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Yizhong Jiang - One of the best experts on this subject based on the ideXlab platform.

  • A time‐domain induced‐polarization method for estimating permeability in a Shaly Sand reservoir
    Geophysical Prospecting, 2006
    Co-Authors: Maosong Tong, Weinan Wang, Yizhong Jiang
    Abstract:

    It is known that the time-domain induced-polarization decay curve for a Shaly Sand reservoir depends on the pore structure of the reservoir, and this curve can be used to estimate permeability, which is a determining factor in making production decisions in the petroleum industry. Compared with NMR logging tools, induced polarization has several advantages, such as a deep depth of investigation and a high signal-to-noise ratio. The purpose of this paper is to establish an appropriate model using induced polarization to estimate the permeability. The curve can be modelled as a weighted superposition of exponential relaxations. The plot of weight versus the relaxation time constant is defined as the relaxation time spectrum. Induced-polarization decay-curve measurements were performed on 123 samples from the Daqing oilfield using a four-electrode technique. A singular-value decomposition method was used to transform the induced-polarization decay data into a spectrum. Different models to estimate the permeability were discussed. The results of the research indicate that the induced-polarization measurements greatly improve the statistical significance of permeability correlations. Compared with the traditional forms, AΦ C and AF C , the forms, AT B Φ C and AT B F C , have lower error factors, where T, Φ and F are the geometric mean time constant of the induced-polarization relaxation time spectrum, the porosity and the resistivity formation factor, respectively, and A, B and C are constants. The mean time constant is the decisive parameter in the permeability estimation and it is not completely independent of the resistivity formation factor. The additional use of the porosity and the resistivity formation factor leads to an appreciable improvement. It is concluded that this new model will make it possible to estimate the permeability of a Shaly Sand reservoir downhole.

  • a time domain induced polarization method for estimating permeability in a Shaly Sand reservoir
    Geophysical Prospecting, 2006
    Co-Authors: Maosong Tong, Weinan Wang, Yizhong Jiang
    Abstract:

    It is known that the time-domain induced-polarization decay curve for a Shaly Sand reservoir depends on the pore structure of the reservoir, and this curve can be used to estimate permeability, which is a determining factor in making production decisions in the petroleum industry. Compared with NMR logging tools, induced polarization has several advantages, such as a deep depth of investigation and a high signal-to-noise ratio. The purpose of this paper is to establish an appropriate model using induced polarization to estimate the permeability. The curve can be modelled as a weighted superposition of exponential relaxations. The plot of weight versus the relaxation time constant is defined as the relaxation time spectrum. Induced-polarization decay-curve measurements were performed on 123 samples from the Daqing oilfield using a four-electrode technique. A singular-value decomposition method was used to transform the induced-polarization decay data into a spectrum. Different models to estimate the permeability were discussed. The results of the research indicate that the induced-polarization measurements greatly improve the statistical significance of permeability correlations. Compared with the traditional forms, AΦ C and AF C , the forms, AT B Φ C and AT B F C , have lower error factors, where T, Φ and F are the geometric mean time constant of the induced-polarization relaxation time spectrum, the porosity and the resistivity formation factor, respectively, and A, B and C are constants. The mean time constant is the decisive parameter in the permeability estimation and it is not completely independent of the resistivity formation factor. The additional use of the porosity and the resistivity formation factor leads to an appreciable improvement. It is concluded that this new model will make it possible to estimate the permeability of a Shaly Sand reservoir downhole.

Maosong Tong - One of the best experts on this subject based on the ideXlab platform.

  • Permeability estimating from complex resistivity measurement of Shaly Sand reservoir
    Geophysical Journal International, 2008
    Co-Authors: Maosong Tong, Honggen Tao
    Abstract:

    SUMMARY Permeability is a key parameter associated with the subsurface production and injection. This paper introduces a new method which uses the complex resistivity of rock to estimate permeability in petroleum reservoirs. Complex resistivity measurements were carried out on 53 Shaly Sand samples from Daqing Oil Filed with a wide variation in permeability and porosity in the frequency range from 100 Hz to 20 MHz using a four-electrode technique. This paper investigates the relationship between the complex resistivity measurements and the permeabilities of the samples. The imaginary part of the complex impedance shows a power-law relation to the frequency ranges from 100 Hz to 1.5 kHz. The results show that permeability can be estimated well with expressions of the form of A·φB·βC, where β is the slope of the bilogarthmic plot of the imaginary part versus frequency, φ is the porosity, A, B and C are constants. The salinity of NaCl has little influence of the slope in the range of 1–10 g l−1. The isovalue maps of the error factor δ, which show substantial regions of near-minimum values of δ, are used to analyse the behaviour of δ with the change of the exponents B and C. The permeability estimation is more sensitive to the changes of the slopes than the porosity. The slope and the porosity are not completely independent. The slope is the decisive parameter for the estimation of the permeability. The additional use of the porosity improves the formula fit to the data significantly.

  • A time‐domain induced‐polarization method for estimating permeability in a Shaly Sand reservoir
    Geophysical Prospecting, 2006
    Co-Authors: Maosong Tong, Weinan Wang, Yizhong Jiang
    Abstract:

    It is known that the time-domain induced-polarization decay curve for a Shaly Sand reservoir depends on the pore structure of the reservoir, and this curve can be used to estimate permeability, which is a determining factor in making production decisions in the petroleum industry. Compared with NMR logging tools, induced polarization has several advantages, such as a deep depth of investigation and a high signal-to-noise ratio. The purpose of this paper is to establish an appropriate model using induced polarization to estimate the permeability. The curve can be modelled as a weighted superposition of exponential relaxations. The plot of weight versus the relaxation time constant is defined as the relaxation time spectrum. Induced-polarization decay-curve measurements were performed on 123 samples from the Daqing oilfield using a four-electrode technique. A singular-value decomposition method was used to transform the induced-polarization decay data into a spectrum. Different models to estimate the permeability were discussed. The results of the research indicate that the induced-polarization measurements greatly improve the statistical significance of permeability correlations. Compared with the traditional forms, AΦ C and AF C , the forms, AT B Φ C and AT B F C , have lower error factors, where T, Φ and F are the geometric mean time constant of the induced-polarization relaxation time spectrum, the porosity and the resistivity formation factor, respectively, and A, B and C are constants. The mean time constant is the decisive parameter in the permeability estimation and it is not completely independent of the resistivity formation factor. The additional use of the porosity and the resistivity formation factor leads to an appreciable improvement. It is concluded that this new model will make it possible to estimate the permeability of a Shaly Sand reservoir downhole.

  • a time domain induced polarization method for estimating permeability in a Shaly Sand reservoir
    Geophysical Prospecting, 2006
    Co-Authors: Maosong Tong, Weinan Wang, Yizhong Jiang
    Abstract:

    It is known that the time-domain induced-polarization decay curve for a Shaly Sand reservoir depends on the pore structure of the reservoir, and this curve can be used to estimate permeability, which is a determining factor in making production decisions in the petroleum industry. Compared with NMR logging tools, induced polarization has several advantages, such as a deep depth of investigation and a high signal-to-noise ratio. The purpose of this paper is to establish an appropriate model using induced polarization to estimate the permeability. The curve can be modelled as a weighted superposition of exponential relaxations. The plot of weight versus the relaxation time constant is defined as the relaxation time spectrum. Induced-polarization decay-curve measurements were performed on 123 samples from the Daqing oilfield using a four-electrode technique. A singular-value decomposition method was used to transform the induced-polarization decay data into a spectrum. Different models to estimate the permeability were discussed. The results of the research indicate that the induced-polarization measurements greatly improve the statistical significance of permeability correlations. Compared with the traditional forms, AΦ C and AF C , the forms, AT B Φ C and AT B F C , have lower error factors, where T, Φ and F are the geometric mean time constant of the induced-polarization relaxation time spectrum, the porosity and the resistivity formation factor, respectively, and A, B and C are constants. The mean time constant is the decisive parameter in the permeability estimation and it is not completely independent of the resistivity formation factor. The additional use of the porosity and the resistivity formation factor leads to an appreciable improvement. It is concluded that this new model will make it possible to estimate the permeability of a Shaly Sand reservoir downhole.

Sri Niwas - One of the best experts on this subject based on the ideXlab platform.

  • Nonlinear electrical conductivity response of Shaly-Sand reservoir
    Current Science, 2007
    Co-Authors: Sri Niwas, Pravin K. Gupta, O. A. L. De Lima
    Abstract:

    A brief review of electrical conductivity modelling of the porous medium is presented here to establish that, merely for the sake of applicability, the sound physico-mathematical model of Maxwell has been replaced by Archie's empirical one. The extension of clean Sand models to Shaly-Sand models is discussed emphasizing the inadequacy of the former to represent true physical situations. Since the experimental data show nonlinear dependence of rock conductivity on pore fluid conductivity, three nonlinear model equations of Glover, Mixing and Bussian are studied for a wide range of parameters and the results are analysed in the light of physical expectations. It is concluded that only the Bussian model is able to simulate the behaviour of effective conductivity of saturated Shaly-Sand reservoir over the complete range of water and matrix conductivity and porosity values.

  • Estimation of permeability of Shaly Sand from induced polarization relaxation time spectra
    2007
    Co-Authors: Vikas Saluja, Sri Niwas
    Abstract:

    The Singular Value Decomposition (SVD) method is used to invert induced polarization (IP) decay curve for the IP relaxation time spectrum. A nonnegative restriction is added during inversion for meaningful solution of the amplitude of the relaxation spectrum. The analysis of the experiment design, by comparing results in different range, shows that the appropriate number of relaxation arrangement points in data inversion lies with 32 to 64. The attenuation of noise in this range is better and resolution is good. IP relaxation spectrum indicates the pore size distribution that in turn indicates the permeability of Shaly Sand reservoir. Combining the average relaxation time (geometric average time) with the porosity can improve the accuracy of estimation of the permeability in comparison to that obtained using total porosity from core measurements.

  • Combined Straightforward Inversion Of Resistivity And Induced Polarization Sounding Data
    20th EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems, 2007
    Co-Authors: Sri Niwas, Pravin K. Gupta
    Abstract:

    Straightforward Inversion Scheme (SIS) developed by the authors for 1D interpretation of resistivity sounding data is used in a combined fashion for interpreting the Schlumberger configuration time-domain induced polarization (IP) sounding data. For this purpose a formulation based on dynamic dipole theory is presented. The test examples presented validate the use of SIS. The proposed scheme would complement the resistivity interpretation with special reference to Shaly Sand formations.

Tong Mao-song - One of the best experts on this subject based on the ideXlab platform.

  • An Induced Polarization Method for Estimating Permeability of Shaly Sand Reservoir
    Well Logging Technology, 2008
    Co-Authors: Tong Mao-song
    Abstract:

    Time-domain Induced Polarization(IP) decay curve depends on pore structure of Shaly Sand reservoir and it can be used to estimate the permeability which is a determining factor for making production decision in petroleum industry.The purpose of this paper is to establish an appreciate model to estimate the permeability.IP decay curve measurements have been performed on 123 samples from Daqing oilfield using four-electrode technique.A singular value decomposition method was used to transform the IP decay data into the spectrum.Different models were established to estimate the permeability.The results of the research indicate that the IP measurements greatly improve statistical significance of permeability correlations.Compared to the traditional method using porosity only or formation factor only,the constructed models which contain the IP relaxation time spectra have lower error factor.It is concluded that the models using the geometric mean time constant of the IP relaxation time spectrum combining with the porosity or the resistivity formation factor will be better to estimate the permeability of the Shaly Sand reservoir in the downhole.

  • MULTI-EXPONENTIAL INVERSION OF INDUCED POLARIZATION DECAY CURVE OF Shaly Sand
    Computing Techniques for Geophysical and Geochemical Exploration, 2006
    Co-Authors: Tong Mao-song
    Abstract:

    The induced polarization(IP) decay curve contains more information than the polarizability.It relates to the pore structure,permeability,formation water resistivity and shality.The decay curve can be inversed to form the relaxation spectrum.The normalized IP decay signal is a superposition of IP signal from individual pore and can be inversed to a relaxation time spectrum.The spectrum is very useful to characterize the reservoirs.The normal non-negative least-square method is unable to obtain the reasonable results.In this paper a damp least-squares inversion method combined with the singular value decomposition method is used to inverse the induced polarization relaxation spectra of the Shaly Sands.The resulted spectra are continuous.The appropriate number of relaxation arrangement points in relaxation data inversion ranges from 32 to 64.The algorithm and the software are suitable for the multi-exponential inversion of core samples.

Pravin K. Gupta - One of the best experts on this subject based on the ideXlab platform.

  • A genetic algorithm approach to evaluate models for electrical conductivity response of Shaly Sand reservoir, based on volumetric approach.
    SEG Technical Program Expanded Abstracts 2013, 2013
    Co-Authors: Alok R. Gupta, Pravin K. Gupta, V. N. Singh
    Abstract:

    This paper focuses on evaluation of three models; 1) Bussian (1983), 2) Mixture (Korvin, 1982; Technov, 1998) and 3) Glover et al. (2000) for electrical conductivity response of Shaly Sand reservoir based on volumetric approach and looking for some scheme to solve corresponding equations better than the used schemes so far in literature. As all the models result in non-linear equations, so, there was a need of non-linear scheme to solve these equations. Genetic algorithm (GA), implementing the concept of stretching (Stoffa and Sen, 1991) has been applied to solve non-linear equations and to interpret experimental data of the sample C-26 from Waxman and Smits (1968) paper. The same job has been done by Lima et al. (1995), using the grid search method by minimizing the chi-square error (Bevington, 1969) with a relative RMS error 10.11% for Bussian model and 14.03% for Mixture model. A great improvement is obtained using GA with a relative RMS error 2.47% for Bussian model and 3.92% for mixture model. For Glover‟s model which was not evaluated by Lima et al., it was difficult to obtain a relative RMS error less than 13% using GA. Lima et al. (2005) have pointed out that Bussian model shows anomalous behaviour in low salinity range, so, a modified Bussian equation is proposed for low salinity range which is tested for two cases; 1) matrix conductivity ~ fluid conductivity, leads to bulk conductivity ~ fluid conductivity ~ matrix conductivity irrespective of values of other parameters because the system turns to a single phase system and 2) For very small value of porosity, bulk density tends to matrix conductivity for low salinity range.

  • Nonlinear electrical conductivity response of Shaly-Sand reservoir
    Current Science, 2007
    Co-Authors: Sri Niwas, Pravin K. Gupta, O. A. L. De Lima
    Abstract:

    A brief review of electrical conductivity modelling of the porous medium is presented here to establish that, merely for the sake of applicability, the sound physico-mathematical model of Maxwell has been replaced by Archie's empirical one. The extension of clean Sand models to Shaly-Sand models is discussed emphasizing the inadequacy of the former to represent true physical situations. Since the experimental data show nonlinear dependence of rock conductivity on pore fluid conductivity, three nonlinear model equations of Glover, Mixing and Bussian are studied for a wide range of parameters and the results are analysed in the light of physical expectations. It is concluded that only the Bussian model is able to simulate the behaviour of effective conductivity of saturated Shaly-Sand reservoir over the complete range of water and matrix conductivity and porosity values.

  • Combined Straightforward Inversion Of Resistivity And Induced Polarization Sounding Data
    20th EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems, 2007
    Co-Authors: Sri Niwas, Pravin K. Gupta
    Abstract:

    Straightforward Inversion Scheme (SIS) developed by the authors for 1D interpretation of resistivity sounding data is used in a combined fashion for interpreting the Schlumberger configuration time-domain induced polarization (IP) sounding data. For this purpose a formulation based on dynamic dipole theory is presented. The test examples presented validate the use of SIS. The proposed scheme would complement the resistivity interpretation with special reference to Shaly Sand formations.