Abstract
NMR logging, as one of the primary methods for calculating bound water saturation of reservoir, can be used to directly characterize properties of reservoir fluid and distinguish the volume of clay bound water and capillary bound water, respectively. And then, the bound water saturation can be obtained based on the total volume of bound water including clay bound water and capillary bound water. Both the T2 cut-off value and spectral irreducible water saturation can explain and ascertain the bound water saturation. Since the T2 cut-off value may have distinct variations in different layers and different blocks, the T2 cut-off value would cause obvious errors if it is not determined properly. In the original spectral coefficient model, all spectral coefficients depend on the data from rock core analysis without considering the occurrence mechanism of the bound water. Thus, this model would create many errors in the evaluation of the bound water saturation. In this paper, we proposed an improved spectral coefficient model instead of the original model in order to determine the bound water saturation. All the spectra coefficients in the new model are modified according to the laboratory core data to cut down the fitting error. We also verified the applicability of the improved model by the actual core data. By eliminating the influence of the bound water effectively, our new model showed potential to improve the accuracy of the estimated bound water saturation from NMR logging remarkably, which is regarded as a good reference to explain the bound water saturation for complicated reservoirs.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- A:
-
The coefficient matrix of echo inversion
- \(A_{1} ,A_{2} , \ldots ,A_{n}\) :
-
The T2 inversion spectral amplitude
- \(\mathrm{a},\mathrm{b}\) :
-
The fitting parameters
- \(M\) :
-
The number of echoes
- \(\mathrm{N}\) :
-
The number of table data points
- \({Q}_{ax}\) :
-
The fitting variance
- \(r\) :
-
The square root of the percent variability of the dependent variable
- \({S}_{wi}({T}_{2i})\) :
-
The spectral coefficient of different sizes by equation.
- \({S}_{win}\) :
-
The modified spectral coefficient
- T 2ct :
-
The cut-off value (ms)
- \({S}_{wi-core}\) :
-
The bound water saturation by centrifuge NMR data
- \({S}_{wi-lab-ctf},\) :
-
The bound water saturation by T2cut-off model
- \({S}_{wi-lab-sbvi}\) :
-
The bound water saturation by spectral coefficient model
- \({S}_{wi-ctf-new}\) :
-
The bound water saturation by new SVD algorithm combined with T2 cut-off model
- \({S}_{wi-sbvi-new}\) :
-
The bound water saturation by new SVD algorithm combined with spectral coefficient model
- \({S}_{wi-x}\) :
-
The bound water saturation from the different models and inversion algorithm
- \({t}_{j}\) :
-
The sampling time of J time (ms)
- \({T}_{2}\) :
-
The inversion point given by laboratory data (ms)
- \({T}_{2gm}\) :
-
The geometric mean of T2(ms)
- \(T_{21} ,T_{22} , \ldots ,T_{2n}\) :
-
The distribution value of T2 inversion
- \({X}_{o}\) :
-
The initial solution of inversion echo
- \(Y\) :
-
The measured echo data
- \({\uplambda }_{1}\) :
-
The damping factor
References
AnandHirasaki VGJ (2007) Diffusional coupling between micro and macro porosity for NMR relaxation in sandstones and grain stones. Petr phys. 48(4):289–307
BrownsteinTarr KRCE (1979) Importance of classical diffusion in NMR studies of water in biological cells. Phys rev A 19(6):2446–2453
Carneiro G, Souza A, Boyd A, et al (2014)Evaluating pore space connectivity by NMR diffusive coupling. SPWLA55th Annual Logging Symposium, Abu Dhabi, United Arab Emirates.
ChengLuoDu ZGSCZW (2014) The method to calculate tight sandstone reservoir permeability using pore throat characteristic parameters. Well Logging Technol 38(2):185–189
ChiHeidari LZ (2015) diffusional coupling between micro fractures and pore structure and its impact on NMR measurements in multiple-porosity systems. Geophys 80(1):D31–D42
CohenMendelson MHKS (1982) Nuclear magnetic relaxation and the internal geometry of sedimentary rocks. J ApplPhys 53(2):1127–1135
FleurySoualem MJ (2009) Quantitative analysis of diffusional pore coupling from T2-store-T2 NMR experiments. J Colloid Interface Sci 336(1):250–259
HeMaoXiao YDZQLZ (2005) A new method to obtain capillary pressure curve using NMR T 2 distribution. J JilingUniv Earth Sci Ed 35(2):185–189
Kenyon WE, Day PI, Straley C (1988)A three-part study of NMR longitudinal relaxation properties of water-saturated sandstones.SPE Fomation Evaluation on Society of Petroleum Engineers.622–636.
LuoChengLin SCZGWC (2015) Research on saturation model of rock-electric parameters for reservoirs with complicated pore structures. Well Logging Technol 39(1):43–47
MccallJohnsonGuyer KRDLRA (1993) Magnetization evolution in connected pore systems. Phys Rev b: Condens Matter 48(48):6007–6013
Straley C, Morriss CE, Kenyon WE (1991) NMR in partially saturated rocks: laboratory insights on free fluid index and comparison with borehole logs.SPWLA 32nd Annual Logging Symposium, Las Vegas, USA
TangEhlig-EconomidesFanCaiMao JCBBW (2019a) A microseismic-based fracture properties characterization and visualization model for the selection of infill wells in shale reservoirs. J Natural Gas SciEng 67:147–159
TangWuZengHuangHuGuoZuo JKBHXXL (2018) Investigate effects of weak bedding interfaces on fracture geometry in unconventional reservoirs. J Petrol SciEng 165:992–1009
Tang J, Wu K, Zuo L, Xiao L, Sun S, Ehlig-Economides C (2019a). Investigation of rupture and slip mechanisms of hydraulic fracture in multiple-layered formations. SPE Journal.Preprint.SPE-197054-PA.
Trevizan W, Coutinho B, Netto P (2015).Magnetic resonance (NMR) approach for permeability estimation in carbonate rocks. OTC Brasil on Offshore Technology Conference: 27–29
TrevizanNettoCoutinho WPB (2014) Method for predicting permeability of complex carbonate reservoirs using NMR logging measurements. Petrophys 55(3):240–252
Xiao L, Shi H (1998) Low field NMR core analysis and its applications in log analysis. Well Logging Technol 22(1):42–49
XiaoLiuMao LXPZQ (2009) A computationmethod for reservoir permeability by combining NMR log and capillary pressure data. Acta Pet Sin 30(1):100–103
XiaoMaoJin LZQY (2012) Calculation of irreducible water saturation (Swirr) from NMR logs in tight gas sands. ApplMagnReson 42(1):113–125
Yue W, Guo T, Zhao K (2002) An approach to calculate bound water saturation and average pore radius with NMR logs and petrophysical experiments. Well Logging Technol
ZielinksiSongRyuSen LJY-QSPN (2002) Characterization of coupled pore systems from the diffusion eigen spectrum. J ChemPhys 117(11):5361–5365
ZhangMaoJin CZQY (2010) Experimental studies of NMR logging irreducible water saturation. Nuclear Electron Detect Technol 30(4):514–518
Zhao H, Ning Z, Zhao T, et al (2015) Applicability comparison of nuclear magnetic resonance and mercury injection capillary pressure in characterization pore structure of tight oil reservoirs.SPE Asia Pacific Unconventional Resources Conference and Exhibition. 2711–2713
Acknowledgements
This work is supported by the National 863 Program (2006AA06Z214), Natural Science Foundation of China (41476027), National Major Project of Technology and Science (2011ZX05007-006) and CNPC Research Project (2011B-4000). All the research funding supports are greatly appreciated.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
Authors declare that the research was conducted without any commercial or financial relationships that could be a potential conflict of interest.
Additional information
Edited by Dr. Liang Xiao (ASSOCIATE EDITOR).
Rights and permissions
About this article
Cite this article
Zhao, W., Hu, F., Tang, J. et al. An approach to calculate bound water saturation by NMR logging spectral coefficient method. Acta Geophys. 70, 525–535 (2022). https://doi.org/10.1007/s11600-021-00635-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11600-021-00635-0