Based on practices of CO_(2) flooding tests in China and abroad,the recovery factor of carbon dioxide capture,utilization in displacing oil and storage(CCUS-EOR)in permanent sequestration scenario has been investigate...Based on practices of CO_(2) flooding tests in China and abroad,the recovery factor of carbon dioxide capture,utilization in displacing oil and storage(CCUS-EOR)in permanent sequestration scenario has been investigated in this work.Under the background of carbon neutrality,carbon dioxide injection into geological bodies should pursue the goal of permanent sequestration for effective carbon emission reduction.Hence,CCUS-EOR is an ultimate development method for oil reservoirs to maximize oil recovery.The limit recovery factor of CCUS-EOR development mode is put forward,the connotation differences between it and ultimate recovery factor and economically reasonable recovery factor are clarified.It is concluded that limit recovery factor is achievable with mature supporting technical base for the whole process of CCUS-EOR.Based on statistics of practical data of CO_(2) flooding projects in China and abroad such as North H79 block CO_(2) flooding pilot test at small well spacing in Jilin Oilfield etc.,the empirical relationship between the oil recovery factor of miscible CO_(2) flooding and cumulative CO_(2) volume injected is obtained by regression.Combined with the concept of oil production rate multiplier of gas flooding,a reservoir engineering method calculating CO_(2) flooding recovery factor under any miscible degree is established by derivation.It is found that when the cumulative CO_(2) volume injected is 1.5 times the hydrocarbon pore volume(HCPV),the relative deviation and the absolute difference between the recovery percentage and the limit recovery factor are less than 5%and less than 2.0 percentage points respectively.The limit recovery factor of CCUS-EOR can only be approached by large pore volume(PV)injection based on the technology of expanding swept volume.It needs to be realized from three aspects:large PV injection scheme design,enhancing miscibility degree and continuously expanding swept volume of injected CO_(2).展开更多
Based on Rayleigh-Sommerfeld scalar diffraction formula, analyzed is the diffraction field distribution of the restricted output end surface of multiple quantum wells planar waveguide by slit. Obtained is its analytic...Based on Rayleigh-Sommerfeld scalar diffraction formula, analyzed is the diffraction field distribution of the restricted output end surface of multiple quantum wells planar waveguide by slit. Obtained is its analytical expression of field distribution, which permits accurate and effective study on the characteristic of diffraction field from the restricted output end surface of the waveguide by slit. Then, the variation curve of the beam propagation factor M2 versus the slit width is computed by the second moment method. It is useful for understanding the restricted diffraction properties of the multiple quantum wells planar waveguide. When the slit half width is bigger than the core layer's half width, the beam propagation factor M2 value tends to a constant 1.108. Therefore, the corresponding field amplitude distribution is approximated by Gaussian function, and the far field divergence half angle(θ0,G=0.091 8) is calculated by matching efficiency method.展开更多
Rural settlements are the main carriers of agriculture, rural areas and farmers; thus, optimizing the production and living space of rural settlements is highly significant to rural development. Taking the effective a...Rural settlements are the main carriers of agriculture, rural areas and farmers; thus, optimizing the production and living space of rural settlements is highly significant to rural development. Taking the effective allocation of resources as the starting point, a suitability evaluation system of rural settlements, based on accessibility of production and living, was proposed in this study to provide scientific basis for the optimization of production and living space. The accessibility of production and living was measured by an im- proved two-step floating catchment area method, which considered proximity and availability based on the inclination of rural residents. The suitability evaluation system consisted of traditional suitability evaluation and newly proposed limiting factor identification based on the loss score proportion of suitability. Tingzu Town of Hubei Province, China, was chosen as the case study area. Based on the re- suits of the suitability evaluation system, corresponding suggestions on rural land consolidation, industry division, as well as the layout of health care and education facilities were proposed to optimize the production and living space of rural settlements in Tingzu Town. It is found that the suitability evaluation based on accessibility of production and living is more scientific and accurate than the traditional ones which significantly overestimate production and living convenience. Moreover, the limiting factor identification can help us put forward suggestions according to local conditions and bring about the highly targeted optimization of production and living space of rural settlements.展开更多
基金Supported by CNPC Science and Technology Project(kt2022-8-202021ZZ01).
文摘Based on practices of CO_(2) flooding tests in China and abroad,the recovery factor of carbon dioxide capture,utilization in displacing oil and storage(CCUS-EOR)in permanent sequestration scenario has been investigated in this work.Under the background of carbon neutrality,carbon dioxide injection into geological bodies should pursue the goal of permanent sequestration for effective carbon emission reduction.Hence,CCUS-EOR is an ultimate development method for oil reservoirs to maximize oil recovery.The limit recovery factor of CCUS-EOR development mode is put forward,the connotation differences between it and ultimate recovery factor and economically reasonable recovery factor are clarified.It is concluded that limit recovery factor is achievable with mature supporting technical base for the whole process of CCUS-EOR.Based on statistics of practical data of CO_(2) flooding projects in China and abroad such as North H79 block CO_(2) flooding pilot test at small well spacing in Jilin Oilfield etc.,the empirical relationship between the oil recovery factor of miscible CO_(2) flooding and cumulative CO_(2) volume injected is obtained by regression.Combined with the concept of oil production rate multiplier of gas flooding,a reservoir engineering method calculating CO_(2) flooding recovery factor under any miscible degree is established by derivation.It is found that when the cumulative CO_(2) volume injected is 1.5 times the hydrocarbon pore volume(HCPV),the relative deviation and the absolute difference between the recovery percentage and the limit recovery factor are less than 5%and less than 2.0 percentage points respectively.The limit recovery factor of CCUS-EOR can only be approached by large pore volume(PV)injection based on the technology of expanding swept volume.It needs to be realized from three aspects:large PV injection scheme design,enhancing miscibility degree and continuously expanding swept volume of injected CO_(2).
基金Program of the Science and technology Depart ment of Fujian Province(2007F5040)Natural Science Foundation of Fujian Province(A0540001)
文摘Based on Rayleigh-Sommerfeld scalar diffraction formula, analyzed is the diffraction field distribution of the restricted output end surface of multiple quantum wells planar waveguide by slit. Obtained is its analytical expression of field distribution, which permits accurate and effective study on the characteristic of diffraction field from the restricted output end surface of the waveguide by slit. Then, the variation curve of the beam propagation factor M2 versus the slit width is computed by the second moment method. It is useful for understanding the restricted diffraction properties of the multiple quantum wells planar waveguide. When the slit half width is bigger than the core layer's half width, the beam propagation factor M2 value tends to a constant 1.108. Therefore, the corresponding field amplitude distribution is approximated by Gaussian function, and the far field divergence half angle(θ0,G=0.091 8) is calculated by matching efficiency method.
基金Under the auspices of National Scientific and Technical Supporting Programs During 12th Five-year Plan(No.2012BAJ22B02)
文摘Rural settlements are the main carriers of agriculture, rural areas and farmers; thus, optimizing the production and living space of rural settlements is highly significant to rural development. Taking the effective allocation of resources as the starting point, a suitability evaluation system of rural settlements, based on accessibility of production and living, was proposed in this study to provide scientific basis for the optimization of production and living space. The accessibility of production and living was measured by an im- proved two-step floating catchment area method, which considered proximity and availability based on the inclination of rural residents. The suitability evaluation system consisted of traditional suitability evaluation and newly proposed limiting factor identification based on the loss score proportion of suitability. Tingzu Town of Hubei Province, China, was chosen as the case study area. Based on the re- suits of the suitability evaluation system, corresponding suggestions on rural land consolidation, industry division, as well as the layout of health care and education facilities were proposed to optimize the production and living space of rural settlements in Tingzu Town. It is found that the suitability evaluation based on accessibility of production and living is more scientific and accurate than the traditional ones which significantly overestimate production and living convenience. Moreover, the limiting factor identification can help us put forward suggestions according to local conditions and bring about the highly targeted optimization of production and living space of rural settlements.
