Hydraulic fracturing facilitates the development and exploitation of unconventional reservoirs.In this study,the injected hydraulic fracturing fluid(HFF)and flowback and produced water(FPW)in tight oil reservoirs of t...Hydraulic fracturing facilitates the development and exploitation of unconventional reservoirs.In this study,the injected hydraulic fracturing fluid(HFF)and flowback and produced water(FPW)in tight oil reservoirs of the Lucaogou Formation in the Junggar Basin are temporally sampled from day 1 to day 64.Freshwater is used for fracturing,and HFF is obtained.The chemical and isotopic parameters(including the water type,total salinity,total dissolved solids(TDS),pH,concentrations of Na^(+),Cl^(-),Ba^(+),K^(+),Fe^(2+)+Fe^(3+),and CO_(3)^(2-),dD,and δ^(18)O)are experimentally obtained,and their variations with time are systematically analyzed based on the flowback water.The results show that the water type,Na/Cl ratio,total salinity,and TDS of the FPW change periodically primarily due to the HFF mixing with formation water,thus causing δD and δ^(18)O to deviate from the meteoric water line of Xinjiang.Because of watererock interaction(WRI),the concentrations of Fe^(2+)+Fe^(3+)and CO_(3)^(2-)of the FPW increase over time,with the solution pH becoming more alkaline.Furthermore,based on the significant changes observed in the geochemistry of the FPW,three separate time intervals of flowback time are identified:Stage Ⅰ(<10 days),where the FPW is dominated by the HFF and the changes in ions and isotopes are mainly caused by the WRI;Stage Ⅱ(10-37 days),where the FPW is dominated by the addition of formation water to the HFF and the WRI is weakened;and finally,Stage Ⅲ(>37 days),where the FPW is dominated by the chemistry of the formation water.The methodology implemented in this study can provide critical support for the source identification of formation water.展开更多
In this study,D→P(π,K) helicity form factors(HFFs) are investigated by applying the QCD light-cone sum rule(LCSR) approach.The calculation accuracy is up to the next-to-leading order(NLO) gluon radiation correction ...In this study,D→P(π,K) helicity form factors(HFFs) are investigated by applying the QCD light-cone sum rule(LCSR) approach.The calculation accuracy is up to the next-to-leading order(NLO) gluon radiation correction of twist-(2,3) distribution amplitude.The resultant HFFs at a large recoil point are Pt,0π(0)=0.688-0.024+0.020 and Pt,0K(O)=0.780-0.029+0.024,in which the contributions from the three particles of the leading order(LO) are so small that they can be safely neglected.The maximal contribution of the NLO gluon radiation correction for Pt,0r,K(0) is less than3%.After extrapolating the LCSR predictions for these HFFs to the whole q2-region,we obtain the decay widths for semileptonic decay processes D→Plvl,which are consistent with the BES-Ⅲ collaboration predictions within error limits.After considering the D+/D0-meson lifetime,we give the branching fractions of D→Plvl with l=e,μ;our predictions also agree with the BES-Ⅲ collaboration results within error limits,especially for the D→πlvl decay process.Finally,we present the forward-backward asymmetry AFBl(q2) and lepton convexity parameter CFl(q2),and further calculate the mean value of these two observations,<AFBl> and {CFl),which may provide a way to test those HFFs in future experiments.展开更多
基金supported by the National Natural Science Foundation of China(No.U2003102).
文摘Hydraulic fracturing facilitates the development and exploitation of unconventional reservoirs.In this study,the injected hydraulic fracturing fluid(HFF)and flowback and produced water(FPW)in tight oil reservoirs of the Lucaogou Formation in the Junggar Basin are temporally sampled from day 1 to day 64.Freshwater is used for fracturing,and HFF is obtained.The chemical and isotopic parameters(including the water type,total salinity,total dissolved solids(TDS),pH,concentrations of Na^(+),Cl^(-),Ba^(+),K^(+),Fe^(2+)+Fe^(3+),and CO_(3)^(2-),dD,and δ^(18)O)are experimentally obtained,and their variations with time are systematically analyzed based on the flowback water.The results show that the water type,Na/Cl ratio,total salinity,and TDS of the FPW change periodically primarily due to the HFF mixing with formation water,thus causing δD and δ^(18)O to deviate from the meteoric water line of Xinjiang.Because of watererock interaction(WRI),the concentrations of Fe^(2+)+Fe^(3+)and CO_(3)^(2-)of the FPW increase over time,with the solution pH becoming more alkaline.Furthermore,based on the significant changes observed in the geochemistry of the FPW,three separate time intervals of flowback time are identified:Stage Ⅰ(<10 days),where the FPW is dominated by the HFF and the changes in ions and isotopes are mainly caused by the WRI;Stage Ⅱ(10-37 days),where the FPW is dominated by the addition of formation water to the HFF and the WRI is weakened;and finally,Stage Ⅲ(>37 days),where the FPW is dominated by the chemistry of the formation water.The methodology implemented in this study can provide critical support for the source identification of formation water.
基金Supported in part by the National Science Foundation of China(11765007)the National Natural Science Foundation of China(11947302)+1 种基金the Project of Guizhou Provincial Department of Science and Technology(KY[2017]1089,No.KY[2019]1171)the China Postdoctoral Science Foundation(2019TQ0329)。
文摘In this study,D→P(π,K) helicity form factors(HFFs) are investigated by applying the QCD light-cone sum rule(LCSR) approach.The calculation accuracy is up to the next-to-leading order(NLO) gluon radiation correction of twist-(2,3) distribution amplitude.The resultant HFFs at a large recoil point are Pt,0π(0)=0.688-0.024+0.020 and Pt,0K(O)=0.780-0.029+0.024,in which the contributions from the three particles of the leading order(LO) are so small that they can be safely neglected.The maximal contribution of the NLO gluon radiation correction for Pt,0r,K(0) is less than3%.After extrapolating the LCSR predictions for these HFFs to the whole q2-region,we obtain the decay widths for semileptonic decay processes D→Plvl,which are consistent with the BES-Ⅲ collaboration predictions within error limits.After considering the D+/D0-meson lifetime,we give the branching fractions of D→Plvl with l=e,μ;our predictions also agree with the BES-Ⅲ collaboration results within error limits,especially for the D→πlvl decay process.Finally,we present the forward-backward asymmetry AFBl(q2) and lepton convexity parameter CFl(q2),and further calculate the mean value of these two observations,<AFBl> and {CFl),which may provide a way to test those HFFs in future experiments.
