Solving asphaltene precipitation issue in vertical wells via redesigning of production facilities

Precipitation of heavy hydrocarbon components such as Wax and Asphaltenes are one of the most challenging issues in oil production processes.The associated complications extend from the reservoir to refineries and petrochemical plants.Precipitation is most destructive when the affected areas are hard to reach,for example the wellbore of producing wells.This work demonstrates the effect of adjusting choke valve sizes on thermodynamic parameters of fluid flowing in a vertical well.Our simulation results revealed optimum choke valve sizes that could keep producing vertical wells away from Asphaltene precipitation.The results of this study were implemented on a well in Darquin Reservoir that had been experiencing asphaltene precipitation.Experimental analysis of reservoir fluid,Asphaltene tests and thermodynamic simulations of well column were carried out and the most appropriate size of choke valve was determined.After replacing the well's original choke valve with the suggested choke valve,the Asphaltene precipitation problem diminished.

Technical and economic feasibility study of flue gas injection in an Iranian oil field

Nowadays,the non-hydrocarbon gases are the main sources for gas injection projects in different countries.The main advantages of the flue gas injection are low cost,readily available sources(which consists mainly of N2 and CO2)and low compressibility in comparison with other gases like CO2 or CH4(for a given volume at the same conditions).In addition,it occupies more space in the reservoir and it is an appropriate way for CO2 sequestering and consequently reducing greenhouse gases.In the aforementioned method,N2 and/or CO2 is injected into the oil reservoir for miscible and/or immiscible displacement of remaining oil.Moreover,a key parameter in the designing of a gas injection project is the minimum miscibility pressure(MMP)which is commonly calculated by running simulation case or implementing conventional correlations.From technical viewpoints,the lower MMP values are more flavor for miscible gas injection process due to lower injection pressure and consequently lower maintenance and lower injection costs.The main aim of this research is to investigate various gas injection methods(N2,CO2,produced reservoir gas,and flue gas)in one of the northern Persian gulf oil fields by a numerical simulation method.Moreover,for each scenario of gas injection technical and economical considerations are took into account.Finally,an economic analysis is implemented to compare the net present value(NPV)of the different gas injection scenarios in the aforementioned oil field.

Developing grey-box model to diagnose asphaltene stability in crude oils: Application of refractive index

Asphaltene precipitation can cause serious problems in petroleum industry while diagnosing the asphaltene stability conditions in crude oil system is still a challenge and has been subject of many investigations.To monitor and diagnose asphaltene stability,high performance intelligent approaches based bio-inspired science like artificial neural network which have been optimized by various optimization techniques have been carried out.The main purpose of the implemented optimization algorithms is to decide high accurate interconnected weights of proposed neural network model.The proposed intelligent approaches are examined by using extensive experimental data reported in open literature.Moreover,to highlight robustness and precision of the addressed approaches,two different regression models have been developed and results obtained from the aforementioned intelligent models and regression approaches are compared with the corresponding refractive index data measured in laboratory.Based on the results,hybrid of genetic algorithm and particle swarm optimization have high performance and average relative absolute deviation between the model outputs and the relevant experimental data was found to be less than 0.2%.Routs from this work indicate that implication of HGAPSO-ANN in monitoring refractive index can lead to more reliable estimation of addressed issue which can lead to design of more reliable phase behavior simulation and further plans of oil production.