During ultradeep oil and gas drilling,fluid loss reducers are highly important for water-based drilling fluids,while preparing high temperature-and salt-resistance fluid loss reducers with excellent rheology and filtr...During ultradeep oil and gas drilling,fluid loss reducers are highly important for water-based drilling fluids,while preparing high temperature-and salt-resistance fluid loss reducers with excellent rheology and filtration performance remains a challenge.Herein,a micro-crosslinked amphoteric hydrophobic association copolymer(i.e.,DADC)was synthesized using N,N-dimethyl acrylamide,diallyl dimethyl ammonium chloride,2-acrylamido-2-methylpropane sulfonic acid,hydrophobic monomer,and pentaerythritol triallyl ether crosslinker.Due to the synergistic effects of hydrogen bonds,electrostatic interaction,hydrophobic association,and micro-crosslinking,the DADC copolymer exhibited outstanding temperature-and salt-resistance.The rheological experiments have shown that the DADC copolymer had excellent shear dilution performance and a certain degree of salt-responsive viscosity-increasing performance.The DADC copolymer could effectively adsorb on the surface of bentonite particles through electrostatic interaction and hydrogen bonds,which bring more negative charge to the bentonite,thus improving the hydration and dispersion of bentonite particles as well as the colloidal stability of the drilling fluids.Moreover,the drilling fluids constructed based on the DADC copolymer exhibited satisfactory rheological and filtration properties(FLHTHP=12 m L)after aging at high temperatures(up to200℃)and high salinity(saturated salt)environments.Therefore,this work provided new insights into designing and fabricating high-performance drilling fluid treatment agents,demonstrating good potential applications in deep and ultradeep drilling engineering.展开更多
Incipient charnockites represent granulite formation on a mesoscopic scale and have received considerable attention in understanding fluid processes in the deep crust. Here we report new petrological data from an inci...Incipient charnockites represent granulite formation on a mesoscopic scale and have received considerable attention in understanding fluid processes in the deep crust. Here we report new petrological data from an incipient charuockite locality at Rajapalaiyam in the Madurai Block, southern India, and discuss the petrogenesis based on mineral phase equilibrium modeling and pseudosection analysis. Rajapalaiyam is a key locality in southern India from where diagnostic mineral assemblages for ultrahigh-temperature （UHT） metamorphism have been reported. Proximal to the UHT rocks are patches and lenses of charnockite （Kfs＋Qtz ＋Pl＋ Bt ＋ Opx＋ Grt ＋Ilm） occurring within Opx-free Grt-Bt gneiss （Kfs ＋Pl ＋ Qtz ＋ Bt ＋ Grt ＋ Ilm ＋ Mt） which we report in this study. The application of mineral equilibrium modeling on the charnockitic assemblage in NCKFMASHTO system yields a p-T range of 820 ℃ and -9 kbar. Modeling of the charnockite assemblage in the MnNCKFMASHTO system indicates a slight shift of the equilibrium condition toward lower p and T （- 760 ℃ and - 7.5 kbar）, which is consistent with the results obtained fiom geothermobarometry （710--760 ℃, 6.7-7.5 kbar）, but significantly lower than the peak temperatures （〉1000 ℃） recorded from the UHT rocks in this locality, suggesting that charnockitization is a post-peak event. The modeling of 7 versus molar H2O content in the rock （M（H2O）） demonstrates that the Opx-bearing assemblage in charnockite and Opx- free assemblage in Grt-Bt gneiss are both stable at M（H2O） = 0.3 mol%--0.6 mol%, and there is no significant difference in water activity between the two domains. Our finding is in contrast to the previous petrogenetic model of incipient charnockite formation which envisages lowering of water activity and stabilization of orthopyroxene through breakdown of biotite by dehydration caused by the infiltration of CO2-rich fluid. T-XFe3＋ （= Fe2O3/（FeO ＋ Fe2O3） in mole） pseudosections suggest that the oxidation condition of the rocks played a major role on the stability of orthopyroxene; Opx is stable at XFe3＋〈0.03 in charnockite, while Opx-free assemblage in Grt-Bt gneiss is stabilized at XFe3＋ 〉0.12. Such low oxygen fugacity conditions of XFe3＋ 〈0.03 in the charnockite compared to Ort-Bt gneiss might be related to the infiltration of a reduced fluid （e.g., H2O ＋ CH4） during the retrograde stage.展开更多
The Tongcun Mo（Cu） deposit in Kaihua city of Zhejiang Province,eastern China,occurs in and adjacent to the Songjiazhuang granodiorite porphyry and is a medium-sized and important porphyry type ore deposit.Two irregu...The Tongcun Mo（Cu） deposit in Kaihua city of Zhejiang Province,eastern China,occurs in and adjacent to the Songjiazhuang granodiorite porphyry and is a medium-sized and important porphyry type ore deposit.Two irregular Mo（Cu） orebodies consist of various types of hydrothermal veinlets.Intensive hydrothermal alteration contains skarnization,chloritization,carbonatization,silicification and sericitization.Based on mineral assemblages and crosscutting relationships,the oreforming processes are divided into five stages,i.e.,the early stage of garnet ＋ epidote ± chlorite associated with skarnization and K-feldspar ＋ quartz ± molybdenite veins associated with potassicsilicic alteration,the quartz-sulfides stage of quartz ＋ molybdenite ± chalcopyrite ± pyrite veins,the carbonatization stage of calcite veinlets or stockworks,the sericite ＋ chalcopyrite ± pyrite stage,and the late calcite ＋ quartz stage.Only the quartz-bearing samples in the early stage and in the quartzsulfides stage are suitable for fluid inclusions（FIs） study.Four types of FIs were observed,including1） CO2-CH4 single phase FIs,2） CO2-bearing two- or three-phase FIs,3） Aqueous two-phase FIs,and4） Aqueous single phase FIs.FIs of the early stages are predominantly CO2- and CH4-rich FIs of the CO2-CH4-H2O-NaCl system,whereas minerals in the quartz-sulfides stage contain CO2-rich FIs of the CO2-H2O-NaCl system and liquid-rich FIs of the H2O-NaCl system.For the CO2-CH4 single phase FIs of the early mineralization stage,the homogenization temperatures of the CO2 phase range from 15.4 ℃ to 25.3 ℃（to liquid）,and the fluid density varies from 0.7 g/cm^3 to 0.8 g/cm^3;for two- or three-phase FIs of the CO2-CH4-H2O-NaCl system,the homogenization temperatures,salinities and densities range from 312℃ to 412℃,7.7 wt%NaCl eqv.to 10.9 wt%NaCl eqv.,and 0.9 g/cm^3 to 1.0 g/cm^3,respectively.For CO2-H2O-NaCI two- or threephase FIs of the quartz-sulfides stage,the homogenization temperatures and salinities range from255℃ to 418℃,4.8 wt%NaCl eqv.to 12.4 wt%NaCl eqv.,respectively;for H2O-NaCl two-phase FIs,the homogenization temperatures range from 230 ℃ to 368 ℃,salinities from 11.7 wt%NaCl eqv.to16.9 wt%NaCl eqv.,and densities from 0.7 g/cm^3 to 1.0 g/cm^3.Microthermometric measurements and Laser Raman spectroscopy analyses indicate that CO2 and CH4 contents and reducibility（indicated by the presence of CH4） of the fluid inclusions trapped in quartz-sulfides stage minerals are lower than those in the early stage.Twelve molybdenite separates yield a Re-Os isochron age of 163 ± 2.4 Ma,which is consistent with the emplacement age of the Tongcun,Songjiazhuang,Dayutang and Huangbaikeng granodiorite porphyries.The 〈S18OSMow values of fluids calculated from quartz of the quartz-sulfides stage range from 5.6‰ to 8.6‰,and the 〈JDSMOw values of fluid inclusions in quartz of this stage range from-71.8‰ to-88.9‰,indicating a primary magmatic fluid source.〈534SV-cdt values of sulfides range from＋1.6‰ to ＋3.8‰,which indicate that the sulfur in the ores was sourced from magmatic origins.Phase separation is inferred to have occurred from the early stage to the quartz-sulfides stage and resulted in ore mineral precipitation.The characteristics of alteration and mineralization,fluid inclusion,sulfur and hydrogen-oxygen isotope data,and molybdenite Re-Os ages all suggest that the Tongcun Mo（Cu） deposit is likely to be a reduced porphyry Mo（Cu） deposit associated with the granodiorite porphyry in the Tongcun area.展开更多
基金the National Natural Science Foundation of China(No.52204023)China Postdoctoral Science Foundation(2022M713465)Postdoctoral Innovation Talent Support of Shandong Province(SDBX2022033)。
文摘During ultradeep oil and gas drilling,fluid loss reducers are highly important for water-based drilling fluids,while preparing high temperature-and salt-resistance fluid loss reducers with excellent rheology and filtration performance remains a challenge.Herein,a micro-crosslinked amphoteric hydrophobic association copolymer(i.e.,DADC)was synthesized using N,N-dimethyl acrylamide,diallyl dimethyl ammonium chloride,2-acrylamido-2-methylpropane sulfonic acid,hydrophobic monomer,and pentaerythritol triallyl ether crosslinker.Due to the synergistic effects of hydrogen bonds,electrostatic interaction,hydrophobic association,and micro-crosslinking,the DADC copolymer exhibited outstanding temperature-and salt-resistance.The rheological experiments have shown that the DADC copolymer had excellent shear dilution performance and a certain degree of salt-responsive viscosity-increasing performance.The DADC copolymer could effectively adsorb on the surface of bentonite particles through electrostatic interaction and hydrogen bonds,which bring more negative charge to the bentonite,thus improving the hydration and dispersion of bentonite particles as well as the colloidal stability of the drilling fluids.Moreover,the drilling fluids constructed based on the DADC copolymer exhibited satisfactory rheological and filtration properties(FLHTHP=12 m L)after aging at high temperatures(up to200℃)and high salinity(saturated salt)environments.Therefore,this work provided new insights into designing and fabricating high-performance drilling fluid treatment agents,demonstrating good potential applications in deep and ultradeep drilling engineering.
基金funding for this project was produced by a Grant-in-Aid for Scientific Research(B) from Japan Society for the Promotion of Science(JSPS) to Tsunogae(Nos.20340148, 22403017)
文摘Incipient charnockites represent granulite formation on a mesoscopic scale and have received considerable attention in understanding fluid processes in the deep crust. Here we report new petrological data from an incipient charuockite locality at Rajapalaiyam in the Madurai Block, southern India, and discuss the petrogenesis based on mineral phase equilibrium modeling and pseudosection analysis. Rajapalaiyam is a key locality in southern India from where diagnostic mineral assemblages for ultrahigh-temperature （UHT） metamorphism have been reported. Proximal to the UHT rocks are patches and lenses of charnockite （Kfs＋Qtz ＋Pl＋ Bt ＋ Opx＋ Grt ＋Ilm） occurring within Opx-free Grt-Bt gneiss （Kfs ＋Pl ＋ Qtz ＋ Bt ＋ Grt ＋ Ilm ＋ Mt） which we report in this study. The application of mineral equilibrium modeling on the charnockitic assemblage in NCKFMASHTO system yields a p-T range of 820 ℃ and -9 kbar. Modeling of the charnockite assemblage in the MnNCKFMASHTO system indicates a slight shift of the equilibrium condition toward lower p and T （- 760 ℃ and - 7.5 kbar）, which is consistent with the results obtained fiom geothermobarometry （710--760 ℃, 6.7-7.5 kbar）, but significantly lower than the peak temperatures （〉1000 ℃） recorded from the UHT rocks in this locality, suggesting that charnockitization is a post-peak event. The modeling of 7 versus molar H2O content in the rock （M（H2O）） demonstrates that the Opx-bearing assemblage in charnockite and Opx- free assemblage in Grt-Bt gneiss are both stable at M（H2O） = 0.3 mol%--0.6 mol%, and there is no significant difference in water activity between the two domains. Our finding is in contrast to the previous petrogenetic model of incipient charnockite formation which envisages lowering of water activity and stabilization of orthopyroxene through breakdown of biotite by dehydration caused by the infiltration of CO2-rich fluid. T-XFe3＋ （= Fe2O3/（FeO ＋ Fe2O3） in mole） pseudosections suggest that the oxidation condition of the rocks played a major role on the stability of orthopyroxene; Opx is stable at XFe3＋〈0.03 in charnockite, while Opx-free assemblage in Grt-Bt gneiss is stabilized at XFe3＋ 〉0.12. Such low oxygen fugacity conditions of XFe3＋ 〈0.03 in the charnockite compared to Ort-Bt gneiss might be related to the infiltration of a reduced fluid （e.g., H2O ＋ CH4） during the retrograde stage.
基金financially supported by the State Key Fundamental Research Project of China(2012CB476505)the 12th Five-Year Plan project of the National Science & Technology Pillar Program(2011BAB04B02)+1 种基金the Frontier Program(Y3CJ001000)from the Institute of Geochemistry,Chinese Academy of Sciencesthe Frontier Program(Y3KJA20001)from the State Key Laboratory of Ore Deposit Geochemistry
文摘The Tongcun Mo（Cu） deposit in Kaihua city of Zhejiang Province,eastern China,occurs in and adjacent to the Songjiazhuang granodiorite porphyry and is a medium-sized and important porphyry type ore deposit.Two irregular Mo（Cu） orebodies consist of various types of hydrothermal veinlets.Intensive hydrothermal alteration contains skarnization,chloritization,carbonatization,silicification and sericitization.Based on mineral assemblages and crosscutting relationships,the oreforming processes are divided into five stages,i.e.,the early stage of garnet ＋ epidote ± chlorite associated with skarnization and K-feldspar ＋ quartz ± molybdenite veins associated with potassicsilicic alteration,the quartz-sulfides stage of quartz ＋ molybdenite ± chalcopyrite ± pyrite veins,the carbonatization stage of calcite veinlets or stockworks,the sericite ＋ chalcopyrite ± pyrite stage,and the late calcite ＋ quartz stage.Only the quartz-bearing samples in the early stage and in the quartzsulfides stage are suitable for fluid inclusions（FIs） study.Four types of FIs were observed,including1） CO2-CH4 single phase FIs,2） CO2-bearing two- or three-phase FIs,3） Aqueous two-phase FIs,and4） Aqueous single phase FIs.FIs of the early stages are predominantly CO2- and CH4-rich FIs of the CO2-CH4-H2O-NaCl system,whereas minerals in the quartz-sulfides stage contain CO2-rich FIs of the CO2-H2O-NaCl system and liquid-rich FIs of the H2O-NaCl system.For the CO2-CH4 single phase FIs of the early mineralization stage,the homogenization temperatures of the CO2 phase range from 15.4 ℃ to 25.3 ℃（to liquid）,and the fluid density varies from 0.7 g/cm^3 to 0.8 g/cm^3;for two- or three-phase FIs of the CO2-CH4-H2O-NaCl system,the homogenization temperatures,salinities and densities range from 312℃ to 412℃,7.7 wt%NaCl eqv.to 10.9 wt%NaCl eqv.,and 0.9 g/cm^3 to 1.0 g/cm^3,respectively.For CO2-H2O-NaCI two- or threephase FIs of the quartz-sulfides stage,the homogenization temperatures and salinities range from255℃ to 418℃,4.8 wt%NaCl eqv.to 12.4 wt%NaCl eqv.,respectively;for H2O-NaCl two-phase FIs,the homogenization temperatures range from 230 ℃ to 368 ℃,salinities from 11.7 wt%NaCl eqv.to16.9 wt%NaCl eqv.,and densities from 0.7 g/cm^3 to 1.0 g/cm^3.Microthermometric measurements and Laser Raman spectroscopy analyses indicate that CO2 and CH4 contents and reducibility（indicated by the presence of CH4） of the fluid inclusions trapped in quartz-sulfides stage minerals are lower than those in the early stage.Twelve molybdenite separates yield a Re-Os isochron age of 163 ± 2.4 Ma,which is consistent with the emplacement age of the Tongcun,Songjiazhuang,Dayutang and Huangbaikeng granodiorite porphyries.The 〈S18OSMow values of fluids calculated from quartz of the quartz-sulfides stage range from 5.6‰ to 8.6‰,and the 〈JDSMOw values of fluid inclusions in quartz of this stage range from-71.8‰ to-88.9‰,indicating a primary magmatic fluid source.〈534SV-cdt values of sulfides range from＋1.6‰ to ＋3.8‰,which indicate that the sulfur in the ores was sourced from magmatic origins.Phase separation is inferred to have occurred from the early stage to the quartz-sulfides stage and resulted in ore mineral precipitation.The characteristics of alteration and mineralization,fluid inclusion,sulfur and hydrogen-oxygen isotope data,and molybdenite Re-Os ages all suggest that the Tongcun Mo（Cu） deposit is likely to be a reduced porphyry Mo（Cu） deposit associated with the granodiorite porphyry in the Tongcun area.
