Process and device for the determination of the characteristics of the geological formations traversed by a borehole
AssigneeInstitut Francais du Petrole
InventorsRegis Pelet, Pierre Morlier, Jean-Paul Sarda, Jean-Francois Bard
Life of this patent
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Abstract
Process for determining characteristics of the geological formations traversed by a borehole, making use of a sonde by means of which the intensity of the .gamma. rays naturally radiated from the formations is measured, both longitudinal and transversal acoustic waves are transmitted to the formations, their travel time and their attenuation between two receivers placed in contact with the formations are measured and by combination of the so-obtained values a resulting value is elaborated which is representative of one characteristic of the surveyed formations.
Claims27
A process for determining the characteristics of the geological formations traversed by a bore hole, making use of a measuring sonde in combination with an automatic system for the treatment of the data delivered by the sonde, comprising the combination of the following steps:
- a. determining the spectrum of the .gamma. rays naturally radiated from the geological formations in the form of a plurality of quantities associated to said radiation, each of which depends on the intensity of this natural radiation, in a given energy range,
- b. alternately transmitting acoustic waves which propagate essentially according to the longitudinal way of propagation and acoustic waves having essentially a transversal way of propagation,
- c. successively determining the travel time of said longitudinal waves and of said transversal waves between two receivers placed in contact with the geological formations, by producing two quantities which are functions of the respective travel times of said longitudinal waves and transversal waves,
- d. successively determining, between said receivers, the attenuation of said longitudinal and of said transversal waves, by producing two quantities representative of said attenuation respectively for the longitudinal waves and for the transversal waves, and
- e. elaborating, on the basis of said quantities, in said automatic system, at least one resulting quantity, representative of a characteristic of said formations, by linearly combining said quantities associated to the .gamma. radiation with said quantities which are functions of the travel time of the longitudinal and transversal waves and with said quantities representative of the attenuations of said acoustic waves.
A process for determining the characteristics of the geological formations traversed by a bore hole, comprising the combination of the following steps:
- a. determining the spectrum of the natural .gamma. rays radiated from the geological formations in the form of a plurality of signals associated to said radiation, each of which depends on the intensity of this natural radiation in a given energy range,
- b. alternately transmitting acoustic waves propagating in the geological formations essentially according to the longitudinal way of propagation and acoustic waves propagating essentially according to the transversal way of propagation,
- c. successively determining the travel time of said longitudinal waves and of said transversal waves between two receivers placed in contact with the geological formation, by producing two signals related to the respective travel times of the longitudinal waves and the transversal waves,
- d. successively determining between said receivers, the attenuation of said longitudinal waves and of said transversal waves, by producing two signals representative of said attenuation respectively for the longitudinal waves and for the transversal waves,
- e. recording said signals, and
- f. elaborating, on the basis of said recorded signals, at least one resulting signal, representative of a characteristic of said formations, by linearly combining said signals associated to the .gamma. radiation with said signals related to the travel time of said longitudinal and transversal waves, and with said signals representative of the attenuation of said acoustic waves.
A device for determining the characteristics of the geological formations traversed by a bore hole, comprising a sonde connected to a surface apparatus through a cable provided with electric conductors, said sonde comprising the combination of:
- a. means for detecting the natural .gamma. radiation transmitted from the formations, said means delivering electric signals representative of the radiation emanating from the geological formations,
- b. means for transmitting acoustic waves, adapted to transmit to the geological formations, acoustic waves having essentially a longitudinal way of propagation,
- c. means for transmitting acoustic waves, adapted to transmit to the geological formations, acoustic waves having essentially a transversal way of propagation,
- d. means for alternately operating said first and second transmitting means,
- e. at least two acoustic wave receivers spaced vertically, adapted to deliver electric signals at the time of reception of said acoustic waves,
- f. means for determining the travel time and the waves attenuation between said receivers of said acoustic waves, said means being connected to said receivers and adapted to deliver a first series of electric signals representative of the travel time and a second series of electric signals representative of the attenuation of said acoustic waves, and
- g. means for transmitting to the surface all these electric signals.
A process for quantitatively determining [the characteristics] at least one of a lithological and petrophysical characteristic of the geological formations traversed by a borehole, utilizing a measuring sonde which delivers signals, and an automatic system for treating the signals delivered by the sonde, said process comprising the steps of:
- a. determining values of coefficients depending on the characteristics of the geological formations and registering the values of the coefficients in the automatic system,
- b. determining the spectrum of the .gamma. rays naturally radiated from the geological formations in the form of a plurality of quantities associated to said radiation, each of which depends on the intensity of this natural radiation in a given predetermined energy range of the spectrum, and
- c. elaborating on the basis of said quantities in said automatic system at least one resulting quantity representative of a characteristic of said formation by linearly combining said quantities as a function of the values of said coefficients.
[23. A device for determining the characteristics of the geological formations traversed by a borehole, comprising a measuring sonde placed in the borehole and delivering electrical signals, a surface apparatus combined with said sonde for the automatic treatment of the signals delivered by the sonde, said surface apparatus comprising means for registering values of coefficients depending on the characteristics of the geological formations a cable having electrical conductors, said sonde comprising:
- a. means for detecting the natural .gamma. radiation emitted by the formations, and for producing electrical signals representative of the .gamma. radiation emitted by the geological formations each of the signals being a function of the intensity of the natural radiation within a given predetermined energy range of the spectrum, and
- b. means for transmitting the electrical signals to the surface
- apparatus.] 24. A device for quantitatively determining [the characteristics] at least one of a lithological and petrophysical characteristic of the geological formations traversed by a borehole, comprising a measuring sonde placed in the borehole and delivering electrical signals, a surface apparatus combined with said sonde for the automatic treatment of the signals delivered by the sonde, values of coefficients depending on the characteristics of the geological formations being registered in the automatic system, a cable having electrical conductors, said sonde comprising:
- a. means for detecting the natural .gamma. radiation emitted by the formations and for producing electrical signals representative of the .gamma. radiation emitted by the geological formations, each of the signals being a function of the intensity of the natural radiation within a given predetermined energy range of the spectrum, and
- b. means for transmitting the electrical signals to the surface apparatus, and
- wherein the surface apparatus comprises means for recording said electrical signals delivered by and transmitted form said sonde, and means for elaborating in real time from said electrical signals at least one resulting signal representative of a characteristic of said formations, said means for elaborating being connected to said recording means and linearly combining said electrical signals associated to the .gamma.
- radiation. 25. A device according to claim 24, wherein said means for elaborating in real time comprises [flat] first memory means to which predetermined coefficients are supplied and are recorded therein in the form of signals, second memory means in which said signals delivered by the sonde are recorded, clock means delivering a clock signal and connected to said first and second memory means, combining means connected to said first and second memory means and responsive to a clock signal for combining the signals from said first and second memory means and providing at least one digital resultant signal which is representative of an information element concerning a characteristic of the geological formations, and third memory means connected to said
- combining means for recording said representative resultant signal. 26. A process for quantitatively determining [the characteristics] at least one of a lithological and petrophysical characteristic of the geological formations traversed by a borehole, using a combination a measuring sonde which delivers signals and an automatic system for treating the signals delivered by the sonde, said process comprising the steps of:
- a. determining values of coefficients depending on the characteristics of the geological formations and registering the values of the coefficients,
- b. determining the spectrum of the natural .gamma. rays radiated from the geological formations in the form of a plurality of signals associated to said radiation, each of which depends on the intensity of this natural radiation in a given predetermined energy range of the spectrum,
- c. recording said signals, and
- d. elaborating on the basis of said signals in said automatic system, at least one resulting signal representative of a characteristic of said formation by linearly combining said signals as a function of the values
- of said coefficients. 27. A process for quantitatively determining [characteristics] at least one of a lithological and petrophysical characteristic of a geological formation traversed by a borehole, utilizing a measuring sonde including means delivering measuring signals, and a data processing system for treating said measuring signals, this process comprising the steps of:
- a. determining from said measuring signals a plurality of quantities associated to the natural .gamma. radiation of the geological formations, each of said quantities depending on the intensity of said natural radiation in a given predetermined energy range of the spectrum,
- b. determining the values of calibration coefficients [depending on at least one characteristic of the geological formation], and
- c. elaborating through said data processing system, on the basis of said measured quantities and of said coefficients, a [plurality of] resulting [quantities] quantity representative of said at least one characteristic of said formation, said resulting [quantities] quantity being derived from said measuring quantities through [a plurality of] at least one linear [relationships] relationship including a plurality of coefficients having said values determined in step (b).
A process according to claim 26 wherein the values of the coefficients determined in step (b) depend on at least one lithology characteristic.
A process for determining the clay content of a geological formation traversed by a borehole, utilizing a measuring sonde including means delivering measuring signals, and a data processing system for treating said measuring signals, this process comprising the steps of:
- (a) determining from said measuring signals a plurality of quantities associated to the natural .gamma. radiation of the geological formations, each of said quantities depending on the intensity of said natural radiation in a given predetermined energy range of the spectrum,
- (b) determining the values of calibration coefficients, and
- (c) elaborating through said data processing system, on the basis of said measured quantities and of said coefficients, resulting quantity representative of the clay content of said formation, said resulting quantity being derived from said measured quantities through a linear relationship including a plurality of coefficients having said values determined in step (b).
Dependencies are inferred from the claim text.