The processes of flooding—water flooding, polymer flooding and ternary combination flooding—were simulated respectively on a 2-D positive rhythm profile geological model by using the ASP numerical modeling softw...The processes of flooding—water flooding, polymer flooding and ternary combination flooding—were simulated respectively on a 2-D positive rhythm profile geological model by using the ASP numerical modeling software developed by RIPED (Yuan, et al. 1995). The recovery coefficient, remaining oil saturation, sweep efficiency and displacement efficiency were calculated and correlated layer by layer. The results show that the sweep efficiency and displacement efficiency work different effects on different layers in the severely heterogeneous reservoir. The study shows that the displacement efficiency and sweep efficiency play different roles in different layers for severely heterogeneous reservoirs. The displacement efficiency contributes mainly to the high permeability zones, the sweep efficiency to the low permeability zones, both of which contribute to the middle permeable zones. To improve the sweep efficiency in the low permeability zones is of significance for enhancing the whole recovery of the reservoir. It is an important path for improving the effectiveness of chemical flooding in the severely heterogeneous reservoirs to inject ternary combination slug after profile control.展开更多
This paper describes the experience of Jilin oilfield trials for Microbial Enhanced Oil Recovery (MEOR). A new technique to identify microbes with DNA for MEOR has been established, and useful microbes selected f...This paper describes the experience of Jilin oilfield trials for Microbial Enhanced Oil Recovery (MEOR). A new technique to identify microbes with DNA for MEOR has been established, and useful microbes selected for use in field trials. Behaviors of bacteria activated in the reservoir, oil recovery and water cut, and the viscosity of crude oil produced through huff & puff testing and flooding with molasses-injection tests, have been investigated in situ. CJF-002, which produces biopolysaccharide, is the best among the microbes used for field trials, as it can use molasses as nutrient and produce a small quantity of CO2 and a mass of water-insoluble biopolymer. The metabolic behavior in the reservoir showed that CJF-002 had a good potentiality for MEOR.展开更多
Actual sandstone micromodel was used in this work to conduct the microscopic waterflooding experiment of ultra-low sandstone reservoir,since the inside seepage characteristics of microscopic waterflooding process of C...Actual sandstone micromodel was used in this work to conduct the microscopic waterflooding experiment of ultra-low sandstone reservoir,since the inside seepage characteristics of microscopic waterflooding process of Chang 8 ultra-low permeability sandstone reservoir of Upper Triassic Yanchang formation in Huaqing region of the Ordos Basin,China is difficult to observe directly.Combined with physical property,casting thin sections,constant-rate mercury injection capillary pressure and nuclear magnetic resonance,the influence of reservoir property on the waterflooding characteristics in pores were analyzed and evaluated.Seepage paths of waterflooding characteristics were divided into four types:homogeneous seepage,reticular-homogeneous seepage,finger-reticular seepage and finger-like seepage,the waterflooding efficiency of which decreases in turn.More than 70%of residual oil occurs as flowing-around seepage and oil film.Physical property,pore structure and movable fluid characteristics are all controlled by digenesis and their impacts on waterflooding efficiency are in accordance.Generally,the pore throat radius size and distribution and movable fluid percentage are closely related to waterflooding law.展开更多
It is well-known that barriers have a significant impact on the production performance of horizontal wells developed in a bottom water drive reservoir. In most cases, reservoir barriers are semi-permeable. Based on pr...It is well-known that barriers have a significant impact on the production performance of horizontal wells developed in a bottom water drive reservoir. In most cases, reservoir barriers are semi-permeable. Based on previous research on impermeable reservoir barrier, a mathematical flow model was derived for a horizontal well of a bottom water drive reservoir with a semi-permeable barrier. Besides, analytical equations were also presented to calculate critical parameters, such as production rate,pressure and potential difference. The effects of barrier, well and reservoir parameters on our model results were further investigated.The results show that the larger the barrier size is or the higher the barrier location is, the higher the critical production rate and potential difference of a horizontal well are. When the barrier permeability equals the formation permeability or the barrier width equals zero, the critical production rates converge to the values same to that of the case with no barrier. When the barrier permeability equals zero, the problem is regarded as a case of impermeable barrier. This model can be applied to predicting horizontal wells' critical production parameters in reservoirs with semi-permeable barriers.展开更多
This article is aimed to discuss the impact of using two different kinds of surfactant in enhancing oil recovery in heterogeneous reservoirs. With the background of Jidong oilfield, Rui Feng surfactant which could rea...This article is aimed to discuss the impact of using two different kinds of surfactant in enhancing oil recovery in heterogeneous reservoirs. With the background of Jidong oilfield, Rui Feng surfactant which could reach ultra-low interracial tension and combination surfactant RZ-JD80 with strong emulsifying property are chosen to do oil displacement and profile control-oil displacement experiment in homogeneous core and heterogeneous core respectively. The experiment is aimed to study the effect of oil displacement by injecting surfactant individually and the effect after injecting different profile control agent slug before surfactant flooding in heterogeneous cores. The results suggest that injecting Rui Feng surfactant and RZ-JD80 individually could enhance the oil displacement efficiency about 15 percentage points for homogeneous core. For strongly heterogeneous core, it is low efficiency by using either of these two surfactants individually. However, if injected a very little profile control agent slug before surfactant flooding, both of these two kinds of surfactant could enhance the oil recovery by different degree, especially, polymer microsphere plugging^RZ-JD80 flooding composite technology is more adaptable to Gao-63 reservoir. This technology could increase the recovery by 18.52 percentage points aRer surfactant flooding.展开更多
CO2 flooding is a process whereby carbon dioxide is injected into an oil reservoir in order to increase output when extracting oil. Since 1952, Wharton obtained the patent concern CO2 flooding, CO2-EOR （CO2 flooding ...CO2 flooding is a process whereby carbon dioxide is injected into an oil reservoir in order to increase output when extracting oil. Since 1952, Wharton obtained the patent concern CO2 flooding, CO2-EOR （CO2 flooding enhance oil recovery） has been one of research hot-spot around the world. According to the statistical data of 2006, there are total of 94 global CO2-EOR projects, including 65 low permeability oilfield projects （79% of the total）. Daqing Oilfield is the largest one of China, after more than 50 years of continuous development, oilfield comprehensive water cut has reached over 90%, and the difficulty of oilfield development has been gradually increasing. In recent years, low and ultra-low permeability reservoirs development have played a more and more important role accompany with low permeability reserves in proportion of the total reserves have been increasing year by year. But water-flooding recovery of low permeability reservoir is very low under the influence of reservoir poor properties and heterogeneity. As a kind of greenhouse gas, CO2 flooding can obtain good results for the low permeability reservoir in which the water flooding has proven ineffective. CO2 flooding Pilot Test was conducted under such background since Dec. 2002, over 10 years of practice has proved that CO2 flooding is an effective method to improve the development effect of low permeability reservoir, all experience during the mechanism study and field test should present important references for further larger-scale CO2 flooding projects.展开更多
基金This project is supported by the China National Key Basis Research Project (No: G1999022512)
文摘The processes of flooding—water flooding, polymer flooding and ternary combination flooding—were simulated respectively on a 2-D positive rhythm profile geological model by using the ASP numerical modeling software developed by RIPED (Yuan, et al. 1995). The recovery coefficient, remaining oil saturation, sweep efficiency and displacement efficiency were calculated and correlated layer by layer. The results show that the sweep efficiency and displacement efficiency work different effects on different layers in the severely heterogeneous reservoir. The study shows that the displacement efficiency and sweep efficiency play different roles in different layers for severely heterogeneous reservoirs. The displacement efficiency contributes mainly to the high permeability zones, the sweep efficiency to the low permeability zones, both of which contribute to the middle permeable zones. To improve the sweep efficiency in the low permeability zones is of significance for enhancing the whole recovery of the reservoir. It is an important path for improving the effectiveness of chemical flooding in the severely heterogeneous reservoirs to inject ternary combination slug after profile control.
文摘This paper describes the experience of Jilin oilfield trials for Microbial Enhanced Oil Recovery (MEOR). A new technique to identify microbes with DNA for MEOR has been established, and useful microbes selected for use in field trials. Behaviors of bacteria activated in the reservoir, oil recovery and water cut, and the viscosity of crude oil produced through huff & puff testing and flooding with molasses-injection tests, have been investigated in situ. CJF-002, which produces biopolysaccharide, is the best among the microbes used for field trials, as it can use molasses as nutrient and produce a small quantity of CO2 and a mass of water-insoluble biopolymer. The metabolic behavior in the reservoir showed that CJF-002 had a good potentiality for MEOR.
基金Project(2015KTCL01-09)supported by the Innovation Project of Science and Technology of Shaanxi Province,ChinaProject(2015M582699)supported by the China Postdoctoral Science Foundation+1 种基金Project(2016JQ4022)supported by the Natural Science Foundation Research Project of Shaanxi Province,ChinaProject(41702146)supported by the National Natural Science Foundation of China
文摘Actual sandstone micromodel was used in this work to conduct the microscopic waterflooding experiment of ultra-low sandstone reservoir,since the inside seepage characteristics of microscopic waterflooding process of Chang 8 ultra-low permeability sandstone reservoir of Upper Triassic Yanchang formation in Huaqing region of the Ordos Basin,China is difficult to observe directly.Combined with physical property,casting thin sections,constant-rate mercury injection capillary pressure and nuclear magnetic resonance,the influence of reservoir property on the waterflooding characteristics in pores were analyzed and evaluated.Seepage paths of waterflooding characteristics were divided into four types:homogeneous seepage,reticular-homogeneous seepage,finger-reticular seepage and finger-like seepage,the waterflooding efficiency of which decreases in turn.More than 70%of residual oil occurs as flowing-around seepage and oil film.Physical property,pore structure and movable fluid characteristics are all controlled by digenesis and their impacts on waterflooding efficiency are in accordance.Generally,the pore throat radius size and distribution and movable fluid percentage are closely related to waterflooding law.
基金Project(51404201)supported by the National Natural Science Foundation of ChinaProject(2011ZX05024-003)supported by the National Science and Technology Major Project of China+1 种基金Project(14ZB0045)supported by the Scientific Project of Sichuan Provincial Education Department,ChinaProject(2015JY0076)supported by Basic Application Research of Science and Technology Department of Sichuan Province,China
文摘It is well-known that barriers have a significant impact on the production performance of horizontal wells developed in a bottom water drive reservoir. In most cases, reservoir barriers are semi-permeable. Based on previous research on impermeable reservoir barrier, a mathematical flow model was derived for a horizontal well of a bottom water drive reservoir with a semi-permeable barrier. Besides, analytical equations were also presented to calculate critical parameters, such as production rate,pressure and potential difference. The effects of barrier, well and reservoir parameters on our model results were further investigated.The results show that the larger the barrier size is or the higher the barrier location is, the higher the critical production rate and potential difference of a horizontal well are. When the barrier permeability equals the formation permeability or the barrier width equals zero, the critical production rates converge to the values same to that of the case with no barrier. When the barrier permeability equals zero, the problem is regarded as a case of impermeable barrier. This model can be applied to predicting horizontal wells' critical production parameters in reservoirs with semi-permeable barriers.
文摘This article is aimed to discuss the impact of using two different kinds of surfactant in enhancing oil recovery in heterogeneous reservoirs. With the background of Jidong oilfield, Rui Feng surfactant which could reach ultra-low interracial tension and combination surfactant RZ-JD80 with strong emulsifying property are chosen to do oil displacement and profile control-oil displacement experiment in homogeneous core and heterogeneous core respectively. The experiment is aimed to study the effect of oil displacement by injecting surfactant individually and the effect after injecting different profile control agent slug before surfactant flooding in heterogeneous cores. The results suggest that injecting Rui Feng surfactant and RZ-JD80 individually could enhance the oil displacement efficiency about 15 percentage points for homogeneous core. For strongly heterogeneous core, it is low efficiency by using either of these two surfactants individually. However, if injected a very little profile control agent slug before surfactant flooding, both of these two kinds of surfactant could enhance the oil recovery by different degree, especially, polymer microsphere plugging^RZ-JD80 flooding composite technology is more adaptable to Gao-63 reservoir. This technology could increase the recovery by 18.52 percentage points aRer surfactant flooding.
文摘CO2 flooding is a process whereby carbon dioxide is injected into an oil reservoir in order to increase output when extracting oil. Since 1952, Wharton obtained the patent concern CO2 flooding, CO2-EOR （CO2 flooding enhance oil recovery） has been one of research hot-spot around the world. According to the statistical data of 2006, there are total of 94 global CO2-EOR projects, including 65 low permeability oilfield projects （79% of the total）. Daqing Oilfield is the largest one of China, after more than 50 years of continuous development, oilfield comprehensive water cut has reached over 90%, and the difficulty of oilfield development has been gradually increasing. In recent years, low and ultra-low permeability reservoirs development have played a more and more important role accompany with low permeability reserves in proportion of the total reserves have been increasing year by year. But water-flooding recovery of low permeability reservoir is very low under the influence of reservoir poor properties and heterogeneity. As a kind of greenhouse gas, CO2 flooding can obtain good results for the low permeability reservoir in which the water flooding has proven ineffective. CO2 flooding Pilot Test was conducted under such background since Dec. 2002, over 10 years of practice has proved that CO2 flooding is an effective method to improve the development effect of low permeability reservoir, all experience during the mechanism study and field test should present important references for further larger-scale CO2 flooding projects.
