CN115494552A - Method for correcting logging curve of inclined well and application thereof - Google Patents
Method for correcting logging curve of inclined well and application thereof Download PDFInfo
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Abstract
The invention discloses a logging curve correction method for an inclined shaft, which comprises the following steps: analyzing and interpreting the seismic section to obtain construction interpretation data; drilling a well and measuring related geological parameters to obtain original data of the inclined well and analyzing and comparing the original data to obtain well point hierarchical data; establishing a structural frame model, and performing three-dimensional grid division to obtain a three-dimensional structural model; leading the well logging curve needing to be corrected into a three-dimensional structure model; uniform interpolation is carried out under the constraint of a three-dimensional construction model; and establishing an equivalent virtual straight well, and extracting the parameters of the geological parameter model to the equivalent virtual straight well to obtain a corrected logging curve. The invention also discloses an application of the logging curve correction method of the inclined shaft. The method realizes the three-dimensional space spread characteristic description of the logging data of the inclined shaft in a three-dimensional modeling mode, and samples the logging data in the three-dimensional space to the equivalent virtual vertical shaft by fictitious equivalent virtual vertical shaft, thereby realizing the correction of the logging curve of the inclined shaft.
Description
Technical Field
The invention relates to the technical field of logging curve correction, in particular to a logging curve correction method of an inclined well and application thereof.
Background
The development of offshore oil fields is mostly developed by adopting a directional well mode due to the limitation of the range of a wellhead platform. Because some onshore oil fields are limited by factors such as terrain, geological conditions and the like, oil and gas reservoirs can be developed by adopting a directional well mode. Meanwhile, a part of exploratory wells with high target horizon points and poor superposition can be drilled in a directional well mode. However, the thickness of the stratum encountered by the inclined well drilling is influenced by factors such as stratum inclination angle, well inclination angle and azimuth angle, and has a certain deviation from the real thickness of the stratum, and the deviation degree is different under different conditions. Logging curves measured in inclined wells have different degrees of deformation compared with straight wells. The formation comparison is directly carried out by using the logging curve and lithological information of the inclined shaft, the result and the actual condition generate larger deviation due to the influence of the well track, the accuracy of interwell sand body comparison and reservoir distribution analysis is influenced, and the requirements of fine water injection and residual oil prediction of an oil field cannot be met. Meanwhile, the difference between the apparent thickness and the apparent vertical thickness of the inclined wells with different tracks is large, so that the real thickness parameter of the underground reservoir is difficult to correctly know, and the evaluation on the aspects of the reserves, the residual development potential and the like of the oil-gas field is influenced.
A method for correcting logging information of a directional well belongs to the technical field of oil and gas exploration and development. According to the invention, the influence of the formation dip angle is fully considered, the dip angle of the logging data is corrected to the virtual straight well depth by utilizing the formation dip angle and the directional well inclination data through a trigonometric function and a differential thought according to the intersection position relation of the directional well trajectory and the formation, so that the comparison research of the whole-area dip well and the straight well under the same standard can be realized, and the method has important guiding significance for the sedimentary reservoir spreading research of an exploratory area.
However, the above-mentioned scheme utilizes the formation dip angle, directional well inclination data, and corrects the inclined well depth of the logging data to the virtual straight well depth through trigonometric function and differential thought, the scheme is only suitable for the situation that the formation dip angle is stable, the correction error is large when the formation dip angle changes greatly and the formation structural surface top and bottom are not parallel, and the correlation between the drilling direction and the formation inclination according to the directional well needs to be distinguished in the calculation process, which is more complicated.
Disclosure of Invention
The invention aims to overcome the defects that the method for correcting the logging information of the directional well in the prior art is small in application range, complex in calculation process and large in correction error of a complex stratum structure, and provides a method for correcting a curve of an inclined well. The method realizes the three-dimensional space spread characteristic description of the logging data of the inclined shaft in a three-dimensional modeling mode, and samples the logging data in the three-dimensional space to the equivalent virtual straight shaft by fictitious equivalent virtual straight shaft, thereby realizing the correction of the logging curve of the inclined shaft, and having wide application range, small correction error and convenient application.
The purpose of the invention can be achieved by adopting the following technical scheme:
a logging curve correction method for an inclined well comprises the following steps:
s1: analyzing and interpreting an underground seismic section at a position where well drilling operation is required to obtain construction interpretation data;
s2: carrying out drilling operation, measuring related geological parameters to obtain inclined shaft original data comprising various logging curves, and analyzing and comparing the inclined shaft original data to obtain well point hierarchical data;
s3: determining a horizontal plane boundary of a constructed model according to a horizontal plane projection range of the inclined shaft track, performing horizontal plane grid division in the boundary range, establishing a constructed frame model for describing the inclined shaft track and stratum relation according to construction interpretation data and well point hierarchical data, and performing vertical grid division on the constructed frame model to obtain a three-dimensional constructed model;
s4: importing a logging curve needing to be corrected in the original data into a three-dimensional construction model;
s5: carrying out uniform interpolation under the constraint of a three-dimensional grid of the three-dimensional structure model to obtain a geological parameter model;
s6: determining the plane position of the equivalent virtual straight well according to the intersection point coordinates of the inclined well and the geological layer in the geological parameter model, establishing the equivalent virtual straight well, extracting the parameters in the geological parameter model to the equivalent virtual straight well, and obtaining the corrected logging curve.
The inclined shaft is a shaft with a certain inclination angle, and due to the limitation of a drilling field, an offshore oil field and a part of onshore oil fields can drill underground targets in a directional well mode with a certain inclination angle, and the inclined shaft is drilled along a specific direction by using a rotary steering technology during drilling until the task of drilling the underground targets is completed. The raw data of the inclined well comprises logging data of natural gamma rays, resistivity, natural potential, sound waves, density, neutrons and the like obtained when an instrument is used for geological logging, and logging data of gas logging data, lithological data and the like obtained when geological logging is carried out, wherein the logging data are all functions of depth and are various logging curves, the logging curves comprise logging curves and logging curves, the logging curves are obtained through geological logging, and the logging curves are obtained through geological logging. However, due to the influence of factors such as the well inclination angle, the formation inclination angle, the azimuth angle and the like, the inclined well drilled out at the same time is not in an ideal shape as the plan, so that various logging curves in the original data of the inclined well drilled and collected by the inclined well usually have different degrees of deformation compared with the logging curves of the straight well, and the deformation degrees of different wells are different, so that the real state of the underground geologic body is difficult to analyze by directly applying the data of the inclined well, the evaluation on the aspects of underground oil and gas reserves, the development mode, the development potential and the like is influenced, the development and utilization effects of the underground oil and gas resources cannot be accurately analyzed, and the effective development of the underground oil and gas resources is difficult to guide.
The invention utilizes the construction interpretation data and the well point hierarchical data to establish a construction frame model, and then carries out three-dimensional grid division on the established construction frame model to obtain the three-dimensional construction model. And obtaining a three-dimensional structure model. And introducing a logging curve to be corrected into a grid of the three-dimensional structure model, wherein only the grid intersected with the inclined well track in the three-dimensional structure model after the logging curve is introduced has parameter values, in order to ensure that the whole three-dimensional structure model has numerical values, or in order to ensure that the three-dimensional structure model at least equals to the grid intersected with the three-dimensional structure model and has parameter values, the three-dimensional structure model is required to be subjected to uniform interpolation under the constraint of the three-dimensional grid to obtain the geological parameter model. The equivalent virtual vertical well is established at the midpoint of the top-layer interface and the drilled bottom-layer interface of the three-dimensional structure model drilled in the inclined well, and is a vertical simulated ideal well. After the parameters on the geological parameter model are extracted from the established equivalent virtual straight well, the correction of the logging curve is completed, the parameters eliminate the problem that the formation thickness and other information are inaccurate due to the fact that the depth of the inclined well is influenced by factors such as the track and the like, and the correspondence between each depth and each parameter is closer to the real situation. The above process may use computer-aided work.
Further, in the step S1, seismic information acquisition is performed on the underground geologic body to obtain a seismic section, and the seismic section is analyzed and interpreted to obtain structure interpretation data.
The method is characterized in that a preliminary investigation needs to be carried out on an area to be operated before mining operation, seismic information of the underground geologic body can be collected and used by predecessors, and if no data collected by predecessors exists, the seismic information can be collected by the predecessors and then analyzed and explained.
Further, in the step S2, according to the regional deposition background, the specific depth position data of different layers on the inclined shaft, which is determined by the cycle characteristics of the logging curve in the original data of the inclined shaft and the prosodic characteristic information of the lithology of the logging, is obtained through stratum contrast analysis, so as to obtain well point hierarchical data.
And searching the corresponding inclined well track data at the depth position according to the depth value of the well point hierarchical data, so that the spatial position X, Y and Z coordinates of the well point hierarchical position can be determined.
Further, in step S3, after determining a horizontal plane boundary of the formation model according to a horizontal plane projection range of the inclined shaft trajectory, two mutually perpendicular directions are selected within the boundary range, and appropriate intervals are respectively defined in the two directions to perform grid division on the horizontal plane, the formation interpretation data is corrected according to the well point hierarchical data, the formation interpretation data near the well point position is matched with the well point hierarchical data to obtain a top surface geological layer and a bottom surface geological layer of the geological body, a topological relationship of data points of the corrected top surface geological layer and bottom surface geological layer of the geological body is analyzed to obtain a formation frame model, the number of grids in the vertical direction is set for the formation frame model, and the interior of the geological body is further vertically subdivided within a space range defined between the top surface geological layer and the bottom surface geological layer of the geological body to obtain a three-dimensional formation model.
When the grid in the vertical direction is divided for constructing the frame model, each unit value corresponding to the vertical grid can be determined according to the sampling rate of original data, and then the vertical grid is divided by setting proper intervals in the vertical direction according to the sampling rate, so that the three-dimensional grid model is obtained.
Further, in step S4, the depth data of the logging curve and the depth data of the three-dimensional structure model are matched, and the corresponding relationship between the two depths is found for matching, so that the logging parameters represented by the logging curve are assigned to the grid of the three-dimensional structure model, and the importing of the logging parameters is completed.
Because the logging curve is a function of the depth, when the logging curve is imported into the three-dimensional structure model, the depth is matched, and then the parameter value corresponding to the depth on the logging curve can be assigned to the three-dimensional structure model.
Further, in step S6, according to the X and Y coordinates of two intersection points of the inclined shaft and the top surface and the bottom surface of the target layer, the coordinate value of the middle point of the two intersection points is calculated, the X and Y values of the middle point are used as the plane position parameters of the equivalent virtual straight shaft, the vertical direction uses 0m as the starting point of the Z value of the equivalent virtual straight shaft trajectory, and the maximum Z value of the grid at the plane position is used as the maximum Z value of the trajectory.
In the scheme, the midpoint between the inclined well and two of the top surface geological layer and the bottom surface geological layer of the geologic body is taken as a point of the equivalent virtual straight well, the equivalent virtual straight well is a vertical well, and the equivalent virtual straight well can be established only by determining the point of the equivalent virtual well on the plane where the X axis and the Y axis are located.
Further, in step S6, matching the coordinate data on the equivalent virtual straight well trajectory with the spatial position of the geological parameter model, and assigning a value to a corresponding position on the equivalent virtual straight well according to an interpolation result in the geological parameter model to obtain logging parameters on the equivalent virtual straight well, thereby completing the correction of the logging curve.
After the geological parameter model completes interpolation, the intersection of the geological parameter model and the equivalent virtual straight well track is assigned, logging parameters corresponding to all depths on the equivalent virtual straight well can be obtained according to correspondence between the depths on the equivalent virtual straight well and the depths of the geological parameter model, and the functional relation between the depths on the equivalent virtual straight well and the logging parameters is the corrected logging parameters.
The application of the logging curve correction method of the inclined shaft comprises the logging curve correction method of the inclined shaft, and further comprises the following steps:
s7: repeating the steps S4-S6 for the various logging curves of each inclined well to obtain various corrected logging curves;
s8: and carrying out fine sand body comparison among adjacent inclined wells, inclined wells and vertical wells.
The fine sand body comparison among the adjacent inclined wells, the adjacent inclined wells and the vertical well is an important basis for guiding the fine water injection operation of the oil field, and meanwhile, the residual oil prediction can be guided by using the comparison result. However, under the condition that the logging curve is not corrected, the result of fine sand body comparison has larger deviation from the actual condition, so that the accuracy of sand body comparison between wells and reservoir distribution analysis is influenced, the evaluation on the operation effect is inconsistent with the actual condition, the accurate evaluation on the development effect of oil and gas resources is influenced, and the effective development of the underground oil and gas resources in the follow-up process is difficult to guide effectively.
Further, in step S7, each inclined well at least needs to correct a natural gamma curve, a resistivity curve and a lithology curve in the original data of the inclined well, so as to obtain at least three logging curves.
The most basic parameters of the sand body comparison are a natural gamma curve, a resistivity curve, lithology and other parameters, and the accuracy of the comparison result can be improved by using the parameters under the condition that the parameters are different.
Further, in the step S8, each inclined well measures the corresponding thickness of each section of sandstone and mudstone according to the corrected logging curve, and then the thickness and the depth of the stratum of each interval are counted, so as to perform comparison among adjacent inclined wells, inclined wells and straight wells.
Compared with the prior art, the invention has the beneficial effects that:
the three-dimensional space spread characteristic description of the logging data of the inclined shaft is realized in a three-dimensional modeling mode, the logging data in the three-dimensional space are sampled to the equivalent virtual straight shaft by the fictitious equivalent virtual straight shaft, and therefore the correction of the logging curve of the inclined shaft is realized, the application range is wide, the correction error is small, and the application is convenient. Meanwhile, the corrected logging curve is used for carrying out fine sand body comparison, so that the comparison result is closer to the real situation, and the production operation is better guided.
Drawings
FIG. 1 is a schematic diagram showing the thickness of a deviated well formation and the variation of a logging curve in different situations of a monoclinic formation according to the present invention;
FIG. 2 is a schematic view of a deviated well drilled through a formation with varying dip angle in accordance with the present invention;
FIG. 3 is a schematic view of a three-dimensional construction model according to the present invention;
FIG. 4 is a schematic illustration of the introduction of a natural gamma log of the present invention into a three-dimensional formation model;
FIG. 5 is a schematic diagram of a spatial interpolation result of a natural gamma log and an equivalent virtual vertical well according to the present invention;
FIG. 6 is a comparative illustration of a fine sand body according to the present invention.
Detailed Description
The present invention will be further described with reference to the following embodiments. Wherein the showings are for the purpose of illustration only and are shown by way of illustration only and not in actual form, and are not to be construed as limiting the present patent; for a better explanation of the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. based on the orientation or positional relationship shown in the drawings, it is only for convenience of describing the present invention and simplifying the description, but it is not intended to indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and are not to be construed as limiting the present patent, and the specific meaning of the terms may be understood by those skilled in the art according to specific circumstances.
Example 1
A logging curve correction method for an inclined well comprises the following steps:
s1: analyzing and interpreting an underground seismic section at a position where well drilling operation is required to obtain construction interpretation data;
s2: carrying out drilling operation, measuring related geological parameters to obtain inclined shaft original data comprising various logging curves, and analyzing and comparing the inclined shaft original data to obtain well point hierarchical data;
s3: determining a horizontal plane boundary of a constructed model according to a horizontal plane projection range of the inclined shaft track, performing horizontal plane grid division in the boundary range, establishing a constructed frame model for describing the inclined shaft track and stratum relation according to construction interpretation data and well point hierarchical data, and performing vertical grid division on the constructed frame model to obtain a three-dimensional constructed model;
s4: importing a logging curve which needs to be corrected in original data into a three-dimensional construction model;
s5: carrying out uniform interpolation under the constraint of a three-dimensional grid of the three-dimensional structure model to obtain a geological parameter model;
s6: determining the plane position of the equivalent virtual straight well according to the intersection point coordinates of the inclined well and the geological layer in the geological parameter model, establishing the equivalent virtual straight well, extracting the parameters in the geological parameter model to the equivalent virtual straight well, and obtaining the corrected logging curve.
The inclined shaft is a shaft with a certain inclination angle, and due to the limitation of a drilling field, an offshore oil field and a part of onshore oil fields can drill underground targets in a directional well mode with a certain inclination angle, and the inclined shaft is drilled along a specific direction by using a rotary steering technology during drilling until the task of drilling the underground targets is completed. The raw data of the inclined well comprises logging data of natural gamma rays, resistivity, natural potential, sound waves, density, neutrons and the like obtained when an instrument is used for geological logging, and logging data of gas logging data, lithological data and the like obtained when geological logging is carried out, wherein the logging data are all functions of depth and are various logging curves, the logging curves comprise logging curves and logging curves, the logging curves are obtained through geological logging, and the logging curves are obtained through geological logging. However, due to the influence of factors such as the well inclination angle, the formation inclination angle, the azimuth angle and the like, the inclined well drilled out at the same time is not in an ideal shape as the plan, so that various logging curves in the original data of the inclined well drilled and collected by the inclined well usually have different degrees of deformation compared with the logging curves of the straight well, and the deformation degrees of different wells are different, so that the real state of the underground geologic body is difficult to analyze by directly applying the data of the inclined well, the evaluation on the aspects of underground oil and gas reserves, the development mode, the development potential and the like is influenced, the development and utilization effects of the underground oil and gas resources cannot be accurately analyzed, and the effective development of the underground oil and gas resources is difficult to guide.
The invention utilizes the construction interpretation data and the well point hierarchical data to establish a construction frame model, and then carries out three-dimensional grid division on the established construction frame model to obtain the three-dimensional construction model. And introducing a logging curve to be corrected into a grid of the three-dimensional structure model, wherein only the grid intersected with the inclined well track in the three-dimensional structure model after the logging curve is introduced has parameter values, in order to ensure that the whole three-dimensional structure model has numerical values, or in order to ensure that the three-dimensional structure model at least equals to the grid intersected with the three-dimensional structure model and has parameter values, the three-dimensional structure model is required to be subjected to uniform interpolation under the constraint of the three-dimensional grid to obtain the geological parameter model. The equivalent virtual vertical well is established at the midpoint of the top-layer interface and the drilled bottom-layer interface of the three-dimensional structure model drilled in the inclined well, and is a vertical simulated ideal well. After the parameters on the geological parameter model are extracted from the established equivalent virtual straight well, the correction of the logging curve is completed, the parameters eliminate the problem that the formation thickness and other information are inaccurate due to the fact that the depth of the inclined well is influenced by factors such as the track and the like, and the correspondence between each depth and each parameter is closer to the real situation. The above process may use computer-aided work.
Further, in the step S1, seismic information acquisition is performed on the underground geologic body to obtain a seismic section, and the seismic section is analyzed and interpreted to obtain structure interpretation data.
The method is characterized in that a preliminary investigation needs to be carried out on an area to be operated before mining operation, seismic information of the underground geologic body can be collected and used by a predecessor, and if no data collected by the predecessor exists, the seismic information can be collected by the predecessor and then analyzed and explained.
Further, in the step S2, according to the regional deposition background, the specific depth position data of different horizons on the inclined shaft, which is determined by combining the cycle characteristics of the logging curve in the original data of the inclined shaft and the prosodic characteristic information of the lithology of the logging, is obtained through stratum contrast analysis, so as to obtain the well point hierarchical data.
And searching the corresponding inclined well track data at the depth position according to the depth value of the well point hierarchical data, so that the spatial position X, Y and Z coordinates of the well point hierarchical position can be determined.
Further, in step S3, after determining a horizontal plane boundary of the formation model according to a horizontal plane projection range of the inclined shaft trajectory, selecting two mutually perpendicular directions within the boundary range, and defining suitable intervals in the two directions to perform grid division on a horizontal plane, correcting formation interpretation data according to the well point layering data, so that the formation interpretation data near the well point position matches with the well point layering data to obtain a top surface geological layer and a bottom surface geological layer of the geological body, analyzing a topological relationship of data points of the top surface geological layer and the bottom surface geological layer of the corrected geological body to obtain a formation frame model, setting a grid number in a vertical direction for the formation frame model, and further vertically subdividing the interior of the geological body within a space range defined between the top surface geological layer and the bottom surface geological layer of the geological body to obtain a three-dimensional formation model.
In this embodiment, the specific steps of meshing the structural frame model are as follows:
in the embodiment, two mutually perpendicular directions of an X axis and a Y axis are selected, and grid division on the horizontal plane is performed according to a proper grid interval, for example, a rectangular plane boundary is defined by outwards expanding 200m according to the plane projection range of the inclined shaft track, and a plane grid is divided along the long side and the short side of the rectangle according to the 10 m interval. And estimating the number of grid divisions in the vertical direction according to the maximum vertical spacing between the top surface geological layer and the bottom surface geological layer of the geological body, wherein the number of vertical grids is equal to the maximum vertical spacing (unit: meter) of the top surface and the bottom surface divided by the minimum vertical resolution (generally 0.125 meter) of the logging data, and the number of vertical grids is an integer obtained by downward rounding, so that the vertical grid spacing is smaller than or equal to the minimum vertical resolution of the logging data. If the structural data of the top and the bottom surfaces at the same plane position are subtracted, the maximum vertical distance is 60.1 meters, the minimum vertical resolution of logging data is 0.125 meters, and the vertical grid number is 481. And setting a vertical grid division number for the structural frame model, and further vertically subdividing the interior of the geologic body according to the determined vertical grid number in the space range defined between the top surface geologic layer and the bottom surface geologic layer of the geologic body to obtain a three-dimensional structural model.
Further, in step S4, the depth data of the logging curve and the depth data of the three-dimensional structure model are matched, and the corresponding relationship between the two depths is found for matching, so that the logging parameters represented by the logging curve are assigned to the grid of the three-dimensional structure model, and the importing of the logging parameters is completed.
Because the logging curve is a function related to the depth, when the logging curve is led into the three-dimensional structure model, the depth is matched, and then the parameter value corresponding to the depth on the logging curve can be assigned to the three-dimensional structure model. The assignment process is as follows: according to the spatial coordinate position of the well track and the spatial coordinate position in the three-dimensional construction model, matching the corresponding relation between data on the well logging curves at different depth positions of the inclined well track and the three-dimensional grid in the three-dimensional construction model, carrying out averaging operation on parameter values at the same depth on a plurality of corresponding well logging curves in the three-dimensional grid by using an arithmetic mean algorithm, representing the parameter values on the three-dimensional grid of the response position by using the average value, assigning the parameter values of the well logging curves to the corresponding grid in the three-dimensional grid model, and finishing the import of the parameter values on the well logging curves.
Further, in step S6, according to the X and Y coordinates of two intersection points of the inclined shaft and the top surface and the bottom surface of the target layer, the coordinate value of the middle point of the two intersection points is calculated, the X and Y values of the middle point are used as the plane position parameters of the equivalent virtual straight shaft, the vertical direction uses 0m as the starting point of the Z value of the equivalent virtual straight shaft trajectory, and the maximum Z value of the grid at the plane position is used as the maximum Z value of the trajectory.
In the scheme, the midpoint between the inclined shaft and two of the top surface geological layer and the bottom surface geological layer of the geologic body is taken as a point of the equivalent virtual straight shaft, the equivalent virtual straight shaft is a vertical shaft, and the equivalent virtual straight shaft can be established only by determining the position of the equivalent virtual shaft on the plane where the X axis and the Y axis are located and the maximum vertical depth value of the shaft track.
Further, in step S6, matching the coordinate data on the equivalent virtual straight well trajectory with the spatial position of the geological parameter model, and assigning a value to a corresponding position on the equivalent virtual straight well according to an interpolation result in the geological parameter model to obtain logging parameters on the equivalent virtual straight well, thereby completing the correction of the logging curve.
After the geological parameter model completes interpolation, the intersection of the geological parameter model and the equivalent virtual straight well track is assigned, at the moment, logging parameters corresponding to all depths on the equivalent virtual straight well can be obtained according to the correspondence between the depths on the equivalent virtual straight well and the depths of the geological parameter model, and the functional relation between the equivalent virtual well depth and the logging parameters is the corrected logging parameters.
Example 2
This example corrects the natural gamma log of the deviated well using the correction method described in example 1. FIG. 1 is a schematic diagram showing the thickness of a formation and the variation of a logging curve of a deviated well under different conditions of a monoclinic formation, so that the logging curves measured by the formation and the deviated well under different conditions have different deviations, and the formation and the deviated well under various conditions can be corrected in a modeling mode. Fig. 2 is a schematic diagram of a stratum with a changed dip angle of a drilling-through stratum according to a certain dog-leg degree, fig. 3 is a schematic diagram of a three-dimensional structural model after the grid is established and divided in the step S3, and fig. 4 is a schematic diagram of a natural gamma logging curve introduced into the three-dimensional structural model in the step S4. Fig. 5 is a schematic diagram of the spatial interpolation result of the natural gamma log in step S5 and the equivalent virtual vertical well in step S6. As shown in fig. 4 and 5, the range of the numerical values possessed by the interpolated geologic parameter model is expanded, so that the positions where the trajectory passes in the equivalent virtual vertical well also possess the numerical values.
Example 3
An application of the method for correcting the logging curve of the inclined well comprises the method for correcting the logging curve of the inclined well as described in embodiment 1, and further comprises the following steps:
s7: repeating the steps S4-S6 for the various logging curves of each inclined well to obtain various corrected logging curves;
s8: and carrying out inter-well fine sand body comparison on adjacent inclined wells, inclined wells and vertical wells.
The fine sand body comparison of adjacent inclined wells and vertical wells is an important basis for guiding the fine water injection operation of the oil field, and meanwhile, the residual oil prediction can be guided by using the comparison result. However, under the condition that the logging curve is not corrected, the result of fine sand body comparison has larger deviation from the actual condition, the accuracy of sand body comparison between wells and reservoir distribution analysis is influenced, and the actual output of operation is smaller than the expected output.
In the step S7, each inclined shaft at least needs to correct the natural gamma curve, the resistivity curve and the lithology curve in the original data of the inclined shaft, so as to obtain at least three logging curves.
The most basic parameters of the sand body comparison are a natural gamma curve, a resistivity curve, lithology and other parameters, and the accuracy of the comparison result can be improved by using the parameters under the condition that the parameters are different.
In the step S8, each inclined well measures the corresponding thickness of each section of sandstone and mudstone according to the corrected logging curve, and then the thickness and the depth of the stratum of each interval are counted, so as to compare adjacent inclined wells, inclined wells and straight wells.
As shown in fig. 6, for fine sand body comparison, it can be seen that after correction, the depth position and thickness of each sand body in the three inclined wells are changed compared with those before correction, especially the sand bodies in the three inclined wells are considered as the same sand body before correction, and after correction, two different sand bodies are obviously seen, such as sand body No. (3) and sand body No. (5) in water injection well a and oil production well B; or two isolated sand bodies which are not communicated with each other before correction, and obvious overlapped communication characteristics after correction, such as the sand body (1) in the oil production well B and the water injection well C. The change in the knowledge before and after the above correction has a large influence on the actual operation.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.
Claims (10)
1. A logging curve correction method for an inclined well is characterized by comprising the following steps:
s1: analyzing and interpreting an underground seismic section at a position where well drilling operation is required to obtain construction interpretation data;
s2: carrying out drilling operation, measuring related geological parameters to obtain inclined shaft original data comprising various logging curves, and analyzing and comparing the inclined shaft original data to obtain well point hierarchical data;
s3: determining a horizontal plane boundary of a constructed model according to a horizontal plane projection range of the inclined shaft track, performing horizontal plane grid division in the boundary range, establishing a constructed frame model for describing the inclined shaft track and stratum relation according to construction interpretation data and well point hierarchical data, and performing vertical grid division on the constructed frame model to obtain a three-dimensional constructed model;
s4: importing a logging curve which needs to be corrected in original data into a three-dimensional construction model;
s5: carrying out uniform interpolation under the constraint of a three-dimensional grid of the three-dimensional structure model to obtain a geological parameter model;
s6: determining the plane position of the equivalent virtual straight well according to the intersection point coordinates of the inclined well and the geological layer in the geological parameter model, establishing the equivalent virtual straight well, extracting the parameters in the geological parameter model to the equivalent virtual straight well, and obtaining the corrected logging curve.
2. The method for correcting the logging curve of the deviated well according to claim 1, wherein in the step S1, the seismic information is collected from the underground geologic body to obtain a seismic profile, and the seismic profile is analyzed and interpreted to obtain the structural interpretation data.
3. The method for correcting the logging curve of the inclined shaft according to claim 1, wherein in the step S2, well point hierarchical data is obtained through formation contrast analysis according to regional sedimentary backgrounds and specific depth position data of different layers on the inclined shaft, which is determined by combining the cycle characteristics of the logging curve in the original data of the inclined shaft and the prosodic characteristic information of the lithology of the logging.
4. The method as claimed in claim 1, wherein in step S3, after determining a horizontal plane boundary of the formation model according to a horizontal plane projection range of the inclined shaft trajectory, two mutually perpendicular directions are selected within the boundary range, and suitable intervals are respectively defined in the two directions to perform grid division on the horizontal plane, the formation interpretation data is corrected according to the well point hierarchical data, the formation interpretation data near the well point position is matched with the well point hierarchical data to obtain a top surface geological level and a bottom surface geological level of the geologic body, the geological relationship of the top surface level and the bottom surface geological level data points of the geologic body after correction is analyzed to obtain a formation frame model, the number of grids in the vertical direction is set for the formation frame model, and the interior of the geologic body is further vertically subdivided within a space range defined between the top surface geological level and the bottom surface geological level of the geologic body to obtain a three-dimensional formation model.
5. The method according to claim 1, wherein in step S4, the logging curve depth data and the depth data of the three-dimensional model are matched to find a corresponding relationship between the two depths for matching, so as to assign logging parameters represented by the logging curve to the grid of the three-dimensional model, thereby completing importing the logging parameters.
6. The method as claimed in claim 1, wherein in step S6, the coordinate value of the middle point of the two intersection points is calculated according to the X and Y marks of the intersection points of the inclined well and the top and bottom surfaces of the target layer, the X and Y values of the middle point are used as the plane position parameters of the equivalent virtual vertical well, the vertical direction is 0m as the starting point of the Z value of the equivalent virtual vertical well trajectory, and the maximum Z value of the grid at the plane position is used as the maximum Z value of the trajectory.
7. The method for correcting the logging curve of the slant well according to claim 6, wherein in step S6, the coordinate data on the equivalent virtual straight well trajectory is matched with the spatial position of the geological parameter model, and the corresponding position on the equivalent virtual straight well is assigned according to the interpolation result in the geological parameter model to obtain the logging parameters on the equivalent virtual straight well, thereby completing the correction of the logging curve.
8. A method for correcting a logging curve of a deviated well, comprising the method for correcting a logging curve of a deviated well according to any one of claims 1 to 7, further comprising the steps of:
s7: repeating the steps S4-S6 for the multiple logging curves of each inclined well to obtain multiple corrected logging curves;
s8: and carrying out inter-well fine sand body comparison on adjacent inclined wells, inclined wells and vertical wells.
9. The method of claim 1, wherein in step S7, each slant well at least needs to correct a natural gamma curve, a resistivity curve and a lithology curve in the raw data of the slant well, so as to obtain at least three kinds of logging curves.
10. The method for correcting the logging curve of the inclined shaft according to claim 1, wherein in the step S8, each inclined shaft measures the corresponding thickness of each section of sandstone and mudstone according to the corrected logging curve, and then the thickness and the depth of the stratum of each interval are counted, so that the comparison among the adjacent inclined shaft, the inclined shaft and the straight shaft is performed.
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