Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Earth science
Reexamination Certificate
1999-03-01
2001-09-11
Williams, Hezron (Department: 2862)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Earth science
C367S057000, C367S039000, C181S102000, C181S112000
Reexamination Certificate
active
06289284
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of imaging the permeability and fluid content structure within geological sediments, more particularly to the use of cross-well tomography to image geological structures, and more particularly to the use of cross-well tomography to image the porosity and shear strength in geological structures.
BACKGROUND OF THE INVENTION
Imaging the permeability structure within sediments has been a challenge to exploration geophysicists for many years. The results so far have been very limited.
In practice, perhaps the most reliable conventional method of measuring permeability within sedimental earth is through the use of a pumping test. This method requires at least two wells to pump water continuously out of one well at a constant rate and to observe the amount of change in the resulting water level of the other well. These two wells must also penetrate down to the layer of interest, and the well section above the layer of interest must be cased to isolate the layer. In such conventional systems, the two wells have to be separated by a horizontal distance of at least 500 ft.
However, this method has the significant disadvantage that it is very expensive and time-consuming, and only produces the measurement of an average permeability of the layer between the wells. This method also does not provide any information concerning the spatial distribution of permeability, known as the permeability image of the layer.
Cross-well seismic tomography has been widely used to image geological structures within the earth. Usually, the seismic velocity and attenuation information are inverted from measured arrival times and amplitudes of the seismic pulses received in a well, which pulses were originated from another well, the wells being separated at a certain horizontal distance. Two systems of conducting cross-well tomography are disclosed in U.S. Pat. Nos. 5,142,500 and 5,406,530, the contents of which are hereby incorporated by reference herein.
U.S. Pat. No. 5,142,500 discloses a method of measuring the permeability, porosity and shear strength of a geological structure. This patent also discloses how the average permeability of beach sand between a source and a receiver can be measured acoustically by measuring the sound velocity and attenuation at multiple frequencies and comparing the data to the theoretical values of velocity and attenuation at the same frequencies, as calculated using the Biot theory, which is discussed in detail in Biot, M.A., “The theory of propagation of elastic waves in a fluid-saturated porous solid, II high frequency range,” J. Acoust. Soc. Am., Vol. 28, 179-191, 1956, the contents of which are incorporated by reference herein.
U.S. Pat. No. 5,406,530 discloses a non-destructive system of measuring the range, the accuracy, and the frequency resolution of acoustic cross-well tomography. It dramatically improves the measurement of these characteristics through the use of a pseudo-random binary sequence (“PRBS”) method. The invention of PRBS analysis has enabled users of the system to obtain accurate and long distance images of sound velocity and attenuation within sediments.
However, while the PRBS method disclosed in U.S. Pat. No. 5,406,530 provides significant advantages in the accuracy of long distance imaging of sound velocity, it produces only the average permeability between a source and receiver by repeating acoustic transmission at multiple PRBS frequencies. No spatial distribution or imaging of the permeability structure within the sediments was obtained from that invention, and sound velocity and attenuation still had to be measured at multiple frequencies.
The methods disclosed in the aforementioned patents provide significant advantages over the more conventional methods, such as pumping tests, which are very expensive and time-consuming, and only measure an average permeability of the layer between the wells. Great advantage would be achieved in the use of a cross-well tomography system which needs to use only a single PRBS signal to create a spatial distribution measurement of permeability throughout a geological structure.
OBJECTS OF THE INVENTION
Accordingly, it is an object of the present invention to provide a highly accurate non-destructive method of measuring physical characteristics of sediments and, particularly to obtain accurate cross-sectional spatial distributions of porosity and permeability values and variations, and to obtain accurate and clear measurement even when the method is practiced in a noisy environment.
It is another object of the invention to practice the method at great distances between cross wells, such as a mile or more.
It is still another object of the invention to provide such a novel and highly accurate non-destructive method of measurement at high frequencies not heretofore possible.
Further, is an object of the invention to obtain accurate evaluations of porosity and permeability through the use of limited acoustic frequencies.
Other important objects and advantages of the present invention will be apparent to those of skill in the art based upon the following disclosure, drawings, and claims.
REFERENCES:
patent: 5142500 (1992-08-01), Yamamoto et al.
patent: 5406530 (1995-04-01), Yamamoto
patent: 6061300 (2000-05-01), Yamamoto
Anselmetti, F.S., Salis, G.A. von, Cunningham, K.J., and Eberli, G.P., “Acoustic properties of Neogene carbonate Neogene Carbonates and Siliciclastics from the subsurface of the Florida Keys: implications for seismic reflectivity,” Marine Geology, vol. 144, (1997), pp. 9-31.
Biot, M.A., “Theory of Propagation of Elastic Waves in a Fluid-Saturated Porous Solid. I. Low-Frequency Range,”J. Acoust. Soc. Am.,vol. 28, No. 2, Mar. 1956, pp. 168-178.
Biot, M.A., “Theory of Propagation of Elastic Waves in a Fluid-Saturated Porous Solid. II. Higher-Frequency Range,”J. Acoust. Soc. Am.,vol 28, No. 2, Mar. 1956, pp. 179-191.
Bregman, N.D., Bailey, R.C., and Chapman, C.H., “Crosshole seismic tomography,”Geophysics, vol. 54, No. 2, (Feb. 1989), pp. 200-127, 11 Figs.
Bregman, N.D., Chapman, C.H., and Bailey, R.C., “Travel Time and Amplitude Analysis in Seismic Tomography,”J. Geoph. Res.,vol.4, No. B6, Jun. 10, 1989, pp. 7577-7587.
Dvorkin, J., and Nur, A., “Dynamic porelasticity: A unified model with the squirt and the Biot mechanism,”Geophysics,vol. 58, No. 4, (Apr. 1993), pp. 524-532, 6 Figs.
Jones, Terry D., “Pore fluids and frequency-dependent wave propagation in rocks,” Geophysics, vol. 51, No. 10 (Oct. 1986) pp.1939-1953, 18 Figs., 2 Tables.
Yamamoto, T., “Acoustic Imaging of Permeability of Limestone Formations by Crosswell Tomography,” Geo-Acoustics Laboratory, RSMAS, University of Miami, Miami, Florida, 33149, USA, pp. 2 and 3 of 19.
Yamamoto, T., “Acoustic propagation in the ocean with a poro-elastic bottom,”J. Acoust. Soc. Am.,73(5), May 1983, pp. 1587-1596.
Yamamoto, T., “Acoustic scattering in the ocean from velocity and density fluctuations in the sediments, ”Geo-Acoustics Laboratory, RSMAS, University of Miami, Miami, Florida, 33149, USA, Abstract, pp. 1-32, 1 Table, 12 Figs.
Yamamoto, T., “Imaging the permeability-porosity structure within the near-surface sediments of Tokyo by acoustic crosswell tomography,” Geo-Acoustics Laboratory, RSMAS, University of Miami, Miami, Florida, 33149, USA, pp. 1-5.
Yamamoto, T., “A Poro-Elastic Model of Extreamly Permeable Limestone for Permeability Imagining,” Geo-Acoustics Laboratory, Applied Marine Physics Division, RSMAS, University of Miami, Miami, Florida, 33149, USA, pp. 1-18, 3 Tables, 6 Figs.
Yamamoto, T., Nye, T., and Kuru, M., “Imaging the permeability structure of a limestone aquifer by crosswell acoustic tomography,”Geophysics,vol. 60, No. 6 (Nov.-Dec. 1995), pp. 1634-1645, 12 Figs., 1 Table.
Yamamoto, T., Nye, T., and Kuru, M., “Porosity, Permeability, Shear Strength: Cross-Well Tomography Below an Iron Foundry,” Geo-Acoustics Laboratory, Applied Marine Physics Division, RSMAS, University of Miami, Florida, 33149, USA, pp. 1-31, 8 Figs.
Yamamoto, T., and Sakakibara, J., “Crosswell tomo
Jolly Anthony
Schnader Harrison Segal & Lewis LLP
Williams Hezron
Yamamoto Engineering Corporation
LandOfFree
Method of imaging the permeability and fluid content... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of imaging the permeability and fluid content..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of imaging the permeability and fluid content... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2498824