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 pet...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.展开更多
Additional stress formed by postconstruction buildings in loess-filling areas affects water infiltration in soil and causes soil deformation.To investigate this effect,under constant water head,vertical infiltration t...Additional stress formed by postconstruction buildings in loess-filling areas affects water infiltration in soil and causes soil deformation.To investigate this effect,under constant water head,vertical infiltration tests on compacted loess with two initial dry densities for different applied vertical stresses were developed using vertical stresscontrollable one-dimensional soil columns.The timehistory curves of vertical deformation,wetting front depth,cumulative infiltration depth,volumetric water content(VWC)and suction were measured,and the soil-water characteristic curves(SWCCs)were determined.The results showed that:(1)the infiltration ability of the soil column weakens with increasing applied vertical stress and initial dry density;(2)vertical deformation increases rapidly at first and then tends to be stable slowly at the consolidation and wetting-induced deformation stage,and is positively correlated with applied vertical stress and is negatively correlated with initial dry density.The stability time of wetting-induced deformation and the corresponding wetting front depth increase with the increase of applied vertical stress,while they decrease obviously when initial dry density increases;(3)the influence of applied vertical stress on soilwater characteristics in soil columns with various initial dry densities is related to the deformation depth of soil column.The VG(Van Genuchten)model is suitable for fitting the SWCCs at different monitoring positions.A normalized SWCC model introducing the applied vertical stress was proposed for each initial dry density using the mathematical relationship between the fitting parameters and the applied vertical stress.展开更多
文摘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.
基金funded by the Fundamental Research Funds for the Central UniversitiesCHD(Grant No.300102262503)+2 种基金the Natural Science Basic Research Program of Shaanxi(Grants No.2022JM-167)the National Natural Science Foundation of China(Grant Nos.41790442,41772278,41877242,42072311)the Yan’an Science and Technology Plan Project(Grant No.2022SLSFGG-004)。
文摘Additional stress formed by postconstruction buildings in loess-filling areas affects water infiltration in soil and causes soil deformation.To investigate this effect,under constant water head,vertical infiltration tests on compacted loess with two initial dry densities for different applied vertical stresses were developed using vertical stresscontrollable one-dimensional soil columns.The timehistory curves of vertical deformation,wetting front depth,cumulative infiltration depth,volumetric water content(VWC)and suction were measured,and the soil-water characteristic curves(SWCCs)were determined.The results showed that:(1)the infiltration ability of the soil column weakens with increasing applied vertical stress and initial dry density;(2)vertical deformation increases rapidly at first and then tends to be stable slowly at the consolidation and wetting-induced deformation stage,and is positively correlated with applied vertical stress and is negatively correlated with initial dry density.The stability time of wetting-induced deformation and the corresponding wetting front depth increase with the increase of applied vertical stress,while they decrease obviously when initial dry density increases;(3)the influence of applied vertical stress on soilwater characteristics in soil columns with various initial dry densities is related to the deformation depth of soil column.The VG(Van Genuchten)model is suitable for fitting the SWCCs at different monitoring positions.A normalized SWCC model introducing the applied vertical stress was proposed for each initial dry density using the mathematical relationship between the fitting parameters and the applied vertical stress.
