Boqin Sun - Academia.edu (original) (raw)
Papers by Boqin Sun
... is to discuss the principles behind recently developed T1-based novel methodologies that ... ... more ... is to discuss the principles behind recently developed T1-based novel methodologies that ... determined by solving a nonlinear least squares problem with the following objective function ... The basic steps in the contamination estimation algorithm can be summarized as follows: 1 ...
Copyright 2007, held jointly by the Society of Petrophysicists and Well Log Analysts (SPWLA) and ... more Copyright 2007, held jointly by the Society of Petrophysicists and Well Log Analysts (SPWLA) and the submitting authors. This paper was prepared for presentation at the SPWLA 48th Annual Logging Symposium held in Austin, Texas, United States, June 3-6, 2007.
AIP Conference Proceedings, 2008
The spurious signals in NMR logging often cause neighboring depth intervals of the same rock type... more The spurious signals in NMR logging often cause neighboring depth intervals of the same rock type to have dissimilar T2 distributions and oscillatory porosity responses. We found that we can use the 2D NMR concept to jointly invert T2 distributions of sequential depth records using the depth as the extra dimension and basis functions as the regularizing tool for smoothing,
... Chengbing Liu, Boqin Sun, Tom Wild and Stephen Van Dalen Chevron Energy Technology Company ..... more ... Chengbing Liu, Boqin Sun, Tom Wild and Stephen Van Dalen Chevron Energy Technology Company ... of dead oil samples and the viscosity measurements of the dead oil samples resaturated with gas (to simulate live oil) in laboratory, R. Trienen[Trienen and Waite 2005 ...
NMR logging data are often acquired by a long CPMG sequence followed by a set of short bursts. Th... more NMR logging data are often acquired by a long CPMG sequence followed by a set of short bursts. These short bursts have a wait times of the order of 20 ms and they are primarily used to improve the porosity accuracy of short T2 components. A joint inversion method is then ...
PETROPHYSICS
We present a new class of inversion methods for Nuclear Magnetic Resonance (NMR) log data based o... more We present a new class of inversion methods for Nuclear Magnetic Resonance (NMR) log data based on Monte Carlo techniques which gives multi-dimensional distribution of proton density as a function of petrophysical parameters such as T 1 , T 2 , D. This new class is an alternative to traditional linear inversion methods, such as Singular Value Decomposition (SVD). We present in this paper two methods of this class. We fi rst implement the Monte Carlo optimization scheme based on a log-normal random walk to propose changes and Metropolis criterion to accept such changes directly on the amplitudes of the T 2 relaxation time distribution (the linear case). An exponential annealing schedule is used. The inversion solution is given by a statistical average of a family of optimized results. We next implement a nonlinear parameterization method using a Gaussian basis set, where the center and width of the basis functions are allowed to vary in addition to the amplitude. By removing the linear restriction in traditional inversion methods, we can extend the applicability of fl uid/rock typing methods to multi-dimensional NMR inversions, where traditional methods are less convenient. Our tests indicate that the new inversion methods are very robust requiring only a few input parameters.
Journal of Macromolecular Science: Part A - Chemistry, 1988
3,4/cis-1,4-Polyisoprenes were prepared with Fe(acac)3-Al(i-Bu)3 catalyst. These polymers are of ... more 3,4/cis-1,4-Polyisoprenes were prepared with Fe(acac)3-Al(i-Bu)3 catalyst. These polymers are of interest because of their higher 3,4 content and different degree of crystallinity. The C-NMR spectra of these polymers were much more complex than those previously reported and were assigned using slightly modified empirical parameters based on Gronski et al. In order to further clarify the assignments, hydrogenation of the polymers
Analytical Methods in Petroleum Upstream Applications, 2015
Proceedings of International Petroleum Technology Conference, 2008
Copyright 2008, International Petroleum Technology Conference This paper was prepared for present... more Copyright 2008, International Petroleum Technology Conference This paper was prepared for presentation at the International Petroleum Technology Conference held in Kuala Lumpur, Malaysia, 35 December 2008. This paper was selected for presentation by an IPTC ...
Proceedings of SPE Annual Technical Conference and Exhibition, 2004
... is to discuss the principles behind recently developed T1-based novel methodologies that ... ... more ... is to discuss the principles behind recently developed T1-based novel methodologies that ... determined by solving a nonlinear least squares problem with the following objective function ... The basic steps in the contamination estimation algorithm can be summarized as follows: 1 ...
Proceedings of SPE Annual Technical Conference and Exhibition, 2004
Abstract Recent developments of two-dimensional (2D) NMR techniques have been advertised as effic... more Abstract Recent developments of two-dimensional (2D) NMR techniques have been advertised as efficient and accurate methods to interpret a variety of petrophysical parameters, including mixed fluid saturation, in-situ oil viscosity, wettability, and pore ...
SPE Journal, 2006
Summary Two-dimensional (2D) NMR techniques have been proposed as efficient methods to infer a va... more Summary Two-dimensional (2D) NMR techniques have been proposed as efficient methods to infer a variety of petrophysical parameters, including mixed fluid saturation, in-situ oil viscosity, wettability, and pore structure. However, no study has been presented to quan- ...
Journal of the American Chemical Society, 1997
Accurate distance measurements between pairs of nuclear spins can provide detailed information ab... more Accurate distance measurements between pairs of nuclear spins can provide detailed information about molecular structure in the solid state. The rotational resonance (R 2 ) technique, in particular, has been used to measure internuclear distances in a variety of compounds, often between pairs of 13 C nuclei where the outer range is 5-6 Å. Recent studies have revealed that the spin dynamics at rotational resonance are influenced by zero-quantum line shape parameters including T 2 zq and the dispersion in isotropic chemical shift differences. Errors in the estimation of these parameters are often the limiting factor in determining the accuracy of a distance measurement. Here we present a modification of R 2 , termed "rotational resonance tickling" (R 2 T), which uses a ramped rf field to induce fast passage through the dipolar resonance condition, thereby greatly reducing the dependence of the spin dynamics on zero-quantum parameters. Extraction of distance information from the resulting exchange curves is approximately a single-parameter fit, with accuracies in model systems that appear to be on the order of (0.1 Å or better. An additional feature of the technique is that it does not demand the very high-power 1 H decoupling fields typically required in other recoupling experiments to limit signal loss during mixing. We demonstrate the technique in a pair of 13 C 2 -labeled model compounds, tyrosine ethyl ester and glycylglycine hydrochloride, with effective internuclear distances (including intermolecular effects) of 5.05 and 4.3 Å, respectively.
![Research paper thumbnail of A Solid-State NMR Study of Tungsten Methyl Group Dynamics in [W(η 5 -C 5 Me 5 )Me 4 ][PF 6 ]](https://attachments.academia-assets.com/49040316/thumbnails/1.jpg)
](Journal of the American Chemical Society, 1996
We report the results of Magic Angle Spinning (MAS) 13 C and static 2 H NMR studies of the dynami... more We report the results of Magic Angle Spinning (MAS) 13 C and static 2 H NMR studies of the dynamics of the methyl groups coordinated to tungsten in [WCp*Me 4 ][PF 6 ] (Cp* ) η 5 -C 5 Me 5 ). The temperature-dependent broadening of the axial methyl 13 C line can be ascribed to interference between 1 H decoupling and methyl motion when the motional rate and decoupling nutation frequency are comparable. This proposal is consistent with the absence of broadening in the 2 H labeled compound and the motional rate constants inferred from 2 H NMR lineshape and T 1 studies, which range from 10 7 s -1 at 25°C to 10 3 s -1 at -125°C. The measured barrier to axial methyl hopping (26 kJ/mol) is among the highest reported to date. An X-ray crystal study of [W(η 5 -C 5 Me 4 Et)Me 4 ][PF 6 ] reveals no evidence (in terms of the core geometry) for an agostic interaction in either the axial methyl group or the equatorial methyl groups.
Journal of Magnetic Resonance, 2003
The solid state NMR technique of rotational resonance (R2) has been used extensively to measure d... more The solid state NMR technique of rotational resonance (R2) has been used extensively to measure distances approaching 5-6 A between 13C nuclei in a variety of compounds including amyloidogenic peptides and membrane proteins. The accuracy of the distance information extracted from the time-dependent spin dynamics at R2 is often limited by the accuracy with which the relevant zero-quantum lineshape parameters are estimated. Here we demonstrate that measurement of spinning frequency dependent magnetization exchange dynamics provides data from which both distance and zero-quantum relaxation parameters can be extracted independently. In addition to providing more accurate distance information, this technique allows examination of the zero-quantum lineshape, which can indicate the presence of correlated relaxation or chemical shift distributions between dipolar-coupled sites. With this approach we have separated the contribution of dipolar couplings and zero quantum relaxation to R2 exchange curves. Thus, we have significantly improved the accuracy of the measurement of the intramolecular, internuclear distances between a pair of 13C's in two model compounds (N-acetyl-D,L-valine and glycylglycine.HCl) that lie in the distance range 4.6-4.7 A.
Journal of Magnetic Resonance, 2007
We revisit random-walk methods to simulate the NMR response of fluids in porous media. Simulation... more We revisit random-walk methods to simulate the NMR response of fluids in porous media. Simulations reproduce the effects of diffusion within external inhomogeneous background magnetic fields, imperfect and finite-duration B(1) pulses, T(1)/T(2) contrasts, and relaxing or permeable boundaries. The simulation approach consolidates existing NMR numerical methods used in biology and engineering into a single formulation that expands on the magnetic-dipole equivalent of spin packets. When fluids exhibit low T(1)/T(2) contrasts and when CPMG pulse sequences are used to acquire NMR measurements, we verify that classical NMR numerical models that neglect T(1) effects accurately reproduce surface magnetization decays of saturated granular porous media regardless of the diffusion/relaxation regime. Currently, analytical expressions exist only for the case of arbitrary pore shapes within the fast-diffusion limit. However, when fluids include several components or when magnetic fields are strongly inhomogeneous, we show that simulations results obtained using the complete set of Bloch's equations differ substantially from those of classical NMR models. In addition, our random-walk formulation accurately reproduces magnetization echoes stemming from coherent-pathway calculations. We show that the random-walk approach is especially suited to generate parametric multi-dimensional T(1)/T(2)/D NMR maps to improve the characterization of pore structures and saturating fluids.
... is to discuss the principles behind recently developed T1-based novel methodologies that ... ... more ... is to discuss the principles behind recently developed T1-based novel methodologies that ... determined by solving a nonlinear least squares problem with the following objective function ... The basic steps in the contamination estimation algorithm can be summarized as follows: 1 ...
Copyright 2007, held jointly by the Society of Petrophysicists and Well Log Analysts (SPWLA) and ... more Copyright 2007, held jointly by the Society of Petrophysicists and Well Log Analysts (SPWLA) and the submitting authors. This paper was prepared for presentation at the SPWLA 48th Annual Logging Symposium held in Austin, Texas, United States, June 3-6, 2007.
AIP Conference Proceedings, 2008
The spurious signals in NMR logging often cause neighboring depth intervals of the same rock type... more The spurious signals in NMR logging often cause neighboring depth intervals of the same rock type to have dissimilar T2 distributions and oscillatory porosity responses. We found that we can use the 2D NMR concept to jointly invert T2 distributions of sequential depth records using the depth as the extra dimension and basis functions as the regularizing tool for smoothing,
... Chengbing Liu, Boqin Sun, Tom Wild and Stephen Van Dalen Chevron Energy Technology Company ..... more ... Chengbing Liu, Boqin Sun, Tom Wild and Stephen Van Dalen Chevron Energy Technology Company ... of dead oil samples and the viscosity measurements of the dead oil samples resaturated with gas (to simulate live oil) in laboratory, R. Trienen[Trienen and Waite 2005 ...
NMR logging data are often acquired by a long CPMG sequence followed by a set of short bursts. Th... more NMR logging data are often acquired by a long CPMG sequence followed by a set of short bursts. These short bursts have a wait times of the order of 20 ms and they are primarily used to improve the porosity accuracy of short T2 components. A joint inversion method is then ...
PETROPHYSICS
We present a new class of inversion methods for Nuclear Magnetic Resonance (NMR) log data based o... more We present a new class of inversion methods for Nuclear Magnetic Resonance (NMR) log data based on Monte Carlo techniques which gives multi-dimensional distribution of proton density as a function of petrophysical parameters such as T 1 , T 2 , D. This new class is an alternative to traditional linear inversion methods, such as Singular Value Decomposition (SVD). We present in this paper two methods of this class. We fi rst implement the Monte Carlo optimization scheme based on a log-normal random walk to propose changes and Metropolis criterion to accept such changes directly on the amplitudes of the T 2 relaxation time distribution (the linear case). An exponential annealing schedule is used. The inversion solution is given by a statistical average of a family of optimized results. We next implement a nonlinear parameterization method using a Gaussian basis set, where the center and width of the basis functions are allowed to vary in addition to the amplitude. By removing the linear restriction in traditional inversion methods, we can extend the applicability of fl uid/rock typing methods to multi-dimensional NMR inversions, where traditional methods are less convenient. Our tests indicate that the new inversion methods are very robust requiring only a few input parameters.
Journal of Macromolecular Science: Part A - Chemistry, 1988
3,4/cis-1,4-Polyisoprenes were prepared with Fe(acac)3-Al(i-Bu)3 catalyst. These polymers are of ... more 3,4/cis-1,4-Polyisoprenes were prepared with Fe(acac)3-Al(i-Bu)3 catalyst. These polymers are of interest because of their higher 3,4 content and different degree of crystallinity. The C-NMR spectra of these polymers were much more complex than those previously reported and were assigned using slightly modified empirical parameters based on Gronski et al. In order to further clarify the assignments, hydrogenation of the polymers
Analytical Methods in Petroleum Upstream Applications, 2015
Proceedings of International Petroleum Technology Conference, 2008
Copyright 2008, International Petroleum Technology Conference This paper was prepared for present... more Copyright 2008, International Petroleum Technology Conference This paper was prepared for presentation at the International Petroleum Technology Conference held in Kuala Lumpur, Malaysia, 35 December 2008. This paper was selected for presentation by an IPTC ...
Proceedings of SPE Annual Technical Conference and Exhibition, 2004
... is to discuss the principles behind recently developed T1-based novel methodologies that ... ... more ... is to discuss the principles behind recently developed T1-based novel methodologies that ... determined by solving a nonlinear least squares problem with the following objective function ... The basic steps in the contamination estimation algorithm can be summarized as follows: 1 ...
Proceedings of SPE Annual Technical Conference and Exhibition, 2004
Abstract Recent developments of two-dimensional (2D) NMR techniques have been advertised as effic... more Abstract Recent developments of two-dimensional (2D) NMR techniques have been advertised as efficient and accurate methods to interpret a variety of petrophysical parameters, including mixed fluid saturation, in-situ oil viscosity, wettability, and pore ...
SPE Journal, 2006
Summary Two-dimensional (2D) NMR techniques have been proposed as efficient methods to infer a va... more Summary Two-dimensional (2D) NMR techniques have been proposed as efficient methods to infer a variety of petrophysical parameters, including mixed fluid saturation, in-situ oil viscosity, wettability, and pore structure. However, no study has been presented to quan- ...
Journal of the American Chemical Society, 1997
Accurate distance measurements between pairs of nuclear spins can provide detailed information ab... more Accurate distance measurements between pairs of nuclear spins can provide detailed information about molecular structure in the solid state. The rotational resonance (R 2 ) technique, in particular, has been used to measure internuclear distances in a variety of compounds, often between pairs of 13 C nuclei where the outer range is 5-6 Å. Recent studies have revealed that the spin dynamics at rotational resonance are influenced by zero-quantum line shape parameters including T 2 zq and the dispersion in isotropic chemical shift differences. Errors in the estimation of these parameters are often the limiting factor in determining the accuracy of a distance measurement. Here we present a modification of R 2 , termed "rotational resonance tickling" (R 2 T), which uses a ramped rf field to induce fast passage through the dipolar resonance condition, thereby greatly reducing the dependence of the spin dynamics on zero-quantum parameters. Extraction of distance information from the resulting exchange curves is approximately a single-parameter fit, with accuracies in model systems that appear to be on the order of (0.1 Å or better. An additional feature of the technique is that it does not demand the very high-power 1 H decoupling fields typically required in other recoupling experiments to limit signal loss during mixing. We demonstrate the technique in a pair of 13 C 2 -labeled model compounds, tyrosine ethyl ester and glycylglycine hydrochloride, with effective internuclear distances (including intermolecular effects) of 5.05 and 4.3 Å, respectively.
Journal of the American Chemical Society, 1996
We report the results of Magic Angle Spinning (MAS) 13 C and static 2 H NMR studies of the dynami... more We report the results of Magic Angle Spinning (MAS) 13 C and static 2 H NMR studies of the dynamics of the methyl groups coordinated to tungsten in [WCp*Me 4 ][PF 6 ] (Cp* ) η 5 -C 5 Me 5 ). The temperature-dependent broadening of the axial methyl 13 C line can be ascribed to interference between 1 H decoupling and methyl motion when the motional rate and decoupling nutation frequency are comparable. This proposal is consistent with the absence of broadening in the 2 H labeled compound and the motional rate constants inferred from 2 H NMR lineshape and T 1 studies, which range from 10 7 s -1 at 25°C to 10 3 s -1 at -125°C. The measured barrier to axial methyl hopping (26 kJ/mol) is among the highest reported to date. An X-ray crystal study of [W(η 5 -C 5 Me 4 Et)Me 4 ][PF 6 ] reveals no evidence (in terms of the core geometry) for an agostic interaction in either the axial methyl group or the equatorial methyl groups.
Journal of Magnetic Resonance, 2003
The solid state NMR technique of rotational resonance (R2) has been used extensively to measure d... more The solid state NMR technique of rotational resonance (R2) has been used extensively to measure distances approaching 5-6 A between 13C nuclei in a variety of compounds including amyloidogenic peptides and membrane proteins. The accuracy of the distance information extracted from the time-dependent spin dynamics at R2 is often limited by the accuracy with which the relevant zero-quantum lineshape parameters are estimated. Here we demonstrate that measurement of spinning frequency dependent magnetization exchange dynamics provides data from which both distance and zero-quantum relaxation parameters can be extracted independently. In addition to providing more accurate distance information, this technique allows examination of the zero-quantum lineshape, which can indicate the presence of correlated relaxation or chemical shift distributions between dipolar-coupled sites. With this approach we have separated the contribution of dipolar couplings and zero quantum relaxation to R2 exchange curves. Thus, we have significantly improved the accuracy of the measurement of the intramolecular, internuclear distances between a pair of 13C's in two model compounds (N-acetyl-D,L-valine and glycylglycine.HCl) that lie in the distance range 4.6-4.7 A.
Journal of Magnetic Resonance, 2007
We revisit random-walk methods to simulate the NMR response of fluids in porous media. Simulation... more We revisit random-walk methods to simulate the NMR response of fluids in porous media. Simulations reproduce the effects of diffusion within external inhomogeneous background magnetic fields, imperfect and finite-duration B(1) pulses, T(1)/T(2) contrasts, and relaxing or permeable boundaries. The simulation approach consolidates existing NMR numerical methods used in biology and engineering into a single formulation that expands on the magnetic-dipole equivalent of spin packets. When fluids exhibit low T(1)/T(2) contrasts and when CPMG pulse sequences are used to acquire NMR measurements, we verify that classical NMR numerical models that neglect T(1) effects accurately reproduce surface magnetization decays of saturated granular porous media regardless of the diffusion/relaxation regime. Currently, analytical expressions exist only for the case of arbitrary pore shapes within the fast-diffusion limit. However, when fluids include several components or when magnetic fields are strongly inhomogeneous, we show that simulations results obtained using the complete set of Bloch's equations differ substantially from those of classical NMR models. In addition, our random-walk formulation accurately reproduces magnetization echoes stemming from coherent-pathway calculations. We show that the random-walk approach is especially suited to generate parametric multi-dimensional T(1)/T(2)/D NMR maps to improve the characterization of pore structures and saturating fluids.