CN113356833A - Method for correcting borehole environment of density logging - Google Patents

Method for correcting borehole environment of density logging Download PDF

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CN113356833A
CN113356833A CN202110797395.2A CN202110797395A CN113356833A CN 113356833 A CN113356833 A CN 113356833A CN 202110797395 A CN202110797395 A CN 202110797395A CN 113356833 A CN113356833 A CN 113356833A
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value
density
corrected
logging
log
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CN113356833B (en
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肖玉峰
窦立荣
郭晓龙
薛宗安
孙莎莎
李贵忠
姜仁
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Petrochina Co Ltd
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B47/00—Survey of boreholes or wells
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B47/00—Survey of boreholes or wells
    • E21B47/08—Measuring diameters or related dimensions at the borehole
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/30—Assessment of water resources

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Abstract

The embodiment of the application provides a method for correcting a borehole environment of density logging, which comprises the following steps: collecting a borehole diameter logging measurement value, a density logging measurement value and geological information of a well to be corrected; acquiring the relative variable quantity of the diameter expansion based on the measured value of the borehole diameter logging; acquiring a correction coefficient based on the relative variation of the diameter expansion and the measured value of the density logging; acquiring a corrected density value based on the correction coefficient, geological information of the well to be corrected and an actual density logging value; and determining a density logging estimated value of the well to be corrected based on the corrected density value. The borehole environment correction method for the density logging provided by the invention is based on the relative variable quantity of the diameter expansion, so that the correction result can reflect the physical change characteristics of the stratum more truly, the influence of borehole wall collapse on the density logging is reduced, and reliable data quality guarantee is provided for the accurate calculation of the physical property parameters of the reservoir and the calculation of the elastic modulus of the stratum. The method is suitable for processing through a computer, and has the advantages of simple execution mode, high efficiency and strong applicability.

Description

Method for correcting borehole environment of density logging
Technical Field
The invention relates to the technical field of logging, in particular to a borehole environment correction method for density logging.
Background
Because the density logging is in a wall-attached measurement mode, the detection range is small, the pushing device is difficult to attach to the wall of the well under the condition of irregular wall of the well or collapse of the well, most logging information at the collapse part of the well is seriously distorted, the interpretation difficulty of logging information is very high, and reliable interpretation results and reservoir evaluation parameters cannot be provided. On the basis that the original density curve is basically credible, the conventional chart can achieve the correction effect, but when the well wall is seriously collapsed and the density logging curve is seriously distorted, the influence of the environment cannot be eliminated by correcting by using the chart. The correction amount of the plate for the effect of the density expansion is small, and is generally within 0.1g/cm 3.
In the prior art, a caliper correction chart of density logging data is used as a basis, and a geometric factor method is adopted to carry out mathematical fitting on the caliper correction chart to obtain a corresponding correction formula and a correction chart. The interpretation chart correction is made according to theoretical calculation and experimental results, and the method can only correct individual environmental influence factors for some well logs of a few reservoirs, is not suitable for computer data processing, and cannot correct all stratums of a well section comprehensively. Based on the prior art, the efficiency of correcting the borehole environment is low, and the practicability is poor.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art or the related art.
In view of this, an embodiment of the present application provides a method for correcting a borehole environment for density logging, including:
collecting a borehole diameter logging measurement value, a density logging measurement value and geological information of a well to be corrected;
acquiring the relative variable quantity of the diameter expansion based on the borehole diameter logging measured value;
acquiring a correction coefficient based on the relative variation of the diameter expansion and the density logging measurement value;
acquiring a corrected density value based on the correction coefficient, the geological information of the well to be corrected and an actual density logging value;
and determining a density logging estimated value of the well to be corrected based on the corrected density value.
In a first possible implementation manner of the embodiment of the present application, the step of obtaining a relative change amount of diameter expansion based on the caliper log measurement value includes:
and determining the relative change of the diameter expansion based on the maximum value of the well diameter logging and the minimum value of the well diameter logging.
In a second possible implementation manner of the embodiment of the present application, the step of determining the relative change amount of the diameter expansion based on the maximum value of the caliper log and the minimum value of the caliper log includes:
and calculating and obtaining the relative change quantity of the diameter expansion by the following formula:
Figure BDA0003163243180000021
wherein, when CAL is less than BIT, the value of Delta CAL is 0, and the difference between CAL and BIT is greater than CALmaxAnd CALminWhen the difference is positive, the value of the delta CAL is 1;
wherein, Delta CAL is the relative variation of the diameter expansion, CAL is the well diameter, BIT is the drill diameter, CAL is the drill diametermaxFor maximum caliper logging, CALminIs the minimum value of the caliper log.
In a third possible implementation manner of the embodiment of the present application, the step of obtaining a correction coefficient based on the relative change in diameter expansion and the density log measurement value includes:
and determining the correction coefficient based on the relative change of the diameter expansion, the maximum value of the density logging and the minimum value of the density logging.
In a fourth possible implementation manner of the embodiment of the present application, the determining the correction coefficient based on the relative change of the diameter expansion, the maximum value of the density log, and the minimum value of the density log includes:
the correction coefficient is obtained by calculation as follows:
ΔDEN＝ΔCAL·(ρmax-ρmin)
wherein, Delta DEN is a correction coefficient, Delta CAL is a relative variation of diameter expansion, rhomaxAs a maximum value of the density log, ρminIs the minimum value of the density log.
In a fifth possible implementation manner of the embodiment of the present application, the step of obtaining the corrected density value based on the correction coefficient, the geological information of the well to be corrected, and the actual density log value includes:
and acquiring the corrected density value based on the correction coefficient, the shale content, the maximum value of the density log of the pure shale in the regular section of the borehole, the minimum value of the density log of the pure shale in the regular section of the borehole and the actual density log value.
In a sixth possible implementation manner of the embodiment of the present application, the step of obtaining the corrected density value based on the correction coefficient, the shale content, the maximum value of the pure shale density log in the regular section of the borehole, the minimum value of the pure shale density log in the regular section of the borehole, and the actual density log value includes:
obtaining the corrected density value by calculating:
DENc＝ΔCAL·[(ρmax-ρmin)·(1-Vsh)+(ρmaxSH-ρminSH)·Vsh]+DEN
wherein DENcFor correcting density value, Δ CAL is the relative variation of hole enlargement, ρmaxAs a maximum value of the density log, ρminIs the minimum value of density log, VshIs the mud content, rhomaxSHLogging maximum value, rho, of pure shale density for regular sections of a boreholeminSHAnd the density logging minimum value of the pure shale in the regular section of the well bore is obtained, and DEN is an actual density logging value.
In a seventh possible implementation manner of the embodiment of the present application, the step of determining a predicted value of a density log of a well to be corrected based on the corrected density value includes:
acquiring a check density value based on the acoustic porosity and the geological information of the well to be corrected;
and determining a density logging estimated value of the well to be corrected based on the checking density value and the correcting density value.
In an eighth possible implementation manner of the embodiment of the present application, the step of obtaining the verified density value based on the acoustic porosity and the geological information of the well to be corrected includes:
obtaining the check density value by calculating:
DENac＝Vsh·ρsh+(1-Vsh-φs)·ρma+φs·ρf
Figure BDA0003163243180000031
wherein DENacFor examining the density value, VshIs the mud content, rhoshAs mudstone density, ρmaIs the density of the pure lithologic skeleton of the stratum phisIs the acoustic porosity, ρfAs formation fluid density, Δ t is the sonic moveout log, Δ tmaIs the time difference frame value of the acoustic wave of the pure lithology of the stratum, delta tfFor the acoustic time difference, Δ t, of the formation fluidshThe difference value of the mud rock sound wave is shown, and the CP is a mud rock compaction correction coefficient.
In a ninth possible implementation manner of the embodiment of the present application, the step of determining the predicted value of the density log of the well to be corrected based on the checked density value and the corrected density value includes:
taking the actual density log value as a density log estimated value under the condition that the corrected density value is larger than the checked density value;
taking the actual density log value as a density log estimated value if the corrected density value is less than or equal to the verified density value and the difference between the verified density value and the corrected density value is greater than a first threshold value;
if the corrected density value is less than or equal to the verified density value and the difference between the verified density value and the corrected density value is less than or equal to the first threshold value, taking the corrected density value as a density log estimate;
wherein the value of the first threshold is 0.05.
Compared with the prior art, the invention at least comprises the following beneficial effects: the invention provides a borehole environment correction method for density logging, which comprises the steps of firstly obtaining the relative variation of the diameter expansion, then obtaining a correction coefficient based on the relative variation of the diameter expansion, further obtaining a correction density value based on the correction coefficient, and obtaining a predicted value of the density logging of a well to be corrected based on the correction density value. The method is suitable for processing through a computer, and has the advantages of simple execution mode, high efficiency and strong applicability.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a flowchart illustrating a method for correcting a borehole environment for density logging according to an embodiment of the present disclosure;
FIG. 2 is a comparison of predicted and original density of a density log corrected according to a borehole environment correction method for density logging provided herein;
FIG. 3 is a graph of raw data that has not been corrected by a method of borehole environment correction for density logging in accordance with an embodiment provided herein;
FIG. 4 is a data diagram of the raw data in FIG. 3 after being corrected by a borehole environment correction method for density logging according to an embodiment of the present disclosure.
Detailed Description
In order that the above objects, features and advantages of the present invention can be more clearly understood, the present invention will be described in further detail below with reference to the accompanying drawings and detailed description. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.
As shown in fig. 1, a method for correcting a borehole environment for density logging is provided according to an embodiment of the present application, including:
step 101: and acquiring the borehole diameter logging measurement value, the density logging measurement value and the geological information of the well to be corrected. It is understood that caliper and density measurements may be obtained by monitoring the well to be calibrated.
Step 102: and acquiring the relative variable quantity of the diameter expansion based on the measured value of the borehole diameter logging. The hole diameter relative variation of the well to be corrected is obtained through the measured value of the well diameter logging, and then the density logging predicted value is obtained through the hole diameter relative variation, so that the density logging predicted value has an incidence relation between the hole diameter relative variation and the density logging predicted value, and the method for correcting the well hole environment of the density logging is particularly suitable for well sections with serious well hole collapse.
Step 103: and acquiring a correction coefficient based on the relative variation of the diameter expansion and the measured value of the density logging. The correction coefficient is obtained through the relative variation of the diameter expansion and the measured value of the density logging, the correction coefficient has an incidence relation with the relative variation of the diameter expansion and the measured value of the density logging, and then the corrected density value is determined based on the correction coefficient, so that the borehole environment correction method of the density logging is particularly suitable for well sections with serious borehole collapse.
Step 104: and acquiring a corrected density value based on the correction coefficient, the geological information of the well to be corrected and the actual density logging value. And by acquiring the corrected density value, the density log of the well to be corrected can be estimated according to the corrected density value.
Step 105: and determining a density logging estimated value of the well to be corrected based on the corrected density value. The density logging estimated value reflects the physical change characteristics of the stratum more truly, reduces the influence of borehole wall collapse on density logging, and provides reliable data quality guarantee for accurate calculation of reservoir physical property parameters and calculation of stratum elastic modulus.
The invention provides a borehole environment correction method for density logging, which comprises the steps of obtaining relative variation of diameter expansion, obtaining a correction coefficient based on the relative variation of diameter expansion, further obtaining a correction density value based on the correction coefficient, and obtaining a predicted value of the density logging of a well to be corrected based on the correction density value. The method is suitable for processing through a computer, and has the advantages of simple execution mode, high efficiency and strong applicability.
In some examples, the step of obtaining the relative change in hole enlargement based on the caliper measurements comprises:
and determining the relative change of the diameter expansion based on the maximum value of the borehole diameter logging and the minimum value of the borehole diameter logging.
The relative variable quantity of the hole enlargement can be determined through the maximum value of the hole diameter logging and the minimum value of the hole diameter logging, further, the hole diameter of the hole enlargement section with the maximum hole diameter can be selected as the maximum value of the hole diameter logging, the hole diameter close to the hole diameter section of the drill bit is selected as the minimum value of the hole diameter logging, and the relative variable quantity of the hole enlargement can be better adapted to the change of the hole diameter.
In some examples, the step of determining the relative change in hole diameter based on the maximum value of the caliper log and the minimum value of the caliper log comprises:
and calculating to obtain the relative change of the diameter expansion by the following formula:
Figure BDA0003163243180000061
wherein, when CAL is less than BIT, the value of Delta CAL is 0, and the difference between CAL and BIT is greater than CALmaxAnd CALminWhen the difference is positive, the value of the delta CAL is 1;
wherein, Delta CAL is the relative variation of the diameter expansion, CAL is the well diameter, BIT is the drill diameter, CAL is the drill diametermaxFor maximum caliper logging, CALminIs the minimum value of the caliper log.
Through the determination of the formula, the error correction during the diameter reduction of the borehole can be prevented, the relative variation of the borehole is ensured to be varied between 0 and 1 through a normalization method, the relative variation of the diameter expansion is maintained between 0 and 1, and the determination of the estimated value of the density logging can be more accurate.
In some examples, the step of obtaining the correction factor based on the hole enlargement relative change amount and the density log measurement comprises:
and determining a correction coefficient based on the relative change of the diameter expansion, the maximum value of the density logging and the minimum value of the density logging.
Since the density of the mud is less than the formation density, the density measurement is made less than the true density of the formation under the influence of the borehole diameter, and the decrease in the density measurement increases with increasing borehole diameter. Therefore, when correcting the hole diameter of the density log, it is required that the correction amount is increased correspondingly for a large hole diameter, and vice versa. Because the density logging and the borehole diameter logging have approximate negative correlation, namely the larger the borehole diameter expansion is, the smaller the density logging value is, and the density logging value at the position with the maximum borehole diameter expansion correspondingly should be the minimum value. And obtaining a correction coefficient according to the relative variation value of the hole diameter and the relative variation value of the density.
The density logging method can be used for solving the problems that the density logging is not uniform, and the density logging is not uniform.
In some examples, the step of determining the correction factor based on the relative change in hole enlargement, the maximum value of the density log, and the minimum value of the density log comprises:
the correction coefficient is obtained by calculation as follows:
ΔDEN＝ΔCAL·(ρmax-ρmin)
wherein, Delta DEN is a correction coefficient, Delta CAL is a relative variation of diameter expansion, rhomaxAs a maximum value of the density log, ρminIs the minimum value of the density log.
Through the determination of the formula, the value of the correction coefficient is more accurate, the correlation relationship is formed between the correction coefficient and the relative variation of the diameter expansion and the density logging measurement value, and then the correction density value is determined based on the correction coefficient, so that the borehole environment correction method for the density logging is particularly suitable for well sections with serious borehole collapse.
In some examples, the step of obtaining the corrected density value based on the correction factor, the well geological information to be corrected and the actual density log value includes:
and acquiring a corrected density value based on the correction coefficient, the shale content, the maximum value of the pure shale density log in the regular section of the borehole, the minimum value of the pure shale density log in the regular section of the borehole and the actual density log value.
The corrected density value is obtained through the correction coefficient, the shale content, the maximum value of the pure shale density log in the regular section of the well bore, the minimum value of the pure shale density log in the regular section of the well bore and the actual density log value, so that the corrected density value can reflect the physical change characteristics of the stratum more truly, the influence of the collapse of the well wall on the density log is reduced, and reliable data quality guarantee is provided for the accurate calculation of the physical property parameters of the reservoir and the calculation of the elastic modulus of the stratum.
In some examples, the step of obtaining the corrected density value based on the correction factor, the shale content, the maximum value of the pure shale density log for the regular section of the borehole, the minimum value of the pure shale density log for the regular section of the borehole, and the actual density log value comprises:
the corrected density value is obtained by calculation as follows:
DENc＝ΔCAL·[(ρmax-ρmin)·(1-Vsh)+(ρmaxSH-ρminSH)·Vsh]+DEN
wherein DENcFor correcting density value, Δ CAL is the relative variation of hole enlargement, ρmaxAs a maximum value of the density log, ρminIs the minimum value of density log, VshIs the mud content, rhomaxSHLogging maximum value, rho, of pure shale density for regular sections of a boreholeminSHAnd the density logging minimum value of the pure shale in the regular section of the well bore is obtained, and DEN is an actual density logging value.
Through the determination of the formula, the calculation mode of the corrected density value is further defined, so that the density value is well corrected, and the density logging estimated value can be conveniently and accurately determined. The porosity calculated by intersecting the density before correction and the neutron porosity is obviously larger, so that misjudgment of reservoir physical properties and fluid properties is easily caused, the porosity calculated by intersecting the density logging estimated value after borehole correction and the neutron porosity is more reasonable, and the reservoir evaluation result can be greatly improved.
In some examples, the step of determining a predicted value of the density log for the well to be corrected based on the corrected density values comprises: acquiring a check density value based on the acoustic porosity and geological information of the well to be corrected; and determining a density logging estimated value of the well to be corrected based on the checking density value and the correction density value.
The corrected density value can be back-calculated through the acoustic porosity, and the density logging estimated value is obtained through the corrected density value and the checked density value, so that the determination of the density logging estimated value is more accurate.
In some examples, the step of obtaining the verified density value based on the acoustic porosity and the well geological information to be corrected comprises:
the check density value is obtained by calculation as follows:
DENac＝Vsh·ρsh+(1-Vsh-φs)·ρma+φs·ρf
Figure BDA0003163243180000081
wherein DENacFor examining the density value, VshIs the mud content, rhoshAs mudstone density, ρmaIs the density of the pure lithologic skeleton of the stratum phisIs the acoustic porosity, ρfAs formation fluid density, Δ t is the sonic moveout log, Δ tmaIs the time difference frame value of the acoustic wave of the pure lithology of the stratum, delta tfFor the acoustic time difference, Δ t, of the formation fluidshThe difference value of the mud rock sound wave is shown, and the CP is a mud rock compaction correction coefficient.
Through the determination of the formula, a specific mode for determining the inspection density value is further provided, and the density logging estimated value is obtained through correcting the density value and inspecting the density value, so that the determination of the density logging estimated value can be more accurate.
In some examples, the step of determining a predicted value of the density log for the well to be corrected based on the verified density value and the corrected density value includes: taking the actual density logging value as a density logging estimated value under the condition that the corrected density value is larger than the checked density value; taking the actual density logging value as a density logging estimated value under the condition that the corrected density value is smaller than or equal to the checked density value and the difference value between the checked density value and the corrected density value is larger than a first threshold value; taking the corrected density value as a density logging estimated value under the condition that the corrected density value is smaller than or equal to the checked density value and the difference value between the checked density value and the corrected density value is smaller than or equal to a first threshold value; wherein the value of the first threshold is 0.05.
And comparing the corrected density value with the checked density value, and considering that the density logging instrument is pushed against the well wall when the corrected density value is larger than the checked density value, wherein the actual density logging value is used as a density logging estimated value in the situation. It will be appreciated that the verified density value may also be used as a density log estimate in the event that the corrected density value is greater than the verified density value.
In the case that the corrected density value is smaller than or equal to the verified density value, and the difference between the verified density value and the corrected density value is larger than the first threshold value, the difference is considered to be possibly caused by certain system errors and noise interference existing in the density logging instrument, so that the actual density logging value can be used as the density logging estimated value.
It is understood that the estimated density value can also be obtained by the following equation in the case where the corrected density value is less than or equal to the verified density value and the difference between the verified density value and the corrected density value is greater than the first threshold value.
DENEstimation of＝DEN+(DENac-DEN)2
Wherein DENEstimation ofFor density log predictive value, DEN is actual density log value, DENacTo check density values.
And under the condition that the corrected density value is smaller than or equal to the checked density value and the difference value between the checked density value and the corrected density value is smaller than or equal to the first threshold value, the actual density logging value is considered to need to be corrected, and the corrected density value is used as a density logging estimated value.
As shown in fig. 2 to 4, in fig. 2, the 1 st path from the left to the right of fig. 2 is a depth path, the 2 nd path is a borehole diameter and a natural gamma, the 3 rd path is an original density, a corrected density and an acoustic wave time difference, and the 4 th path is an original density and a density curve inverted by an acoustic wave time difference. In fig. 3 and 4, from left to right, the 1 st trace is a depth trace, the 2 nd trace is a borehole shape, the 3 rd trace is a natural gamma curve, the 4 th trace is a three-porosity curve, the 5 th trace is a deep resistivity, a shallow resistivity, the 6 th trace is a lithologic trace, the 7 th trace is a porosity and saturation, and the 8 th trace is an explanation conclusion.
As can be seen from fig. 2 to 4, the density log is well corrected in the severe section of the borehole collapse. The porosity calculated after the intersection of the density before correction and the neutron porosity is obviously larger, the calculated high porosity is actually caused by borehole collapse, the misjudgment of the physical property and the fluid property of the reservoir is easily caused, and as can be seen from the graph in fig. 3 and 4, the processing result is used for wrongly explaining the compact reservoir as an oil-gas reservoir. The porosity calculated by the intersection of the density corrected by the well hole and the neutron porosity is reasonable, and the conclusion originally interpreted as the hydrocarbon reservoir is corrected into a compact reservoir, so that the reservoir evaluation result is greatly improved, and the well logging interpretation coincidence rate can be improved.
In the description of the present invention, the terms "plurality" or "a plurality" refer to two or more, and unless otherwise specifically limited, the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are merely for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention; the terms "connected," "mounted," "secured," and the like are to be construed broadly and include, for example, fixed connections, removable connections, or integral connections; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the description of the present invention, the description of the terms "one embodiment," "some embodiments," "specific embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In the present invention, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A method of correcting a borehole environment for density logging, comprising:
collecting a borehole diameter logging measurement value, a density logging measurement value and geological information of a well to be corrected;
acquiring the relative variable quantity of the diameter expansion based on the borehole diameter logging measured value;
acquiring a correction coefficient based on the relative variation of the diameter expansion and the density logging measurement value;
acquiring a corrected density value based on the correction coefficient, the geological information of the well to be corrected and an actual density logging value;
and determining a density logging estimated value of the well to be corrected based on the corrected density value.
2. The method of claim 1, wherein the step of obtaining the relative change in hole expansion based on the caliper measurements comprises:
and determining the relative change of the diameter expansion based on the maximum value of the well diameter logging and the minimum value of the well diameter logging.
3. The method of claim 2, wherein the step of determining the relative change in the hole enlargement based on the maximum value of the caliper log and the minimum value of the caliper log comprises:
and calculating and obtaining the relative change quantity of the diameter expansion by the following formula:
Figure FDA0003163243170000011
wherein, when CAL is less than BIT, the value of Delta CAL is 0, and the difference between CAL and BIT is greater than CALmaxAnd CALminWhen the difference is positive, the value of the delta CAL is 1;
wherein, Delta CAL is the relative variation of the diameter expansion, CAL is the well diameter, BIT is the drill diameter, CAL is the drill diametermaxFor maximum caliper logging, CALminIs the minimum value of the caliper log.
4. The method of claim 1, wherein the step of obtaining a correction factor based on the relative change in hole expansion and the density log measurement comprises:
and determining the correction coefficient based on the relative change of the diameter expansion, the maximum value of the density logging and the minimum value of the density logging.
5. The method of claim 4, wherein the step of determining the correction factor based on the relative change in the hole enlargement, the maximum value of the density log, and the minimum value of the density log comprises:
the correction coefficient is obtained by calculation as follows:
ΔDEN＝ΔCAL·(ρmax-ρmin)
wherein, Delta DEN is a correction coefficient, Delta CAL is a relative variation of diameter expansion, rhomaxAs a maximum value of the density log, ρminIs the minimum value of the density log.
6. The method of claim 1, wherein the step of obtaining the corrected density value based on the correction factor, the geological information of the well to be corrected and the actual density log value comprises:
and acquiring the corrected density value based on the correction coefficient, the shale content, the maximum value of the density log of the pure shale in the regular section of the borehole, the minimum value of the density log of the pure shale in the regular section of the borehole and the actual density log value.
7. The method of claim 6, wherein the step of obtaining the corrected density value based on the correction factor, the shale content, the maximum pure shale density log value of the regular section of the borehole, the minimum pure shale density log value of the regular section of the borehole, and the actual density log value comprises:
obtaining the corrected density value by calculating:
DENc＝ΔCAL·[(ρmax-ρmin)·(1-Vsh)+(ρmaxSH-ρminSH)·Vsh]+DEN
wherein DENcFor correcting density value, Δ CAL is the relative variation of hole enlargement, ρmaxAs a maximum value of the density log, ρminIs the minimum value of density log, VshIs the mud content, rhomaxSHLogging maximum value, rho, of pure shale density for regular sections of a boreholeminSHAnd the density logging minimum value of the pure shale in the regular section of the well bore is obtained, and DEN is an actual density logging value.
8. The method of claim 1, wherein the step of determining a predicted value of the density log for the well to be corrected based on the corrected density value comprises:
acquiring a check density value based on the acoustic porosity and the geological information of the well to be corrected;
and determining a density logging estimated value of the well to be corrected based on the checking density value and the correcting density value.
9. The method of claim 8, wherein the step of obtaining the verified density value based on the acoustic porosity and the geological information of the well to be corrected comprises:
obtaining the check density value by calculating:
DENac＝Vsh·ρsh+(1-Vsh-φs)·ρma+φs·ρf
Figure FDA0003163243170000031
wherein DENacFor examining the density value, VshIs the mud content, rhoshAs mudstone density, ρmaIs the density of the pure lithologic skeleton of the stratum phisIs the acoustic porosity, ρfAs formation fluid density, Δ t is the sonic moveout log, Δ tmaAcoustic moveout for formation pure lithologySkeleton value, Δ tfFor the acoustic time difference, Δ t, of the formation fluidshThe difference value of the mud rock sound wave is shown, and the CP is a mud rock compaction correction coefficient.
10. The method of claim 8, wherein the step of determining a predicted value of the density log for the well to be corrected based on the verified density value and the corrected density value comprises:
taking the actual density log value as a density log estimated value under the condition that the corrected density value is larger than the checked density value;
taking the actual density log value as a density log estimated value if the corrected density value is less than or equal to the verified density value and the difference between the verified density value and the corrected density value is greater than a first threshold value;
if the corrected density value is less than or equal to the verified density value and the difference between the verified density value and the corrected density value is less than or equal to the first threshold value, taking the corrected density value as a density log estimate;
wherein the value of the first threshold is 0.05.
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