NATIONAL CONFERENCE ON HYDROCARBON RESERVOIR ENGINEERING, SCIENCE AND RELATED INDUSTRIES | Year:2013 | دوره:2 |Papers Count:11

IT IS THE NATURAL RIGHT OF EACH COUNTRY TO EXPLOIT ITS UNDERGROUND RESOURCES. PRODUCTION AND DEVELOPMENT OF A SHARED HYDROCARBON FORMATIONS CAN BE PERFORMED INDEPENDENTLY, NEVERTHELESS ANY PRODUCTION OR PRESSURE CHANGE CAN HAVE IRREVERSIBLE EFFECT ON THE WHOLE RESERVOIR. IRAN IS ONE OF THE UNIQUE COUNTRIES IN THE WORLD, HAVING SHARED OIL AND GAS FIELDS WITH AT LEAST SIX NEIGHBORHOOD COUNTRIES. SOME OF THESE FIELDS HAVE BEEN DEVELOPED EARLIER AND SOME ARE JUST UNDER DEVELOPMENT. THE PURPOSE OF THIS PAPER IS TO INVESTIGATE DEVELOPMENT PLANS THAT CAN MAXIMIZE THE PRODUCTIVITY OF ONE PARTY FROM A SHARED FIELD.FLUID MIGRATION CROSSING BORDER IS SIMULATED BASED ON REAL FIELD DATA WITH ECLIPSE SOFTWARE. DIFFERENT SCENARIOS ARE RUN TO FIND DIFFERENT CROSS-BORDER FLUID ENCROACHMENT.FINALLY, TWO SETS OF FACTORS ARE RECOGNIZED: DEVELOPMENT PARAMETERS AND THE INTACT RESERVOIR PROPERTIES. APPLICATION OF THESE TWO TYPES OF PARAMETERS ENABLES ANY COUNTRY TO MANAGE THE BORDER FLUID AND TO COMPENSATE THE POSSIBLE ARREARAGE OF PRODUCTION FROM SHARED RESERVOIRS. FINDINGS OF THIS STUDY ARE APPLIED TO INVESTIGATE THE DEVELOPMENT PLAN OF A GIANT GAS FIELD NAMED PASO. SOME CROSS-BORDER GAS MIGRATION HAS ALREADY HAPPENED BUT MANAGING THE FLUID IN THE BORDER CAN COMPENSATE FURTHER LOSE OF UNDERGROUND RESOURCES.

IMMISCIBLE GAS INJECTION IS ONE OF THE MOST COMMON EOR METHODS USED FOR VARIOUS RESERVOIR CONDITIONS. IN THIS WORK, IMMISCIBLE RECYCLE GAS INJECTION, AS AN ENHANCED OIL RECOVERY SCENARIO FOR IMPROVING RECOVERY EFFICIENCY IN ONE OF THE SOUTH-WEST IRANIAN OIL RESERVOIRS, IS SIMULATED BY COMMERCIAL SIMULATOR, ECLIPSE. THE RESERVOIR FLUID IS LIGHT OIL WITH GRAVITY OF 43O API. THE OIL BEARING FORMATIONS ARE CARBONATE AND SO DUAL POROSITY/DUAL PERMEABILITY BEHAVIOR WAS CHOSEN FOR BETTER REPRESENTATION OF THE FRACTURE SYSTEM. DIFFERENT SENSITIVITY ANALYSIS WITH RESPECT TO SEVERAL PARAMETERS LIKE NUMBER AND LOCATION OF INJECTION/PRODUCTION WELLS, PRODUCTION/INJECTION RATE, COMPLETION INTERVAL AND ETC IS PERFORMED. IT HAS BEEN OBSERVED THAT IN SENSITIVITY WITH NUMBER OF WELLS, 1 INJECTION/3 PRODUCTION WELLS WAS THE MOST EFFICIENT CASE. ALSO WELL OIL PRODUCTION RATE OF 200 SM3/DAY AND WELL BOTTOM-HOLE PRESSURE OF 75 BAR PROVIDED HIGHER OIL RECOVERY.COMPLETING INJECTION WELLS IN FRACTURE AND PRODUCTION WELLS IN MATRIX HAS A BETTER FIELD OIL EFFICIENCY IN COMPARISON TO OTHER CASES. FINALLY WE PROPOSED OPTIMUM CONDITIONS FOR IMMISCIBLE RECYCLE GAS INJECTION IN THIS RESERVOIR WHICH MAXIMIZES OIL RECOVERY EFFICIENCY.

FOAM DRILLING IS INCREASINGLY USED TO DEVELOP LOW PRESSURE RESERVOIR OR HIGHLY DEPLETED MATURE RESERVOIRS BECAUSE OF MINIMIZING THE FORMATION DAMAGE AND POTENTIAL HAZARDOUS DRILLING PROBLEMS. PREDICTION OF THE CUTTINGS CONCENTRATION IN THE WELLBORE ANNULUS AS A FUNCTION OF OPERATIONAL DRILLING PARAMETERS SUCH AS WELLBORE GEOMETRY, PUMPING RATE, DRILLING FLUID RHEOLOGY AND DENSITY, AND MAXIMUM DRILLING RATE IS VERY IMPORTANT FOR OPTIMIZING THESE PARAMETERS. THIS PAPER DESCRIBES A SIMPLE AND MORE RELIABLE ARTIFICIAL NEURAL NETWORK (ANN) METHOD AND MULTIPLE LINEAR REGRESSION (MLR) TO PREDICT CUTTINGS CONCENTRATION DURING FOAM DRILLING OPERATION.THIS MODEL IS APPLICABLE FOR VARIOUS BOREHOLE CONDITIONS USING SOME CRITICAL PARAMETERS ASSOCIATED WITH FOAM VELOCITY, FOAM QUALITY, HOLE GEOMETRY, SUBSURFACE CONDITION (PRESSURE AND TEMPERATURE), AND PIPE ROTATION. THE AVERAGE ABSOLUTE PERCENT RELATIVE ERROR (AAPE) BETWEEN THE EXPERIMENTAL CUTTINGS CONCENTRATION AND ANN MODEL IS LESS THAN 6%, AND USING MLR, AAPE IS LESS THAN 9%. A COMPARISON OF THE ANN AND MECHANISTIC MODEL WAS DONE. THE AAPE VALUES FOR ALL DATASETS IN THIS STUDY WERE 3.2 % AND 10.3 % FOR ANN MODEL AND MECHANISTIC MODEL RESPECTIVELY.

MODELING OF DISCREET PARAMETERS SUCH AS GEOLOGICAL FACIES, LITHOLOGY, OR ROCK TYPES, IS A VERY IMPORTANT TOPIC IN RESERVOIR CHARACTERIZATION AND IS DESCRIBED IN MORE DETAIL BY DUBRULE (1998).GEOLOGICAL QUANTIFICATION IS A TOPIC THAT HAS ALWAYS RAISED MUCH INTEREST AND DEBATE AMONG GEOLOGISTS. DEPENDING ON THE DEPOSITIONAL ENVIRONMENT AND USING THE WELL DATA AS A CONSTRAINT, THE RESERVOIR GEOLOGIST CAN DRAW SKETCHES OF THE DISTRIBUTION OF SANDS AND SHALES.UNFORTUNATELY, HAND-DRAWN CROSS-SECTIONS ARE LIMITED IN THAT THEY DO NOT LEAD TO A 3D MODEL, AND THEY REPRESENT ONLY ONE POSSIBLE MODEL AMONG INFINITY OF SCENARIOS MATCHING THE WELLS AND COMPATIBLE WITH THE DEPOSITIONAL ENVIRONMENT.IN THE EARLY 1980S, IT BECAME CLEAR THAT GEOSTATISTICAL TECHNIQUES COULD HELP GENERATE SUCH 3D GEOLOGICAL SCENARIOS. THESE SCENARIOS WILL NEVER BE QUITE AS REALISTIC OR "GEOLOGICALLY LOADED" AS THOSE PRODUCED BY A GEOLOGIST, YET THEY PRESENT THE ADVANTAGE OF BEING MULTIPLE AND THREE-DIMENSIONAL. TODAY, THERE ARE TWO MAJOR CLASSES OF TECHNIQUES AVAILABLE FOR GENERATING 3D STOCHASTIC MODELS: PIXEL-BASED AND OBJECT-BASED MODELS. IN THIS STUDY SOME DIFFERENT ASPECTS OF GEOSTATISTICAL MODELING IS CONSIDERED. AFTER THAT THE DIFFERENT METHODS OF FACIES MODELING LIKE IK, SIS AND OBJECT MODELING RUN BY PETREL SOFTWARE IN THE FOLLOWING A REAL CASE STUDY. FACIES ARE OFTEN IMPORTANT IN RESERVOIR MODELING BECAUSE THE PETROPHYSICAL PROPERTIES OF INTEREST ARE HIGHLY CORRELATED WITH FACIES TYPE. KNOWLEDGE OF FACIES CONSTRAINS THE RANGE OF VARIABILITY IN POROSITY AND PERMEABILITY. MORE-OVER, SATURATION FUNCTIONS DEPEND ON THE FACIES EVEN WHEN THE DISTRIBUTIONS OF POROSITY AND PERMEABILITY DO NOT.

DE-CONVOLUTION IS A METHOD OF CONVERTING A VARIABLE RATE DISTORTED PRESSURE PROFILE INTO THE PRESSURE PROFILE FOR AN EQUIVALENT CONSTANT RATE PRODUCTION SEQUENCE. THERE ARE TWO METHODS USED FOR DE-CONVOLVING DISTORTED PRESSURE DATA: BETA DE-CONVOLUTION AND MATERIAL BALANCE DE-CONVOLUTION METHODS. THE APPLICATION OF BOTH METHODS WAS TESTED IN WELL TEST ANALYSIS OF A NATURALLY FRACTURED RESERVOIR. THE END OF WELL BORE STORAGE WAS ESTIMATED BY BOTH METHODS, AND THEN THE RESERVOIR DATA WERE ANALYZED BY WELL TESTING SOFTWARE. THE CALCULATED PERMEABILITY, INTERACTION COEFFICIENT AND STORATIVITY RATIO ARE DIFFERENT IN BOTH APPROACHES. THE COMPARISON OF DATA SHOWS THAT THE MATERIAL BALANCE METHOD PREDICTS THE PRESSURE RESPONSE BETTER AND IS SUGGESTED FOR APPLYING IN FIELD CASES.

MATRIX ACIDIZING IS A TECHNIQUE TO STIMULATE WELLS FOR IMPROVING WELL INFLOW PERFORMANCE.IN THIS TREATMENT, ACID SOLUTION IS INJECTED INTO THE FORMATION AT PRESSURE BELOW THE ROCK FAILURE PRESSURE TO DISSOLVE SOME OF THE MINERALS TO INCREASE PERMEABILITY OF CARBONATES NEAR THE WELLBORE. IN THIS WORK, MATRIX ACIDIZING HAS BEEN SIMULATED IN THE RADIAL 3-D DOMAIN USING CONTINUUM/AVERAGE MODEL. THE REACTION KINETICS HAS BEEN CONSIDERED TO BE NONLINEAR AT SOLIDLIQUID INTERFACE. THE RESERVOIR IS CONSIDERED AS A HETEROGENEOUS MEDIA AND THE EFFECTS OF ACID MOLECULAR DIFFUSION, ACID CONVECTION BY FLUID BULK AND ACID REACTION WITH ROCK IN POROUS MEDIA ARE CONSIDERED. DIFFERENT DISSOLUTION PATTERNS OBSERVED IN THE EXPERIMENTS ARE SHOWN BY NUMERICAL SIMULATION RESULTS. TO VALIDATE THE MODEL, ONE SET OF ACIDIZING FIELD DATA OF WELL-5 SARKHOON WAS USED. RESULTS ARE DISCUSSED IN TERM OF SKIN FACTOR. IN PARTICULAR, THE CHANGE IN THE DOMINANT WORMHOLE GROWTH DYNAMIC IS INVESTIGATED DURING WORMHOLE PROPAGATION AROUND THE WELLBORE.

INTERFACIAL TENSION IS A PHYSICAL PARAMETER WHICH PLAYS AN IMPORTANT ROLE IN MANY PROCESSES IN A NUMBER OF INDUSTRIAL APPLICATIONS. IN THE PETROLEUM INDUSTRY, NEAR-CRITICAL FLUIDS RECOVERY, GAS CONDENSATE RECOVERY, IN PARTICULAR BY GAS INJECTION, WETTING BEHAVIOR, SECONDARY AND TERTIARY CRUDE OIL RECOVERY, LOW SURFACE TENSIONS ARE VERY IMPORTANT TO MEASURE. THESE SURFACE TENSIONS (I.E. LIQUID/VAPOR INTERFACIAL TENSIONS) MUST BE ACCURATELY KNOWN BECAUSE OF THEIR DOMINATING INFLUENCE ON CAPILLARY PRESSURES, RELATIVE PERMEABILITIES AND RESIDUAL LIQUID SATURATIONS. THESE PROPERTIES DEPEND HEAVILY ON THE DENSITY OF THE PHASES INVOLVED.ONE OBJECTIVE OF THIS STUDY WAS TO DEVELOP AN ACCURATE MEASURING PROCEDURE FOR THIS SYSTEM USING THE PENDANT DROP METHOD BASED ON IRANIAN OIL RESERVOIR SAMPLES AND ITS IMMISCIBLE INJECTING GAS AT RESERVOIR CONDITION. ANOTHER OBJECTIVE WAS TO STUDY THE BEHAVIOR OF THE INTERFACIAL TENSION WITH PRESSURE AND TEMPERATURE IN A RANGE OF (14.7-4500 PSIA) AND (110-200OF). SINCE EXPERIMENTAL MEASUREMENTS ARE OFTEN UNAVAILABLE, EXPENSIVE AND TIMECONSUMING, MODELS ARE REGULARLY USED. A NEW CORRELATION FOR ESTIMATING OF IFT WAS PROVIDED USING NON-LINEAR MULTIVARIABLE REGRESSION METHOD. THIS CORRELATION USES DENSITY DIFFERENCE AS INPUT VALUE, DETAILED COMPARISONS SHOW THAT VALIDITY AND ACCURACY OF THE NEW CORRELATION ARE IN GOOD AGREEMENT WITH EXPERIMENTAL DATA SET OF IRANIAN OIL RESERVOIR FLUIDS.THIS PAPER IS ORGANIZED AS FOLLOWS. SECTION 1 IS RELATED TO INTRODUCTION. SECTION 2 DESCRIBES THE EXPERIMENTAL METHOD AND APPARATUS AND DISCUSSES THE OBTAINED RESULTS AND THEIR ACCURACY AND REPRODUCIBILITY. SECTION 3 FOCUSES ON NEW CORRELATION AND COMPARING WITH EXPERIMENTAL DATA. WE OUTLINE OUR CONCLUSIONS IN SECTION 4.

FOAM DRILLING IS THE ONE OF MAIN BRANCHES OF UNDERBALANCED DRILLING. THE RHEOLOGICAL PROPERTIES OF DRILLING FLUIDS SUCH AS FOAM DIRECTLY AFFECT ON FLOW CHARACTERISTICS AND HYDRAULIC PERFORMANCE. TWO RHEOLOGICAL HERSCHEL-BULKLY AND POWER LAW MODELS WERE FITTED TO TWO FOAM SYSTEMS IN THIS STUDY. COMPUTATIONAL FLUID DYNAMICS (CFD) WAS USED TO SIMULATE THE EFFECT OF RHEOLOGICAL MODEL, FOAM VELOCITY AND FOAM QUALITY ON CUTTINGS TRANSPORT (SOLID- LIQUID FLOW) HYDRODYNAMICS IN CONCENTRIC AND ECCENTRIC ANNULUS DURING FOAM DRILLING OPERATION.THE SIMULATION RESULTS ARE COMPARED TO THE EXPERIMENTAL DATA FROM PREVIOUS STUDIES. THE RESULTS OF CFD USING POWER LAW MODEL ARE IN GOOD AGREEMENT WITH EXPERIMENTAL RESULTS IN HORIZONTAL ANNULUS RESPECT TO HERSCHEL-BULKLY MODEL WITH RELATIVE ERROR LESS THAN 8%. SO, FOR CFD CUTTINGS TRANSPORT SIMULATION IN INCLINED AND HORIZONTAL ANNULUS, IT IS BEST TO USE POWER LAW MODEL RHEOLOGICAL MODEL PARAMETERS.

IN THIS PAPER, WE SIMULATE DYNAMIC IMBIBITION ON A SMALL SCALE HOMOGENOUS FRACTURED BLOCK. THE PURPOSE IS TO SEEK OPTIMUM CONDITIONS UNDER WHICH THE OIL RECOVERY IS MAXIMAL.IN ORDER TO DO THIS, WE CONSIDER A BASE CASE SIMULATION AND THEN WE DOSENSITIVITY ANALYSES ON SEVERAL PARAMETERS. 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, 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 FOR EACH SENSITIVITY ANALYSIS AND APPROPRIATE PROFILES ARE DEMONSTRATED IN ORDER TO UNDERSTAND THE RESULTS.

THE WATER CONING PHENOMENON USUALLY OCCURS IN WATER DRIVE RESERVOIRS. WATER CONING IN IRANIAN HYDROCARBON RESERVOIRS IS ONE OF THE MOST IMPORTANT PROBLEMS THAT AFFECTS THE CUMULATIVE PRODUCTION, OPERATION COSTS AND CAUSES ENVIRONMENTAL PROBLEMS. BEFORE PRODUCING FROM A RESERVOIR, THE FLUIDS ARE IN EQUILIBRIUM AND THEIR CONTACT SURFACES REMAIN UNCHANGED, BUT AFTER STARTING PRODUCTION FROM THE RESERVOIR, WHEN THE VISCOUS FORCE OVERCOME GRAVITATIONAL FORCE IN VERTICAL DIRECTION, CONTACT SURFACES WILL DISPLACE AND CONING WILL OCCUR. THEREFORE, THE PRODUCTION RATES WILL BE CONTROLLED IN A RANGE THAT PREVENTS ENTERING WATER TO THE PRODUCTION WELL. FOR THIS REASON, INVESTIGATION AND MODELING OF THIS PHENOMENON IS EXTREMELY NECESSARY. IN THIS STUDY, THE CONING PHENOMENON, CONTROLLING METHODS (I.E. BELOW CRITICAL RATE PRODUCTION, PLUG IN AND DWS TECHNOLOGY) AND PROBLEMS DUE TO CONING (SUCH AS INCREASE IN PRESSURE GRADIENT IN WELL, PERMEABILITY REDUCTION NEAR WELLBORE REGION AND INCREASE IN RESIDUAL GAS SATURATION) HAD BEEN STUDIED FOR ONE OF THE IRANIAN GAS RESERVOIRS. THE SIMULATION STUDY SHOWS THAT THE BEST CHOICE FOR WATER CONING CONTROLLING METHOD IN GAS RESERVOIRS, AT RATES ABOVE CRITICAL IS STRONG FUNCTION OF ALLOWABLE WATER PRODUCTION RATE IN DWS TECHNOLOGY; BUT A MORE SIMPLE AND EFFICIENT METHOD IN THESE CASES IS PLUG IN.

CONVENTIONAL LOG BASED RESERVOIR CHARACTERIZATION OF A GAS RESERVOIR IN THE KANGAN AND DALAN FORMATIONS HAVE RECENTLY BEEN IMPROVED BY THE APPLICATION OF THE NUCLEAR MAGNETIC RESONANCE (NMR) LOG.THE PROBLEM OF NMR MEASUREMENTS IN GAS RESERVOIRS IS THAT IN GAS-BEARING ZONES, TOTAL NMR POROSITIES READ MUCH LESS THAN DENSITY-DERIVED POROSITIES.POROSITY DERIVED FROM NMR ALONE SUFFERS FROM THE LOW HYDROGEN INDEX OF THE GAS AND THE LONG T1 POLARIZATION TIME OF THE GAS WHEN THE DATA IS ACQUIRED WITH INSUFFICIENT WAIT TIME.TO PROVIDE A ROBUST ESTIMATE OF POROSITY, A METHOD CALLED DENSITY-MAGNETIC RESONANCE (DMR) THAT COMBINES DENSITY POROSITY AND TOTAL NMR POROSITY WAS SUCCESSFULLY APPLIED TO THE 4 WELLS LOGGED WITH NMR.THE DMR TECHNIQUE WAS ABLE TO PRODUCE A VERY GOOD POROSITY ESTIMATION COMPARABLE TO THAT MEASURED ON CONVENTIONAL CORES. IMPROVED POROSITY CALCULATION LEAD TO BETTER CORE INDEPENDENT PERMEABILITY ESTIMATION ON THE WELLS LOGGED WITH NMR. PERMEABILITY DERIVED FROM NMR WAS INVOLVED TO AN ELECTROFACIES MODELING AS AN ASSOCIATED LOG TO PREDICT FACIES BASE PERMEABILITY ON 20 WELLS WITHOUT NMR LOG.TO TEST THE PERMEABILITY PREDICTION, ESTIMATED PERMEABILITY WAS COMPARED WITH CORE DERIVED PERMEABILITY ON 5 CORED WELLS TO SEE HOW WELL, ESTIMATED PERMEABILITY FITTED THE ACTUAL CORE PERMEABILITY.