Due to the poor physical properties of tight reservoirs,CO_(2) huff-n-puff(HNP)is considered a potential enhanced oil recovery(EOR)method after primary depletion.Optimization plays a critical role in the effective imp...Due to the poor physical properties of tight reservoirs,CO_(2) huff-n-puff(HNP)is considered a potential enhanced oil recovery(EOR)method after primary depletion.Optimization plays a critical role in the effective implementation of CO_(2) huff-n-puff.But the optimization requires a good understanding of the EOR mechanisms.In this work,the spatial distribution of oil saturation under different experimental conditions was analyzed by the NMR method to further discuss the HNP mechanisms.According to the variation of 1D frequency signal amplitude,we divided the core into the hardly movable area and movable area,the region with the obvious signal decline was defined as the movable area,and the hardly movable area was the region with limited signal decline.Based on that the recovery characteristics of different scenarios were evaluated.Firstly,the necessity of the soaking stage was studied,where three scenarios with different soaking times were carried out.Secondly,the injection pressure was adjusted to investigate the effect of the pressure gradient.The T_(2) spectra show that soaking has significantly improved the production of crude oil in small pores,and higher oil recovery in a single cycle is observed,but it is lower when the elapsed time(total operation time)is the same.31.03% of oil can be recovered after 3 cycles HNP,which increases to 33.8% and 37.06% for the 4 cycles and 6 cycles cases.As the pressure gradient increases,more oil is removed out of the matrix,and the oil in the deep part of the reservoir can be effectively recovered.During the CO_(2) huff-n-puff process,the oil distributions are similar to the solution gas drive,the residual oil is distributed at the close end of the core and the range that the oil can be efficiently recovered is limited.展开更多
The intricate distribution of oil and water in tight rocks makes pinpointing oil layers challenging.While conventional identification methods offer potential solutions,their limited accuracy precludes them from being ...The intricate distribution of oil and water in tight rocks makes pinpointing oil layers challenging.While conventional identification methods offer potential solutions,their limited accuracy precludes them from being effective in their applications to unconventional reservoirs.This study employed nuclear magnetic resonance(NMR)spectrum decomposition to dissect the NMR T_(2)spectrum into multiple subspectra.Furthermore,it employed laboratory NMR experiments to ascertain the fluid properties of these sub-spectra,aiming to enhance identification accuracy.The findings indicate that fluids of distinct properties overlap in the T_(2)spectra,with bound water,movable water,bound oil,and movable oil appearing sequentially from the low-value zone to the high-value zone.Consequently,an oil layer classification scheme was proposed,which considers the physical properties of reservoirs,oil-bearing capacity,and the characteristics of both mobility and the oil-water two-phase flow.When applied to tight oil layer identification,the scheme's outcomes align closely with actual test results.A horizontal well,deployed based on these findings,has produced high-yield industrial oil flow,underscoring the precision and dependability of this new approach.展开更多
The resistivity experimental measurements of core samples drilled from low permeability reservoirs of Ordos Basin, Northwest China, illustrate that the cementation factors are not agminate, but vary from 1.335 to 1.74...The resistivity experimental measurements of core samples drilled from low permeability reservoirs of Ordos Basin, Northwest China, illustrate that the cementation factors are not agminate, but vary from 1.335 to 1.749. This leads to a challenge for the estimation of water and hydrocarbon sa- turation. Based on the analysis of Purcell equation and assumption that rock resistivity is determined by the parallel connection of numerous capillary resistances, a theoretical expression of cementation factor in terms of porosity and permeability is established. Then, cementation factor can be calculated if the parameters of porosity and permeability are determined. In the field application, porosity can be easily obtained by conventional logs. However, it is a tough challenge to estimate permeability due to the strong heterogeneity of low permeability reservoirs. Thus, the Schlumberger Doll Research （SDR） model derived from NMR logs has been proposed to estimate permeability. Based on the analysis of the theoretical expressions of cementation factor and SDR model, a novel cementation factor prediction model, which is relevant to porosity and logarithmic mean of NMR T2 spectrum （T21m）, is derived. The advantage of this model is that all the input information can be acquired from NMR logs accurately. In order to confirm the credibility of the novel model, the resistivity and corresponding laboratory NMR measurements of 27 core samples are conducted. The credibility of the model is confirmed by compar- ing the predicted cementation factors with the core analyzed results. The absolute errors for all core samples are lower than 0.071. Once this model is extended to field application, the accuracy of water and hydrocarbon saturation estimation will be significantly improved.展开更多
建立了核磁共振氟谱法测定氰化物的氟化衍生化合物1-氰基-2,2,2-三氟-1-苯乙基乙酸酯(CTPA)含量的方法。以乙酸3-氟苄酯为内标,采用5mm Auto XBB探头,探头温度298.2K,考察了不同浓度化合物的定量条件;通过比较化合物样品定量峰与内标物...建立了核磁共振氟谱法测定氰化物的氟化衍生化合物1-氰基-2,2,2-三氟-1-苯乙基乙酸酯(CTPA)含量的方法。以乙酸3-氟苄酯为内标,采用5mm Auto XBB探头,探头温度298.2K,考察了不同浓度化合物的定量条件;通过比较化合物样品定量峰与内标物质响应峰面积,计算化合物的含量。结果该化合物的19 F-NMR检测方法在0.5~50μg/mL具有良好的线性(r2=0.9966),该方法的定量限0.5μg/mL,检出限0.2μg/mL;同时考察了该化合物在不同浓度下的测量准确度。展开更多
Nuclear magnetic resonance (NMR) has many advantages, such as little testing time, no harm to rock specimen, and is widely used in the measurement of reservoir pore structure. 3D printing also has many advantages, suc...Nuclear magnetic resonance (NMR) has many advantages, such as little testing time, no harm to rock specimen, and is widely used in the measurement of reservoir pore structure. 3D printing also has many advantages, such as repeating the printing the same attributes samples, forming sample by known rock pore structure, adding different pores or fractures to sample. For the study of fractured reservoir provides a new train of thought by combining NMR and 3D printing. Nuclear magnetic core analysis is an important work in the study of core, using a T2 spectrum at a certain echo time can also be found in the core fractures. The study, by CT scans to establish reservoir pore structure, based on the basic of adding different attitude fracture forming four fracture characteristics of rock sample, using 3D printing for solid sample, through the analysis of the nuclear magnetic resonance (NMR) of these sample, get the response characteristics of fracture characteristics on the T2 curve, the quantitative calculation of fracture porosity of rock sample, the result accord with to establish the model of fracture porosity is very good. For the study of fractured oil and gas reservoir development the new field.展开更多
Fibroblast growth factor receptors(FGFRs)play an important role in the regulation of cell proliferation,migration and differentiation,while the juxtamembrane domain(JMD)of FGFRs is the key in mediating these transmemb...Fibroblast growth factor receptors(FGFRs)play an important role in the regulation of cell proliferation,migration and differentiation,while the juxtamembrane domain(JMD)of FGFRs is the key in mediating these transmembrane signal transduction processes.Here,we expressed and purified the JMD(398K-470R)of FGFR1 with the presence of transmembrane domain(377I-397Y).The results from nuclear magnetic resonance(NMR)chemical shift analysis demonstrate that the main structure of JMD is disordered.Yet,the N-terminus of JMD was observed to form a short a-helix upon introducing negatively charged lipid 1,2-dioleoyl-sn-glycero-3-phospho-L-serine(DOPS)into its membrane mimic bicelles.Moreover,the N-terminus of JMD interacts with FRS2a,which is a substrate 2a of FGFR.Hence,we propose a model that FGFR1-JMD may interact with FRS2a and negatively charged lipids competitively.Our study provides a new understanding on the role of the JMD of FGFRs.展开更多
The abnormal expansion of G-rich hexanucleotide repeat,GGGGCC(G4C2),in chromosome 9 open reading frame 72(C9orf72)is known to be the prevailing genetic cause of two fatal degenerative neurological diseases,amyotrophi...The abnormal expansion of G-rich hexanucleotide repeat,GGGGCC(G4C2),in chromosome 9 open reading frame 72(C9orf72)is known to be the prevailing genetic cause of two fatal degenerative neurological diseases,amyotrophic lateral sclerosis(ALS)and frontotemporal dementia(FTD).It is well known that the DNA G4C2 repeat expansion with different lengths can form G-quadruplexes which affect gene transcription related to ALS/FTD,therefore it is crucial to understand DNA G4C2 G-quadruplex structures.Herein,by utilizing nuclear magnetic resonance(NMR)spectroscopy,we examined DNA G-quadruplex structure adopted by two G4C2 hexanucleotide repeats with an inosine substitution at position 4,d(G4C2)2-I4.We show that d(G4C2)2-I4 folds into an eight-layer parallel tetrameric G-quadruplex containing two parallel dimeric G-quadruplexes stacking together through p-p interaction via 50-to-50 mode in solution.Each dimeric G-quadruplex unit involves two propeller loops composed of two cytosine bases.This result is consistent with the observation in the crystal structure of d(G4C2)2.Our work not only sheds light on the structural diversity of G-quadruplexes adopted by d(G4C2)n but also provides a structural basis for drug design in treatment of ALS and FTD.展开更多
基金The work is supported by the Strategic Cooperation Technology Projects of CNPC and CUPB(ZLZX2020)by the Fundamental Research Funds for the Central Universities of China.
文摘Due to the poor physical properties of tight reservoirs,CO_(2) huff-n-puff(HNP)is considered a potential enhanced oil recovery(EOR)method after primary depletion.Optimization plays a critical role in the effective implementation of CO_(2) huff-n-puff.But the optimization requires a good understanding of the EOR mechanisms.In this work,the spatial distribution of oil saturation under different experimental conditions was analyzed by the NMR method to further discuss the HNP mechanisms.According to the variation of 1D frequency signal amplitude,we divided the core into the hardly movable area and movable area,the region with the obvious signal decline was defined as the movable area,and the hardly movable area was the region with limited signal decline.Based on that the recovery characteristics of different scenarios were evaluated.Firstly,the necessity of the soaking stage was studied,where three scenarios with different soaking times were carried out.Secondly,the injection pressure was adjusted to investigate the effect of the pressure gradient.The T_(2) spectra show that soaking has significantly improved the production of crude oil in small pores,and higher oil recovery in a single cycle is observed,but it is lower when the elapsed time(total operation time)is the same.31.03% of oil can be recovered after 3 cycles HNP,which increases to 33.8% and 37.06% for the 4 cycles and 6 cycles cases.As the pressure gradient increases,more oil is removed out of the matrix,and the oil in the deep part of the reservoir can be effectively recovered.During the CO_(2) huff-n-puff process,the oil distributions are similar to the solution gas drive,the residual oil is distributed at the close end of the core and the range that the oil can be efficiently recovered is limited.
基金funded by a major special project of PetroChina Company Limited(No.2021DJ1003No.2023ZZ2).
文摘The intricate distribution of oil and water in tight rocks makes pinpointing oil layers challenging.While conventional identification methods offer potential solutions,their limited accuracy precludes them from being effective in their applications to unconventional reservoirs.This study employed nuclear magnetic resonance(NMR)spectrum decomposition to dissect the NMR T_(2)spectrum into multiple subspectra.Furthermore,it employed laboratory NMR experiments to ascertain the fluid properties of these sub-spectra,aiming to enhance identification accuracy.The findings indicate that fluids of distinct properties overlap in the T_(2)spectra,with bound water,movable water,bound oil,and movable oil appearing sequentially from the low-value zone to the high-value zone.Consequently,an oil layer classification scheme was proposed,which considers the physical properties of reservoirs,oil-bearing capacity,and the characteristics of both mobility and the oil-water two-phase flow.When applied to tight oil layer identification,the scheme's outcomes align closely with actual test results.A horizontal well,deployed based on these findings,has produced high-yield industrial oil flow,underscoring the precision and dependability of this new approach.
基金supported by the Major National Oil&Gas Specific Project of China(No.2011ZX05044)
文摘The resistivity experimental measurements of core samples drilled from low permeability reservoirs of Ordos Basin, Northwest China, illustrate that the cementation factors are not agminate, but vary from 1.335 to 1.749. This leads to a challenge for the estimation of water and hydrocarbon sa- turation. Based on the analysis of Purcell equation and assumption that rock resistivity is determined by the parallel connection of numerous capillary resistances, a theoretical expression of cementation factor in terms of porosity and permeability is established. Then, cementation factor can be calculated if the parameters of porosity and permeability are determined. In the field application, porosity can be easily obtained by conventional logs. However, it is a tough challenge to estimate permeability due to the strong heterogeneity of low permeability reservoirs. Thus, the Schlumberger Doll Research （SDR） model derived from NMR logs has been proposed to estimate permeability. Based on the analysis of the theoretical expressions of cementation factor and SDR model, a novel cementation factor prediction model, which is relevant to porosity and logarithmic mean of NMR T2 spectrum （T21m）, is derived. The advantage of this model is that all the input information can be acquired from NMR logs accurately. In order to confirm the credibility of the novel model, the resistivity and corresponding laboratory NMR measurements of 27 core samples are conducted. The credibility of the model is confirmed by compar- ing the predicted cementation factors with the core analyzed results. The absolute errors for all core samples are lower than 0.071. Once this model is extended to field application, the accuracy of water and hydrocarbon saturation estimation will be significantly improved.
文摘建立了核磁共振氟谱法测定氰化物的氟化衍生化合物1-氰基-2,2,2-三氟-1-苯乙基乙酸酯(CTPA)含量的方法。以乙酸3-氟苄酯为内标,采用5mm Auto XBB探头,探头温度298.2K,考察了不同浓度化合物的定量条件;通过比较化合物样品定量峰与内标物质响应峰面积,计算化合物的含量。结果该化合物的19 F-NMR检测方法在0.5~50μg/mL具有良好的线性(r2=0.9966),该方法的定量限0.5μg/mL,检出限0.2μg/mL;同时考察了该化合物在不同浓度下的测量准确度。
文摘Nuclear magnetic resonance (NMR) has many advantages, such as little testing time, no harm to rock specimen, and is widely used in the measurement of reservoir pore structure. 3D printing also has many advantages, such as repeating the printing the same attributes samples, forming sample by known rock pore structure, adding different pores or fractures to sample. For the study of fractured reservoir provides a new train of thought by combining NMR and 3D printing. Nuclear magnetic core analysis is an important work in the study of core, using a T2 spectrum at a certain echo time can also be found in the core fractures. The study, by CT scans to establish reservoir pore structure, based on the basic of adding different attitude fracture forming four fracture characteristics of rock sample, using 3D printing for solid sample, through the analysis of the nuclear magnetic resonance (NMR) of these sample, get the response characteristics of fracture characteristics on the T2 curve, the quantitative calculation of fracture porosity of rock sample, the result accord with to establish the model of fracture porosity is very good. For the study of fractured oil and gas reservoir development the new field.
基金Special Foundation of President of the Chinese Academy of Sciences(Grant No.,YZJJ2021QN33,YZJJ2020QN27)Collaborative Innovation Program of Hefei Science Center,CAS(2020HSC-CIP008).
文摘Fibroblast growth factor receptors(FGFRs)play an important role in the regulation of cell proliferation,migration and differentiation,while the juxtamembrane domain(JMD)of FGFRs is the key in mediating these transmembrane signal transduction processes.Here,we expressed and purified the JMD(398K-470R)of FGFR1 with the presence of transmembrane domain(377I-397Y).The results from nuclear magnetic resonance(NMR)chemical shift analysis demonstrate that the main structure of JMD is disordered.Yet,the N-terminus of JMD was observed to form a short a-helix upon introducing negatively charged lipid 1,2-dioleoyl-sn-glycero-3-phospho-L-serine(DOPS)into its membrane mimic bicelles.Moreover,the N-terminus of JMD interacts with FRS2a,which is a substrate 2a of FGFR.Hence,we propose a model that FGFR1-JMD may interact with FRS2a and negatively charged lipids competitively.Our study provides a new understanding on the role of the JMD of FGFRs.
基金the National Natural Science Foundation of China to C.L.(No.32071188)Guangdong Basic and Applied Basic Research Foundation to C.L.(No.2020A1515010034)+1 种基金the Research Grants Council of the Hong Kong Special Administrative Region,China to G.Z.(Project No.16103719,16101120,and 161011121,AoE/M-403-16,AOE/M-401/20)Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)to G.Z.(Project No.SMSEGL20SC01eH)and VPRDO19RD03-6.
文摘The abnormal expansion of G-rich hexanucleotide repeat,GGGGCC(G4C2),in chromosome 9 open reading frame 72(C9orf72)is known to be the prevailing genetic cause of two fatal degenerative neurological diseases,amyotrophic lateral sclerosis(ALS)and frontotemporal dementia(FTD).It is well known that the DNA G4C2 repeat expansion with different lengths can form G-quadruplexes which affect gene transcription related to ALS/FTD,therefore it is crucial to understand DNA G4C2 G-quadruplex structures.Herein,by utilizing nuclear magnetic resonance(NMR)spectroscopy,we examined DNA G-quadruplex structure adopted by two G4C2 hexanucleotide repeats with an inosine substitution at position 4,d(G4C2)2-I4.We show that d(G4C2)2-I4 folds into an eight-layer parallel tetrameric G-quadruplex containing two parallel dimeric G-quadruplexes stacking together through p-p interaction via 50-to-50 mode in solution.Each dimeric G-quadruplex unit involves two propeller loops composed of two cytosine bases.This result is consistent with the observation in the crystal structure of d(G4C2)2.Our work not only sheds light on the structural diversity of G-quadruplexes adopted by d(G4C2)n but also provides a structural basis for drug design in treatment of ALS and FTD.
