CN105370274B - Down-hole formation porosity determines method - Google Patents
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Abstract
A kind of down-hole formation porosity of present invention offer determines method, accumulates content according to stratum minerals, determines the rock matrix compressional slowness of underground set depth；According to array sonic log data, the stratum compressional slowness and formation shear slowness of the underground set depth are extracted；Finally according to the rock matrix compressional slowness, stratum compressional slowness and formation shear slowness of the underground set depth, the formation porosity of the underground set depth is determined.Method is determined using down-hole formation porosity provided in an embodiment of the present invention, the porosity value on stratum is determined using stratum compressional slowness and formation shear slowness simultaneously, the porosity of down-hole formation can be accurately obtained, without being corrected to obtained formation pore angle value, the utilization rate for improving Array Sonic Logging Waveformss improves the accuracy of formation pore angle value.
Description
Technical Field
The invention relates to the technical field of petroleum and natural gas exploration, in particular to a method for determining the porosity of an underground stratum.
Background
The porosity is the ratio of the volume of the stratum void to the total volume of the rock, is an important parameter for describing the physical properties of the stratum, and the accurate acquisition of the porosity of the stratum is a basic task for underground mineral exploration. The porosity of the underground stratum can be detected by utilizing the technologies of earthquake and well logging. Logging techniques mainly utilize various instruments to detect physical signals in a drilled well, and then detect subsurface geology and borehole engineering conditions.
In the prior art, a commonly used method for determining porosity is: an empirical formula is established by utilizing indoor core longitudinal wave velocity-porosity and density-porosity experiments, then underground sound wave velocity, density and other physical signals are measured on site through a logging instrument, the measurement result is substituted into the empirical formula for calculation, and the underground porosity is determined.
However, with the porosity determination method in the prior art, lithology correction, compaction correction and the like need to be performed on the calculated porosity value, and since the correction amount changes with changes in formation conditions, the difficulty of field application is increased.
Disclosure of Invention
The embodiment of the invention provides a method for determining the porosity of an underground stratum, which is used for solving the problem that the porosity determination method in the prior art needs lithology correction and compaction correction on a calculated porosity numerical value, so that the difficulty of field application is increased.
The method for determining the porosity of the underground stratum provided by the embodiment of the invention comprises the following steps:
determining the longitudinal wave slowness of a rock skeleton at a set depth underground according to the volume content of the formation minerals;
extracting the formation longitudinal wave slowness and the formation transverse wave slowness of the underground set depth according to the array acoustic logging data;
and determining the formation porosity of the underground set depth according to the rock skeleton longitudinal wave slowness, the formation longitudinal wave slowness and the formation transverse wave slowness of the underground set depth.
In another embodiment, the determining the formation porosity at the set depth downhole according to the rock skeleton compressional slowness, the formation compressional slowness and the formation shear slowness at the set depth downhole comprises:
according to
Determining the formation porosity at the set depth downhole;
wherein,denotes porosity, SmaRepresenting the longitudinal wave slowness, S, of the rock skeletonsIs the formation shear wave slowness, SpRepresenting the formation compressional slowness.
In another embodiment, before determining the longitudinal wave slowness of the rock skeleton at the set depth downhole according to the volume content of the formation minerals, the method further comprises the following steps:
detecting the element abundance of the stratum elements at the set depth under the well;
and determining the volume content of the formation minerals corresponding to the formation elements according to the element abundance of the formation elements.
In another embodiment, the determining the volume content of the formation minerals corresponding to the formation elements according to the element abundances of the formation elements comprises:
according to
[M]＝[C]-1[E]
Determining the volume content of the formation minerals corresponding to the elements;
wherein [ M ] is a column matrix of the volume content of the formation minerals; [E] a column matrix that is an elemental abundance of the formation element; [C] the coefficient matrix is obtained by performing polynomial regression on the contribution of the known abundance of the formation elements to the volume content of the corresponding formation minerals.
In another embodiment, the determining the rock skeleton compressional slowness of the downhole set depth according to the formation mineral volume content comprises:
according to
Wherein v isiRepresenting the volume content of the ith mineral in the formation,is the compressional slowness of the ith mineral in the formation.
In another embodiment, the extracting the formation compressional slowness and the formation shear slowness at the set depth downhole according to the array acoustic logging data comprises:
according to
Calculating correlation coefficients of waveform signals received by a plurality of receivers and transmitted by the same transmission source at time t; the emission source and the plurality of receivers are arranged in a straight line, and the distance between every two adjacent receivers is equal; wherein R represents the correlation coefficient, TWIndicating a set time window length; s represents the slowness; τ is the time at which the time window is windowed on a waveform received by a first receiver, the first receiver being adjacent to the transmission source; f. ofmRepresenting a full-wave waveform signal received by an m-th receiver, t representing the time of any point on the full-wave waveform signal, and Δ z representing the distance between every two adjacent receivers;
determining slowness corresponding to the maximum value of the correlation coefficient obtained in the range of the longitudinal wave waveform of the full-wave waveform signal as the longitudinal wave slowness of the stratum;
and determining the slowness corresponding to the maximum value of the correlation coefficient obtained in the range of the shear wave waveform of the full-wave waveform signal as the shear wave slowness of the stratum.
In another embodiment, the set time window length TWThree wave periods of the longitudinal wave waveform; or, the set time window length TWThree wave periods of the shear wave waveform.
In another embodiment of the present invention, the substrate,
in the process of determining that the slowness corresponding to the maximum value of the correlation coefficient obtained in the range of the longitudinal wave waveform of the full-wave waveform signal is the longitudinal wave slowness of the stratum, the search range of the longitudinal wave slowness is 40-140 microseconds/foot; or,
and in the process of determining that the slowness corresponding to the maximum value of the correlation coefficient obtained in the range of the transverse wave waveform of the full-wave waveform signal is the transverse wave slowness of the stratum, the search range of the transverse wave slowness is 60-180 microseconds/foot.
In another embodiment, before calculating the correlation coefficient of the waveform signals received by the plurality of receivers and transmitted by the same transmission source at the time t, the method further includes:
and determining the first arrival time of the longitudinal wave in the full-wave waveform signal according to the maximum value of the ratio of the energy of the mth short window in the full-wave waveform signal to the normalized energy value from the first short window to the long window of the mth short window.
In another embodiment, the maximum value R of the ratio of the energy of the m-th short window in the full-wave waveform signal to the normalized energy value of the long window from the first short window to the m short windowsmDetermining a first arrival time of a longitudinal wave in the full wave waveform signal comprises: determining the ratio of the energy of the m-th short window in the full-wave waveform signal to the normalized energy value from the first short window to the long window of the m short windows to be 0.2RmaxAnd then, the starting time of the corresponding mth short window is the first arrival time of the longitudinal wave.
The method for determining the porosity of the underground stratum provided by the invention comprises the steps of determining the longitudinal wave slowness of a rock framework at a set depth underground according to the volume content of stratum minerals; extracting the formation longitudinal wave slowness and the formation transverse wave slowness of the underground set depth according to the array acoustic logging data; and finally, determining the formation porosity of the underground set depth according to the rock skeleton longitudinal wave slowness, the formation longitudinal wave slowness and the formation transverse wave slowness of the underground set depth. By adopting the method for determining the porosity of the underground stratum provided by the embodiment of the invention, the porosity of the underground stratum can be accurately obtained by determining the porosity of the stratum by adopting the longitudinal wave slowness and the transverse wave slowness of the stratum without correcting the obtained porosity of the stratum, the utilization rate of array acoustic logging information is improved, and the accuracy of the porosity of the stratum is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic flow chart of a method for determining porosity of a downhole formation according to an embodiment of the invention;
FIG. 2 is a schematic diagram illustrating a principle of determining correlation coefficients of waveform signals received by a plurality of receivers according to an embodiment of the present invention;
FIG. 3 is a schematic waveform diagram of a full wave train in an embodiment of the present invention;
FIG. 4 is a diagram illustrating a full waveform duration window according to an embodiment of the present invention;
FIG. 5 is a graph comparing the effect of the downhole porosity calculated by the method for determining the porosity of the downhole formation according to the embodiment of the invention with the porosity obtained by the core experiment at the corresponding depth.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a method for determining the porosity of an underground stratum, which is established by utilizing characteristic signals detected by two instruments, namely element capture spectrum logging and array acoustic logging, in a well aiming at the problems of multiple logging acquisition series, later correction and the like required by porosity logging detection, is convenient to operate and high in precision, and not only avoids the problem of later correction, but also improves the utilization rate of array acoustic logging information.
FIG. 1 is a schematic flow chart of a method for determining porosity of a downhole formation according to an embodiment of the invention. Referring to fig. 1, a method for determining the porosity of a downhole formation according to an embodiment of the present invention includes:
s101: determining the longitudinal wave slowness of a rock skeleton at a set depth underground according to the volume content of the formation minerals;
before determining the longitudinal wave slowness of the rock framework at the set depth in the well according to the volume content of the stratum minerals, the method further comprises the following steps:
detecting the element abundance of the stratum elements at the set depth under the well;
and determining the volume content of the formation minerals corresponding to the formation elements according to the element abundance of the formation elements.
In particular, the analysis of the mineral composition of the stratum is realized by detecting the content of various elements in the stratum through an element capture spectrum logging instrument. The element capture spectrum logging instrument can be used for measuring in an open hole well and a sleeve well. The instrument structure consists of a neutron source, a crystal detector, a photomultiplier and a high-voltage amplification electronic circuit, and can be used under the conditions of fresh water mud, saturated salt water mud or oil-based mud, potassium chloride mud, gas-containing mud and the like. In the well logging process, fast neutrons are emitted to the stratum through a neutron source to induce the stratum elements to generate inelastic scattering reaction, and meanwhile, gamma rays are released. After multiple scattering, the neutrons are decelerated to form thermal neutrons. Thermal neutrons are captured, producing elemental features that capture gamma rays, which return to the original state by releasing the gamma rays. These inelastic scattering gamma energy spectra and capture gamma energy spectra are detected and recorded with a crystal detector. The inelastic gamma spectrum detected by a detector is utilized, and the contents of elements such as C, O, Si, Ca and the like can be obtained through spectrum decomposition; the main capture gamma spectrum can be subjected to spectrum decomposition to obtain the contents of elements such as Si, Ca, S, Fe, Ti, Gd and the like. According to the content of the elements, the percentage of corresponding minerals in the stratum can be obtained by applying a specific oxide closed model technology. Research proves that the elements of the reservoir are various in variety, but relatively concentrated on a few elements such as oxygen, silicon, aluminum and the like, and various minerals composed of the elements are concentrated on a few elements in sedimentary rocks, wherein quartz 31.5%, carbonate rock 20%, mica and chlorite 19%, pith 9%, feldspar 7.5%, clay mineral 7.5% and ferric oxide 3%. When the chemical composition of the mineral is stable, the percentage content of elements in the mineral is basically kept unchanged. Based on the method, the element capture spectrum logging can convert element content into sedimentary mineral content by selecting mineral indicating elements, and the comprehensive evaluation requirement of the reservoir can be met. In particular, few elements that can characterize a mineral are selected as indicator elements for that mineral. For example, silicon (Si) may be used as an indicator element for quartz, calcium (Ca) may be used as an indicator element for limestone, and magnesium (Mg) and calcium (Ca) may be used as indicator elements for dolomite. For complex minerals, 2-3 elements can be selected as indicator elements, for example, the potash feldspar can select Si, Al and K as indicator elements, and can be distinguished from illite according to the content of K.
The relationship between minerals and elements is close and restricted, and the element abundance can be converted into the mineral content by determining a proper mathematical relation between the element abundance and the mineral content. Specifically, the determining the volume content of the formation minerals corresponding to the formation elements according to the element abundance of the formation elements comprises:
according to
[M]＝[C]-1[E]Formula (1)
Determining the volume content of the formation minerals corresponding to the elements;
wherein [ M ] is a column matrix of the volume content of the formation minerals; [E] a column matrix that is an elemental abundance of the formation element; [C] the coefficient matrix is obtained by performing polynomial regression on the contribution of the known abundance of the formation elements to the volume content of the corresponding formation minerals.
The determining the rock skeleton longitudinal wave slowness of the underground set depth according to the volume content of the stratum minerals comprises the following steps:
according to
Wherein v isiRepresenting the volume content of the ith mineral in the formation,the compressional slowness of the ith mineral in the formation is in units of microseconds per foot.
S102: extracting the formation longitudinal wave slowness and the formation transverse wave slowness of the underground set depth according to the array acoustic logging data;
specifically, the extracting the formation compressional wave slowness and the formation shear wave slowness of the underground set depth according to the array acoustic logging data comprises:
according to
Calculating the phase relation of the wave signals received by a plurality of receivers and emitted by the same emission source at the time tCounting; the emission source and the plurality of receivers are arranged in a straight line, and the distance between every two adjacent receivers is equal; wherein R represents the correlation coefficient, TWIndicating a set time window length; s represents the slowness; τ is the time at which the time window is windowed on a waveform received by a first receiver, the first receiver being adjacent to the transmission source; f. ofmRepresenting a full-wave waveform signal received by an m-th receiver, t representing the time of any point on the full-wave waveform signal, and Δ z representing the distance between every two adjacent receivers;
determining slowness corresponding to the maximum value of the correlation coefficient obtained in the range of the longitudinal wave waveform of the full-wave waveform signal as the longitudinal wave slowness of the stratum;
and determining the slowness corresponding to the maximum value of the correlation coefficient obtained in the range of the shear wave waveform of the full-wave waveform signal as the shear wave slowness of the stratum.
Let the array sonic imaging logging instrument have 6 receivers. The receivers and the emission sources with the set formation depth are arranged at equal intervals along a straight line, and the source distance between each receiver and the emission source is z0, z1, … and z6 respectively. Every two adjacent receiving probes are spaced apart by Δ z (e.g., 6 inches), the source distance of the mth receiving probe can be written as (m is an integer greater than or equal to 1):
zm＝z0+(m-1)Δz
if the received full-wave waveform signal corresponding to each receiving probe is f1(t),f2(t),…,f6(t) of (d). For a discrete time series, the time of any point i on the waveform is:
ti＝t0+(i-1)ΔT
wherein △ T represents the time interval of sampling in microseconds, i represents the number of sampling points, and i is an integer greater than or equal to 1.
FIG. 2 is a block diagram of an embodiment of the present invention for determining correlation coefficients of waveform signals received by multiple receiversSchematic diagram of principle. Referring to fig. 2, R1-R6 are full-wave waveform signals received by 6 receivers respectively from the same transmission source. The slope of the long side of the dashed parallelogram in FIG. 2 represents the slowness S, and the slope of the short side represents the set time window length TW. The position where the short edge intersects the waveform of R1 represents the windowing instant τ of the time window on the waveform received by the first receiver. Equation 3 shows that a plurality of waveforms included in the dashed parallelogram in fig. 2 are added and normalized. When the phases of these waveforms are identical (i.e., the slowness S happens to be the propagation slowness of the corresponding waveform), the waveforms are strengthened, and the result (called the correlation coefficient) is close to 1; when the phases are not uniform, the waveform is attenuated so that the amplitude is small, resulting in a value much less than 1. Therefore, the value range of the correlation coefficient R is more than or equal to 0 and less than or equal to 1. When R is 0, no relation between waveforms is shown; when R is 1, the waveform shape is completely the same.
Specifically, when extracting the slowness of the longitudinal wave and the shear wave from the full-wave waveform data according to the formula 3, firstly, a proper time window length T needs to be selectedWAnd determining the value of the slowness S within a reasonable slowness search range. The correlation coefficient R is maximized when the slowness S value is close to the slowness of the formation compressional or shear. That is, the slowness S corresponding to the maximum value of the correlation coefficient is the estimated value of the slowness of the component wave (formation compressional wave or formation shear wave), that is, the formation compressional wave slowness or the formation shear wave slowness is obtained.
Optionally, in order to improve the system operation efficiency and facilitate determining the formation compressional wave slowness and the shear wave slowness as soon as possible, the set time window length TWThree wave periods of the longitudinal wave waveform; or, the set time window length TWThree wave periods of the shear wave waveform.
Optionally, in order to improve the accuracy of formation compressional wave slowness and shear wave slowness, in the process of determining that slowness corresponding to the maximum value of the correlation coefficient obtained in the compressional wave waveform range of the full-wave waveform signal is compressional wave slowness of the formation, the search range of the compressional wave slowness is 40-140 microseconds/foot;
or,
and in the process of determining that the slowness corresponding to the maximum value of the correlation coefficient obtained in the range of the transverse wave waveform of the full-wave waveform signal is the transverse wave slowness of the stratum, the search range of the transverse wave slowness is 60-180 microseconds/foot.
S103: and determining the formation porosity of the underground set depth according to the rock skeleton longitudinal wave slowness, the formation longitudinal wave slowness and the formation transverse wave slowness of the underground set depth.
Specifically, the determining the formation porosity at the downhole set depth according to the rock skeleton compressional wave slowness, the formation compressional wave slowness and the formation shear wave slowness at the downhole set depth comprises:
according to
Determining the formation porosity at the set depth downhole;
wherein,denotes porosity, SmaRepresenting the longitudinal wave slowness, S, of the rock skeletonsIs the formation shear wave slowness, SpRepresenting the formation compressional slowness.
According to the method for determining the porosity of the underground stratum, provided by the embodiment of the invention, the longitudinal wave slowness of the rock framework at the underground set depth is determined according to the volume content of the stratum minerals; extracting the formation longitudinal wave slowness and the formation transverse wave slowness of the underground set depth according to the array acoustic logging data; and finally, determining the formation porosity of the underground set depth according to the rock skeleton longitudinal wave slowness, the formation longitudinal wave slowness and the formation transverse wave slowness of the underground set depth. By adopting the method for determining the porosity of the underground stratum provided by the embodiment of the invention, the porosity of the underground stratum can be accurately obtained by determining the porosity of the stratum by adopting the longitudinal wave slowness and the transverse wave slowness of the stratum without correcting the obtained porosity of the stratum, the utilization rate of array acoustic logging information is improved, and the accuracy of the porosity of the bottom layer is improved.
Further, before calculating the correlation coefficient of the waveform signals received by the plurality of receivers and transmitted by the same transmission source at the time t, the method further includes:
and determining the first arrival time of the longitudinal wave in the full-wave waveform signal according to the maximum value of the ratio of the energy of the mth short window in the full-wave waveform signal to the normalized energy value from the first short window to the long window of the mth short window.
Specifically, determining the first arrival time of the longitudinal wave in the full-wave waveform signal can be implemented in, but not limited to, the following two ways:
in a first implementation, the first arrival time of the longitudinal wave may be determined by an amplitude ratio method.
Since the received noise information is irregular before the arrival of the longitudinal wave, its amplitude is much smaller than that of the longitudinal wave, and its amplitude does not vary much inside the noise signal or inside the longitudinal wave signal, while the amplitude before and after the arrival point of the longitudinal wave, i.e., the amplitude variation between the noise and the longitudinal wave, varies greatly, the arrival point of the longitudinal wave of the discrete waveform can be detected by the maximum value of the back peak and the front peak in the full-wave waveform.
In a second implementation, the first arrival time of the longitudinal wave can be determined by a short-and-long-window energy ratio method.
FIG. 3 is a waveform diagram of a full wave train according to an embodiment of the present invention. Referring to FIG. 3, the full wave train includes noise, longitudinal waves, transverse waves, and Stoneley waves. Fig. 4 is a schematic diagram of a full waveform long and short time window according to an embodiment of the present invention. Referring to fig. 4, let the energy of the mth short window with the nth sampling point as the windowing point be:
wherein i represents a sampling point, and i is an integer greater than or equal to 1; l represents the time window length of the short window, AiAnd representing the waveform amplitude corresponding to the ith sampling point.
The normalized value of the long window energy at the mth step short window is
The normalized ratio of the energy of the mth short window to the energy of the long window during the mth step short window is
Solving R according to equation 7mMaximum value of RmaxDetermining when R ism＝0.2RmaxSpecifically, the first arrival time of the longitudinal wave is mx △ T, wherein △ T is the time interval of sampling, in order to save time, the longitudinal wave first arrival and window length can be estimated in advance, the estimation value can be selected according to the waveform playback diagram, and the first arrival time is ensured to be within the estimation range.
FIG. 5 is a graph comparing the effect of the downhole porosity calculated by the method for determining the porosity of the downhole formation according to the embodiment of the invention with the porosity obtained by the core experiment at the corresponding depth. Referring to FIG. 5, in the rightmost porosity trace, the dashed line marked with an arrow represents the experimental porosity of the core, and the solid line represents the porosity calculated for logging, which are substantially similar in value and have the same size trend. The method for determining the porosity of the underground stratum can be used for detecting the porosity of the stratum better.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (9)
1. A method for downhole formation porosity determination, comprising:
determining the longitudinal wave slowness of a rock skeleton at a set depth underground according to the volume content of the formation minerals;
extracting the formation longitudinal wave slowness and the formation transverse wave slowness of the underground set depth according to the array acoustic logging data;
determining the formation porosity of the underground set depth according to the rock skeleton longitudinal wave slowness, the formation longitudinal wave slowness and the formation transverse wave slowness of the underground set depth;
determining the formation porosity at the set depth in the well according to the rock skeleton compressional wave slowness, the formation compressional wave slowness and the formation shear wave slowness at the set depth in the well comprises:
according to
Determining the formation porosity at the set depth downhole;
wherein,denotes porosity, SmaRepresenting the longitudinal wave slowness, S, of the rock skeletonsIs the formation shear wave slowness, SpRepresenting the formation compressional slowness.
2. The method of claim 1, wherein prior to determining the rock skeleton compressional slowness at the set depth downhole based on the formation mineral volume content, further comprising:
detecting the element abundance of the stratum elements at the set depth under the well;
and determining the volume content of the formation minerals corresponding to the formation elements according to the element abundance of the formation elements.
3. The method of claim 2, wherein determining the volume content of the formation minerals corresponding to the formation elements from the elemental abundances of the formation elements comprises:
according to
[M]＝[C]-1[E]
Determining the volume content of the formation minerals corresponding to the elements;
wherein [ M ] is a column matrix of the volume content of the formation minerals; [E] a column matrix that is an elemental abundance of the formation element; [C] the coefficient matrix is obtained by performing polynomial regression on the contribution of the known abundance of the formation elements to the volume content of the corresponding formation minerals.
4. The method of any one of claims 1 to 3, wherein determining the rock skeleton compressional slowness for the set depth downhole based on the formation mineral volume content comprises:
according to
Wherein v isiRepresenting the volume content of the ith mineral in the formation,is the compressional slowness of the ith mineral in the formation.
5. The method of claim 1, wherein extracting the formation compressional slowness and the formation shear slowness for the set depth downhole from the arrayed acoustic log data comprises:
according to
Calculating correlation coefficients of waveform signals received by a plurality of receivers and transmitted by the same transmission source at time t; the emission source and the plurality of receivers are arranged in a straight line, and the distance between every two adjacent receivers is equal; wherein R represents the correlation coefficient, TWIndicating a set time window length; s represents the slowness; τ is the time at which the time window is windowed on a waveform received by a first receiver, the first receiver being adjacent to the transmission source; f. ofmRepresents the full wave waveform signal received by the mth receiver, t represents the time of any point on the full wave waveform signal, △ z represents every twoThe spacing between adjacent receivers;
determining slowness corresponding to the maximum value of the correlation coefficient obtained in the range of the longitudinal wave waveform of the full-wave waveform signal as the longitudinal wave slowness of the stratum;
and determining the slowness corresponding to the maximum value of the correlation coefficient obtained in the range of the shear wave waveform of the full-wave waveform signal as the shear wave slowness of the stratum.
6. The method of claim 5, wherein the set time window length T isWThree wave periods of the longitudinal wave waveform; or, the set time window length TWThree wave periods of the shear wave waveform.
7. The method of claim 5,
in the process of determining that the slowness corresponding to the maximum value of the correlation coefficient obtained in the range of the longitudinal wave waveform of the full-wave waveform signal is the longitudinal wave slowness of the stratum, the search range of the longitudinal wave slowness is 40-140 microseconds/foot; or,
and in the process of determining that the slowness corresponding to the maximum value of the correlation coefficient obtained in the range of the transverse wave waveform of the full-wave waveform signal is the transverse wave slowness of the stratum, the search range of the transverse wave slowness is 60-180 microseconds/foot.
8. The method according to any one of claims 5-7, wherein before calculating the correlation coefficient of the waveform signals received by a plurality of receivers and transmitted by the same transmission source at time t, further comprising:
and determining the first arrival time of the longitudinal wave in the full-wave waveform signal according to the maximum value of the ratio of the energy of the mth short window in the full-wave waveform signal to the normalized energy value from the first short window to the long window of the mth short window.
9. The method of claim 8A method of generating a full wave waveform signal, wherein said full wave waveform signal is generated based on a maximum R of a ratio of an energy of an m-th short window to a normalized energy value of a long window from a first short window to said m short windowsmaxDetermining a first arrival time of a longitudinal wave in the full wave waveform signal comprises: determining the ratio of the energy of the m-th short window in the full-wave waveform signal to the normalized energy value from the first short window to the long window of the m short windows to be 0.2RmaxAnd then, the starting time of the corresponding mth short window is the first arrival time of the longitudinal wave.
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| CN107795320B (en) * | 2016-09-05 | 2021-01-05 | 中国石油化工股份有限公司 | Calculation method for horizontal well carbonate reservoir parameters |
| CN108375793A (en) * | 2018-03-01 | 2018-08-07 | 中国石油化工股份有限公司江汉油田分公司物探研究院 | Comprehensive normal compaction speed preparation method and device and pore pressure preparation method and device |
| CN115248463B (en) * | 2022-05-24 | 2024-05-24 | 中国石油大学(华东) | A correction method for the effect of inelastic scattering in D-T source neutron porosity logging |
| CN116626779B (en) * | 2023-07-21 | 2023-11-10 | 中海石油(中国)有限公司深圳分公司 | Method and system for calculating porosity of subsurface mountain stratum |
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| US4692910A (en) * | 1985-03-11 | 1987-09-08 | Amoco Corporation | Methods of determining lithological characteristics of an underground formation which utilize compressional velocity and shear velocity data |
| CN1015671B (en) * | 1990-06-09 | 1992-02-26 | 潘仁芳 | Oil deposit-described method by earthquake date |
| US8630146B2 (en) * | 2009-04-02 | 2014-01-14 | Baker Hughes Incorporated | Method and apparatus for estimating formation permeability and electroacoustic constant of an electrolyte-saturated multi-layered rock taking into account osmosis |
| CN103064118A (en) * | 2013-01-08 | 2013-04-24 | 西南石油大学 | Method of acoustic logging and quantifying cavern filling degree |
| CN104570127B (en) * | 2013-10-09 | 2017-06-20 | 中国石油化工股份有限公司 | A kind of method of utilization seimic wave velocity Simultaneous Inversion porosity and shale content |
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| CN103984009B (en) * | 2014-04-16 | 2016-04-13 | 刘致水 | Based on three kinds of porosity type quantitative inversion methods of P-wave And S well-log information |
| CN104950331B (en) * | 2015-06-30 | 2017-08-11 | 中国石油天然气集团公司 | A kind of porosity of sand mud reservoir and the earthquake prediction method of shale content |
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