Method for determining fracture tendency of vertical well containing imaging logging information

Abstract

The invention discloses a method for determining the fracture tendency of a vertical well containing imaging logging information, which is used for quickly judging the trend and tendency of a natural fracture of a shaft by comparing a recognition result of the natural fracture of the shaft with a plane expansion mode pattern of the natural fracture of the shaft. And establishing a shaft-surrounding dial, carrying out horizontal projection on the shaft natural crack, and determining an accurate numerical value of the trend of the natural crack. And finally, solving the real tendency of the natural crack of the shaft through a numerical value conversion rule. According to the method, the existing imaging logging information is utilized, and the single well natural fracture tendency information containing the imaging logging information is efficiently obtained by applying a quick and simple operation method. The actual problem that in the process of evaluating the effectiveness of the single-well natural fracture, the effectiveness change of the natural fracture is large due to the fact that the tendency difference is not clear is greatly solved. And the engineering problem that the expansion path of the artificial fracture is not clear due to unclear tendency of the natural fracture in reservoir transformation is greatly improved.

Description

Technical Field

[0001] The present application relates to the technical field of oilfield exploration, and in particular to a method for determining the fracture tendency of a vertical well containing imaging logging data. Background Art

[0002] As global oil and gas resources are increasingly depleted, the exploration and development of unconventional oil and gas resources has gradually become a hot topic in the energy field. In this process, fractured reservoirs, as an important part of unconventional oil and gas resources, are particularly important for research and development. Fracture occurrence, as one of the key indicators affecting the evaluation of fractured reservoirs, has a decisive influence on the rational and efficient development of oil fields. Therefore, accurate prediction of reservoir fracture occurrence is of great practical significance for oil and gas exploration and development.

[0003] At present, the study of fracture occurrence mainly relies on imaging logging data. Although imaging logging technology can effectively identify the fracture development sites in a single well and perform numerical calculations of fracture azimuth and inclination, it has obvious deficiencies in obtaining fracture tendency information. Existing technologies are often unable to directly obtain fracture tendency information from imaging logging data, which leads to difficulties in fracture effectiveness research due to the lack of key data and limits the accurate evaluation of fracture reservoir quality. In addition, due to the large scale of fractures, single-well imaging logging data can often only capture limited fracture information. How to use this limited information to obtain fracture tendency data has become an urgent problem to be solved in fracture reservoir research. Summary of the invention

[0004] The present application provides a method for determining the fracture inclination of a vertical well containing imaging logging data, aiming to solve the problem that the prior art performs numerical calculations on fracture azimuth and fracture dip, but cannot obtain fracture inclination information, and that due to the large scale of fractures, imaging logging data of a single well can only capture a small amount of fracture information.

[0005] The present application provides a method for determining fracture tendency of a vertical well containing imaging logging data, the method comprising:

[0006] S1: Use imaging logging data to determine the location and morphological characteristics of natural fractures in the wellbore;

[0007] S2: Compare the identification results of natural fractures in the wellbore with the spatial distribution characteristics and plane expansion pattern of natural fractures in the wellbore to determine the direction and tendency of the natural fractures;

[0008] S3: Establish a wellbore plane expansion scale diagram to determine the precise numerical value of the natural fracture direction, and obtain the true inclination size of the natural fracture in the wellbore through the "numerical conversion rule".

[0009] In the above solution, optionally, S1 includes:

[0010] S11: Analyze the dynamic and static images in the imaging logging data to determine the spatial development location of natural fractures in the wellbore on a single well;

[0011] S12: Based on the results of natural fracture identification in the wellbore, find out the differences in the morphological characteristics of different natural fractures in the wellbore.

[0012] In the above solution, optionally, the analyzing the dynamic and static images in the imaging logging data to determine the spatial development location of the natural fractures in the wellbore on the single well includes:

[0013] In the process of using dynamic and static images in imaging logging data to identify natural fractures in the wellbore, the influence of induced fractures on the wellbore on the natural fracture identification process is eliminated, and the discontinuity phenomenon in the dynamic and static images caused by the change of conductivity is determined as the development location of the natural fracture; the phenomenon that the natural fracture is difficult to identify in the static image is closely combined with the dynamic image to identify the natural fracture;

[0014] Based on the results of natural fracture identification in the wellbore, the differences in morphological characteristics of different natural fractures in the wellbore are identified, including: identifying and analyzing the morphological characteristics of different natural fractures in the wellbore one by one to ensure the accuracy of fracture dip analysis.

[0015] In the above solution, optionally, S2 includes:

[0016] S21: According to the morphological characteristics of various types of natural fractures contained in the actual wellbore, compile the spatial distribution characteristics and plane development pattern diagram of natural fractures in the wellbore;

[0017] S22: Compare the morphology of natural fractures on the dynamic and static images with the compiled spatial distribution characteristics of natural fractures in the wellbore and the plane expansion pattern diagram to determine the spatial distribution characteristics of the wellbore fractures.

[0018] In the above scheme, optionally, the preparation of the spatial distribution characteristics and plane development pattern diagram of natural fractures in the wellbore according to the morphological characteristics of various types of fractures contained in the actual natural fractures in the wellbore includes:

[0019] By observing the morphological characteristics of various types of natural fractures in actual wellbores, the spatial distribution characteristics and plane expansion pattern diagrams of natural fractures in wellbores were compiled, and extended to single wells with imaging logging data that have not yet compiled the spatial distribution characteristics and plane expansion pattern diagrams of natural fractures in wellbores;

[0020] If the natural fractures captured in the wellbore are all the natural fractures existing in the formation, then when all the fractures are contained in the wellbore, no fracture information will be observed on the wellbore wall;

[0021] When the fracture intersects the wellbore, only very little fracture information can be captured, and its spatial distribution characteristics and plane expansion pattern cannot be restored;

[0022] If the natural fracture is large and can penetrate the wellbore wall, the natural fracture that can be captured in the wellbore is a local part of the natural fracture in the formation, which appears as a sine-like or cosine-like curve with a complete cycle in the dynamic and static images;

[0023] If the natural fracture cuts the wellbore obliquely, it is divided into three situations: the fracture end is just located on the wellbore, the fracture end is inside the wellbore, and the fracture arm is in the wellbore; if the fracture end is just located on the wellbore, a dynamic and static image will be formed on the wellbore that is the same as the situation where the natural fracture can penetrate the wellbore wall; if one side of the fracture end is located inside the wellbore and the other side cuts through the wellbore, a short arc or an incomplete ellipse will be formed on the wellbore; if it is a short arc, it appears as a line segment on the dynamic and static images according to the arc; if it is an incomplete ellipse, it appears as an incomplete elliptical curve with peaks or valleys and partial ascending and descending segments on both sides on the dynamic and static images; if the fracture arm is in the wellbore and can only penetrate part of the wellbore, the natural fracture that can be captured in the wellbore is a small part of the natural fracture in the formation, and the information of the partial fracture penetrating the wellbore is a circular arc curve on the dynamic and static images of the wellbore wall, and it appears as an arc line segment on the dynamic and static images according to the arc.

[0024] In the above scheme, optionally, the morphology of natural fractures on the dynamic and static images is compared with the compiled spatial distribution characteristics of natural fractures in the wellbore and the plane expansion pattern diagram to determine the spatial distribution characteristics of the wellbore fractures, including: dividing the compiled spatial distribution characteristics of natural fractures in the wellbore and the plane expansion pattern diagram according to the "four quadrants" principle: taking the azimuth information possessed by the imaging logging as the basic data, taking the azimuth 0-90° as the first quadrant, 90-180° as the second quadrant, 180-270° as the third quadrant, and 270-360° as the fourth quadrant, the wellbore and the plane expansion diagram are divided into four parts; by making the quadrants where the fracture ends and fracture arms on the dynamic and static images of the imaging logging correspond to the plane expansion pattern diagram, and then judging the spatial distribution characteristics of the natural fractures according to the spatial distribution characteristic pattern diagram of the natural fractures in the wellbore corresponding to the plane expansion pattern diagram.

[0025] In the above solution, optionally, S3 includes:

[0026] S31: establishing a wellbore plane expansion scale diagram based on the dynamic and static plane expansion diagrams of the imaging logging and the azimuth information of the imaging logging;

[0027] S32: Find the horizontal plane of the geometric center of the crack, and determine the precise numerical value of the direction of the natural crack by combining the morphology of the natural crack in the dynamic and static images;

[0028] S33: According to the “numerical conversion rule”, the true inclination size of the natural fractures in the wellbore is obtained.

[0029] In the above scheme, optionally, in S31, the wellbore plane expansion scale diagram is based on the azimuth information of imaging logging, L in the dynamic and static plane expansion diagram of imaging logging is used as the diameter D of the wellbore ring scale disk, 0° azimuth in the positive N direction in the dynamic and static plane expansion diagram of imaging logging is used as the starting point, 90° azimuth is used as the due east direction, and 180° azimuth is used as the due south direction to establish the wellbore plane expansion scale diagram; specifically, the accuracy of the wellbore ring scale disk depends first on the accuracy requirements for the direction and inclination of the fracture in actual applications, and secondly on the reduction in the wellbore arm diameter caused by the increase in the wellbore depth, so as to ensure that the scale accuracy of the established wellbore ring plane expansion scale diagram is in the single digit.

[0030] In the above scheme, optionally, in said S32, if the natural fractures captured in the wellbore are all the natural fractures existing in the formation, it is impossible to accurately confirm the horizontal plane of the geometric center of the fractures;

[0031] If the natural fracture is large in scale, it can penetrate the wellbore wall and form a closed circle on the wellbore. It will appear as a sine-like or cosine-like curve with a complete cycle in dynamic and static images. By drawing a connecting line between the peak and valley points of the sine-like or cosine-like curve, the horizontal plane at the midpoint of the connecting line is the horizontal plane of the geometric center of the fracture.

[0032] If the natural fracture cuts the wellbore obliquely and the fracture end is located exactly on the wellbore, it will appear as a sine-like or cosine-like curve with a complete cycle in the dynamic and static images. By drawing a connecting line between the peak and valley points of the sine-like or cosine-like curve, the horizontal plane at the midpoint of the connecting line is the horizontal plane of the geometric center of the fracture.

[0033] If one side of the fracture is located in the wellbore and the other side cuts through the wellbore, a short arc or an incomplete ellipse will be formed on the wellbore. If it is a short arc, the horizontal plane of the geometric center of the fracture cannot be determined;

[0034] If it is an incomplete ellipse, it will appear as an incomplete ellipse curve with a peak or valley value and partial ascending and descending segments on both sides in the dynamic and static images. The location of the crack end on the other side can be inferred and drawn based on the peak or valley value and the arc of the ascending and descending segments of the ellipse curve. After the two crack ends are determined, it can be restored to a complete sine-like or cosine-like curve on the plane. The horizontal plane of the geometric center of the crack can be determined by drawing a connecting line between the peak and valley points of the sine-like or cosine-like curve.

[0035] If the fracture arm is in the wellbore and can only penetrate part of the wellbore, the information of the fracture that penetrates the part of the wellbore is an arc curve on the dynamic and static images of the wellbore wall, and the horizontal plane of the geometric center of the fracture cannot be determined;

[0036] After dividing it by the "four quadrants" principle, the direction and tendency of natural fractures are determined by using the horizontal plane of the fracture geometric center;

[0037] Specifically: the intersection of the sine-like curve or cosine-like curve and the horizontal plane of the geometric center of the fracture is the fracture direction, and the precise value of the fracture direction can be read through the wellbore plane expansion scale diagram; by drawing a connecting line from the peak value to the valley value, the quadrant where the connecting line extends to the valley value is the fracture tendency. The wellbore plane expansion scale diagram can only judge the fracture tendency, and the specific value cannot be determined; if the natural fracture is large in scale and can penetrate the well wall, a closed whole circle will be formed on the wellbore, which will appear as a sine-like or cosine-like curve with a complete cycle on the dynamic and static images. Then observe the quadrant where the peak and valley of a sine-like or cosine-like curve with a complete cycle on the dynamic and static images fall. If the dynamic and static images show a sine-like curve with a peak falling in the first Quadrant, valley value falls in the third quadrant, then the intersection of the sine-like curve and the horizontal plane of the geometric center of the fracture is the fracture direction, and then by drawing a connecting line from the peak value to the valley value, the quadrant where the connecting line extends to the valley value is the fracture inclination, then it is a NW-trending, SW-inclined fracture in the wellbore space; the peak value falls in the second quadrant, and the valley value falls in the fourth quadrant, then it is a NE-trending, NW-inclined fracture in the wellbore space; if it is a cosine-like curve on the dynamic and static images, the peak value falls in the third quadrant, and the valley value falls in the first quadrant, then it is a NW-trending, NE-inclined fracture in the wellbore space; the peak value falls in the fourth quadrant, and the valley value falls in the second quadrant, then it is a NE-trending, SE-inclined fracture in the wellbore space;

[0038] If the natural fracture cuts the wellbore obliquely, and one side of the natural fracture ends in the wellbore and the other side cuts through the wellbore, the analysis method for the fracture direction and tendency is the same as that for the case where the natural fracture can penetrate the wellbore wall;

[0039] If one end of the crack is located in the wellbore and the other end cuts through the wellbore, a short arc or an incomplete ellipse will be formed on the wellbore. If it is a short arc, the direction and inclination of the crack cannot be determined.

[0040] If it is an incomplete ellipse, it will appear as an incomplete ellipse curve with peaks or valleys and partial ascending and descending sections on both sides in dynamic and static images. The quadrant of the other side of the fracture end can be inferred based on the quadrant of the peak or valley and the arc of the incomplete curve of the ascending and descending sections. After determining the quadrants of the two fracture ends, the analysis of their direction and tendency is the same as that of the natural fracture running through the wellbore.

[0041] If the fracture arm is in the wellbore, it will appear as an arc curve on the dynamic and static images of the wellbore wall. It is impossible to restore a sine-like or cosine-like curve based on the arc, and the direction and tendency cannot be analyzed.

[0042] In the above scheme, optionally, in S33, it is stipulated that if the strike line falls in the first and third quadrants, the fracture end peak falls in the second quadrant, and if the numerical value of the strike N1 in the first quadrant in the range of 0-90° is selected to convert the tendency, the tendency Q1 can be expressed as:

[0043] Q1=N1+270°, where N1=0~90°;

[0044] If the trend line falls in the first and third quadrants, and the peak value of the crack end falls in the second quadrant, if the trend N2 in the third quadrant is selected to be in the range of 180-270°, the trend Q1 is expressed as:

[0045] Q1=N2+90°, where N2=0~90°;

[0046] If the trend line falls in the first and third quadrants, and the peak value of the crack end falls in the fourth quadrant, if the trend N1 in the first quadrant is selected to be in the range of 0-90°, the trend Q2 is expressed as:

[0047] Q2=N1+90°, where N1=0~90°;

[0048] If the trend line falls in the first and third quadrants, and the peak value of the crack end falls in the fourth quadrant, if the trend N2 in the third quadrant is selected to be in the range of 180-270°, the trend Q2 is expressed as:

[0049] Q2=N2-90°, where N2=180~270°;

[0050] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the first quadrant, if the trend N3 in the second quadrant is selected to be in the range of 180-270°, the trend Q3 is expressed as:

[0051] Q3=N3+90°, where N3=180~270°;

[0052] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the first quadrant, if the trend N4 in the fourth quadrant is selected to be in the range of 270-360°, the trend Q3 is expressed as:

[0053] Q3 = N4-90°, where N4 = 270-360°;

[0054] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the third quadrant, if the trend N3 in the second quadrant is selected to be in the range of 180-270°, the trend Q4 is expressed as:

[0055] Q4 = N3-90°, where N3 = 180-270°;

[0056] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the third quadrant, if the trend N4 in the fourth quadrant is selected to be in the range of 270-360°, the trend Q4 is expressed as:

[0057] Q4=N4-270°, where N4=270~360°.

[0058] Compared with the prior art, this application has at least the following beneficial effects:

[0059] Based on further analysis and research on the problems of the prior art, this application recognizes that the prior art performs numerical calculations on the fracture azimuth and fracture inclination, but cannot obtain fracture tendency information, and that due to the large scale of the fracture, the single well imaging logging data can only capture a small amount of fracture information. By comparing the natural fracture identification results of the wellbore with the plane expansion pattern diagram of the natural fracture of the wellbore, the natural fracture direction and tendency of the wellbore can be quickly determined. Then, a circular wellbore scale is established to horizontally project the natural fracture of the wellbore to determine the precise numerical value of the natural fracture direction. Finally, a method for obtaining the true tendency size of the natural fracture of the wellbore is obtained by the "numerical conversion rule". This method is to use the existing imaging logging data and apply a quick and simple operation method to efficiently obtain the natural fracture tendency information of a single well containing imaging logging data. It greatly solves the practical problem that the effectiveness of natural fractures varies greatly due to unclear tendency differences in the process of evaluating the effectiveness of natural fractures in a single well. It greatly improves the engineering problem that the natural fracture tendency is unclear in reservoir transformation, resulting in unclear extension path of artificial fractures. It provides a set of effective solutions for professional and technical personnel who study the effectiveness of single well fractures and reservoir transformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A flow chart of a method for determining fracture tendency of a vertical well containing imaging logging data provided by one embodiment of the present application;

[0061] Figure 2 A fracture occurrence reading mode diagram and a "numerical value conversion rule" principle diagram provided for one embodiment of the present application;

[0062] Figure 3 A wellbore provided in one embodiment of the present application contains a natural fracture that penetrates the wellbore wall - a fracture tendency calculation model diagram for imaging logging;

[0063] Figure 4A natural fracture-imaging logging fracture tendency calculation model diagram of a wellbore provided in an embodiment of the present application, wherein the wellbore includes an oblique wellbore and one side of the fracture end is on the wellbore;

[0064] Figure 5 A natural fracture-imaging logging fracture tendency calculation model diagram for a wellbore containing an oblique wellbore and one side of the fracture end is inside the wellbore provided in one embodiment of the present application. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0066] In one embodiment, Figure 1 As shown, a method for determining fracture tendency of a vertical well containing imaging logging data is provided, comprising the following steps:

[0067] S1: Use imaging logging data to determine the location and morphological characteristics of natural fractures in the wellbore;

[0068] S2: Compare the identification results of natural fractures in the wellbore with the spatial distribution characteristics and plane expansion pattern of natural fractures in the wellbore to determine the direction and tendency of the natural fractures;

[0069] S3: Establish a wellbore plane expansion scale diagram to determine the precise numerical value of the natural fracture direction, and obtain the true inclination size of the natural fracture in the wellbore through the "numerical conversion rule".

[0070] In this embodiment, S1 includes:

[0071] S11: Analyze the dynamic and static images in the imaging logging data to determine the spatial development location of natural fractures in the wellbore on a single well;

[0072] S12: Based on the results of natural fracture identification in the wellbore, find out the differences in the morphological characteristics of different natural fractures in the wellbore.

[0073] In this embodiment, the analysis of the dynamic and static images in the imaging logging data to determine the spatial development location of the natural fractures in the wellbore on the single well includes:

[0074] In the process of using dynamic and static images in imaging logging data to identify natural fractures in the wellbore, the influence of induced fractures on the wellbore on the natural fracture identification process is eliminated, and the discontinuity phenomenon in the dynamic and static images caused by the change of conductivity is determined as the development location of the natural fracture; the phenomenon that the natural fracture is difficult to identify in the static image is closely combined with the dynamic image to identify the natural fracture;

[0075] Based on the results of natural fracture identification in the wellbore, the differences in morphological characteristics of different natural fractures in the wellbore are identified, including: identifying and analyzing the morphological characteristics of different natural fractures in the wellbore one by one to ensure the accuracy of fracture dip analysis.

[0076] In this embodiment, S2 includes:

[0077] S21: According to the morphological characteristics of various types of natural fractures contained in the actual wellbore, compile the spatial distribution characteristics and plane development pattern diagram of natural fractures in the wellbore;

[0078] S22: Compare the morphology of natural fractures on the dynamic and static images with the compiled spatial distribution characteristics of natural fractures in the wellbore and the plane expansion pattern diagram to determine the spatial distribution characteristics of the fractures in the wellbore.

[0079] In this embodiment, the preparation of the spatial distribution characteristics and the plane development pattern diagram of the natural fractures in the wellbore according to the various fracture morphological characteristics contained in the actual natural fractures in the wellbore includes:

[0080] By observing the morphological characteristics of various types of natural fractures in actual wellbores, the spatial distribution characteristics and plane expansion pattern diagrams of natural fractures in wellbores were compiled, and extended to single wells with imaging logging data that have not yet compiled the spatial distribution characteristics and plane expansion pattern diagrams of natural fractures in wellbores;

[0081] If the natural fractures captured in the wellbore are all the natural fractures existing in the formation, then when all the fractures are contained in the wellbore, no fracture information will be observed on the wellbore wall;

[0082] When the fracture intersects the wellbore, only very little fracture information can be captured, and its spatial distribution characteristics and plane expansion pattern cannot be restored;

[0083] If the natural fracture is large and can penetrate the wellbore wall, the natural fracture that can be captured in the wellbore is a local part of the natural fracture in the formation, which appears as a sine-like or cosine-like curve with a complete cycle in the dynamic and static images;

[0084] If the natural fracture cuts the wellbore obliquely, it is divided into three situations: the fracture end is just located on the wellbore, the fracture end is inside the wellbore, and the fracture arm is in the wellbore; if the fracture end is just located on the wellbore, a dynamic and static image will be formed on the wellbore that is the same as the situation where the natural fracture can penetrate the wellbore wall; if one side of the fracture end is located inside the wellbore and the other side cuts through the wellbore, a short arc or an incomplete ellipse will be formed on the wellbore; if it is a short arc, it appears as a line segment on the dynamic and static images according to the arc; if it is an incomplete ellipse, it appears as an incomplete elliptical curve with peaks or valleys and partial ascending and descending segments on both sides on the dynamic and static images; if the fracture arm is in the wellbore and can only penetrate part of the wellbore, the natural fracture that can be captured in the wellbore is a small part of the natural fracture in the formation, and the information of the partial fracture penetrating the wellbore is a circular arc curve on the dynamic and static images of the wellbore wall, and it appears as an arc line segment on the dynamic and static images according to the arc.

[0085] In this embodiment, the morphology of natural fractures on the dynamic and static images is compared with the compiled spatial distribution characteristics of natural fractures in the wellbore and the plane expansion pattern diagram to determine the spatial distribution characteristics of the wellbore fractures, including: dividing the compiled spatial distribution characteristics of natural fractures in the wellbore and the plane expansion pattern diagram according to the "four quadrants" principle: taking the azimuth information possessed by the imaging logging as the basic data, taking the azimuth 0-90° as the first quadrant, 90-180° as the second quadrant, 180-270° as the third quadrant, and 270-360° as the fourth quadrant, the wellbore and the plane expansion diagram are divided into four parts; by making the quadrants where the fracture ends and fracture arms on the dynamic and static images of the imaging logging correspond to the plane expansion pattern diagram, and then judging the spatial distribution characteristics of the natural fractures according to the spatial distribution characteristic pattern diagram of the natural fractures in the wellbore corresponding to the plane expansion pattern diagram.

[0086] In this embodiment, S3 includes:

[0087] S31: establishing a wellbore plane expansion scale diagram based on the dynamic and static plane expansion diagrams of the imaging logging and the azimuth information of the imaging logging;

[0088] S32: Find the horizontal plane of the geometric center of the crack, and determine the precise numerical value of the direction of the natural crack by combining the morphology of the natural crack in the dynamic and static images;

[0089] S33: According to the “numerical conversion rule”, the true inclination size of the natural fractures in the wellbore is obtained.

[0090] In this embodiment, in S31, the wellbore plane expansion scale diagram is based on the azimuth information of the imaging logging, L in the dynamic and static plane expansion diagram of the imaging logging is used as the diameter D of the wellbore ring scale disk, 0° azimuth in the positive N direction in the dynamic and static plane expansion diagram of the imaging logging is used as the starting point, 90° azimuth is used as the due east direction, and 180° azimuth is used as the due south direction to establish the wellbore plane expansion scale diagram; specifically, the accuracy of the wellbore ring scale disk depends first on the accuracy requirements for the fracture direction and inclination in actual applications, and secondly on the reduction in the wellbore arm diameter caused by the increase in the wellbore depth, and the scale accuracy of the established wellbore ring plane expansion scale diagram must at least be guaranteed to be in the single digit.

[0091] In this embodiment, in said S32, if the natural fractures captured in the wellbore are all the natural fractures existing in the formation, it is impossible to accurately confirm the horizontal plane of the geometric center of the fractures;

[0092] If the natural fracture is large in scale, it can penetrate the wellbore wall and form a closed circle on the wellbore. It will appear as a sine-like or cosine-like curve with a complete cycle in dynamic and static images. By drawing a connecting line between the peak and valley points of the sine-like or cosine-like curve, the horizontal plane at the midpoint of the connecting line is the horizontal plane of the geometric center of the fracture.

[0093] If the natural fracture cuts the wellbore obliquely and the fracture end is located exactly on the wellbore, it will appear as a sine-like or cosine-like curve with a complete cycle in the dynamic and static images. By drawing a connecting line between the peak and valley points of the sine-like or cosine-like curve, the horizontal plane at the midpoint of the connecting line is the horizontal plane of the geometric center of the fracture.

[0094] If one side of the fracture is located in the wellbore and the other side cuts through the wellbore, a short arc or an incomplete ellipse will be formed on the wellbore. If it is a short arc, the horizontal plane of the geometric center of the fracture cannot be determined;

[0095] If it is an incomplete ellipse, it will appear as an incomplete ellipse curve with a peak or valley value and partial ascending and descending segments on both sides in the dynamic and static images. The location of the crack end on the other side can be inferred and drawn based on the peak or valley value and the arc of the ascending and descending segments of the ellipse curve. After the two crack ends are determined, it can be restored to a complete sine-like or cosine-like curve on the plane. The horizontal plane of the geometric center of the crack can be determined by drawing a connecting line between the peak and valley points of the sine-like or cosine-like curve.

[0096] If the fracture arm is in the wellbore and can only penetrate part of the wellbore, the information of the fracture that penetrates the part of the wellbore is an arc curve on the dynamic and static images of the wellbore wall, and the horizontal plane of the geometric center of the fracture cannot be determined;

[0097] After dividing it by the "four quadrants" principle, the direction and tendency of natural fractures are determined by using the horizontal plane of the fracture geometric center;

[0098] Specifically: the intersection of the sine-like curve or cosine-like curve and the horizontal plane of the geometric center of the fracture is the fracture direction, and the precise value of the fracture direction can be read through the wellbore plane expansion scale diagram; by drawing a connecting line from the peak value to the valley value, the quadrant where the connecting line extends to the valley value is the fracture tendency. The wellbore plane expansion scale diagram can only judge the fracture tendency, and the specific value cannot be determined; if the natural fracture is large in scale and can penetrate the well wall, a closed whole circle will be formed on the wellbore, which will appear as a sine-like or cosine-like curve with a complete cycle on the dynamic and static images. Then observe the quadrant where the peak and valley of a sine-like or cosine-like curve with a complete cycle on the dynamic and static images fall. If the dynamic and static images show a sine-like curve with a peak falling in the first Quadrant, valley value falls in the third quadrant, then the intersection of the sine-like curve and the horizontal plane of the geometric center of the fracture is the fracture direction, and then by drawing a connecting line from the peak value to the valley value, the quadrant where the connecting line extends to the valley value is the fracture inclination, then it is a NW-trending, SW-inclined fracture in the wellbore space; the peak value falls in the second quadrant, and the valley value falls in the fourth quadrant, then it is a NE-trending, NW-inclined fracture in the wellbore space; if it is a cosine-like curve on the dynamic and static images, the peak value falls in the third quadrant, and the valley value falls in the first quadrant, then it is a NW-trending, NE-inclined fracture in the wellbore space; the peak value falls in the fourth quadrant, and the valley value falls in the second quadrant, then it is a NE-trending, SE-inclined fracture in the wellbore space;

[0099] If the natural fracture cuts the wellbore obliquely, and one side of the natural fracture ends in the wellbore and the other side cuts through the wellbore, the analysis method for the fracture direction and tendency is the same as that for the case where the natural fracture can penetrate the wellbore wall;

[0100] If one end of the crack is located in the wellbore and the other end cuts through the wellbore, a short arc or an incomplete ellipse will be formed on the wellbore. If it is a short arc, the direction and inclination of the crack cannot be determined.

[0101] If it is an incomplete ellipse, it will appear as an incomplete ellipse curve with peaks or valleys and partial ascending and descending sections on both sides in dynamic and static images. The quadrant of the other side of the fracture end can be inferred based on the quadrant of the peak or valley and the arc of the incomplete curve of the ascending and descending sections. After determining the quadrants of the two fracture ends, the analysis of their direction and tendency is the same as that of the natural fracture running through the wellbore.

[0102] If the fracture arm is in the wellbore, it will appear as an arc curve on the dynamic and static images of the wellbore wall. It is impossible to restore a sine-like or cosine-like curve based on the arc, and the direction and tendency cannot be analyzed.

[0103] In this embodiment, in S33, it is stipulated that if the trend line falls in the first and third quadrants, the peak value of the crack end falls in the second quadrant, and if the trend N1 in the first quadrant is selected to be in the range of 0-90°, the trend Q1 can be expressed as:

[0104] Q1=N1+270°, where N1=0~90°;

[0105] If the trend line falls in the first and third quadrants, and the peak value of the crack end falls in the second quadrant, if the trend N2 in the third quadrant is selected to be in the range of 180-270°, the trend Q1 is expressed as:

[0106] Q1=N2+90°, where N2=0~90°;

[0107] If the trend line falls in the first and third quadrants, and the peak value of the crack end falls in the fourth quadrant, if the trend N1 in the first quadrant is selected to be in the range of 0-90°, the trend Q2 is expressed as:

[0108] Q2=N1+90°, where N1=0~90°;

[0109] If the trend line falls in the first and third quadrants, and the peak value of the crack end falls in the fourth quadrant, if the trend N2 in the third quadrant is selected to be in the range of 180-270°, the trend Q2 is expressed as:

[0110] Q2=N2-90°, where N2=180~270°;

[0111] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the first quadrant, if the trend N3 in the second quadrant is selected to be in the range of 180-270°, the trend Q3 is expressed as:

[0112] Q3=N3+90°, where N3=180~270°;

[0113] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the first quadrant, if the trend N4 in the fourth quadrant is selected to be in the range of 270-360°, the trend Q3 is expressed as:

[0114] Q3 = N4-90°, where N4 = 270-360°;

[0115] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the third quadrant, if the trend N3 in the second quadrant is selected to be in the range of 180-270°, the trend Q4 is expressed as:

[0116] Q4 = N3-90°, where N3 = 180-270°;

[0117] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the third quadrant, if the trend N4 in the fourth quadrant is selected to be in the range of 270-360°, the trend Q4 is expressed as:

[0118] Q4=N4-270°, where N4=270~360°.

[0119] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the third quadrant, if the trend N3 in the second quadrant is selected to be in the range of 180-270°, the trend Q4 is expressed as:

[0120] Q4 = N3-90°, where N3 = 180-270°;

[0121] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the third quadrant, if the trend N4 in the fourth quadrant is selected to be in the range of 270-360°, the trend Q4 is expressed as:

[0122] Q4=N4-270°, where N4=270-360°.

[0123] In a specific embodiment, the example applies a method for rapidly determining fracture tendency of a vertical well containing imaging logging data to a single well to study fracture tendency of the single well.

[0124] First, the spatial development location of natural fractures is identified based on the dynamic and static images in the actual imaging logging data of a single well. Based on the results of natural fracture identification in the wellbore, the differences in the morphological characteristics of different natural fractures in the wellbore are found. Secondly, based on the morphological characteristics of various types of fractures contained in the actual wellbore natural fractures, the spatial distribution characteristics and plane expansion pattern diagrams of natural fractures in the wellbore are compiled to ensure that all types of fractures have a reference pattern diagram for analysis, and the spatial distribution characteristics and plane expansion pattern diagrams of natural fractures in the wellbore are universal and can be applied to single wells for which the spatial distribution characteristics and plane expansion pattern diagrams of natural fractures in the wellbore have not yet been established. Therefore, by observing the types of natural fractures in the wellbore, the natural fractures that can be captured in the wellbore can be divided into two situations: all or part of the natural fractures in the formation. If the natural fractures that can be captured in the wellbore are all the natural fractures in the formation, then when all the fractures are contained in the wellbore, no fracture information can be observed on the wellbore wall; when the fractures intersect with the wellbore, then because the wellbore wall is cylindrical, only very little fracture information can be captured, and its spatial distribution characteristics and plane expansion pattern cannot be restored. However, when the following three situations exist, this method is used for analysis, combined with the "numerical conversion rule" (such as Figure 2 The crack tendency can be quickly determined.

[0125] Currently, there are two large-scale natural fractures in a single well that can penetrate the well wall. Only parts of the two natural fractures can be captured in the wellbore, and they form a closed circle on the wellbore (such as Figure 3 As shown in a-1, b-1). In dynamic and static images, it appears as a sine-like curve with a complete period and a cosine-like curve with a complete period (as shown in a-1, b-1). Figure 3 As shown in a-2, b-2). By drawing connecting lines between the peak and valley points of the sine-like curves and cosine-like curves of the two natural fractures, the geometric center horizontal plane of the fracture is obtained first. Through observation, it is found that one of the natural fractures that appears as a sine-like curve in dynamic and static images has a peak value falling in the first quadrant (azimuth: 0-90°) and a valley value falling in the third quadrant (azimuth: 180-270°). The intersection of the sine-like curve and the horizontal plane of the geometric center of the fracture falls in the second quadrant. Then, a connecting line is drawn from the peak to the valley value. The connecting line extends to the third quadrant where the valley value is located. In the wellbore space, it is a fracture with SE direction and SW inclination. By drawing a vertical line perpendicular to the wellbore plane to expand the scale chart at the intersection of the sine-like curve and the horizontal plane of the geometric center of the fracture, the precise value of the direction is read as SE158°. Then, according to the "numerical conversion rule" of direction and inclination, the direction of the natural fracture is converted to the inclination of the natural fracture as SW248°. Another natural fracture that appears as a cosine curve in dynamic and static images has a peak value in the third quadrant (azimuth: 180-270°), a valley value in the first quadrant (azimuth: 0-90°), and the intersection of the cosine curve and the horizontal plane of the geometric center of the fracture falls in the second quadrant. A connecting line is drawn from the peak to the valley, and the connecting line extends to the third quadrant where the valley is located. In the wellbore space, it is a SW-trending, NE-inclined fracture. By drawing a vertical line perpendicular to the wellbore plane at the intersection of the cosine curve and the horizontal plane of the geometric center of the fracture, the precise value of the strike is SW204.5°, and then according to the "numerical conversion rule" of strike and inclination, the strike of the natural fracture is converted to the inclination of the natural fracture as NE114.5°.

[0126] At present, there are two natural fractures in a single well that cut obliquely into the wellbore. The natural fracture has one end in the wellbore and the other side cuts through the wellbore. Both natural fractures can form a closed circle on the wellbore (such as Figure 4 As shown in a-1, b-1). In dynamic and static images, it appears as a sine-like curve with a complete period and a cosine-like curve with a complete period (as shown in a-1, b-1). Figure 4 The analysis method of its trend and tendency is the same as the analysis method of natural fractures that can penetrate the well wall.

[0127] Currently, there are two natural fractures in a single well that cut obliquely into the wellbore. One end of the natural fracture is located in the wellbore, while the other end cuts through the wellbore, forming an incomplete ellipse on the wellbore (e.g. Figure 5 As shown in a-1, b-1), it appears as an incomplete elliptic curve with peaks or valleys and partial ascending and descending segments on both sides in dynamic and static images (such as Figure 5 As shown in a-2, b-2), the quadrant of the location of the other side of the fracture end can be inferred based on the quadrant of the peak or valley value and the curvature of the incomplete curve of the ascending and descending sections. After determining the quadrants of the two fracture ends, the analysis of their direction and tendency is the same as the situation where the natural fracture runs through the wellbore.

[0128] As my country's oil and gas exploration shifts from conventional to unconventional fields, research on fractured reservoirs has received attention. Since fracture occurrence is an important indicator affecting the evaluation of fractured reservoirs, the prediction of reservoir fracture occurrence is crucial for the rational and efficient development of oil fields. A large number of studies have shown that the formation of natural fractures is closely related to tectonic deformation or tectonic activity. Fracture occurrence has an evolutionary nature under the influence of tectonic activity. The fractures in the current reservoir are the result of the superposition of multi-stage tectonic activities and tectonic deformation. The existence of natural fractures under the current stress background will cause significant stress disturbance in the reservoir, and the difference in natural fracture occurrence will further affect the distribution of stress in the reservoir and enhance the anisotropy of stress inside the reservoir. Among them, slight changes in fracture inclination will directly determine the mechanical relationship between the fracture surface and the current stress, thereby the activity and effectiveness of the fracture, which further affects the efficiency of reservoir fracturing transformation. Therefore, it is particularly important to establish a method for quickly determining the fracture inclination of vertical wells containing imaging logging data for oil and gas exploration and development.

[0129] At present, imaging logging data can effectively identify the fracture development location in a single well and perform numerical calculations on the fracture azimuth and fracture dip, but cannot obtain fracture tendency information. This often leads to the difficulty of studying the fracture effectiveness due to the lack of fracture tendency information in the actual research process, which restricts the evaluation of the quality of fractured reservoirs.

[0130] In the process of identifying fractures using imaging logging data, it is often observed that due to the large scale of fractures, the imaging logging data of a single well can only capture a small amount of fracture information. How to obtain fracture tendency data using a small amount of information is of great significance to the study of fractured reservoirs.

[0131] This embodiment proposes a method for quickly determining the fracture inclination of a vertical well containing imaging logging data. In order to solve the problem that imaging logging data lacks fracture inclination information and cannot capture complete fracture information, it is difficult to obtain fracture inclination data using a small amount of information, a method is provided to quickly determine the direction and inclination of natural fractures in the wellbore by comparing the natural fracture identification results of the wellbore with the plane expansion pattern diagram of the natural fractures in the wellbore. Then, a circular wellbore scale is established to horizontally project the natural fractures in the wellbore to determine the precise numerical value of the natural fracture direction. Finally, a method for obtaining the true inclination size of the natural fractures in the wellbore is used through the "numerical conversion rule". This method provides a set of effective solutions for professional and technical personnel who study the effectiveness of single well fractures and reservoir transformation.

[0132] In one embodiment, a method for quickly determining fracture tendency of a vertical well containing imaging logging data is provided, characterized in that the method comprises:

[0133] S1: Using imaging logging data, dynamic and static images are combined to determine the location and morphological characteristics of natural fractures in the wellbore.

[0134] S2: Compare the identification results of natural fractures in the wellbore with the spatial distribution characteristics and plane expansion pattern of natural fractures in the wellbore to determine the direction and tendency of the natural fractures.

[0135] S3: Establish a wellbore plane expansion scale diagram to determine the precise numerical value of the natural fracture direction, and obtain the true inclination size of the natural fracture in the wellbore through the "numerical conversion rule".

[0136] In this embodiment, step S1 includes:

[0137] S11: Analyze the dynamic and static images in the imaging logging data, and combine the two to preferentially determine the spatial development locations of natural fractures in the wellbore on a single well.

[0138] S12: Based on the results of natural fracture identification in the wellbore, find out the differences in the morphological characteristics of different natural fractures in the wellbore.

[0139] In this embodiment, in step S11,

[0140] In the process of using dynamic and static images in imaging logging data to identify natural fractures in the wellbore, first of all, it should be emphasized that the influence of induced fractures on the wellbore on the natural fracture identification process should be eliminated first to improve the accuracy of natural fracture identification. Secondly, it should be noted that some fractures have poor continuity, resulting in intermittent phenomena in dynamic and static images caused by changes in conductivity. This situation should be determined as the development site of natural fractures; finally, it should be noted that the natural fractures in the wellbore are difficult to identify in static images due to the thin width of natural fractures. In this case, it is necessary to closely combine dynamic images to identify natural fractures.

[0141] In this embodiment, in step S12,

[0142] Since the occurrence and scale of natural fractures in the formation vary greatly, and although the wellbore is long in the longitudinal direction, its diameter is relatively small, it is difficult to capture all the information of natural fractures with low angles and large scales in the wellbore. Therefore, it is necessary to identify and analyze the morphological characteristics of different natural fractures in the wellbore one by one to ensure the accuracy of fracture dip analysis.

[0143] In this embodiment, step S2 includes:

[0144] S21: Based on the various fracture morphological characteristics contained in the actual natural fractures in the wellbore, compile the spatial distribution characteristics and plane development pattern diagram of the natural fractures in the wellbore.

[0145] S22: Compare the morphology of natural fractures on the dynamic and static images with the compiled spatial distribution characteristics of natural fractures in the wellbore and the plane expansion pattern diagram to determine the spatial distribution characteristics of the fractures in the wellbore.

[0146] In this embodiment, in step S21,

[0147] The spatial distribution characteristics of natural fractures in the wellbore determine their plane expansion mode. By observing the morphological characteristics of various types of natural fractures in the actual wellbore, the spatial distribution characteristics and plane expansion mode diagram of natural fractures in the wellbore are compiled. They are universal and can be extended to other single wells with imaging logging data that have not yet compiled the spatial distribution characteristics and plane expansion mode diagram of natural fractures in the wellbore.

[0148] In this embodiment, the natural cracks that can be captured in the wellbore exist in two situations: all or part of the natural cracks in the formation. The appearance of these two situations leads to the following differences in the morphological characteristics of the natural cracks in the wellbore: if the natural cracks that can be captured in the wellbore are all the natural cracks in the formation, then when the cracks are all contained in the wellbore, the crack information will not be observed on the wellbore wall; when the cracks intersect with the wellbore, then because the wellbore wall is cylindrical, only very little crack information can be captured, and its spatial distribution characteristics and plane expansion style cannot be restored. If the natural cracks are large in scale and can penetrate the wellbore wall, the natural cracks that can be captured in the wellbore are parts of the natural cracks in the formation, then a closed full circle will be formed in the wellbore, which appears as a sine-like or cosine-like curve with a complete period in the dynamic and static images. If the natural cracks cut the wellbore obliquely, it should be divided into three situations: the crack end is just located on the wellbore, the crack end is in the wellbore, and the crack arm is in the wellbore. If the end of the fracture is located exactly on the wellbore, a dynamic and static image will be formed on the wellbore that is the same as the case where the natural fracture can penetrate the wellbore wall. If one end of the fracture is located in the wellbore and the other side cuts through the wellbore, a short arc or an incomplete ellipse will be formed on the wellbore. If it is a short arc, it means that one end of the natural fracture ends in the wellbore, and it is displayed as a line segment on the dynamic and static images according to the arc; if it is an incomplete ellipse, it means that although the natural fracture cannot penetrate the wellbore, it can still cut through part of the wellbore and continue to extend in space. It is displayed as an incomplete elliptical curve with peaks or valleys and partial ascending and descending segments on both sides on the dynamic and static images. If the fracture arm is in the wellbore and can only penetrate part of the wellbore, the natural fracture that can be captured in the wellbore is a small part of the natural fracture in the formation. The information of the fracture that penetrates the wellbore is a circular arc curve on the dynamic and static images of the wellbore wall, and it is displayed as an arc line segment on the dynamic and static images according to the arc.

[0149] In this embodiment, in step S22,

[0150] The compiled spatial distribution characteristics of natural fractures in the wellbore and the plane expansion pattern diagram are divided according to the "four-quadrant" principle: that is, the azimuth information of the imaging logging is used as the basic data, the azimuth 0-90° is used as the first quadrant, 90-180° is used as the second quadrant, 180-270° is used as the third quadrant, and 270-360° is used as the fourth quadrant, and the wellbore and plane expansion diagram are divided into four parts. By matching the quadrants where the fracture ends and fracture arms are located on the dynamic and static images of the imaging logging with the plane expansion pattern diagram, and then according to the spatial distribution characteristic pattern diagram of the natural fractures in the wellbore corresponding to the plane expansion pattern diagram, the spatial distribution characteristics of the natural fractures can be roughly determined.

[0151] In this embodiment, the step S3 includes: S31: establishing a wellbore plane expansion scale diagram based on the dynamic and static plane expansion diagrams of the imaging logging and the azimuth information of the imaging logging.

[0152] S32: Find the horizontal plane of the geometric center of the crack, and determine the precise numerical value of the direction of the natural crack by combining the morphology of the natural crack in the dynamic and static images.

[0153] S33: According to the “numerical conversion rule”, the true inclination size of the natural fractures in the wellbore is obtained.

[0154] In this embodiment, in step S31,

[0155] The wellbore plane expansion scale diagram needs to use the azimuth information of imaging logging as the basic data, use L in the dynamic and static plane expansion diagram of imaging logging as the diameter D of the wellbore scale disk, use the azimuth of 0° (azimuth 360°) in the positive N direction in the dynamic and static plane expansion diagram of imaging logging as the starting point (end point), use the azimuth 90° as the due east direction, and use the azimuth 180° as the due south direction to establish the wellbore plane expansion scale diagram.

[0156] In this embodiment, the accuracy of the wellbore ring scale depends first on the accuracy requirements for the fracture direction and inclination in actual applications, and secondly on the reduction in the wellbore arm diameter caused by the increase in wellbore depth. However, it is at least necessary to ensure that the scale accuracy of the established wellbore ring plane expansion scale diagram is in the single digit.

[0157] In this embodiment, in step S32, the fracture geometric center horizontal plane is the horizontal plane where the center of the fracture on the wellbore is located. Generally, the dynamic and static images of imaging logging are mostly plane development diagrams. If the natural fractures that can be captured in the wellbore are all the natural fractures in the formation, the fracture geometric center horizontal plane cannot be accurately confirmed. If the natural fracture is large in scale and can penetrate the wellbore wall, a closed full circle will be formed on the wellbore, which is manifested as a sine-like or cosine-like curve with a complete cycle on the dynamic and static images. By making a connecting line between the peak and valley points of the sine-like or cosine-like curve, the horizontal plane at the midpoint of the connecting line is the fracture geometric center horizontal plane. If the natural fracture obliquely cuts the wellbore, and the fracture end is located exactly on the wellbore, a dynamic and static image that is the same as the situation where the natural fracture can penetrate the wellbore wall will be formed on the wellbore, which is manifested as a sine-like or cosine-like curve with a complete cycle on the dynamic and static images. By making a connecting line between the peak and valley points of the sine-like or cosine-like curve, the horizontal plane at the midpoint of the connecting line is the fracture geometric center horizontal plane. If one side of the crack end is located in the wellbore and the other side cuts through the wellbore, a short arc or an incomplete ellipse will be formed on the wellbore. If it is a short arc, it means that one end of the natural crack ends in the wellbore, and the horizontal plane of the geometric center of the crack cannot be determined. If it is an incomplete ellipse, it means that although the natural crack cannot penetrate the wellbore, it can still cut through part of the wellbore and continue to extend in space. In the dynamic and static images, it is shown as an incomplete elliptical curve with peaks or valleys and partial ascending and descending sections on both sides. The location of the other side of the crack end can be inferred and drawn based on its peak or valley value and the arc of the ascending and descending sections of the elliptical curve. After determining the two ends of the crack, it can be restored to a complete sine-like or cosine-like curve on the plane. Then, by drawing a connecting line between the peak and valley points of the sine-like or cosine-like curve, the horizontal plane of the geometric center of the crack can be determined. If the fracture arm is in the wellbore and can only penetrate part of the wellbore, the natural fractures that can be captured in the wellbore are only a small part of the natural fractures in the formation. The information of the fracture that penetrates the wellbore is an arc curve on the dynamic and static images of the wellbore wall, and the horizontal plane of the geometric center of the fracture cannot be determined.

[0158] In this embodiment, in step S32, after dividing it by the "four quadrants" principle, the direction and inclination of the natural fracture can be determined by using the horizontal plane of the fracture geometry center. The method is as follows: the intersection of the sine-like curve or cosine-like curve and the horizontal plane of the fracture geometry center is the fracture direction, and the fracture direction can be accurately read through the wellbore plane expansion scale diagram; by making a connecting line from the peak value to the valley value, the quadrant where the connecting line extends to the valley value is the fracture inclination, and the wellbore plane expansion scale diagram can only determine the fracture inclination, and the specific value cannot be determined. If the natural fractures that can be captured in the wellbore are all the natural fractures in the formation, it is difficult to obtain the natural fracture direction and inclination information. If the natural fracture is large in scale and can penetrate the well wall, a closed circle will be formed on the wellbore, which will appear as a quasi-sine or quasi-cosine curve with a complete cycle on the dynamic and static images. Then observe the quadrants where the peak and valley of a quasi-sine or quasi-cosine curve with a complete cycle on the dynamic and static images fall. If the dynamic and static images show a quasi-sine curve with a peak in the first quadrant (azimuth: 0-90°) and a valley in the third quadrant (azimuth: 180-270°), the intersection of the quasi-sine curve and the horizontal plane of the geometric center of the fracture is the fracture direction. Then, by drawing a connecting line from the peak to the valley, the quadrant where the connecting line extends to the valley is the fracture inclination, which is a line in the wellbore space. A fracture with NW trend and SW inclination; the peak value falls in the second quadrant (azimuth: 90-180°) and the valley value falls in the fourth quadrant (azimuth: 270-360°), then it is a fracture with NE trend and NW inclination in the wellbore space; if the dynamic and static images are a cosine-like curve, the peak value falls in the third quadrant (azimuth: 180-270°) and the valley value falls in the first quadrant (azimuth: 0-90°), then it is a fracture with NW trend and NE inclination in the wellbore space; the peak value falls in the fourth quadrant (azimuth: 90-180°) and the valley value falls in the second quadrant (azimuth: 270-360°), then it is a fracture with NE trend and SE inclination in the wellbore space. If the natural fracture cuts the wellbore obliquely, and the natural fracture has one side of the fracture end in the wellbore and the other side cuts through the wellbore, the analysis method of the fracture direction and inclination is the same as the case where the natural fracture can penetrate the wellbore wall. If one end of the crack is located in the wellbore and the other side cuts through the wellbore, a short arc or an incomplete ellipse will be formed on the wellbore. If it is a short arc, it is difficult to determine the direction and inclination of the crack.If it is an incomplete ellipse, it means that although the natural fracture cannot penetrate the wellbore, it can still cut through part of the wellbore and continue to extend in space. In the dynamic and static images, it is shown as an incomplete elliptical curve with peaks or valleys and partial ascending and descending sections on both sides. According to the quadrant where the peak or valley is located and the arc of the incomplete curve of the ascending and descending sections, the quadrant where the other side of the fracture end is located can be inferred. After determining the quadrants where the two fracture ends are located, the analysis of its direction and tendency is the same as that of the natural fracture penetrating the wellbore. If the fracture arm is in the wellbore, it is an arc-shaped curve in the dynamic and static images of the wellbore wall. It is impossible to restore a sine-like or cosine-like curve based on the arc, so the direction and tendency cannot be analyzed.

[0159] In this embodiment, in step S33, the actual wellbore is mostly cylindrical. After the crack passes through the wellbore, except for the horizontal crack that appears as a perfect circle on the well wall, the crack with a certain angle appears as an ellipse or an arc containing one side of the crack end or an unconnected line segment containing only part of the crack arm in the wellbore. In actual situations, the analysis of the crack strike and crack tendency in the crack occurrence (strike, inclination and inclination) is the result of projecting it on a plane and analyzing it, and the strike line and inclination line of the crack strike and crack tendency after projection are mostly perpendicular to each other, which leads to a degree difference of 90° between the two. However, the strike of the same crack is the intersection line with the horizontal plane, so the strike line can point to both ends, which leads to a degree difference of 180° in the expression of the strike. Therefore, in the process of converting the inclination, it is necessary to set the conversion rule of the strike and inclination to ensure the uniformity of the conversion scheme. Therefore, it is stipulated that if the strike line falls in the first and third quadrants, the peak value of the fracture end falls in the second quadrant, and if the numerical conversion of the strike N1 in the first quadrant with a range of 0-90° is selected, the tendency Q1 can be expressed as:

[0160] Q1=N1+270°(N1=0~90°);

[0161] If the trend line falls in the first and third quadrants, and the peak value of the crack end falls in the second quadrant, if the trend N2 in the third quadrant is selected to be in the range of 180-270°, the trend Q1 can be expressed as:

[0162] Q1=N2+90°(N2=0~90°);

[0163] If the trend line falls in the first and third quadrants, and the peak value of the crack end falls in the fourth quadrant, if the trend N1 in the first quadrant is selected to be in the range of 0-90°, the trend Q2 can be expressed as:

[0164] Q2=N1+90°(N1=0~90°);

[0165] If the trend line falls in the first and third quadrants, and the peak value of the crack end falls in the fourth quadrant, if the trend N2 in the third quadrant is selected to be in the range of 180-270°, the trend Q2 can be expressed as:

[0166] Q2=N2-90°(N2=180-270°);

[0167] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the first quadrant, if the trend N3 in the second quadrant is selected to be in the range of 180-270°, the trend Q3 can be expressed as:

[0168] Q3=N3+90°(N3=180-270°);

[0169] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the first quadrant, if the trend N4 in the fourth quadrant is selected to be in the range of 270-360°, the trend Q3 can be expressed as:

[0170] Q3=N4-90°(N4=270-360°);

[0171] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the third quadrant, if the trend N3 in the second quadrant is selected to be in the range of 180-270°, the trend Q4 can be expressed as:

[0172] Q4=N3-90°(N3=180-270°);

[0173] If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the third quadrant, if the trend N4 in the fourth quadrant is selected to be in the range of 270-360°, the trend Q4 can be expressed as:

[0174] Q4=N4-270°(N4=270-360°);

[0175] This embodiment provides a method for determining the fracture tendency in the oil field exploration and development process, and provides a method for using imaging logging data to quickly determine the direction and tendency of the natural fractures in the wellbore by comparing the natural fracture identification results of the wellbore with the plane expansion pattern diagram of the natural fractures in the wellbore. Then, a circular wellbore scale is established to horizontally project the natural fractures in the wellbore to determine the precise numerical value of the natural fracture direction. Finally, a method for obtaining the true tendency size of the natural fractures in the wellbore is used through the "numerical conversion rule". This method provides a set of effective solutions for professional and technical personnel who study the effectiveness of single well fractures and reservoir transformation.

[0176] This embodiment mainly provides a method for determining the fracture tendency in the oil field exploration and development process by using imaging logging data. By comparing the identification results of natural fractures in the wellbore with the plane expansion pattern diagram of natural fractures in the wellbore, the direction and tendency of natural fractures in the wellbore can be quickly determined. Then a circular wellbore scale is established to horizontally project the natural fractures in the wellbore to determine the precise numerical value of the natural fracture direction. Finally, a method for obtaining the true tendency size of the natural fractures in the wellbore is obtained by the "numerical conversion rule". This method is to use the existing imaging logging data and apply a quick and simple operation method to efficiently obtain the natural fracture tendency information of a single well containing imaging logging data. It greatly solves the practical problem that the effectiveness of natural fractures varies greatly due to unclear tendency differences in the process of evaluating the effectiveness of natural fractures in a single well. It greatly improves the engineering problem of unclear extension path of artificial fractures caused by unclear natural fracture tendency in reservoir transformation. It provides a set of effective solutions for professional and technical personnel who study the effectiveness of single well fractures and reservoir transformation.

[0177] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A method for determining fracture tendency of a vertical well containing imaging logging data, characterized in that: The method comprises: S1: Use imaging logging data to determine the location and morphological characteristics of natural fractures in the wellbore; S2: Compare the identification results of natural fractures in the wellbore with the spatial distribution characteristics and plane expansion pattern of natural fractures in the wellbore to determine the direction and tendency of the natural fractures; S3: Establish a wellbore plane expansion scale diagram to determine the precise numerical value of the natural fracture direction, and obtain the true inclination size of the natural fracture in the wellbore through the "numerical conversion rule".

2. The method according to claim 1, characterized in that The S1 includes: S11: Analyze the dynamic and static images in the imaging logging data to determine the spatial development location of natural fractures in the wellbore on a single well; S12: Based on the results of natural fracture identification in the wellbore, find out the differences in the morphological characteristics of different natural fractures in the wellbore.

3. The method according to claim 2, characterized in that The analysis of the dynamic and static images in the imaging logging data to determine the spatial development location of the natural fractures in the wellbore on the single well includes: In the process of using dynamic and static images in imaging logging data to identify natural fractures in the wellbore, the influence of induced fractures on the wellbore on the natural fracture identification process is eliminated, and the discontinuity phenomenon in the dynamic and static images caused by the change of conductivity is determined as the development location of the natural fracture; the phenomenon that the natural fracture is difficult to identify in the static image is closely combined with the dynamic image to identify the natural fracture; Based on the results of natural fracture identification in the wellbore, the differences in morphological characteristics of different natural fractures in the wellbore are identified, including: identifying and analyzing the morphological characteristics of different natural fractures in the wellbore one by one to ensure the accuracy of fracture dip analysis.

4. The method according to claim 2, characterized in that: The S2 includes: S21: According to the morphological characteristics of various types of natural fractures in the actual wellbore, compile the spatial distribution characteristics and plane development pattern diagram of natural fractures in the wellbore; S22: Compare the morphology of natural fractures on the dynamic and static images with the compiled spatial distribution characteristics of natural fractures in the wellbore and the plane expansion pattern diagram to determine the spatial distribution characteristics of the fractures in the wellbore.

5. The method according to claim 4, characterized in that The above-mentioned preparation of the spatial distribution characteristics and plane development pattern diagram of natural fractures in the wellbore according to the various fracture morphological characteristics contained in the actual wellbore natural fractures includes: By observing the morphological characteristics of various types of natural fractures in actual wellbores, the spatial distribution characteristics and plane expansion pattern diagrams of natural fractures in wellbores were compiled, and extended to single wells with imaging logging data that have not yet compiled the spatial distribution characteristics and plane expansion pattern diagrams of natural fractures in wellbores; If the natural fractures captured in the wellbore are all the natural fractures existing in the formation, then when all the fractures are contained in the wellbore, no fracture information will be observed on the wellbore wall; When the fracture intersects the wellbore, only very little fracture information can be captured, and its spatial distribution characteristics and plane expansion pattern cannot be restored; If the natural fracture is large and can penetrate the wellbore wall, the natural fracture that can be captured in the wellbore is a local part of the natural fracture in the formation, which appears as a sine-like or cosine-like curve with a complete cycle in the dynamic and static images; If the natural fracture cuts the wellbore obliquely, it is divided into three situations: the fracture end is just located on the wellbore, the fracture end is inside the wellbore, and the fracture arm is in the wellbore; if the fracture end is just located on the wellbore, a dynamic and static image will be formed on the wellbore that is the same as the situation where the natural fracture can penetrate the wellbore wall; if one side of the fracture end is located inside the wellbore and the other side cuts through the wellbore, a short arc or an incomplete ellipse will be formed on the wellbore; if it is a short arc, it appears as a line segment on the dynamic and static images according to the arc; if it is an incomplete ellipse, it appears as an incomplete elliptical curve with peaks or valleys and partial ascending and descending segments on both sides on the dynamic and static images; if the fracture arm is in the wellbore and can only penetrate part of the wellbore, the natural fracture that can be captured in the wellbore is a small part of the natural fracture in the formation, and the information of the partial fracture penetrating the wellbore is a circular arc curve on the dynamic and static images of the wellbore wall, and it appears as an arc line segment on the dynamic and static images according to the arc.

6. The method according to claim 4, characterized in that The method of comparing the morphology of natural fractures on the dynamic and static images with the spatial distribution characteristics of natural fractures in the wellbore and the plane expansion pattern diagram that have been compiled to determine the spatial distribution characteristics of the fractures in the wellbore comprises: dividing the spatial distribution characteristics of natural fractures in the wellbore and the plane expansion pattern diagram that have been compiled according to the "four quadrants" principle: taking the azimuth information possessed by the imaging logging as basic data, taking the azimuth 0-90° as the first quadrant, 90-180° as the second quadrant, 180-270° as the third quadrant, and 270-360° as the fourth quadrant, and dividing the wellbore and the plane expansion diagram into four parts; by making the quadrants where the fracture ends and fracture arms on the dynamic and static images of the imaging logging correspond to the plane expansion pattern diagram, and then judging the spatial distribution characteristics of the natural fractures according to the spatial distribution characteristic pattern diagram of the natural fractures in the wellbore corresponding to the plane expansion pattern diagram.

7. The method according to claim 1, characterized in that The S3 includes: S31: establishing a wellbore plane expansion scale diagram based on the dynamic and static plane expansion diagrams of the imaging logging and the azimuth information of the imaging logging; S32: Find the horizontal plane of the geometric center of the crack, and determine the precise numerical value of the direction of the natural crack by combining the morphology of the natural crack in the dynamic and static images; S33: According to the "numerical conversion rule", the true dip size of natural fractures in the wellbore is obtained.

8. The method according to claim 7, characterized in that In the S31, the wellbore plane expansion scale diagram is established with the azimuth information of the imaging logging as the basic data, L in the dynamic and static plane expansion diagram of the imaging logging as the diameter D of the wellbore ring scale, 0° azimuth in the positive N direction in the dynamic and static plane expansion diagram of the imaging logging as the starting point, 90° azimuth as the due east direction, and 180° azimuth as the due south direction; specifically, the accuracy of the wellbore ring scale dial depends first on the accuracy requirements for the fracture direction and inclination in actual applications, and secondly on the reduction of the well arm diameter caused by the increase in the wellbore depth, so as to ensure that the scale accuracy of the established wellbore ring plane expansion scale diagram is in the single digit.

9. The method according to claim 7, characterized in that: In the above S32, if the natural fractures captured in the wellbore are all the natural fractures existing in the formation, it is impossible to accurately confirm the horizontal plane of the geometric center of the fractures; If the natural fracture is large in scale, it can penetrate the wellbore wall and form a closed circle on the wellbore. It will appear as a sine-like or cosine-like curve with a complete cycle in dynamic and static images. By drawing a connecting line between the peak and valley points of the sine-like or cosine-like curve, the horizontal plane at the midpoint of the connecting line is the horizontal plane of the geometric center of the fracture. If the natural fracture cuts the wellbore obliquely and the fracture end is located exactly on the wellbore, it will appear as a sine-like or cosine-like curve with a complete cycle in the dynamic and static images. By drawing a connecting line between the peak and valley points of the sine-like or cosine-like curve, the horizontal plane at the midpoint of the connecting line is the horizontal plane of the geometric center of the fracture. If one side of the fracture is located in the wellbore and the other side cuts through the wellbore, a short arc or an incomplete ellipse will be formed on the wellbore. If it is a short arc, the horizontal plane of the geometric center of the fracture cannot be determined; If it is an incomplete ellipse, it will appear as an incomplete ellipse curve with a peak or valley value and partial ascending and descending segments on both sides in the dynamic and static images. The location of the crack end on the other side can be inferred and drawn based on the peak or valley value and the arc of the ascending and descending segments of the ellipse curve. After the two crack ends are determined, it can be restored to a complete sine-like or cosine-like curve on the plane. The horizontal plane of the geometric center of the crack can be determined by drawing a connecting line between the peak and valley points of the sine-like or cosine-like curve. If the fracture arm is in the wellbore and can only penetrate part of the wellbore, the information of the fracture that penetrates the part of the wellbore is an arc curve on the dynamic and static images of the wellbore wall, and the horizontal plane of the fracture geometric center cannot be determined; After dividing it by the "four quadrants" principle, the geometric center horizontal plane of the fracture is used to determine the direction and inclination of the natural fracture. Specifically, the intersection of the sine-like curve or cosine-like curve and the geometric center horizontal plane of the fracture is the fracture direction, and the precise value of the fracture direction can be read through the wellbore plane expansion scale diagram. By drawing a connecting line from the peak value to the valley value, the quadrant where the connecting line extends to the valley value is the fracture inclination. The wellbore plane expansion scale diagram can only determine the fracture inclination, and the specific value cannot be determined. If the natural fracture is large in scale and can penetrate the wellbore wall, a closed full circle will be formed on the wellbore, which will appear as a sine-like or cosine-like curve with a complete cycle in the dynamic and static images. Then observe the quadrant where the peak and valley values ​​of a sine-like or cosine-like curve with a complete cycle in the dynamic and static images. If the dynamic , if the static image is a sine-like curve, the peak value falls in the first quadrant, and the valley value falls in the third quadrant, then the intersection of the sine-like curve and the horizontal plane of the geometric center of the fracture is the fracture direction, and then a connecting line is drawn from the peak value to the valley value, and the quadrant where the connecting line extends to the valley value is the fracture inclination, then it is a NW-trending, SW-inclined fracture in the wellbore space; if the peak value falls in the second quadrant, and the valley value falls in the fourth quadrant, then it is a NE-trending, NW-inclined fracture in the wellbore space; if the dynamic and static images are a cosine-like curve, the peak value falls in the third quadrant, and the valley value falls in the first quadrant, then it is a NW-trending, NE-inclined fracture in the wellbore space; if the peak value falls in the fourth quadrant, and the valley value falls in the second quadrant, then it is a NE-trending, SE-inclined fracture in the wellbore space; If the natural fracture cuts the wellbore obliquely, and one side of the natural fracture is in the wellbore and the other side cuts through the wellbore, the analysis method of the fracture direction and tendency is the same as that of the natural fracture that penetrates the wellbore wall; If one end of the crack is located in the wellbore and the other end cuts through the wellbore, a short arc or an incomplete ellipse will be formed on the wellbore. If it is a short arc, the direction and inclination of the crack cannot be determined. If it is an incomplete ellipse, it will appear as an incomplete ellipse curve with peaks or valleys and partial ascending and descending sections on both sides in dynamic and static images. The quadrant of the other side of the fracture end can be inferred based on the quadrant of the peak or valley and the arc of the incomplete curve of the ascending and descending sections. After determining the quadrants of the two fracture ends, the analysis of their direction and tendency is the same as that of the natural fracture running through the wellbore. If the fracture arm is in the wellbore, it will appear as an arc curve on the dynamic and static images of the wellbore wall. It is impossible to restore a sine-like or cosine-like curve based on the arc, and the direction and tendency cannot be analyzed.

10. The method according to claim 7, characterized in that In the above S33, it is stipulated that if the strike line falls in the first and third quadrants, the fracture end peak falls in the second quadrant, and if the numerical value of the strike N1 in the first quadrant in the range of 0-90° is selected to convert the tendency, the tendency Q1 can be expressed as: Q1=N1+270°, where N1=0~90°; If the trend line falls in the first and third quadrants, and the peak value of the crack end falls in the second quadrant, if the trend N2 in the third quadrant is selected to be in the range of 180-270°, the trend Q1 is expressed as: Q1=N2+90°, where N2=0~90°; If the trend line falls in the first and third quadrants, and the peak value of the crack end falls in the fourth quadrant, if the trend N1 in the first quadrant is selected to be in the range of 0-90°, the trend Q2 is expressed as: Q2=N1+90°, where N1=0~90°; If the trend line falls in the first and third quadrants, and the peak value of the crack end falls in the fourth quadrant, if the trend N2 in the third quadrant is selected to be in the range of 180-270°, the trend Q2 is expressed as: Q2=N2-90°, where N2=180~270°; If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the first quadrant, if the trend N3 in the second quadrant is selected to be in the range of 180-270°, the trend Q3 is expressed as: Q3=N3+90°, where N3=180~270°; If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the first quadrant, if the trend N4 in the fourth quadrant is selected to be in the range of 270-360°, the trend Q3 is expressed as: Q3 = N4-90°, where N4 = 270-360°; If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the third quadrant, if the trend N3 in the second quadrant is selected to be in the range of 180-270°, the trend Q4 is expressed as: Q4 = N3-90°, where N3 = 180-270°; If the trend line falls in the second and fourth quadrants, and the peak value of the crack end falls in the third quadrant, if the trend N4 in the fourth quadrant is selected to be in the range of 270-360°, the trend Q4 is expressed as: Q4=N4-270°, where N4=270~360°.

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