Based on the productivity equation of coalbed methane(CBM) wells, three indexes, main production layer optimization index, main production layer expansion index and capacity contribution index are proposed, with which...Based on the productivity equation of coalbed methane(CBM) wells, three indexes, main production layer optimization index, main production layer expansion index and capacity contribution index are proposed, with which the three-step optimization method of production-layer combination is established. In selecting main production layer, the coal seam thickness, CBM content, coal seam permeability, coal seam reservoir pressure and coal structure are considered comprehensively to evaluate the potential of the production layer. In selecting expansion of the main production layer combination, on the premise of ensuring full and slow desorption of the main production layer and non-exposure of the main production layer out of liquid surface, the degree of mutual interference between the main and non-main production layers is comprehensively evaluated by coupling the critical desorption pressure, layer spacing and reservoir pressure gradient difference. In optimizing production layer combination, the main concern is the economic efficiency of the combined layers. Only when the contribution coefficient of the main production layer is greater than 30% and the contribution index of the other production layers is more than 10%, the economic benefit of a CBM well after being put into production can be ensured. Based on the comparative analysis of the development effect of the development test wells in Songhe of Guizhou province, it is proved that the "three-step method" for the optimization of production-layer combination is scientific and practical, and can be used to design the multi-layer commingling scheme of coalbed methane.展开更多
This paper moves one step forward to build?a?numerical model to research quantitative characterization and dynamic law for interlayer interference factor (IIF) in the multilayer reservoir which was heavy oil reservoir...This paper moves one step forward to build?a?numerical model to research quantitative characterization and dynamic law for interlayer interference factor (IIF) in the multilayer reservoir which was heavy oil reservoirs and produced by directional wells. There are mainly four contributions of this paper to the existing body of literature. Firstly, an equivalent simulation method of the pseudo start pressure gradient (PSPG) is developed to quantitatively predict the value of?IIF?under different geological reservoir conditions. Secondly, the interlayer interference is extended in time, and the time period of the study extends from a water cut stage to the whole process from the oil well open to produce?a?high water cut. Thirdly, besides the conventional productivity interlayer interference factor (PIIF), a new parameter, that is, the oil recovery interlayer interference factor (RIIF) is put forward.?RIIF?can be used to evaluate the technical indexes of stratified development and multilayer co-production effectively. Fourthly,?the?effectsof various geological reservoir parameters such as reservoir permeability and crude oil viscosity, etc. on the?PIIF?and?RIIF’s?type curves?are?discussed in detail and the typical plate?is?plotted. The research results provide a foundation for the effective development of multilayer heavy oil reservoirs.展开更多
Human-made and natural disasters can result in severely fragmented,compromised,and commingled human remains.The related disaster victim identification(DVI)operations are invariably challenging,with the state of the re...Human-made and natural disasters can result in severely fragmented,compromised,and commingled human remains.The related disaster victim identification(DVI)operations are invariably challenging,with the state of the remains potentially precluding some identifications.Practitioners involved in these DVI operations will routinely face logistical,practical,and ethical challenges.This review provides information and guidance derived from firsthand experiences to individuals tasked with managing DVI operations with fragmented human remains.We outline several key issues that should be addressed during disaster preparedness planning and at the outset of an operation,when incident-specific strategies are developed.Specific challenges during recovery and examination of fragmented remains are addressed,highlighting the importance of experienced specialists at the scene and in the mortuary.DNA sample selection and sampling techniques are reviewed,as well as downstream effects of commingling and contamination,which can complicate reconciliation and emphasise the need for rigorous quality control.We also touch on issues that may arise during communication with families.While recommendations are provided,they are not intended as proscriptive policy but rather as an addition to the general recommendations given in the International Criminal Police Organization(INTERPOL)DVI Guide,to inform preparative discussions between government officials,judiciary,police,and forensic specialists.展开更多
The use of maleic anhydride (MA) coupling agent in polypropylene (PP) matrix system is promising technique to enhance the fibre-matrix interface in composite applications. However, most of the previous studies are foc...The use of maleic anhydride (MA) coupling agent in polypropylene (PP) matrix system is promising technique to enhance the fibre-matrix interface in composite applications. However, most of the previous studies are focused on either treatment of the natural fibres or the PP matrix with this coupling agent, which are not commercially viable. In this work, a cost-effective technique “hybrid yarns” was used to manufacture commingled reinforcing flax fibres and MA-grafted PP matrix fibres. Two types of twist-less flax/PP and flax/MAPP hybrid yarns were produced containing 40% flax and 60% matrix fibres by volume. Both PP and MAPP fibres were thermally and rheologically characterised using DSC, MFI, TGA, DTA and capillary rheometer. It is found that the composites manufactured from flax/MAPP blends exhibited 15% higher strength and 25% higher modulus compared to those made of flax/PP. This was due to the improved flax/matrix interface, the higher melt flow rate and lower share viscosity behaviour of the MAPP matrix fibres compared to the standard PP fibres used.展开更多
Traditional fluid production profile logging is not usually suitable for heavy-viscous crude oil wells.Biodegradation of heavy oil can lead to the loss of n-alkanes,and the use of chromatogram fingerprint techniques i...Traditional fluid production profile logging is not usually suitable for heavy-viscous crude oil wells.Biodegradation of heavy oil can lead to the loss of n-alkanes,and the use of chromatogram fingerprint techniques in studying the production contributions of single layers in heavy oil commingled wells has limitations.However,aromatic compounds are relatively well preserved.We took the heavy oil commingled wells of small layers NG55 and NG61 in the ninth area of the Gudong oil field as examples.Based on the principle of chromatography,the whole-oil GC-MS was used,and the aromatic parameters which have a strongly linear relationship with the ratio of mixed two end member oils were verified and selected in laboratory.Studies showed that the ratio of （1,4,6-＋ 2,3,6-trimethylnaphthalene） to 1,2,5-trimethylnaphthalene has a strongly linear relationship with the ratio of the mixed two end member oils （R2=0.992）.The oil contributions from single layers NG55 and NG61 in six commingled heavy oil wells were calculated using established charts and this relationship.The calculated results are consistent with the results of long period dynamic monitoring and logging interpretation in the study area and can provide a scientific basis for monitoring production performance and hierarchical management of reservoirs.The study provides a new geochemical method for calculation of the contributions of single layers in heavy oil commingled wells when conventional fluid production profile logging is not suitable.展开更多
A thermoplastic based composite material is suitable for automobile and aerospace applications. The recyclability of thermoplastic and clean processing further enhance its use. The only limitation encountered in using...A thermoplastic based composite material is suitable for automobile and aerospace applications. The recyclability of thermoplastic and clean processing further enhance its use. The only limitation encountered in using this material is its high-melt viscosity. Various techniques have been developed to overcome this problem. Commingled materials are one of such methods adopted for making proper use of thermoplastic. A major problem observed during the use of a commingled material is its de-commingling, wherein, the uniform distribution of fiber and thermoplastic yam gets disturbed and affects the final quality of the composite. The effects of the braiding process on laminate quality were investigated. Flat plaques were produced by braiding the commingled yam, using a 48- carrier braiding machine. The braids （and control woven samples） were subsequently heated and consolidated in a nonisothermal compression molding operation. Prior to the manufacture of the ＇best quality＇ plaques, a series of moldings were produced under different consolidation conditions, to study the dependence of properties on the process variables. This enabled a processing window to be established for each material and helped to separate the respective effects of yam handling, textile processing, and consolidation on laminate properties.展开更多
基金Supported by the China National Science and Technology Major Project(2016ZX05044-002)the National Natural Science Foundation of China(41772155)the Fundamental Research Funds for the Central Universities of China(No.2015XKZD07)
文摘Based on the productivity equation of coalbed methane(CBM) wells, three indexes, main production layer optimization index, main production layer expansion index and capacity contribution index are proposed, with which the three-step optimization method of production-layer combination is established. In selecting main production layer, the coal seam thickness, CBM content, coal seam permeability, coal seam reservoir pressure and coal structure are considered comprehensively to evaluate the potential of the production layer. In selecting expansion of the main production layer combination, on the premise of ensuring full and slow desorption of the main production layer and non-exposure of the main production layer out of liquid surface, the degree of mutual interference between the main and non-main production layers is comprehensively evaluated by coupling the critical desorption pressure, layer spacing and reservoir pressure gradient difference. In optimizing production layer combination, the main concern is the economic efficiency of the combined layers. Only when the contribution coefficient of the main production layer is greater than 30% and the contribution index of the other production layers is more than 10%, the economic benefit of a CBM well after being put into production can be ensured. Based on the comparative analysis of the development effect of the development test wells in Songhe of Guizhou province, it is proved that the "three-step method" for the optimization of production-layer combination is scientific and practical, and can be used to design the multi-layer commingling scheme of coalbed methane.
文摘This paper moves one step forward to build?a?numerical model to research quantitative characterization and dynamic law for interlayer interference factor (IIF) in the multilayer reservoir which was heavy oil reservoirs and produced by directional wells. There are mainly four contributions of this paper to the existing body of literature. Firstly, an equivalent simulation method of the pseudo start pressure gradient (PSPG) is developed to quantitatively predict the value of?IIF?under different geological reservoir conditions. Secondly, the interlayer interference is extended in time, and the time period of the study extends from a water cut stage to the whole process from the oil well open to produce?a?high water cut. Thirdly, besides the conventional productivity interlayer interference factor (PIIF), a new parameter, that is, the oil recovery interlayer interference factor (RIIF) is put forward.?RIIF?can be used to evaluate the technical indexes of stratified development and multilayer co-production effectively. Fourthly,?the?effectsof various geological reservoir parameters such as reservoir permeability and crude oil viscosity, etc. on the?PIIF?and?RIIF’s?type curves?are?discussed in detail and the typical plate?is?plotted. The research results provide a foundation for the effective development of multilayer heavy oil reservoirs.
文摘Human-made and natural disasters can result in severely fragmented,compromised,and commingled human remains.The related disaster victim identification(DVI)operations are invariably challenging,with the state of the remains potentially precluding some identifications.Practitioners involved in these DVI operations will routinely face logistical,practical,and ethical challenges.This review provides information and guidance derived from firsthand experiences to individuals tasked with managing DVI operations with fragmented human remains.We outline several key issues that should be addressed during disaster preparedness planning and at the outset of an operation,when incident-specific strategies are developed.Specific challenges during recovery and examination of fragmented remains are addressed,highlighting the importance of experienced specialists at the scene and in the mortuary.DNA sample selection and sampling techniques are reviewed,as well as downstream effects of commingling and contamination,which can complicate reconciliation and emphasise the need for rigorous quality control.We also touch on issues that may arise during communication with families.While recommendations are provided,they are not intended as proscriptive policy but rather as an addition to the general recommendations given in the International Criminal Police Organization(INTERPOL)DVI Guide,to inform preparative discussions between government officials,judiciary,police,and forensic specialists.
文摘The use of maleic anhydride (MA) coupling agent in polypropylene (PP) matrix system is promising technique to enhance the fibre-matrix interface in composite applications. However, most of the previous studies are focused on either treatment of the natural fibres or the PP matrix with this coupling agent, which are not commercially viable. In this work, a cost-effective technique “hybrid yarns” was used to manufacture commingled reinforcing flax fibres and MA-grafted PP matrix fibres. Two types of twist-less flax/PP and flax/MAPP hybrid yarns were produced containing 40% flax and 60% matrix fibres by volume. Both PP and MAPP fibres were thermally and rheologically characterised using DSC, MFI, TGA, DTA and capillary rheometer. It is found that the composites manufactured from flax/MAPP blends exhibited 15% higher strength and 25% higher modulus compared to those made of flax/PP. This was due to the improved flax/matrix interface, the higher melt flow rate and lower share viscosity behaviour of the MAPP matrix fibres compared to the standard PP fibres used.
基金supported by the Gudong Oil Production Plant of Shengli Oilfield Subsidiary Company,China Postdoctoral Science Foundation(Project 2013M530681)Hubei Province Natural Science Foundation(Project 2013CFB394)
文摘Traditional fluid production profile logging is not usually suitable for heavy-viscous crude oil wells.Biodegradation of heavy oil can lead to the loss of n-alkanes,and the use of chromatogram fingerprint techniques in studying the production contributions of single layers in heavy oil commingled wells has limitations.However,aromatic compounds are relatively well preserved.We took the heavy oil commingled wells of small layers NG55 and NG61 in the ninth area of the Gudong oil field as examples.Based on the principle of chromatography,the whole-oil GC-MS was used,and the aromatic parameters which have a strongly linear relationship with the ratio of mixed two end member oils were verified and selected in laboratory.Studies showed that the ratio of （1,4,6-＋ 2,3,6-trimethylnaphthalene） to 1,2,5-trimethylnaphthalene has a strongly linear relationship with the ratio of the mixed two end member oils （R2=0.992）.The oil contributions from single layers NG55 and NG61 in six commingled heavy oil wells were calculated using established charts and this relationship.The calculated results are consistent with the results of long period dynamic monitoring and logging interpretation in the study area and can provide a scientific basis for monitoring production performance and hierarchical management of reservoirs.The study provides a new geochemical method for calculation of the contributions of single layers in heavy oil commingled wells when conventional fluid production profile logging is not suitable.
文摘A thermoplastic based composite material is suitable for automobile and aerospace applications. The recyclability of thermoplastic and clean processing further enhance its use. The only limitation encountered in using this material is its high-melt viscosity. Various techniques have been developed to overcome this problem. Commingled materials are one of such methods adopted for making proper use of thermoplastic. A major problem observed during the use of a commingled material is its de-commingling, wherein, the uniform distribution of fiber and thermoplastic yam gets disturbed and affects the final quality of the composite. The effects of the braiding process on laminate quality were investigated. Flat plaques were produced by braiding the commingled yam, using a 48- carrier braiding machine. The braids （and control woven samples） were subsequently heated and consolidated in a nonisothermal compression molding operation. Prior to the manufacture of the ＇best quality＇ plaques, a series of moldings were produced under different consolidation conditions, to study the dependence of properties on the process variables. This enabled a processing window to be established for each material and helped to separate the respective effects of yam handling, textile processing, and consolidation on laminate properties.
