Special well type horizontal well reservoir plumb bob thickness correction method

Abstract

The invention discloses a special well type horizontal well reservoir plumb bob thickness correction method, and relates to the technical field of earthquakes and well logging. According to the method, a fault well section and a common well section are divided for a target well along a well track, a plurality of small reservoir layers are divided based on the porosity lower limit for the common well section, and the plumb bob thickness of each small reservoir layer is calculated layer by layer; the repeatedly calculated small layers of the reservoir are removed, and correction of the thickness of the reservoir plumb bob of the common well section is achieved; for a fault well section, making an auxiliary line in a seismic depth profile map, comparing a connecting line of a starting point and an ending point with an extension line of a stratum interface or a top layer interface of a reservoir where the starting point is located at an intersection point, reading the distance from the starting point to the intersection point by utilizing geosteering software, and calculating the plumb bob thickness of the reservoir of the fault well section, and summarizing the plumb bob thicknesses of the common well section and the fault well section to obtain the plumb bob thickness of the target well reservoir. According to the method, the fault well section and the common well section are considered, so that the calculation of the plumb bob thickness of the special well type horizontal well reservoir is more accurate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of seismic and logging technology, and in particular to a special well type horizontal well reservoir plumb thickness correction method. BACKGROUND

[0002] At present, with the continuous development of oil and gas exploration and development, it is very important to obtain the plumb thickness of the drilled reservoir in actual production. As an important geological parameter, the plumb thickness of the reservoir is the basis for correctly interpreting and evaluating the characteristics and sedimentary characteristics of the underground formation, and is also a key indicator for reserves declaration, well deployment and exploration evaluation.

[0003] However, it is not easy to obtain the accurate plumb thickness of the drilled reservoir. When the well type of the drilling is a small diameter and small inclination well, the plumb thickness of the drilled reservoir is approximately equal to the vertical thickness, and the calculation of the plumb thickness of these two well types is not difficult. If the well type of the drilling is a high inclination well or a horizontal well with continuously changing inclination angles, the calculation of the plumb thickness of the drilled reservoir will be very difficult, and the calculation of the plumb thickness of the drilled reservoir will become more difficult due to the complex and changing formation dip angles.

[0004] For example, the application publication date is October 22, 2021, the application publication number is CN113534244A, and the name is "determination method and device for plumb thickness of drilled reservoir". According to the seismic data, the seismic dip angle attribute body is determined; the accurate spatial distribution position of the drilled reservoir is determined according to the acoustic curve of the logging data; the pseudo well inclination curve is determined according to the accurate spatial distribution position of the drilled reservoir and the seismic dip angle attribute body; and the plumb thickness of the drilled reservoir is determined according to the drilling information and the pseudo well inclination curve.

[0005] The above-mentioned prior art only considers the ideal state of the well type, and does not consider the special well type with many repeated well sections or faults. The error of the reservoir plumb thickness determined by the prior art is large. SUMMARY

[0006] In order to overcome the defects and deficiencies in the above-mentioned prior art, the present application provides a special well type horizontal well reservoir plumb thickness correction method. The purpose of the present application is to solve the problem that the calculation result of the plumb thickness of the drilled reservoir is large when the special well type with many repeated well sections or faults is encountered.

[0007] In order to solve the problems existing in the above-mentioned prior art, the present application is realized by the following technical scheme.

[0008] The first aspect of the present application provides a special well type horizontal well reservoir plumb thickness correction method, which comprises: S1, obtaining seismic data and logging data of a target well, interpreting the logging data to obtain an interpreted profile, and interpreting the seismic data to obtain a seismic depth profile; dividing a well section of the target well into a fault well section and a normal well section along a borehole trajectory of the target well according to the seismic depth profile in the seismic data of the target well; S2, for the normal well section, dividing a reservoir based on a porosity lower limit to obtain a plurality of reservoir sublayers, and recording a starting depth and an ending depth of each reservoir sublayer; obtaining a seismic stratigraphic dip angle and a deviation angle along the borehole trajectory from the seismic depth profile or logging imaging data; corresponding the plurality of divided reservoir sublayers with the seismic stratigraphic dip angle and the deviation angle; determining a relationship between the borehole trajectory and the stratum according to the starting depth, the ending depth of the reservoir sublayer, and the corresponding seismic stratigraphic dip angle and deviation angle along the borehole trajectory; selecting a corresponding calculation formula according to the determined relationship between the borehole trajectory and the stratum, and calculating a plumb thickness of each reservoir sublayer layer by layer; finding repeated reservoir sublayers according to the vertical depth, and eliminating the repeatedly calculated reservoir sublayers; the stratigraphic dip angle of the subsequent two reservoir sublayers of the eliminated reservoir sublayer is calculated according to the average of the stratigraphic dip angles of the previous reservoir sublayer of the eliminated reservoir sublayer, the eliminated reservoir sublayer, and the next two reservoir sublayers of the eliminated reservoir sublayer; and correcting the plumb thickness of the reservoir sublayer with the recalculated stratigraphic dip angle; S3, for the fault well section, obtaining a seismic stratigraphic dip angle and a deviation angle of a reservoir along the borehole trajectory of the fault well section from the seismic depth profile or logging imaging data; drawing a line connecting a starting point and an ending point of the reservoir of the fault well section in the seismic depth profile, and drawing an extension line of a bottom interface or a top interface of the reservoir at the starting point, so that the line connecting the starting point and the ending point intersects with the extension line of the stratigraphic interface or the top interface of the reservoir at the starting point at a point; reading out a distance from the starting point to the point by using a geosteering software, and calculating a plumb thickness of the reservoir of the fault well section by using the seismic stratigraphic dip angle, the deviation angle, and the distance from the starting point to the point. S4, summarizing the corrected plumb thicknesses of the reservoir sublayers calculated in the step S2 and the plumb thickness of the reservoir of the fault well section obtained in the step S3, so as to obtain a plumb thickness of a reservoir of the target well.

[0009] Further preferably, in the step S1, interpreting the logging data to obtain the interpreted profile comprises: applying a logging interpretation software to interpret the logging data to obtain a lithology profile, and porosity parameters, water saturation parameters, and permeability parameters.

[0010] Further preferably, dividing the reservoir based on the porosity lower limit to obtain the plurality of reservoir sublayers, and recording the starting depth and the ending depth of each reservoir sublayer comprises: dividing the reservoir according to the lower limit of the porosity of the stratum, and simultaneously obtaining the top depth and the bottom depth of the depth measurement of each reservoir sublayer, and the top depth and the bottom depth of the vertical depth.

[0011] More preferably, the reservoirs are classified according to the lower limit of the formation porosity, specifically, the reservoirs with the formation porosity ≥ 2% are extracted and numbered in sequence.

[0012] Further preferably, the seismic formation dip along the borehole trajectory is obtained from the logging imaging data, including: The true dip of the formation obtained from the logging imaging data is corrected to obtain the apparent dip of the formation along the borehole trajectory direction, and the apparent dip of the formation along the borehole trajectory direction is the seismic formation dip along the borehole trajectory.

[0013] More preferably, the true dip of the formation is corrected to obtain the apparent dip of the formation along the borehole trajectory direction, specifically, the direction perpendicular to the formation contour is the true direction, and the corresponding dip is the true dip; the direction not perpendicular to the formation contour is the apparent direction, and the corresponding dip is the apparent dip, the included angle between the true direction and the apparent direction is ; the true dip > the apparent dip, and the apparent dip = the true dip*cos .

[0014] Further preferably, the seismic formation dip along the borehole trajectory is obtained from the seismic depth profile, including: The seismic profile is cut along the borehole trajectory, and the formation dip is read from the seismic profile, with a negative value representing an upward dip and a positive value representing a downward dip.

[0015] Further preferably, according to the relationship between the determined borehole trajectory and the formation, a corresponding calculation formula is selected to calculate the plumb thickness of each reservoir sublayer layer by layer, including: The calculation formula for the downward drilling direction and the downward formation direction, the calculation formula for the downward drilling direction and the upward formation direction, the calculation formula for the upward drilling direction and the upward formation direction, and the calculation formula for the upward drilling direction and the downward formation direction.

[0016] More preferably, the calculation formula for the downward drilling direction and the downward formation direction is: AC = AB*COS(α+θ) / COS(θ); in the formula, AC represents the reservoir plumb thickness, α represents the inclination angle, θ represents the formation dip, and AB*COS(α+θ) represents the vertical thickness of the reservoir.

[0017] More preferably, the calculation formula for the downward drilling direction and the upward formation direction is: AC = AB*COS(α-θ) / COS(θ); in the formula, AC represents the reservoir plumb thickness, α represents the inclination angle, θ represents the formation dip, and AB*COS(α-θ) represents the vertical thickness of the reservoir.

[0018] Further preferably, when the drilling direction is upward and the stratum direction is upward, the calculation formula is: AC=AB*COS(α-θ) / COS(θ); wherein, AC represents the reservoir plumb thickness, α represents the hole inclination angle, θ represents the stratum dip angle, and AB*COS(α-θ) represents the reservoir vertical thickness.

[0019] Further preferably, when the drilling direction is upward and the stratum direction is downward, the calculation formula is: AC=AB*COS(α+θ) / COS(θ); wherein, AC represents the reservoir plumb thickness, α represents the hole inclination angle, θ represents the stratum dip angle, and AB*COS(α+θ) represents the reservoir vertical thickness.

[0020] Further preferably, in the step S3, when the drilling direction is downward and the stratum direction is downward, for a normal fault, the bottom interface extension line of the reservoir at the starting point A is on the extension line of the line connecting the starting point A and the ending point B; for a reverse fault, the bottom interface extension line of the reservoir at the starting point A is on the extension line of the line connecting the starting point A and the ending point B; and the intersection point is F. The calculation formula of the plumb thickness of the reservoir in the fault well section is: AC=AF*COS(α+θ) / COS(θ); wherein, AC represents the plumb thickness of the reservoir in the fault well section, AF represents the length between the starting point A and the intersection point F, α represents the hole inclination angle, and θ represents the stratum dip angle.

[0021] Further preferably, in the step S3, when the drilling direction is downward and the stratum direction is upward, for a normal fault, the bottom interface extension line of the reservoir at the starting point A is on the extension line of the line connecting the starting point A and the ending point B; for a reverse fault, the bottom interface extension line of the reservoir at the starting point A is on the line connecting the starting point A and the ending point B; and the intersection point is F. The calculation formula of the plumb thickness of the reservoir in the fault well section is: AC=AF*COS(α-θ) / COS(θ); wherein, AC represents the plumb thickness of the reservoir in the fault well section, AF represents the length between the starting point A and the intersection point F, α represents the hole inclination angle, and θ represents the stratum dip angle.

[0022] Further preferably, in the step S3, when the drilling direction is upward and the stratum direction is downward, for a normal fault, the top interface extension line of the reservoir at the starting point A is on the extension line of the line connecting the starting point A and the ending point B; for a reverse fault, the top interface extension line of the reservoir at the starting point A is on the line connecting the starting point A and the ending point B; and the intersection point is F. The calculation formula of the plumb thickness of the reservoir in the fault well section is: AC=AF*COS(α-θ) / COS(θ); wherein, AC represents the plumb thickness of the reservoir in the fault well section, AF represents the length between the starting point A and the intersection point F, α represents the hole inclination angle, and θ represents the stratum dip angle.

[0023] Further preferably, in step S3, when the drilling direction is upward and the formation direction is upward; for a normal fault, the extension line of the top layer interface of the reservoir where the starting point A is located is compared with the line connecting the starting point A and the ending point B; for a reverse fault, the extension line of the top layer interface of the reservoir where the starting point A is located is compared with the line connecting the starting point A and the ending point B; the intersection point is F. The formula for calculating the plumb thickness of the reservoir in the fault section is AC=AF*COS(α+θ) / COS(θ), where AC represents the plumb thickness of the reservoir in the fault section, AF represents the length between the starting point A and the intersection point F, α represents the well inclination angle, and θ represents the formation dip angle.

[0024] Compared with the prior art, the beneficial technical effects of the present invention are as follows: 1. This invention can completely replace existing methods for determining the plumb line thickness of drilled reservoirs, calculating the plumb line thickness of reservoirs encountered in special and complex well types for mineral reserve calculation. In practical applications, this invention considers faulted well sections and ordinary well sections, correcting calculation errors for reservoir plumb line thickness in faulted sections. Simultaneously, for ordinary well sections, it removes redundantly calculated reservoir sublayers, making the calculation of reservoir plumb line thickness in special well types and horizontal wells more accurate, while also improving calculation efficiency.

[0025] 2. Compared with reading the thickness from geological guidance software, the present invention is more convenient and intuitive. At the same time, it solves the problem of large calculation errors in complex well types by traditional formulas. It can correct the reservoir plumb line thickness of special and complex well types, ensure the accuracy of reservoir plumb line thickness calculation results and reduce calculation errors. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a flowchart of the special well type horizontal well reservoir plumb bob thickness correction process of the present invention; Figure 2 This is a reservoir delineation diagram of a well in Gaoshi, Sichuan Basin, in an example of this invention. Figure 3 This is a statistical table of a small layer in a well in Gaoshi, Sichuan Basin, in an example of this invention; Figure 4 This is a diagram illustrating the formation dip angle picking scheme of the present invention. Figure 5This is a schematic diagram of the formation dip angle being picked up in a well in Gaoshi, Sichuan Basin, in an example of the present invention. Figure 6 This is a table showing the calculation results of the plumb bob thickness in a well in Gaoshi, Sichuan Basin, as an example of this invention. Figure 7 This is a table showing the thickness correction results of a plumb bob in a well in Gaoshi, Sichuan Basin, in an example of this invention. Figure 8 This is a calculation model diagram of the ordinary well section of the present invention, with the drilling direction downward and the formation direction downward. Figure 9 This is a calculation model diagram of the ordinary well section of the present invention, with the drilling direction downward and the formation direction upward; Figure 10 This is a calculation model diagram of the ordinary well section of the present invention with the drilling direction upward and the formation direction upward; Figure 11 This is a calculation model diagram of the ordinary well section of the present invention, with the drilling direction upward and the formation direction downward. Figure 12 This is a calculation model diagram of the fault well section of the present invention, showing the drilling direction downwards and the formation direction downwards. Figure 13 This is a calculation model diagram of the reverse fault drilling direction downward and the formation direction downward in the fault well section of the present invention; Figure 14 This is a calculation model diagram of the fault well section of the present invention, showing the drilling direction downward and the formation direction upward. Figure 15 This is a calculation model diagram of the reverse fault drilling direction downward and the formation direction upward in the fault well section of the present invention; Figure 16 This is a calculation model diagram of the fault well section of the present invention, showing the drilling direction of the fault upward and the formation direction downward. Figure 17 This is a calculation model diagram of the reverse fault drilling direction upward and the formation direction downward in the fault well section of the present invention; Figure 18 This is a calculation model diagram of the fault well section of the present invention with the drilling direction of the fault upward and the formation direction upward; Figure 19 This is a calculation model diagram of the reverse fault drilling direction and the formation direction in the fault well section of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0028] Example 1 This invention provides a method for correcting the thickness of a vertical plumb line in a horizontal well reservoir of a special well type. The method includes: S1. Obtain seismic data and well logging data of the target well, interpret the well logging data to obtain the interpretation profile, and interpret the seismic data to obtain the seismic depth profile; based on the seismic depth profile in the seismic data of the target well, divide the well section of the target well into fault sections and ordinary sections along the wellbore trajectory of the target well. S2. For ordinary well sections, reservoirs are divided based on the lower limit of porosity, resulting in multiple reservoir sub-layers. The starting and ending depths of each reservoir sub-layer are recorded. Seismic formation dip and wellbore inclination angles along the wellbore trajectory are obtained from seismic depth profiles or well logging imaging data. The divided reservoir sub-layers are correlated with the seismic formation dip and wellbore inclination angles. The relationship between the wellbore trajectory and the formation is determined based on the starting and ending depths of the reservoir sub-layers and the corresponding seismic formation dip and wellbore inclination angles along the wellbore trajectory. Based on the relationship between the layers, select the corresponding calculation formula and calculate the plumb thickness of each reservoir sublayer layer by layer; find the duplicate reservoir sublayers according to the vertical depth, and remove the duplicate reservoir sublayers. The formation dip angle of the two reservoir sublayers following the removed reservoir sublayer is calculated based on the average of the formation dip angles of the reservoir sublayer preceding the removed reservoir sublayer, the removed reservoir sublayer, and the two reservoir sublayers following the removed reservoir sublayer. Based on the recalculated formation dip angle, correct the plumb thickness of the reservoir sublayer with the recalculated formation dip angle. S3. For fault sections, the seismic dip angle and well inclination angle of the reservoir along the wellbore trajectory are obtained from the seismic depth profile or well logging imaging data. In the seismic depth profile, a line is drawn connecting the starting point and the ending point of the reservoir in the fault section. An extension line of the bottom or top interface of the reservoir where the starting point is located is drawn. The line connecting the starting point and the ending point intersects with the extension line of the formation interface or top interface of the reservoir where the starting point is located. The distance from the starting point to the intersection point is read using geological steering software. The plumb line thickness of the reservoir in the fault section is calculated using the seismic dip angle, well inclination angle, and the distance from the starting point to the intersection point. S4. By summing the corrected plumb thickness of each reservoir layer obtained in step S2 and the plumb thickness of the fault well section obtained in step S3, the plumb thickness of the target well reservoir can be obtained.

[0029] This invention can completely replace existing methods for determining the plumb line thickness of reservoirs encountered during drilling, calculating the plumb line thickness of reservoirs encountered in special and complex well types for mineral reserve calculation. The method of this invention considers faulted well sections and ordinary well sections, correcting the calculation error of reservoir plumb line thickness in faulted well sections. Simultaneously, for ordinary well sections, it removes redundantly calculated reservoir sublayers, making the calculation of reservoir plumb line thickness in special well types (horizontal wells) more accurate and improving calculation efficiency.

[0030] In a specific implementation of the present invention, a method for correcting the thickness of a horizontal well reservoir using a plumb bob is provided, as shown in the appendix to the specification. Figure 1 The flowchart for the special well type horizontal well reservoir plumb line thickness correction of this invention is shown, and may include: Seismic and logging data of the target well are acquired. The logging data is interpreted to obtain an interpretation profile, and the seismic data is interpreted to obtain a seismic depth profile. Based on the seismic depth profile in the target well's seismic data, the well section is divided into faulted and ordinary sections along the wellbore trajectory. For ordinary sections, reservoirs are divided based on the lower porosity limit, resulting in multiple reservoir sub-layers. The starting and ending depths of each reservoir sub-layer are recorded. The seismic formation dip and well inclination along the wellbore trajectory are obtained from the seismic depth profile or logging imaging data. The process involves mapping the divided reservoir sub-layers to seismic formation dip angles and wellbore inclination angles; determining the relationship between the wellbore trajectory and the formation based on the starting and ending depths of the reservoir sub-layers, the corresponding seismic formation dip angles along the wellbore trajectory, and the wellbore inclination angle; selecting the appropriate calculation formula based on the determined relationship between the wellbore trajectory and the formation, and calculating the plumb line thickness of each reservoir sub-layer layer by layer; identifying duplicate reservoir sub-layers based on vertical depth, removing duplicated reservoir sub-layers, and determining the formation dip angle of the two subsequent reservoir sub-layers following the removed sub-layer based on the dip angle of the removed sub-layer. The dip angle of the reservoir sub-layer preceding the removed sub-layer, the removed sub-layer, and the two sub-layers following the removed sub-layer are calculated. Based on the recalculated dip angle, the plumb line thickness of the reservoir sub-layer with the recalculated dip angle is corrected. For fault sections, the seismic dip angle and well inclination angle of the reservoir along the wellbore trajectory are obtained from seismic depth profiles or well logging imaging data. A line is drawn connecting the starting and ending points of the fault section reservoir on the seismic depth profile, and the reservoir at the starting point is plotted. The bottom or top interface extension line is used to make the line connecting the starting point and the ending point intersect with the extension line of the formation interface or top interface of the reservoir where the starting point is located. The distance from the starting point to the intersection point is read using geological guidance software. The plumb line thickness of the reservoir in the fault section is calculated by using the seismic formation dip angle, well inclination angle and the distance from the starting point to the intersection point. The plumb line thickness of the target well reservoir is obtained by summing the corrected plumb line thickness of each reservoir layer calculated in step S2 and the plumb line thickness of the fault section reservoir obtained in step S3.

[0031] In a specific implementation of a method for correcting the thickness of a horizontal well reservoir using a plumb bob, according to an embodiment of the present invention, in one embodiment, interpreting logging data to obtain an interpretation profile includes: Well logging data were interpreted using well logging interpretation software to obtain lithological profiles, porosity parameters, water saturation parameters, and permeability parameters.

[0032] In this embodiment, based on the logging data of the target well, the lithological profile, porosity parameters, water saturation parameters, and permeability parameters of the target well are extracted. The logging data can be interpreted using logging interpretation software.

[0033] In a specific implementation of the method for correcting the thickness of a horizontal well reservoir using a plumb line according to a particular well type of the present invention, in one embodiment, the reservoir is divided based on the lower limit of porosity to obtain multiple reservoir sub-layers, and the starting depth and ending depth of each reservoir sub-layer are recorded, including: Reservoirs are classified based on the lower limit of formation porosity, and the top and bottom depths of each reservoir sublayer, as well as the top and bottom depths of the vertical depth, are obtained. Classifying reservoirs based on the lower limit of formation porosity specifically means classifying reservoirs according to porosity > 2%. In particular, reservoirs with formation porosity ≥ 2% are extracted and numbered sequentially.

[0034] In a specific implementation of a method for correcting the thickness of a horizontal well reservoir using a plumb bob, one embodiment of the present invention involves obtaining the seismic formation dip angle along the wellbore trajectory from well logging imaging data, including: The apparent dip angle of the formation, obtained from well logging imaging data, is corrected to obtain the apparent dip angle along the wellbore trajectory. This apparent dip angle along the wellbore trajectory is the seismic formation dip angle along the wellbore trajectory. Specifically, the azimuth perpendicular to the formation contour lines is the true azimuth, and the corresponding dip angle is the true dip angle; the azimuth not perpendicular to the formation contour lines is the apparent azimuth, and the corresponding dip angle is the apparent dip angle. The angle between the true azimuth and the apparent azimuth is... True dip angle > apparent dip angle, apparent dip angle = true dip angle * cos .

[0035] In a specific implementation of the method for correcting the thickness of a horizontal well reservoir using a special well type according to an embodiment of the present invention, in one embodiment, the seismic formation dip angle along the wellbore trajectory is obtained from a seismic depth profile. This includes: cutting a seismic profile along the wellbore trajectory and reading the formation dip angle from the seismic profile; negative values ​​represent updip, and positive values ​​represent downdip. In this embodiment, the accuracy of reading the formation dip angle from the seismic profile can be verified by correcting the true dip angle of the formation obtained from the well logging imaging data to obtain the apparent dip angle along the wellbore trajectory.

[0036] In a specific implementation of the method for correcting the plumb line thickness of a horizontal well reservoir of a special well type according to an embodiment of the present invention, in one embodiment, based on the determined relationship between the wellbore trajectory and the formation, a corresponding calculation formula is selected, and the plumb line thickness of each reservoir sublayer is calculated layer by layer, including: a calculation formula with the drilling direction downward and the formation direction downward, a calculation formula with the drilling direction downward and the formation direction upward, a calculation formula with the drilling direction upward and the formation direction upward, and a calculation formula with the drilling direction upward and the formation direction downward.

[0037] Refer to the instruction manual appendix Figure 8 As shown, the formula for calculating the vertical thickness of the reservoir is: AC=AB*COS(α+θ) / COS(θ); where AC represents the vertical thickness of the reservoir, α represents the well inclination angle, θ represents the formation dip angle, and AB*COS(α+θ) represents the vertical thickness of the reservoir.

[0038] Refer to the instruction manual appendix Figure 9 As shown, the calculation formula for drilling direction downward and formation direction upward is: AC=AB*COS(α-θ) / COS(θ); where AC represents the vertical thickness of the reservoir, α represents the well inclination angle, θ represents the formation dip angle, and AB*COS(α-θ) represents the vertical thickness of the reservoir.

[0039] Refer to the instruction manual appendix Figure 10 As shown, the formula for calculating the vertical thickness of the reservoir is: AC=AB*COS(α-θ) / COS(θ); where AC represents the vertical thickness of the reservoir, α represents the well inclination angle, θ represents the formation dip angle, and AB*COS(α-θ) represents the vertical thickness of the reservoir.

[0040] Refer to the instruction manual appendix Figure 11 As shown, the formula for calculating the vertical thickness of the reservoir is: AC=AB*COS(α+θ) / COS(θ); where AC represents the vertical thickness of the reservoir, α represents the well inclination angle, θ represents the formation dip angle, and AB*COS(α+θ) represents the vertical thickness of the reservoir.

[0041] In a specific implementation of the method for correcting the thickness of a horizontal well reservoir using a plumb bob in a special well type according to an embodiment of the present invention, in step S3, when the drilling direction is downward and the formation direction is downward, for a normal fault, the extension line of the bottom interface of the reservoir where the starting point A is located is compared with the line connecting the starting point A and the ending point B; for a reverse fault, the intersection point of the extension line of the bottom interface of the reservoir where the starting point A is located compared with the line connecting the starting point A and the ending point B is F. The formula for calculating the plumb thickness of the reservoir in the fault section is AC=AF*COS(α+θ) / COS(θ), where AC represents the plumb thickness of the reservoir in the fault section, AF represents the length between the starting point A and the intersection point F, α represents the well inclination angle, and θ represents the formation dip angle.

[0042] In a specific implementation of a special well type horizontal well reservoir plumb line thickness correction method according to an embodiment of the present invention, in step S3, when the drilling direction is downward and the formation direction is upward, for a normal fault, the extension line of the bottom interface of the reservoir where the starting point A is located is compared with the extension line of the line connecting the starting point A and the ending point B; for a reverse fault, the extension line of the bottom interface of the reservoir where the starting point A is located is compared with the line connecting the starting point A and the ending point B; the intersection point is F. The formula for calculating the plumb thickness of the reservoir in the fault section is AC=AF*COS(α-θ) / COS(θ), where AC represents the plumb thickness of the reservoir in the fault section, AF represents the length between the starting point A and the intersection point F, α represents the well inclination angle, and θ represents the formation dip angle.

[0043] In a specific implementation of the method for correcting the thickness of a horizontal well reservoir using a plumb bob in a special well type according to an embodiment of the present invention, in step S3, when the drilling direction is upward and the formation direction is downward; for a normal fault, the extension line of the top layer interface of the reservoir where the starting point A is located is compared with the extension line of the line connecting the starting point A and the ending point B; for a reverse fault, the extension line of the top layer interface of the reservoir where the starting point A is located is compared with the line connecting the starting point A and the ending point B; the intersection point is F; The formula for calculating the plumb thickness of the reservoir in the fault section is AC=AF*COS(α-θ) / COS(θ), where AC represents the plumb thickness of the reservoir in the fault section, AF represents the length between the starting point A and the intersection point F, α represents the well inclination angle, and θ represents the formation dip angle.

[0044] In a specific implementation of a special well type horizontal well reservoir plumb line thickness correction method according to an embodiment of the present invention, in step S3, when the drilling direction is upward and the formation direction is upward; for a normal fault, the extension line of the top layer interface of the reservoir where the starting point A is located is compared with the line connecting the starting point A and the ending point B; for a reverse fault, the extension line of the top layer interface of the reservoir where the starting point A is located is compared with the extension line connecting the starting point A and the ending point B; the intersection point is F; The formula for calculating the plumb thickness of the reservoir in the fault section is AC=AF*COS(α+θ) / COS(θ), where AC represents the plumb thickness of the reservoir in the fault section, AF represents the length between the starting point A and the intersection point F, α represents the well inclination angle, and θ represents the formation dip angle.

[0045] The above-mentioned calculation formulas for drilling direction downwards and formation direction downwards, drilling direction downwards and formation direction upwards, drilling direction upwards and formation direction upwards, and drilling direction upwards and formation direction downwards are illustrative examples. Those skilled in the art will understand that, in practice, the above formulas can be modified in a certain way and other parameters or data can be added, or other specific formulas can be provided, all of which should fall within the protection scope of this invention.

[0046] Example 2 In this embodiment, a well in Gaoshi, Sichuan Basin, is used as an example to illustrate the plumb line thickness correction method for horizontal well reservoirs of the present invention. This well in Gaoshi, Sichuan Basin, does not have fault sections, only ordinary sections. Therefore, in this example, plumb line thickness correction is only performed on the ordinary sections.

[0047] In this embodiment, well logging interpretation software was first run to interpret the well logging data of a well in Gaoshi, Sichuan Basin, to obtain the well's lithological profile, porosity parameters, water saturation parameters, and permeability parameters. The interpretation results are attached. Figure 2 As shown.

[0048] Reservoirs were delineated based on the lower limit of formation porosity, and the top and bottom depths of the depth sounding and vertical depth of each reservoir sublayer were obtained. Delineation based on the lower limit of formation porosity specifically means delineating reservoirs according to a porosity > 2%. The statistical table of the delineation results for each reservoir sublayer is shown below. Figure 3 As shown.

[0049] Refer to the instruction manual appendix Figure 4 As shown, the apparent dip angle of the formation obtained by well logging imaging data is corrected to obtain the apparent dip angle of the formation along the wellbore trajectory. This apparent dip angle of the formation along the wellbore trajectory is the seismic dip angle of the formation along the wellbore trajectory.

[0050] Alternatively, refer to the instruction manual appendix. Figure 5 As shown, a seismic profile is cut along the wellbore trajectory, and the formation dip angle is read from the seismic profile. Negative values ​​represent updip, and positive values ​​represent downdip. In this embodiment, the accuracy of the formation dip angle read from the seismic profile can be verified by the apparent dip angle of the formation obtained along the wellbore trajectory after correction of the true dip angle of the formation picked up from the well logging imaging data.

[0051] Import the seismic formation dip angles along the wellbore trajectory into an Excel spreadsheet to ensure that the sub-layer well inclination angle, formation dip angle, starting depth, and ending depth correspond; then, determine the relationship between the wellbore trajectory and the formation based on this spreadsheet, and select the corresponding calculation formula based on the determined relationship between the wellbore trajectory and the formation. Figures 8-11 The calculation models corresponding to the four relationships shown are used to calculate the plumb thickness of each reservoir layer layer by layer; the results are shown in the attached figure. Figure 6 The calculation results are shown in the table below.

[0052] In practical applications, the method of this invention can easily and directly calculate the reservoir plumb line thickness using an Excel spreadsheet, which not only saves enterprise costs but also improves calculation efficiency.

[0053] From the appendix Figure 6The calculation results table shows that, starting from the vertical depth, the ending vertical depth of layer 4 is consistent with the starting vertical depth of layer 10, indicating that layers 5-9 were calculated repeatedly and need to be removed. However, the dip angles of sub-layers 10 and 11 need to be recalculated using differential values. The dip angle of layer 10 changes from 2.87° to 2.39°, and that of layer 11 changes from 1.25° to 2.39°. This is calculated using the average value of sub-layers 4-11: 2.39 = (2.78 + 1.15 + 1.15 + 3.84 + 3.84 + 2.31 + 1.25) / 8. Therefore, the dip angles of sub-layers 10 and 11 become 2.39°. Then, using the removed reservoir sub-layers and the corrected dip angles, the plumb line thickness of each reservoir sub-layer is recalculated, resulting in the following... Figure 7 The results are shown.

[0054] Example 3 In this embodiment, when a fault section exists in the target well, the seismic dip angle and well inclination angle of the reservoir along the wellbore trajectory are obtained from the seismic depth profile or well logging imaging data. A line is drawn connecting the starting point and the ending point of the fault section reservoir in the seismic depth profile, and an extension line is drawn for the bottom or top interface of the reservoir where the starting point is located. The line connecting the starting point and the ending point intersects with the extension line of the formation interface or top interface of the reservoir where the starting point is located. The distance from the starting point to this intersection point is read using geological steering software. The plumb line thickness of the fault section reservoir is calculated using the seismic dip angle, well inclination angle, and the distance from the starting point to this intersection point.

[0055] As an example of this embodiment, when the drilling direction is downward and the formation direction is downward, refer to the appendix of the specification. Figure 12 As shown, for a normal fault, the extended line of the bottom interface of the reservoir where the starting point A is located is relative to the line connecting the starting point A and the ending point B. (Refer to the appendix of the instruction manual.) Figure 13 As shown, for a reverse fault, the intersection point of the extended line of the bottom interface of the reservoir where the starting point A is located with the extended line of the line connecting the starting point A and the ending point B is F; the formula for calculating the plumb thickness of the reservoir in this fault section is AC=AF*COS(α+θ) / COS(θ), where AC represents the plumb thickness of the reservoir in this fault section, AF represents the length between the starting point A and the intersection point F, α represents the well inclination angle, and θ represents the formation dip angle.

[0056] As another example of this embodiment, when the drilling direction is downward and the formation direction is upward, refer to the appendix of the specification. Figure 14 As shown, for a normal fault, the extension line of the bottom interface of the reservoir where the starting point A is located is on the extension line of the line connecting the starting point A and the ending point B. (Refer to the appendix of the instruction manual.) Figure 15As shown, for a reverse fault, the extended line of the bottom interface of the reservoir where the starting point A is located is compared to the line connecting the starting point A and the ending point B. The intersection point is F. The formula for calculating the plumb thickness of the reservoir in this fault section is: AC = AF * COS(α-θ) / COS(θ), where AC represents the plumb thickness of the reservoir in this fault section, AF represents the length between the starting point A and the intersection point F, α represents the well inclination angle, and θ represents the formation dip angle.

[0057] As another example of this embodiment, when the drilling direction is upward and the formation direction is downward, refer to the appendix of the specification. Figure 16 As shown, for a normal fault, the extension line of the top interface of the reservoir where the starting point A is located is relative to the extension line of the line connecting the starting point A and the ending point B. (Refer to the appendix of the instruction manual.) Figure 17 As shown, for a reverse fault, the extended line of the top interface of the reservoir where the starting point A is located is compared to the line connecting the starting point A and the ending point B. The intersection point is F. The formula for calculating the plumb thickness of the reservoir in this fault section is: AC = AF * COS(α-θ) / COS(θ), where AC represents the plumb thickness of the reservoir in this fault section, AF represents the length between the starting point A and the intersection point F, α represents the well inclination angle, and θ represents the formation dip angle.

[0058] As another example of this embodiment, when the drilling direction is upward and the formation direction is upward, refer to the appendix of the specification. Figure 18 As shown, for a normal fault, the extension line of the top interface of the reservoir where the starting point A is located is relative to the line connecting the starting point A and the ending point B. (Refer to the appendix of the instruction manual.) Figure 19 As shown, for a reverse fault, the extension line of the top interface of the reservoir where the starting point A is located is compared to the extension line of the line connecting the starting point A and the ending point B. The intersection point is F. The formula for calculating the plumb thickness of the reservoir in this fault section is AC=AF*COS(α+θ) / COS(θ), where AC represents the plumb thickness of the reservoir in this fault section, AF represents the length between the starting point A and the intersection point F, α represents the well inclination angle, and θ represents the formation dip angle.

[0059] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for special well type horizontal well reservoir plumb thickness correction, characterized in that, The method comprises: S1, obtaining seismic data and logging data of a target well, interpreting the logging data to obtain an interpreted profile, and interpreting the seismic data to obtain a seismic depth profile; dividing a fault well section and a normal well section of a well section of the target well along a borehole trajectory of the target well according to a seismic depth profile graph in the seismic data of the target well; S2, for the normal well section, dividing a reservoir based on a porosity lower limit to obtain a plurality of reservoir sublayers, and recording a starting depth and an ending depth of each reservoir sublayer; obtaining a seismic stratigraphic dip angle and a deviation angle along the borehole trajectory from the seismic depth profile graph or logging imaging data; corresponding the plurality of divided reservoir sublayers with the seismic stratigraphic dip angle and the deviation angle; determining a relationship between the borehole trajectory and the stratum according to the starting depth, the ending depth of the reservoir sublayer, and the corresponding seismic stratigraphic dip angle and deviation angle along the borehole trajectory; selecting a corresponding calculation formula according to the determined relationship between the borehole trajectory and the stratum, and calculating a plumb thickness of each reservoir sublayer layer by layer; finding a repeated reservoir sublayer according to a vertical depth, eliminating the repeatedly calculated reservoir sublayer, and calculating a stratigraphic dip angle of the subsequent two reservoir sublayers of the eliminated reservoir sublayer according to an average of the stratigraphic dip angle of the previous reservoir sublayer of the eliminated reservoir sublayer, the eliminated reservoir sublayer, and the next two reservoir sublayers of the eliminated reservoir sublayer; and correcting the plumb thickness of the reservoir sublayer with the recalculated stratigraphic dip angle; S3, for the fault well section, obtaining a seismic stratigraphic dip angle and a deviation angle of a reservoir along the borehole trajectory from the seismic depth profile graph or logging imaging data; drawing a connecting line of a starting point and an ending point of the reservoir of the fault well section in the seismic depth profile graph, and drawing an extension line of a bottom interface or a top interface of a reservoir at the starting point, so that the connecting line of the starting point and the ending point intersects with the extension line of the stratigraphic interface or the top interface of the reservoir at the starting point to form an intersection point; reading out a distance from the starting point to the intersection point by using a geosteering software, and calculating the plumb thickness of the reservoir of the fault well section by using the seismic stratigraphic dip angle, the deviation angle, and the distance from the starting point to the intersection point; S4, collecting the corrected plumb thickness of each reservoir sublayer calculated in the S2 step and the plumb thickness of the reservoir of the fault well section obtained in the S3 step, so as to obtain the plumb thickness of the reservoir of the target well.

2. A method for special well type horizontal well reservoir plumb thickness correction as claimed in claim 1 wherein, In the S1 step, the interpreted profile obtained by interpreting the logging data comprises: Using logging interpretation software to interpret the logging data to obtain a lithology profile and porosity parameters, water saturation parameters, and permeability parameters.

3. A method for special well type horizontal well reservoir plumb thickness correction as claimed in claim 1 wherein, Dividing the reservoir based on the porosity lower limit to obtain a plurality of reservoir sublayers, and recording a starting depth and an ending depth of each reservoir sublayer, comprises: Dividing the reservoir according to the lower limit of the porosity of the stratum, and simultaneously obtaining the top depth and the bottom depth of the depth measurement of each reservoir sublayer and the top depth and the bottom depth of the vertical depth.

4. A method of special well type horizontal well reservoir plumb thickness correction as claimed in claim 3, wherein, The reservoir with a porosity ≥ 2% is extracted and numbered in sequence.

5. The method for correcting the thickness of a horizontal well reservoir using a plumb bob as described in claim 1, characterized in that... The seismic stratigraphic dip angle along the borehole trajectory is obtained from the logging imaging data, comprising: The true dip angle of the stratum picked up through the well logging imaging data is corrected to obtain the apparent dip angle of the stratum along the well trajectory direction, which is the seismic stratum dip angle along the well trajectory.

6. A special well type horizontal well reservoir plumb thickness correction method as claimed in claim 5, characterized in that, The true dip angle of the stratum is obtained along the wellbore trajectory direction after correction, specifically, the direction perpendicular to the stratum contour is the true direction, and the corresponding dip angle is the true dip angle; the direction not perpendicular to the stratum contour is the apparent direction, and the corresponding dip angle is the apparent dip angle, the included angle between the true direction and the apparent direction is ; the true dip angle > the apparent dip angle, the apparent dip angle = the true dip angle*cos .

7. A special well type horizontal well reservoir plumb thickness correction method as claimed in claim 1, wherein, The seismic stratum dip angle along the well trajectory is picked up from the seismic depth profile, including: The seismic profile is cut along the well trajectory, and the stratum dip angle is read from the seismic profile, with the negative value representing the upward dip and the positive value representing the downward dip.

8. A method for special well type horizontal well reservoir plumb thickness correction according to any of claims 1-7, characterized in that, According to the determined relationship between the well trajectory and the stratum, the corresponding calculation formula is selected to calculate the plumb thickness of each reservoir sublayer, including: The calculation formula for the downward drilling direction and the downward stratum direction, the calculation formula for the downward drilling direction and the upward stratum direction, the calculation formula for the upward drilling direction and the upward stratum direction, and the calculation formula for the upward drilling direction and the downward stratum direction.

9. A special well type horizontal well reservoir plumb thickness correction method as claimed in claim 8, characterized in that, The calculation formula for the downward drilling direction and the downward stratum direction is: AC=AB*COS(α+θ) / COS(θ); in the formula, AC represents the reservoir plumb thickness, α represents the inclination angle, θ represents the stratum dip angle, and AB*COS(α+θ) represents the reservoir vertical thickness.

10. A method for special well type horizontal well reservoir plumb thickness correction as claimed in claim 8 wherein, The calculation formula for the downward drilling direction and the upward stratum direction is: AC=AB*COS(α-θ) / COS(θ); in the formula, AC represents the reservoir plumb thickness, α represents the inclination angle, θ represents the stratum dip angle, and AB*COS(α-θ) represents the reservoir vertical thickness.

11. A special well type horizontal well reservoir plumb thickness correction method as claimed in claim 8, characterized in that, The calculation formula for the upward drilling direction and the upward stratum direction is: AC=AB*COS(α-θ) / COS(θ); in the formula, AC represents the reservoir plumb thickness, α represents the inclination angle, θ represents the stratum dip angle, and AB*COS(α-θ) represents the reservoir vertical thickness.

12. A special well type horizontal well reservoir plumb thickness correction method as claimed in claim 8, characterized in that, The calculation formula for the upward drilling direction and the downward stratum direction is: AC=AB*COS(α+θ) / COS(θ); in the formula, AC represents the reservoir plumb thickness, α represents the inclination angle, θ represents the stratum dip angle, and AB*COS(α+θ) represents the reservoir vertical thickness.

13. A method for correcting the thickness of a reservoir in a horizontal well of a special well type according to any one of claims 1 to 7, characterized in that, In the S3 step, when the drilling direction is downward and the stratum direction is downward, for a normal fault, the bottom interface extension line of the reservoir at the starting point A is on the line connecting the starting point A and the ending point B; for a reverse fault, the bottom interface extension line of the reservoir at the starting point A is on the extension line of the line connecting the starting point A and the ending point B; the intersection point is F; The plumb thickness calculation formula of the reservoir in the fault well section is: AC=AF*COS(α+θ) / COS(θ), in the formula, AC represents the plumb thickness of the reservoir in the fault well section, AF represents the length between the starting point A and the intersection point F, α represents the inclination angle, and θ represents the stratum dip angle.

14. A method for correcting the thickness of a reservoir in a horizontal well according to any one of claims 1 to 7, characterized in that, In the S3 step, when the drilling direction is downward and the stratum direction is upward, for a normal fault, the bottom interface extension line of the reservoir at the starting point A is on the extension line of the line connecting the starting point A and the ending point B; for a reverse fault, the bottom interface extension line of the reservoir at the starting point A is on the line connecting the starting point A and the ending point B; the intersection point is F; The formula for calculating the plumb thickness of the reservoir in the fault well section is AC=AF*COS(alpha-theta) / COS(theta), wherein AC represents the plumb thickness of the reservoir in the fault well section, AF represents the length between the starting point A and the intersection point F, alpha represents the hole inclination angle, and theta represents the stratum dip angle.

15. A method for correcting the thickness of a reservoir in a horizontal well according to any one of claims 1 to 7, characterized in that, In the step S3, when the drilling direction is upward and the stratum direction is downward; for normal faults, the top interface extension line of the reservoir where the starting point A is located is on the extension line of the connecting line of the starting point A and the ending point B; for reverse faults, the top interface extension line of the reservoir where the starting point A is located is on the extension line of the connecting line of the starting point A and the ending point B; the intersection point is F; The formula for calculating the plumb thickness of the reservoir in the fault well section is AC=AF*COS(alpha-theta) / COS(theta), wherein AC represents the plumb thickness of the reservoir in the fault well section, AF represents the length between the starting point A and the intersection point F, alpha represents the hole inclination angle, and theta represents the stratum dip angle.

16. A method for correcting the thickness of a reservoir in a horizontal well according to any one of claims 1 to 7, characterized in that, In the step S3, when the drilling direction is upward and the stratum direction is upward; for normal faults, the top interface extension line of the reservoir where the starting point A is located is on the extension line of the connecting line of the starting point A and the ending point B; for reverse faults, the top interface extension line of the reservoir where the starting point A is located is on the extension line of the connecting line of the starting point A and the ending point B; the intersection point is F; The formula for calculating the plumb thickness of the reservoir in the fault well section is AC=AF*COS(alpha-theta) / COS(theta), wherein AC represents the plumb thickness of the reservoir in the fault well section, AF represents the length between the starting point A and the intersection point F, alpha represents the hole inclination angle, and theta represents the stratum dip angle.

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