Direct viscosification of CO_(2) offers promising alternative for mobility control and reduction in residual brine saturation,thus to improve the CO_(2) trapping in saline aquifers.Hydrocarbon oligomers,recognized for...Direct viscosification of CO_(2) offers promising alternative for mobility control and reduction in residual brine saturation,thus to improve the CO_(2) trapping in saline aquifers.Hydrocarbon oligomers,recognized for their exceptional properties,are considered as one of the most promising viscosifiers in displacement of brine-saturated porous media.However,the molecular-level mechanisms governing the solubility and viscosification of hydrocarbon oligomers in scCO_(2) remain poorly understood.In this study,we employ coarse-grained molecular models to advance our understanding in the effects of molecular structure of hydrocarbon oligomers on their solubility in scCO_(2).The coarse-grained models of five hydrocarbon oligomers with different numbers of methyl-branch(n-C32,P1D-2,P1D-3,P1D-6 and squalane)are established to investigate their effects on solubilization in scCO_(2).We demonstrate that the number of methyl groups has a monotonic correlation with the solubility of hydrocarbon oligomers when the molecular weights of oligomers are comparable.The radial distribution function reveals nC32,P1D and squalane are uniformly dispersed with separation distances of approximately 1.0–2.0 nm.The interaction energy between hydrocarbon oligomers and CO_(2) shows that the number of methylbranch in hydrocarbon oligomers can directly influence their solubility in scCO_(2).Molecular simulation results demonstrate that the interaction distances between the methyl-branch and CO_(2) are smaller than those of other molecular fragments.There are approximately 20%more CO_(2) molecules interacting with methyl-branch than with other parts.This work sets the stage for our future molecular dynamics study in viscosification by hydrocarbon oligomers with different branching length and interfacial phenomena in multiphase systems.展开更多
基金the financial support and funding provided by the National Natural Science Foundation of China(Youth Talent Program,Key Special Project,Grant No.52341401 and Distinguished Scholar Program with a Grant No.52425402)High-level Start-up Funding from Peking University Shenzhen Graduate School,Shenzhen Science and Technology Foundation(Grant No.JCYJ20230807120807016)+2 种基金High-level Startup Funding from China University of Petroleum-Beijing(Grant No.2462024YJRC033)the China Postdoctoral Science(CPS)Foundation(Certificate No.2024M750106)the Postdoctoral Fellowship Program of CPS(Grant No.GZC20240051)。
文摘Direct viscosification of CO_(2) offers promising alternative for mobility control and reduction in residual brine saturation,thus to improve the CO_(2) trapping in saline aquifers.Hydrocarbon oligomers,recognized for their exceptional properties,are considered as one of the most promising viscosifiers in displacement of brine-saturated porous media.However,the molecular-level mechanisms governing the solubility and viscosification of hydrocarbon oligomers in scCO_(2) remain poorly understood.In this study,we employ coarse-grained molecular models to advance our understanding in the effects of molecular structure of hydrocarbon oligomers on their solubility in scCO_(2).The coarse-grained models of five hydrocarbon oligomers with different numbers of methyl-branch(n-C32,P1D-2,P1D-3,P1D-6 and squalane)are established to investigate their effects on solubilization in scCO_(2).We demonstrate that the number of methyl groups has a monotonic correlation with the solubility of hydrocarbon oligomers when the molecular weights of oligomers are comparable.The radial distribution function reveals nC32,P1D and squalane are uniformly dispersed with separation distances of approximately 1.0–2.0 nm.The interaction energy between hydrocarbon oligomers and CO_(2) shows that the number of methylbranch in hydrocarbon oligomers can directly influence their solubility in scCO_(2).Molecular simulation results demonstrate that the interaction distances between the methyl-branch and CO_(2) are smaller than those of other molecular fragments.There are approximately 20%more CO_(2) molecules interacting with methyl-branch than with other parts.This work sets the stage for our future molecular dynamics study in viscosification by hydrocarbon oligomers with different branching length and interfacial phenomena in multiphase systems.
