Source-less density measurement using an adaptive neutron-induced gamma correction method

Qiong Zhang; Yi Ge; Yu-Lian Li

doi:10.1007/s41365-023-01274-4

Your Location：

Home >

Browse articles >

Source-less density measurement using an adaptive neutron-induced gamma correction method

NUCLEAR ELECTRONICS AND INSTRUMENTATION | Updated：2023-09-19

- Source-less density measurement using an adaptive neutron-induced gamma correction method
- Source-less density measurement using an adaptive neutron-induced gamma correction method
- 核技术（英文版） 2023年34卷第8期文章编号：125
- Affiliations：
  
  1.University of Electronic Science and Technology of China, Chengdu 610000, China
- Author bio：
  
  * zhanqio@uestc.edu.cn
- Funds：
  
  China Natural Science Fund(52171253);Natural Science Foundation of Sichuan(2022NSFSC0949)
- DOI：10.1007/s41365-023-01274-4
  中图分类号：
Scan for full text
Source-less density measurement using an adaptive neutron-induced gamma correction method[J]. 核技术（英文版）, 2023,34(8):125

Qiong Zhang, Yi Ge, Yu-Lian Li. Source-less density measurement using an adaptive neutron-induced gamma correction method[J]. Nuclear Science and Techniques, 2023,34(8):125
Source-less density measurement using an adaptive neutron-induced gamma correction method[J]. 核技术（英文版）, 2023,34(8):125 DOI： 10.1007/s41365-023-01274-4.

Qiong Zhang, Yi Ge, Yu-Lian Li. Source-less density measurement using an adaptive neutron-induced gamma correction method[J]. Nuclear Science and Techniques, 2023,34(8):125 DOI： 10.1007/s41365-023-01274-4.

摘要

Abstract

The use of radioactive isotopes, such as Cs-137, to measure formation density is a common practice; however, it poses high risks such as environmental contamination from lost sources. To address these challenges, the use of pulsed neutron sources for density measurements, also known as "source-less density", has emerged as a promising alternative. By collecting gamma counts at different time gates according to the duty cycle of the pulsed sequence, the inelastic gamma component can be isolated to obtain more accurate density measurements. However, the collection of gamma rays during the neutron burst-on period often contains a proportion of capture gamma rays, which can reduce the accuracy of density measurements. This proportion can vary depending on the formation environment and neutron duty cycle. To address these challenges, an adaptive capture gamma correction method was developed for density measurements. This method distinguishes between "burst-on" and "burst-off" periods based on the gamma time spectra, and derives the capture ratio in the burst-on period by iteratively fitting the capture gamma time spectra, resulting in a more accurate net inelastic gamma. This method identifies the end of the pulse by automatically calculating the differential, and fits the capture gamma time spectra using Gaussian process regression, which considers the differences in formation attenuation caused by different environments. The method was verified through simulations with errors of below 0.025 g/cm,3, demonstrating its adaptability and feasibility for use in formation density measurements. Overall, the proposed method has the potential to minimize the risks associated with radioactive isotopes and improve the accuracy of density measurements in various duty cycles and formation environments.

关键词

Keywords

Neutron-induced gammaAdaptive correctionSource-less density

references

D. V. Ellis, J. M. Singer, Well logging for earth scientists. (Springer, Dordrecht, 2007), Vol. 692

Q. Zhang, J. Liang, X. Wang et al., Dracarys: High-fidelity nuclear well logging benchmark problems with experimental results. Ann. Nucl. Energy 173, 109116, (2022). doi: 10.1016/j.anucene.2022.109116http://doi.org/10.1016/j.anucene.2022.109116

Q. Zhang, Y. Li, Y. Jin et al., A new gamma density measurement method for cased-hole formation evaluation. Appl. Radiat. Isotopes 184, 110178, (2022). doi: 10.1016/j.apradiso.2022.110178http://doi.org/10.1016/j.apradiso.2022.110178

A. Badruzzaman, An assessment of fundamentals of nuclear-based alternatives to conventional chemical source bulk density measurement. Petrophysics 55, 415-434, (2014).

A. Gilchrist, F. Inanc, L. Roberts, Nuclear source replacement-promises and pitfalls. In SPWLA 52nd Annual Logging Symposium, (Colorado, May. 2011).

Y. Ge, J. Liang, Q. Zhang. et al., A comparison study of GEANT4 and MCNP6 on neutron-induced gamma simulation, Appl. Radiat. Isotopes 190, 110514, (2022). doi: 10.1016/j.apradiso.2022.110514http://doi.org/10.1016/j.apradiso.2022.110514

H. W. Yu, Y. X. Zhang, X. H. Chen et al., Numerical simulation and method study of X-ray litho-density logging. Nucl. Sci. Tech. 31(12), 124, (2020). doi: 10.1007/s41365-020-00826-2http://doi.org/10.1007/s41365-020-00826-2

L. Zhang, H. W. Yu, Y. Li et al., Improved formation density measurement using controllable DD neutron source and its lithological correction for porosity prediction, Nucl. Sci. Tech. 33(1), 3 (2022). doi: 10.1007/s41365-022-00988-1http://doi.org/10.1007/s41365-022-00988-1

M. Simon, A. Tkabladze, S. Beekman et al., A novel X-ray tool for true sourceless density logging. Petrophysics 59(05), 565-587, (2018). doi: 10.30632/PJV59N5-2018a1http://doi.org/10.30632/PJV59N5-2018a1

G. Schmid, R. Pemper, D. Dolliver et al., A diffusion-corrected sigma algorithm for a four-detector pulsed-neutron logging tool, In SPE Annual Technical Conference and Exhibition, (Texas, Sep. 2018). doi: 10.2118/191738-MShttp://doi.org/10.2118/191738-MS

D. Rose, T. Zhou, S. Beekman et al., An innovative slim pulsed neutron logging tool, In SPWLA 56th Annual Logging Symposium, (California, Jul. 2015).

X. Fu, W. Wu, H. Wang, et al., A new neutron-gamma porosity measurement method for pulsed neutron logging tools. Geophysics 88(4), 1-55, (2023). doi: 10.1190/geo2022-0471.1http://doi.org/10.1190/geo2022-0471.1

G. Xing, Q. Zhang, N. Li, et al., A LWD gas-reservoir recognition method based on the inelastic gamma information of the drill collar, Geoenergy Science and Engineering, 225, 211684, (2023). doi: 10.1016/j.geoen.2023.211684http://doi.org/10.1016/j.geoen.2023.211684

Q. Liang, F. Zhang, J. Fan, et al., A Novel Gamma-Thermal Neutron Evaluating Gas Saturation Method Using Pulsed Neutron Logging Tool with Dual-CLYC, In SPWLA 63rd Annual Logging Symposium. OnePetro, (Norway, Jun. 2022). doi: 10.30632/SPWLA-2022-0078http://doi.org/10.30632/SPWLA-2022-0078

W. Tang, J. G. Liang, Y. Ge et al., A method for neutron-induced gamma spectra decomposition analysis based on Geant4 simulation, Nucl. Sci. Tech. 33(12), 154, (2022). doi: 10.1007/s41365-022-01144-5http://doi.org/10.1007/s41365-022-01144-5

F. Inanc, Pulsed neutron generator-driven sourceless density measurements-expectations, physics and issues, In SPWLA 55th Annual Logging Symposium, (United Arab Emirates, May. 2014).

Q. Zhang, F. Zhang, C. Yuan et al., A comparative study on the neutron-gamma density and gamma-gamma density logging, J. Petrol. Sci. Eng. 176, 792-799, (2019). doi: 10.1016/j.petrol.2019.02.007http://doi.org/10.1016/j.petrol.2019.02.007

N. Reichel, M. Evans, F. Allioli et al., Neutron-Gamma Density (NGD): Principles, field test results and log quality control of a radioisotope-free bulk density measurement, In SPWLA 53rd Annual Logging Symposium, (Colombia, Jun. 2012).

N. Reichel, M. Evans, F. Allioli et al., Sourceless neutron-gamma density (SNGD): principles, field-test results and log quality control of a radioisotope-free bulk-density measurement. Petrophysics 54(02), 91-103, (2013).

M. Evans, F. Allioli, V. Cretoiu et al., Sourceless Neutron-Gamma Density SNGD: A Radioisotope-Free Bulk Density Measurement: Physics Principles, Environmental Effects, and Applications, In SPE Annual Technical Conference and Exhibition, (Texas, Oct. 2012). doi: 10.2118/159334-MShttp://doi.org/10.2118/159334-MS

Q. Zhang, F. Zhang, J. Liu et al., A method of determining formation density based on fast-neutron gamma coupled field theory. Petrophysics 58, 411-425, (2017).

H. Wang, W. Wu, T. Tang et al., A new method for calculating bulk density in pulsed neutron-gamma density logging. Geophysics 85(6), D219-D232, (2020). doi: 10.1190/geo2018-0821.1http://doi.org/10.1190/geo2018-0821.1

Q. Zhang, R. Deng, S. Zhang, et al., An alternative method for sourceless density measurement with boron sleeve gamma detectors. Appl. Radiat. Isotopes 174, 109785, (2021). doi: 10.1016/j.apradiso.2021.109785http://doi.org/10.1016/j.apradiso.2021.109785

D. Dong, W. Wu, W. Yue et al., Improving the pulsed neutron-gamma density method with machine learning regression algorithms. J. Petroleum Sci. Eng. 218, 110962 (2022). doi: 10.1016/j.petrol.2022.110962http://doi.org/10.1016/j.petrol.2022.110962

Q. Zhang, F. Zhang, C. Yuan et al., Application analysis on the different neutron gamma density (ngd) logging methods. Appl. Radiat. Isotopes. 172, 109672 (2021). doi: 10.1016/j.apradiso.2021.109672http://doi.org/10.1016/j.apradiso.2021.109672

C. Stoller, B. Adolph, M. Berheide et al., Use of LaBr 3 for downhole spectroscopic applications, In 2011 IEEE Nuclear Science Symposium Conference Record (pp. 191-195), IEEE, (2011). doi: 10.1109/NSSMIC.2011.6154477http://doi.org/10.1109/NSSMIC.2011.6154477

C. Yuan, C. Li, C. Zhou et al., Can the Evaluation Accuracy of Elemental Concentration Be Further Enhanced in Geochemical Logging? —A Break Attempt to Obtain Purer Inelastic Gamma Spectrum, In SPWLA 60th Annual Logging Symposium, (Texas, Jun. 2019). doi: 10.30632/T60ALS-2019_DDDDhttp://doi.org/10.30632/T60ALS-2019_DDDD

R. C. Odom, U.S. Patent No. 5,374,823, 20 Dec 1994

G. Schmid, R. Pemper, D. Dolliver et al., A new cased-hole porosity measurement for a four-detector pulsed-neutron logging tool, In SPE Annual Technical Conference and Exhibition, (Alberta, Sep. 2019). doi: 10.2118/195950-MShttp://doi.org/10.2118/195950-MS

F. Li, X. Han, F. Mendez, Sigma measurement and applications with a pulsed-neutron mineralogy instrument, In SPWLA 52nd Annual Logging Symposium, (Colorado, May. 2011).

E. Schulz, M. Speekenbrink, A. Krause, A tutorial on Gaussian process regression: Modelling, exploring, and exploiting functions. Journal of Mathematical Psychology, 85, 1-16, (2018).

浏览量

Downloads

CSCD

文章被引用时，请邮件提醒。

Submit

工具集

关联资源

A method for neutron-induced gamma spectra decomposition analysis based on Geant4 simulation