The low cost of the injected solvent,which can be also recovered and recycled,and the applicability of VAPEX technique in thin reservoirs are among the main advantages of VAPEX process compared to thermal heavy oil re...The low cost of the injected solvent,which can be also recovered and recycled,and the applicability of VAPEX technique in thin reservoirs are among the main advantages of VAPEX process compared to thermal heavy oil recovery techniques.In this research,an extensive experimental investigation is carried out to first evaluate the technical feasibility of utilization of various solvents for VAPEX process.Then the effect of drainage height on the stabilized drainage rate in VAPEX process was studied by conducting series of experiments in two large-scale 2D VAPEX models of 24.5 cm and 47.5 cm heights.Both models were packed with low permeability Ottawa sand(#530)and saturated with a heavy oil sample from Saskatchewan heavy oil reservoirs with viscosity of 5650 mPa s.Propane,butane,methane,carbon dioxide,propane/carbon dioxide(70%/30%)and propane/methane(70%/30%)were considered as respective solvents for the experiments,and a total of twelve VAPEX tests were carried out.Moreover,separate experiments were carried out at the end of each VAPEX experiment to measure the asphaltene precipitation at various locations of the VAPEX models.It was found that injecting propane would result in the highest drainage rate and oil recovery factor.Further analysis of results showed stabilized drainage rate significantly increased in the larger physical model.展开更多
Colloidal gas aphron(CGA)based fluid has become very popular in drilling in the last two decades,as it reduces formation damages significantly.In this study,sugarcane molasses(Mls)was used for the first time as a poly...Colloidal gas aphron(CGA)based fluid has become very popular in drilling in the last two decades,as it reduces formation damages significantly.In this study,sugarcane molasses(Mls)was used for the first time as a polymer in CGA-based to investigate its ability to improve the role of aphronized fluid as a drilling fluid.The results showed that increasing the concentration of Mls to 12%(v/v)in CGA-based fluid reduces the drainage rate and increases half-life to 10.6 min,resulting in enhanced stability of the aphronized fluid.Also,because of increasing Mls concentration from 1%to 12%(v/v),the yield and the initial gas hold-up decrease to 74%and 299.4 mL,respectively,indicating that the presence of Mls allows less air into the aphron system.Although the rheological properties were improved in this study,the gel strength did not change considerably.Furthermore,the results showed that by increasing the concentration of Mls,the average size of the bubbles decreases,and the particle-size distribution becomes more uniform.Finally,the API filtration test revealed that the higher the Mls concentration in the aphronized fluid,the lower the fluid loss,and at the Mls concentration of 12%(v/v),the fluid loss was estimated at 19.54 mL.A natural polysaccharide with high molecular weight,Mls can be used as a polymer in CGAbased fluid and,thus,improve its performance.展开更多
The filling construction of permeable geosynthetic tubes is considered.First,an analytical approach is developed to determine the internal pressure,tension and shape of the cross section of a geosynthetic tube based o...The filling construction of permeable geosynthetic tubes is considered.First,an analytical approach is developed to determine the internal pressure,tension and shape of the cross section of a geosynthetic tube based on its volume.An analytical solution for the drainage rate of the tube is then derived.The course of the filling construction is divided into several time intervals and the volume of the tube after each interval is obtained from the equilibrium of flow calculated from the drainage rate and filling rate.The validity of our analytical approach is tested by comparing our results with previously published experimental result.The results of this comparison indicate that our method is applicable for simulating the filling construction of permeable geosynthetic tubes.展开更多
文摘The low cost of the injected solvent,which can be also recovered and recycled,and the applicability of VAPEX technique in thin reservoirs are among the main advantages of VAPEX process compared to thermal heavy oil recovery techniques.In this research,an extensive experimental investigation is carried out to first evaluate the technical feasibility of utilization of various solvents for VAPEX process.Then the effect of drainage height on the stabilized drainage rate in VAPEX process was studied by conducting series of experiments in two large-scale 2D VAPEX models of 24.5 cm and 47.5 cm heights.Both models were packed with low permeability Ottawa sand(#530)and saturated with a heavy oil sample from Saskatchewan heavy oil reservoirs with viscosity of 5650 mPa s.Propane,butane,methane,carbon dioxide,propane/carbon dioxide(70%/30%)and propane/methane(70%/30%)were considered as respective solvents for the experiments,and a total of twelve VAPEX tests were carried out.Moreover,separate experiments were carried out at the end of each VAPEX experiment to measure the asphaltene precipitation at various locations of the VAPEX models.It was found that injecting propane would result in the highest drainage rate and oil recovery factor.Further analysis of results showed stabilized drainage rate significantly increased in the larger physical model.
文摘Colloidal gas aphron(CGA)based fluid has become very popular in drilling in the last two decades,as it reduces formation damages significantly.In this study,sugarcane molasses(Mls)was used for the first time as a polymer in CGA-based to investigate its ability to improve the role of aphronized fluid as a drilling fluid.The results showed that increasing the concentration of Mls to 12%(v/v)in CGA-based fluid reduces the drainage rate and increases half-life to 10.6 min,resulting in enhanced stability of the aphronized fluid.Also,because of increasing Mls concentration from 1%to 12%(v/v),the yield and the initial gas hold-up decrease to 74%and 299.4 mL,respectively,indicating that the presence of Mls allows less air into the aphron system.Although the rheological properties were improved in this study,the gel strength did not change considerably.Furthermore,the results showed that by increasing the concentration of Mls,the average size of the bubbles decreases,and the particle-size distribution becomes more uniform.Finally,the API filtration test revealed that the higher the Mls concentration in the aphronized fluid,the lower the fluid loss,and at the Mls concentration of 12%(v/v),the fluid loss was estimated at 19.54 mL.A natural polysaccharide with high molecular weight,Mls can be used as a polymer in CGAbased fluid and,thus,improve its performance.
基金Project (No. KYJD09036) supported by the Fundamental Research Funds for the Central Universities,China
文摘The filling construction of permeable geosynthetic tubes is considered.First,an analytical approach is developed to determine the internal pressure,tension and shape of the cross section of a geosynthetic tube based on its volume.An analytical solution for the drainage rate of the tube is then derived.The course of the filling construction is divided into several time intervals and the volume of the tube after each interval is obtained from the equilibrium of flow calculated from the drainage rate and filling rate.The validity of our analytical approach is tested by comparing our results with previously published experimental result.The results of this comparison indicate that our method is applicable for simulating the filling construction of permeable geosynthetic tubes.
