مدلسازي رياضي فرآيند تزريق بخار در يكي از مخازن نفت سنگين ايران

چكيده انگليسي :

Mathematical Modeling of Steam Injection into an Iranian Heavy Oil Reservoir Sajad Mozaffari s mozaffari@ce iut ac ir Date of Submission 2011 04 12 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree Master of Science Language PersianSupervisor M R Ehsani ehsanimr@cc iut ac irAbstract Thermal recovery methods are the best candidate to improve recovery factor in heavy oil reservoirs Reductionof the heavy oil viscosity is necessary to improve mobility and achieving an economical recovery from heavy oilreservoirs The most efficient method to lower the viscosity is the application of heat to the reservoir containingheavy oil These reservoirs cannot be produced by primary methods because the API of oil is low and theviscosity is high Steam injection can be applied as a recovery method to produce heavy oil sourceseconomically In this study the entire process of steam injection was divided into two parts Steam injection intoinjection well and injected into the reservoir A numerical non isothermal two phase wellbore model wasdeveloped to simulate downward flow of steam and water mixture in the wellbore during steam injection Thismodel entails simultaneous solution of coupled mass and momentum conservation equations inside the wellborewith an energy conservation equation for the fluids within the wellbore and surrounding medium A drift fluxmodel was employed to represent slip between fluid phases The model predictions were validated against realfield data and other available models So by using data of steam injection wells for two oil fields of MarthaBigpond and Sallie Lee in a computer program variations of steam pressure temperature and quality werepredicted along the well depth Then these results were compared with the results of some available models Finally after certainty of the model s accuracy variations of steam pressure temperature and quality at one ofIranian heavy oil reservoirs were predicted along the well depth The model is useful for designing wellcompletion and accurately computing pressure drop and steam quality along the wellbore which is veryimportant for estimating oil recovery by steam injection method Also a three dimensional model for steaminjection into the reservoir was provided Formulation details numerical solution procedures and computationalresults were presented The model described the simultaneous flow of three phases oil water and gas inthree dimensions It included the effects of three phase relative permeabilities capillary pressure andtemperature and pressure dependent fluid properties Interphase mass transfer of water steam was allowed butthe oil was assumed nonvolatile and the hydrocarbon gas insoluble in the liquid phases The three phase massbalances and energy balance were solved simultaneously using finite difference equations Laboratory data werereported for steamfloods were used for checking accuracy and assumptions in this numerical model Comprehensive and comparative studies together with extensive sensitivity analysis among various importantparameters were conducted in order to understand injection operation properties on the oil recoveryperformance This work showed that steam injection could improve oil recovery from almost zero up to nearly60 during fixed period of time In addition it illustrated that only 30 of OOIP could be recovered by hotwater injection method The results showed that there is an optimum time for oil production shall be determinedaccording to the flow of oil production and steam oil ratio SOR Keywords Wellbore reservoir steam injection heavy oil oil recovery

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مدلسازي رياضي فرآيند تزريق بخار در يكي از مخازن نفت سنگين ايران

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