Two main challenges exist in enhancing oil recovery rate from tight oil reservoirs,namely how to create an effective complicated fracture network and how to enhance the imbibition effect of fracturing fluid.In respons...Two main challenges exist in enhancing oil recovery rate from tight oil reservoirs,namely how to create an effective complicated fracture network and how to enhance the imbibition effect of fracturing fluid.In response to the challenges,through modeling experiment in laboratory and evaluation of field application results,a set of integrated efficient fracturing and enhanced oil recovery(EOR)techniques suitable for tight oil development in China has been proposed.(1)Fracturing with temporary plugging agents to realize stimulation in multiple clusters,to form dense fracture network,and thus maximizing the drainage area;(2)Supporting induced fractures with micro-sized proppants during the prepad fluid fracture-making stage,to generate dense fracture network with high conductivity;(3)Using the liquid nanofluid as a fracturing fluid additive to increase oil-water displacement ratio and take advantage of the massive injected fracturing fluid and maximize the oil production after hydraulic fracturing.展开更多
Microscopic computed tomography(Micro-CT)is used to visualize microscopic flow in sandstone core samples during emulsion flooding.The images obtained during the experiment are processed quantitatively with a series of...Microscopic computed tomography(Micro-CT)is used to visualize microscopic flow in sandstone core samples during emulsion flooding.The images obtained during the experiment are processed quantitatively with a series of methods to evaluate the occurrence characteristics and oil recovery enhancement mechanisms of emulsion.(1)The emulsion is distributed in the cores in spherical shape,and its sphericity is significantly different from that of the remaining oil.Sphericity can be taken as a characteristic parameter to identify emulsion.(2)The emulsion with specific size prefers to stay in pores with matching sizes;when the emulsion volume is smaller than the product of the lower limit of pore occupancy and the corresponding pore vol-ume,it will not be able to effectively trap in the pore to achieve conformance control.In the process of emulsion displacement designing,we need to design emulsion with suitable particle size according to the pore distribution of the reservoir.(3)Mobi-lization ratio of the pores can be increased from 23.1%to 59.3%by emulsion flooding after subsequent water flooding,and the average oil displacement efficiency at the pore-scale can be increased from 22.9%to 75.8%under the test conditions;(4)After emulsion flooding,the clustered remaining oil and the oil phase in the trapped emulsion are the main targets for further EOR.展开更多
基金Supported by the China National Science and Technology Major Project(2016ZX05051-03,2016ZX05030-05)PetroChina Innovation Foundation(2018D-5007-0205)the Science Foundation of China University of Petroleum at Beijing(2462017YJRC031).
文摘Two main challenges exist in enhancing oil recovery rate from tight oil reservoirs,namely how to create an effective complicated fracture network and how to enhance the imbibition effect of fracturing fluid.In response to the challenges,through modeling experiment in laboratory and evaluation of field application results,a set of integrated efficient fracturing and enhanced oil recovery(EOR)techniques suitable for tight oil development in China has been proposed.(1)Fracturing with temporary plugging agents to realize stimulation in multiple clusters,to form dense fracture network,and thus maximizing the drainage area;(2)Supporting induced fractures with micro-sized proppants during the prepad fluid fracture-making stage,to generate dense fracture network with high conductivity;(3)Using the liquid nanofluid as a fracturing fluid additive to increase oil-water displacement ratio and take advantage of the massive injected fracturing fluid and maximize the oil production after hydraulic fracturing.
基金Supported by the National Science and Technology Major Project(2017ZX05009-005-003)National Natural Science Foundation of China Funded General Project(52174045)+1 种基金Chinese Academy of Engineering Strategic Consulting Project(2018-XZ-09)China Nation al Petroleum Cor-poration-China University of Petroleum(Beijing)Strategic Cooperation Science and Technology Project(ZLZX2020-01)。
文摘Microscopic computed tomography(Micro-CT)is used to visualize microscopic flow in sandstone core samples during emulsion flooding.The images obtained during the experiment are processed quantitatively with a series of methods to evaluate the occurrence characteristics and oil recovery enhancement mechanisms of emulsion.(1)The emulsion is distributed in the cores in spherical shape,and its sphericity is significantly different from that of the remaining oil.Sphericity can be taken as a characteristic parameter to identify emulsion.(2)The emulsion with specific size prefers to stay in pores with matching sizes;when the emulsion volume is smaller than the product of the lower limit of pore occupancy and the corresponding pore vol-ume,it will not be able to effectively trap in the pore to achieve conformance control.In the process of emulsion displacement designing,we need to design emulsion with suitable particle size according to the pore distribution of the reservoir.(3)Mobi-lization ratio of the pores can be increased from 23.1%to 59.3%by emulsion flooding after subsequent water flooding,and the average oil displacement efficiency at the pore-scale can be increased from 22.9%to 75.8%under the test conditions;(4)After emulsion flooding,the clustered remaining oil and the oil phase in the trapped emulsion are the main targets for further EOR.
