQUES. HOWEVER, WE SHOULD PROPOSE SOME MODIFICATION OF THESE METHODS (LIKE SAGD) AND INITIATE THE PROCESS IN A WAY THAT THE VAPOR CHAMBER IN SAGD PROCESS OR, COMBUSTION FRONT, IN THE CASE OF COMBUSTION PROCESSES, DEVELOPS IN MATRIX BLOCKS INSTEAD OF FRACTURES, THAT DEEMS TO BE APPROPRIATE FOR OUR NATURALLY FRACTURED RESERVOIRS. THIS IS MERELY A PROSPECT FOR FUTURE WORKS. THIS PAPER PRESENTS DIFFERENT ASPECTS OF SAGD OPERATION TOGETHER WITH ITS POSSIBLE VARIATIONS AND NUMEROUS CHALLENGES.

FAULT REGIMES HAVE SIGNIFICANT EFFECTS ON OIL AND GAS WELLS' STABILITY. ALTHOUGH VERTICAL WELLS HAVE DIFFERENT GEO-MECHANICAL BEHAVIORS, HORIZONTAL WELLS HAVE MORE CRITICAL CONDITIONS WHEN THEY WILL BE ENCOUNTERED WITH FAULT REGIMES CHANGES. IN THIS CASE, A HORIZONTAL GAS WELL IN A SPECIFIC DEPTH IN THE SOUTH PARS GAS FIELD IS CONSIDERED IN THE STRIKE-SLIP FAULT REGIME WITH THE POROELASTIC STATE OF THE ROCK MASS AND ANISOTROPIC HORIZONTAL STRESSES WHICH IS ANALYZED WITH THE FINITE ELEMENT METHOD BY THE ABAQUS SOFTWARE. THIS ANALYSIS IS PROCESSED STATICALLY IN A CERTAIN TIME PERIOD (THE TOTAL TIME OF GEO-STATIC AND DRILLING STEPS). THE WELL PRESSURE HAS INCREASED CONTINUOUSLY FROM THE FORMATION PORE PRESSURE (LOWER LIMIT OF ALLOWABLE MUD PRESSURE WINDOW) TO FRACTURE PRESSURE LIMIT (TENSILE FAILURE LIMIT) IN THE SECOND STEP OF THE ANALYSIS. THE MUD PRESSURE OPTIMIZATION HAS BEEN DONE BASED ON THE STRESS AND PLASTIC STRAIN REDUCTION AT THE BOREHOLE WALL. THE RESULTS SHOWED THAT, THE BOREHOLE STABILITY WILL NOT BE SATISFIED BY THE LOWER LIMIT OF WELL PRESSURE WINDOW (FORMATION PRESSURE) OR ITS UPPER LIMIT AND THE OPTIMUM MUD PRESSURE IN HORIZONTAL GAS WELLS IS A LITTLE HIGHER THAN THE MINIMUM LEVEL OF WELL PRESSURE.

IN CHARACTERIZATION OF WIDE BOILING RANGE HEPTANE PLUS (C7+) FRACTIONS IN ADDITION TO BULK PROPERTIES SUCH AS MOLECULAR WEIGHT (MW), SPECIFIC GRAVITY (SG), ETC., PROPERTIES DISTRIBUTION IS ALSO REQUIRED. BULK PROPERTIES CAN BE MEASURED EASILY BUT DETERMINATION OF PROPERTIES DISTRIBUTION IS MORE COSTLY AND TIME CONSUMING. SO THE CHARACTERIZATION METHODS IS USED FOR DETERMINING THE PROPERTIES DISTRIBUTION. METHODS SELECTED FOR THE CHARACTERIZATION OF RESERVOIR FLUIDS HAVE SIGNIFICANT IMPACT ON THE ESTIMATION OF PHYSICAL PROPERTIES AND PHASE BEHAVIOR NEEDED IN RESERVOIR SIMULATION FOR PETROLEUM PRODUCTION. CHARACTERIZATION OF RESERVOIR FLUIDS INVOLVES REPRESENTING THE FLUID AS A CONTINUOUS, SEMI-CONTINUOUS MIXTURE OR THROUGH A NUMBER OF COMPONENTS/PSEUDO COMPONENTS WITH KNOWN BASIC CHARACTERIZATION DATA. UNDERSTANDING OF VARIOUS CHARACTERIZATION SCHEMES AND THEIR LIMITATIONS IS THE KEY TO SELECTING THE RIGHT ONE IN A RESERVOIR SIMULATOR. THE MAIN OBJECTIVE OF THESE PAPER IS TO COMPARE THE RESULTS OF CHARACTERIZATION METHODS FOR ONE OF IRANIAN SOUTH OIL FIELD TO DETERMINE THE BEST METHOD THAT IS COMPACTIBLE WITH THAT RESERVOIR FLUID. THE RESULTS SHOW THAT ALL MODELS CAN ESTIMATE THE MOLE FRACTION DISTRIBUTION VERY CLOSE TO THE EXPERIMENTAL DATA FROM C7 TO C30+ BUT THE AVERAGE ABSOLUTE ERROR FOR SINGLE CARBON NUMBER (SCN) MODEL IS LOWER THAN OTHER MODELS FOR THIS RESERVOIR FLUID.

DUE TO EXCESSIVE PRODUCTION OF CARBON DIOXIDE FROM FOSSIL FUELS, EMISSIONS OF THIS GREENHOUSE GAS IN THE ATMOSPHERE IS OVER 28 GIGA TONS ANNUALLY. IN THE PAST CENTURIES, THE AVERAGE CONCENTRATION OF CARBON DIOXIDE IN THE ATMOSPHERE WAS 280 PPM WHICH HAS INCREASED TO 375 PPM AFTER THE INDUSTRIAL REVOLUTION.ACCORDING TO RECENT STUDIES, INCREASE IN CARBON DIOXIDE CONCENTRATION LEADS TO GLOBAL WARMING AND SEVER CLIMATE CHANGES WHICH COULD AFFECT THE PHYSICAL, CHEMICAL, BIOLOGICAL, ECONOMIC, AND POLITICAL ASPECTS OF THE ENVIRONMENT AND SOCIETY. THEREFORE, TO REDUCE THE CARBON DIOXIDE CONCENTRATION IN THE ATMOSPHERE, CAPTURE AND STORAGE (SEQUESTRATION) OF CARBON DIOXIDE WAS INTRODUCED.THE CARBON CAPTURE AND STORAGE (CCS) SYSTEM CONSISTS OF THREE DISTINCT TECHNOLOGIES: COLLECTION, TRANSPORTATION AND STORAGE. THE STORAGE OF CARBON DIOXIDE IS PERFORMED IN VARIOUS SYSTEMS SUCH AS: THE OCEANS, DEEP SALINE LAYERS, UNMINEABLE COAL SEAMS AND DEPLETED OIL AND GAS RESERVOIRS. IN EACH OF THESE CASES, VARIOUS CHEMICAL OR PHYSICAL TRAPPING MECHANISMS WERE INVOLVED. THE CANDIDATE RESERVOIR FOR CCS PROJECT SHOULD HAVE INTEGRATIVE SEAL LAYER (CAPROCK) AND PROPER POROSITY AND PERMEABILITY FOR INCREASING INJECTIVITY AND STORAGE CAPACITY OF CARBON DIOXIDE.

A KNOWLEDGE OF THE AVERAGE RESERVOIR PRESSURE (P) AND ITS CHANGES AS A FUNCTION OF TIME OR CUMULATIVE PRODUCTION IS ESSENTIAL TO DETERMINE THE OIL-IN-PLACE (OIP) OR ORIGINAL GAS-IN-PLACE (OGIP), TO ESTIMATE RESERVES AND TO TRACK AND OPTIMIZE RESERVOIR PERFORMANCE. THE AVERAGE RESERVOIR PRESSURE IS REQUIRED IN MANY RESERVOIR ENGINEERING CALCULATIONS SUCH AS: MATERIAL BALANCE STUDIES; WATER INFLUX; PRESSURE MAINTENANCE PROJECTS; SECONDARY RECOVERY; DEGREE OF RESERVOIR CONNECTIVITY. THIS PROJECT AIMS TO CALCULATE OF AVERAGE RESERVOIR PRESSURE FOR A SAMPLE RESERVOIR, WITH ANALYTICAL AND NUMERICAL APPROACHES, BY MEANS OF ECLIPSE 100 AND ECRIN AND WILL COMPARE THE RESULTS. FOR THAT SAMPLE RESERVOIR PRESSURE VERSUS TIME DATA ARE GENERATED FROM THE ECLIPSE 100 AND ECRIN WILL USE THEM TO ANALYZE THE RESULTS OF THE BUILDUP TEST AND WE CAN GET AVERAGE RESERVOIR PRESSURE. ECLIPSE 100 ALSO GIVES US THE AVERAGE RESERVOIR PRESSURE TOO. OUR SIMULATION ON THE RESERVOIR HAVE VERY GOOD RESULTS WITH ERROR OF JUST 0.56 PERCENT.IT SHOWS GOOD SIMILARITY BETWEEN THE ANALYTICAL METHODS THAT WE USE AND NEMRICAL METHODS THAT WE USE IN SIMULATORS, ALSO IT IS BETTER TO GETTING P-T DATA FROM FIELD WELL TESTING TO GENERATING THEM FROM SIMULATOR, IT CAN IMPROVE OUR RESULTS. FOR ESTIMATING AVERAGE RESERVOIR PRESSURE, IT IS BETTER TO HAVING SINGLE PHASE BECAUSE OF THE MULTIPHASE COMPLEXITIES.

IN THE OIL PRODUCTION INDUSTRY ONE OF THE MOST IMPORTANT TARGETS IS TO PRODUCE MAXIMUM OIL VOLUME. BECAUSE OF THE OIL PRESSURE DROP IN THE PRODUCTION PLANTS, REMARKABLE VOLUME OF OIL REDUCED DUE TO THE DISSOLVED GAS EXTRACTION FROM LIQUID. TO REDUCE THIS VOLUME REDUCTION OF OIL, SOME SEPARATORS WITH OPTIMUM PRESSURES ARE NEEDED. SO THE MAIN OBJECTIVE OF THIS PAPER IS TO DETERMINE THESE DESIRED PRESSURES. FOR APPROACHING THIS IDEA A MATLAB PROGRAM HAS BEEN WRITTEN THAT USING THE MODIFIED PENG ROBINSON EQUATION OF STATE FOR PHASE CALCULATION AND OPTIMIZE THE PRESSURES BY GA (GENETIC ALGORITHM). THIS PROGRAM WAS VALIDATED BY EXPERIMENTAL DATA OF SEPARATOR TEST AND THEN USED PVT DATA OF ONE OF THE IRANIAN OILFIELD (MARUN) TO OPTIMIZE ITS SEPARATORS PRESSURES. FOR ACCURATE SIMULATION AND DATA ANALYSIS, THE PR EOS PARAMETERS WERE TUNED BY PVTI SOFTWARE AND THE MODIFIED PARAMETERS WERE USED IN PROGRAM. THE RESULTS SHOW THAT THE RECOVERY HAS IMPROVED BY PRESSURE OPTIMIZATION. ALSO THE EFFECT OF TEMPERATURE WAS INVESTIGATED, THAT SHOWS THE RECOVERY INCREASES BY LOWERING TEMPARATURE. AS A RESULT THE TECOVERY IMPROVING TO ABOUT 0.4% THAT INTRODUCED 2000 BBL/DAY MORE RECOVERY OF OIL IN STOCK TANK. IT HAS 200000 DOLLARS PER DAY MORE INCOME.

IN THIS PAPER, WE PERFORM DYNAMIC IMBIBITION SIMULATIONS ON A LARGE SCALE HETEROGENEOUS FRACTURED BLOCK. THE PURPOSE IS TO SEEK OPTIMUM CONDITIONS UNDER WHICH MAXIMUM OIL CAN BE RECOVERED IN LARGE-SCALE EXTREMELY-HETEROGENEOUS RESERVOIRS. IN THIS PAPER, WE ONLY CONSIDER HORIZONTAL WELLS. HOWEVER, WE SIMULATE BOTH CONTINUOUS AND SLUG INJECTION SCENARIOS. VARIOUS CHEMICAL SOLUTIONS ARE INJECTED. THESE INCLUDE: WATER, POLYMER, SURFACTANT, ALKALI, AND DIFFERENT COMBINATIONS OF THEM. FOR CONVENIENCE OF SIMULATION, ALTHOUGH THIS IS NOT PHYSICALLY CORRECT, ALKALI REPRESENTS THE WETTABILITY MODIFYING AGENT, WHILE THE SURFACTANT IS THE AGENT THAT LOWERS THE IFT TO ULTRA-LOW VALUES. THEREFORE, A SIMULATION LABELED AS INDICATES THAT THE INJECTED CHEMICAL SOLUTION LOWERS THE IFT TO ULTRA LOW VALUES AS WELL AS ALTERS THE WETTABILITY FROM MIXED-WET TO WATER-WET. ON THE OTHER HAND, A SIMULATION LABELED ASP DOES THE ABOVE TASK AS WELL AS MAKING THE CHEMICAL SOLUTION VISCOUS (POLYMER). THE RECOVERY CURVES ARE COMPARED AND APPROPRIATE PROFILES ARE DEMONSTRATED IN ORDER TO UNDERSTAND THE RESULTS.

THE OBJECTIVE OF THIS PAPER IS TO INVESTIGATE THE FRACTURE PARAMETERS FOR OIL FRACTURE RESERVOIRS BY USING MULTI-RATE WELL TEST DATA. THIS WORK IS BASED ON THE STEADY STATE FLOW OF HOMOGENOUS LIQUID THROUGH FRACTURE NETWORK TOWARD WELLS USING KAZEMI AND WARREN-ROOT MODELS. MULTI-RATE WELL TESTING IS POWERFUL TOOLS THAT COULD DESCRIBE QUANTITATIVELY THE FRACTURE NETWORKS. FOR CONSTANT OIL PRODUCTION RATE, IF THE FRACTURE DENSITY (I.E. NUMBER OF FRACTURE) INCREASES, THEN THE DRAWDOWN OF OIL WELL DECREASES. ON THE OTHER HANDS, BY DECREASING THE FRACTURE DENSITY, THE DRAWDOWN INCREASES. THEREFORE, THE DRAWDOWN OF THE WELL COULD BE RELATED TO THE FRACTURE NETWORK AND COULD PROVIDE THE DATA ABOUT THE FRACTURE RESERVOIR CHARACTERIZATION. THIS STUDY BASED MULTI-RATE WELL TESTING AND TWO MAIN PREVAILING OF FRACTURE MODEL (I.E. KAZEMI AND WARREN-ROOT) TRIED TO OBTAIN THE FRACTURE RESERVOIR CHARACTERIZATION THAT INCLUDES PERMEABILITY OF FRACTURE AND MATRIX, POROSITY OF FRACTURE, ARIAL FRACTURE DENSITY, BLOCK SIZE AND FRACTURE OPENING. ALSO, THESE DATA COULD BE ASSISTED TO CALCULATE THE WATER AND GAS COINING. FINALLY, THE MODELING WAS CARRIED OUT FOR TWO IRANIAN FRACTURE RESERVOIRS IN SOUTH. THE RESULTS SHOW VERY GOOD AGREEMENT BETWEEN WARREN-ROOT MODEL AND FRACTURE IMAGE LOG.

CHEMICAL FLOODING IS RECOGNIZED AS ONE OF THE MOST COMPLICATED PROCESS IN ENHANCED OIL RECOVERY (EOR) METHODS, SO ACCURATE SIMULATION OF CHEMICAL FLOODING REQUIRES A DETAILED UNDERSTANDING OF NUMEROUS COMPLEX MECHANISMS AND MODEL PARAMETERS DUE TO HIGHLY COUPLED, NONLINEAR INTERACTIONS OF MANY CHEMICAL AND PHYSICAL PROCESSES INVOLVED IN CHEMICAL PROCESS. ENHANCED OIL RECOVERY METHODS SUCH AS CHEMICAL FLOODING REQUIRE LABORATORY ANALYSIS OF THE FLUID FLOW THROUGH POROUS MEDIA AND THE DETERMINATION OF CRUCIAL PARAMETERS. AFTERWARDS, THE RESULTS OF THESE STUDIES MUST BE ANALYZED IN A FIELD SCALE. REGARDING THE HIGH COST AND LONG TIME OF FLOODING PROCESSES FOR LABORATORY MODELS, APPLICATION OF VARIOUS SIMULATORS TO SIMULATE THESE TYPES OF STUDIES BECOMES CLEAR. ON THE OTHER HAND, GEOLOGICAL MODELS WITH MORE THAN ONE MILLION GRID BLOCKS ARE SOMETIMES NECESSARY TO CAPTURE IMPORTANT GEOLOGICAL FEATURES SUCH AS PERMEABILITY AND POROSITY DISTRIBUTION ASSOCIATED WITH AN OIL RESERVOIR. UNFORTUNATELY, SIMULATION OF FIELD SCALE FLOW USING EVEN WITH MORE ADVANCED COMPOSITIONAL RESERVOIR SIMULATORS AND CURRENT COMPUTING POWER ARE COMPUTATIONALLY INTENSIVE. IN THIS PAPER, THE EFFECT OF GRID BLOCK SIZE ON THE PERFORMANCE OF SURFACTANT-POLYMER (SP) FLOODING, AND SURFACTANT (S) FLOODING FOR A SYNTHETIC LAYERED RESERVOIR IS INVESTIGATED. THE SIMULATION STUDY IS PERFORMED BY A THREE-DIMENSIONAL, MULTIPHASE, MULTI-COMPONENT CHEMICAL FLOODING SIMULATOR. THE EFFECTIVE PROPAGATION OF THE S AND SP SLUG IN THE RESERVOIR IS VERY IMPORTANT TO HAVE HIGH OIL RECOVERY EFFICIENCY. THE LARGER THE GRID BLOCK SIZE, THE GREATER THE SURFACTANT DILUTION, WHICH IN TURN DRAMATICALLY REDUCES THE EFFECTIVENESS OF THE PROCESS. SIMULATION RESULTS SHOW THAT THE NEGATIVE EFFECT OF USING COARSE GRID SIMULATION IS MORE PREDOMINANT ON SP FLOODING RATHER THAN S FLOODING. FINALLY, TWO NEW APPROACHES ARE USED AS A SCALE UP METHODOLOGY AND THEIR PERFORMANCE IN THE MENTIONED PROCESSES ARE EXPLORED. IN ADDITION, THE RESULTS SHOW THAT PSEUDO LOWER EFFECTIVE SALINITY APPROACH IS MORE EFFECTIVE TO MATCH COARSE GRID AND FINE GIRD SIMULATION RESULTS.

REMAINING OIL IN THE RESERVOIR CAN BE DIVIDED INTO TWO CLASSES, FIRSTLY RESIDUAL OIL TO THE WATER FLOOD AND SECONDLY OIL BYPASSED BY THE WATER FLOOD. RESIDUAL OIL MAINLY CONTAINS CAPILLARY TRAPPED OIL. WATER FLOODING ONLY IS NOT ABLE TO PRODUCE CAPILLARY TRAPPED OIL SO THAT THERE IS A NEED FOR ADDITIONAL TECHNIQUE AND FORCE TO PRODUCE AS MUCH AS RESIDUAL OIL. ONE WAY OF RECOVERING THIS CAPILLARY TRAPPED OIL IS BY ADDING CHEMICALS SUCH AS ALKALINE, SURFACTANT AND POLYMER TO THE INJECTED WATER. THIS ARTICLE PRESENTS DIFFERENT ASPECTS OF SAP COMBINATION FLOODING AND DISCUSSES ABOUT ONE REAL CASE WHICH SAP PROCESS SUCCESSFULLY HAVE BEEN DONE. THE CRUCIAL ROLE OF ALKALI IN AN ALKALINE SURFACTANT PROCESS IS TO REDUCE ADSORPTION OF SURFACTANT DURING DISPLACEMENT THROUGH THE FORMATION. ALSO ALKALI IS BENEFICIAL FOR REDUCTION OF OIL-WATER IFT BY IN SITU GENERATION OF SOAP, WHICH IS AN ANIONIC SURFACTANT. GENERALLY ALKALI IS INJECTED WITH SURFACTANT TOGETHER. SURFACTANTS ARE CONSIDERED FOR ENHANCED OIL RECOVERY BY REDUCTION OF OIL–WATER INTERFACIAL TENSION (IFT). ON THE OTHER HAND, POLYMER IS VERY EFFECTIVE ADDITION BY INCREASING WATER VISCOSITY WHICH CONTROLS WATER MOBILITY THUS IMPROVING THE SWEEP EFFICIENCY. SAP COMBINATION FLOODING TO ENHANCE OIL RECOVERY IS EFFECTIVE AND ECONOMIC, IT CAN INCREASE OIL RECOVERY RATE BY ABOUT 20% (OOIP) FOR MANY YEARS. CRUDE OIL CHARACTERISTICS, BRINE CHARACTERISTICS, BOTTOM-HOLE TEMPERATURE, ALKALI, WELL HISTORY, AND TREATMENT DESIGN ARE CONSIDERED TO MAXIMIZE THE TREATMENT RESULTS.

IN THIS PAPER WE PERFORM DYNAMIC IMBIBITION SIMULATIONS ON A LARGE SCALE HOMOGENOUS FRACTURED BLOCK. THE PURPOSE IS TO SEEK OPTIMUM CONDITIONS UNDER WHICH THE OIL RECOVERY IS MAXIMAL IN A LARGER SCALE MODEL. IN ORDER TO DO THIS, WE CONSIDER 7 DIFFERENT CASES WITH VARYING RELATIVE IMPORTANCE OF CAPILLARITY AND VISCOUS FORCES. THE INJECTIONS ARE ALL CONTINUOUS. VARIOUS CHEMICAL SOLUTIONS ARE INJECTED. THESE INCLUDE: WATER, POLYMER, SURFACTANT, ALKALI, AND DIFFERENT COMBINATIONS OF THEM. FOR CONVENIENCE OF SIMULATION, EVEN THOUGH THIS IS NOT PHYSICALLY CORRECT, ALKALI REPRESENTS THE WETTABILITY MODIFYING AGENT, WHILE THE SURFACTANT IS THE AGENT THAT LOWERS THE IFT TO ULTRA LOW VALUES. THEREFORE, A SIMULATION LABELED AS INDICATES THAT THE INJECTED CHEMICAL SOLUTION LOWERS THE IFT TO ULTRA LOW VALUES AS WELL AS ALTERS THE WETTABILITY FROM MIXED-WET TO WATER-WET. ON THE OTHER HAND, A SIMULATION LABELED ASP DOES THE ABOVE TASK AS WELL AS MAKING THE CHEMICAL SOLUTION VISCOUS (POLYMER). THE RECOVERY CURVES ARE COMPARED FOR EACH CASE NUMBER AND APPROPRIATE PROFILES ARE DEMONSTRATED IN ORDER TO UNDERSTAND THE RESULTS.