Method and device for explaining micro-logging
阅读说明：本技术 解释微测井的方法及装置 (Method and device for explaining micro-logging ) 是由 吕景峰 陈学强 王彦峰 段孟川 钟海 李平 于 2020-05-29 设计创作，主要内容包括：本申请公开了一种解释微测井的方法及装置,该方法包括：获取通过微测井调查得到的激发点到接收点传播的初至时间,将初至时间转换为垂直时,将垂直时在时间-深度坐标系中展布；在时间-深度坐标系中,根据控制点与控制点之间的深度差和垂直时差计算层速度,根据层速度确定属于每一细小速度分层的控制点；利用每一细小速度分层中的所有控制点进行拟合,得到每一细小速度分层的拟合直线,将拟合直线的斜率作为每一细小速度分层的层速度,将两两相邻细小速度分层拟合直线的交点的深度坐标作为前一细小速度分层的厚度终止值,后一细小速度分层的厚度起始值。本申请可以避免出现微测井解释成果多解性的问题。(The application discloses a method and a device for explaining micro-logging, wherein the method comprises the following steps: acquiring first arrival time of propagation from an excitation point to a receiving point obtained through micro-logging investigation, converting the first arrival time into vertical time, and spreading the vertical time in a time-depth coordinate system; in a time-depth coordinate system, calculating the layer speed according to the depth difference and the vertical time difference between the control point and the control point, and determining the control point belonging to each fine speed layer according to the layer speed; fitting is carried out by utilizing all control points in each fine speed layer to obtain a fitting straight line of each fine speed layer, the slope of the fitting straight line is used as the layer speed of each fine speed layer, the depth coordinate of the intersection point of every two adjacent fine speed layer fitting straight lines is used as the thickness ending value of the previous fine speed layer and the thickness starting value of the next fine speed layer. The problem of multiple solutions of micro-logging interpretation results can be avoided.)
1. A method of interpreting a micro-log, the method comprising:
acquiring first arrival time of propagation from an excitation point to a receiving point obtained through micro-logging investigation, converting the first arrival time into vertical time, and spreading the vertical time in a time-depth coordinate system;
connecting the 1 st to ith control points in a time-depth coordinate system, and determining the first layer speed of the first fine speed layer to which the 1 st to ith control points belong according to the depth difference and the vertical time difference of the 1 st to ith control points;
determining a second layer speed of the medium between the ith control point and the (i + 1) th control point according to the depth difference and the vertical time difference of the ith control point to the (i + 1) th control point;
judging whether the difference value between the second layer speed and the first layer speed is greater than a speed difference threshold value or not;
if the difference value is larger than the speed difference threshold value, determining that the (i + 1) th control point belongs to a second fine speed layer; if the difference value is less than or equal to the speed difference threshold value, determining that the (i + 1) th control point belongs to a first fine speed hierarchy; connecting the 1 st to the (i + 1) th control points, and judging whether the (i + 2) th control point belongs to the first fine speed hierarchy according to a method for judging whether the (i + 1) th control point belongs to the first fine speed hierarchy or not until all control points in the first fine speed hierarchy are determined;
determining a first control point behind the last control point belonging to the first fine speed hierarchy as a 1 st control point of the second fine speed hierarchy, and determining all control points in the second fine speed hierarchy according to a method for determining all control points in the first fine speed hierarchy until the control points of all fine speed hierarchies are determined;
fitting is carried out by utilizing all control points in each fine speed layer to obtain a fitting straight line of each fine speed layer, the slope of the fitting straight line is used as the layer speed of each fine speed layer, the depth coordinate of the intersection point of every two adjacent fine speed layer fitting straight lines is used as the thickness ending value of the previous fine speed layer and the thickness starting value of the next fine speed layer.
2. The method of claim 1, further comprising:
judging whether the control points in the last fine speed layer meet preset conditions or not, wherein the preset conditions comprise that the number of the control points is larger than a specified number, and whether the distance between the 1 st control point and the last control point is larger than or equal to a specified distance or not;
and if the control point in the last fine speed layer does not meet the preset condition, discarding the last fine speed layer.
3. The method of claim 1, wherein converting the first arrival time to vertical comprises:
according toDetermining a vertical time t corresponding to the first arrival time t0；
If an excitation point is set in the micro-logging, H represents the depth of the excitation point in the micro-logging, and D represents the distance between a ground receiving point and a wellhead; if the micro-logging is provided with a receiving point, H represents the depth of the receiving point in the micro-logging, and D represents the distance between the ground excitation point and the wellhead.
4. A method according to claim 1, characterized in that the layer velocity of the medium between two control points is determined according to the following method:
according toDetermining a layer of a medium between two control pointsA speed v;
where Δ H represents the depth difference of the two control points; Δ t0The vertical time difference of the two control points is indicated.
5. An apparatus for interpreting a micro-log, the apparatus comprising:
the acquisition module is used for acquiring first arrival time of propagation from an excitation point to a receiving point obtained through micro-logging investigation, converting the first arrival time into vertical time, and spreading the vertical time in a time-depth coordinate system;
the determining module is used for connecting the 1 st to the ith control points in a time-depth coordinate system and determining the first layer speed of the first fine speed layer to which the 1 st to the ith control points belong according to the depth difference and the vertical time difference of the 1 st to the ith control points;
the determining module is further used for determining a second layer speed of the medium between the ith control point and the (i + 1) th control point according to the depth difference and the vertical time difference of the ith control point to the (i + 1) th control point;
the judging module is used for judging whether the difference value between the second-layer speed and the first-layer speed determined by the determining module is greater than a speed difference threshold value or not;
the determining module is further configured to determine that the (i + 1) th control point belongs to the second fine speed hierarchy when the difference is greater than the speed difference threshold; when the difference value is less than or equal to the speed difference threshold value, determining that the (i + 1) th control point belongs to a first fine speed layer; connecting the 1 st to the (i + 1) th control points, and judging whether the (i + 2) th control point belongs to the first fine speed hierarchy according to a method for judging whether the (i + 1) th control point belongs to the first fine speed hierarchy or not until all control points in the first fine speed hierarchy are determined;
the determining module is further configured to determine a first control point after the last control point belonging to the first fine speed hierarchy as a 1 st control point of the second fine speed hierarchy, and determine all control points in the second fine speed hierarchy according to a method for determining all control points in the first fine speed hierarchy until the control points of all fine speed hierarchies are determined;
the determining module is further configured to perform fitting by using all control points in each fine speed hierarchy to obtain a fitting straight line of each fine speed hierarchy, use a slope of the fitting straight line as a layer speed of each fine speed hierarchy, and use a depth coordinate of an intersection point of every two adjacent fine speed hierarchy fitting straight lines as a thickness ending value of a previous fine speed hierarchy and a thickness starting value of a next fine speed hierarchy.
6. The apparatus of claim 5,
the judging module is further used for judging whether the control points in the last fine speed layer meet preset conditions or not, wherein the preset conditions comprise that the number of the control points is larger than a specified number, and whether the distance between the 1 st control point and the last control point is larger than or equal to a specified distance or not;
the determining module is further configured to discard the last fine speed hierarchy when the judging module judges that the control point in the last fine speed hierarchy does not meet the preset condition.
7. The apparatus of claim 5, wherein the obtaining module is configured to:
according toDetermining a vertical time t corresponding to the first arrival time t0；
If an excitation point is set in the micro-logging, H represents the depth of the excitation point in the micro-logging, and D represents the distance between a ground receiving point and a wellhead; if the micro-logging is provided with a receiving point, H represents the depth of the receiving point in the micro-logging, and D represents the distance between the ground excitation point and the wellhead.
8. The apparatus of claim 5, wherein the determining module is configured to determine the layer velocity of the medium between two control points according to:
according to
where Δ H represents the depth difference of the two control points; Δ t0The vertical time difference of the two control points is indicated.
9. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the method of any one of claims 1 to 4 when executing the computer program.
10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program for executing the method of any one of claims 1 to 4.
Technical Field
The application relates to the technical field of geophysical exploration, in particular to a method and a device for explaining micro-logging.
Background
This section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section.
Near surface survey work is used to determine the thickness of the surface medium and the layer velocity, where layer velocity is the longitudinal wave velocity of seismic waves propagating in the medium. Near-surface surveys are the fundamental work of field seismic exploration and acquisition. Firstly, the interpretation precision of each surface investigation control point is directly related to the subsequent surface modeling precision, the precision of a surface model directly influences the design of the excitation well depth, the design of the geophone combination height difference and the precision of field static correction, and the factors determine the quality of original seismic data. Secondly, near-surface survey can provide accurate initial/constraint conditions for refraction/chromatography inversion, so that the precision of refraction/chromatography inversion is improved. Finally, near-surface layer investigation can provide a near-surface model with higher precision for prestack depth migration processing, and further the imaging effect of the seismic section can be improved.
The near-surface investigation method is most commonly used in two ways, shallow refraction and micro-logging. The shallow refraction method is limited by the application principle, the applicable conditions are harsh, and the complex earth surface area is difficult to meet the applicable conditions, so that the interpretation precision is low.
However, the existing interpretation method of micro-metering well depends heavily on the experience of the interpreter, so that the ambiguity often exists, and especially in the gobi gravel area, gravel mountain area, desert area and loess tableland area, where the physical property of the surface medium is a continuous medium, the uniqueness and the precision of the micro-metering well result are difficult to guarantee. This results in different interpretation by different people, possibly with different interpretation results, for the same micro-log; the same person explains at different times, and the explanation result of each time is not guaranteed to be the same.
In the working areas with the surface medium as the continuous medium, the thickness of the weathered layer is generally thicker, and because of the limitation of the drilling depth capability and the production cost of the drilling tool, the excitation well depth of the areas is usually designed according to the drilling depth capability of the drilling tool, in the drilling depth capability range of the drilling tool, excitation is firstly performed in a high-speed layer, excitation is then performed in a secondary high-speed layer, and finally excitation is performed in a speed layer lower than the secondary high-speed layer. If the precision of the micro-logging result has problems, the precision of a subsequent well depth model can be seriously influenced, the quality of an original single shot can be directly influenced, the precision of a field static correction model can be reduced, a more accurate initial constraint condition can not be provided for first arrival static correction, and the imaging effect of a seismic section can be finally influenced.
In the seismic exploration process, especially in a near-surface area with a thick weathered layer and a continuous medium as the physical property of a surface medium, the problem of multi-solution of a micro-logging interpretation result is solved, the precision and uniqueness of the micro-logging interpretation are ensured, and the problem exists in reality.
Disclosure of Invention
The embodiment of the application provides a method for explaining a micro-logging, which is used for getting rid of the influence of human factors in the process of explaining the micro-logging, avoiding the problem of multi-solution of micro-logging explained results and ensuring the precision and uniqueness of the micro-logging explained results, and comprises the following steps:
acquiring first arrival time of propagation from an excitation point to a receiving point obtained through micro-logging investigation, converting the first arrival time into vertical time, and spreading the vertical time in a time-depth coordinate system;
connecting the 1 st to ith control points in a time-depth coordinate system, and determining the first layer speed of the first fine speed layer to which the 1 st to ith control points belong according to the depth difference and the vertical time difference of the 1 st to ith control points;
determining a second layer speed of the medium between the ith control point and the (i + 1) th control point according to the depth difference and the vertical time difference of the ith control point to the (i + 1) th control point;
judging whether the difference value between the second layer speed and the first layer speed is greater than a speed difference threshold value or not;
if the difference value is larger than the speed difference threshold value, determining that the (i + 1) th control point belongs to a second fine speed layer; if the difference value is less than or equal to the speed difference threshold value, determining that the (i + 1) th control point belongs to a first fine speed hierarchy; connecting the 1 st to the (i + 1) th control points, and judging whether the (i + 2) th control point belongs to the first fine speed hierarchy according to a method for judging whether the (i + 1) th control point belongs to the first fine speed hierarchy or not until all control points in the first fine speed hierarchy are determined;
determining a first control point behind the last control point belonging to the first fine speed hierarchy as a 1 st control point of the second fine speed hierarchy, and determining all control points in the second fine speed hierarchy according to a method for determining all control points in the first fine speed hierarchy until the control points of all fine speed hierarchies are determined;
fitting is carried out by utilizing all control points in each fine speed layer to obtain a fitting straight line of each fine speed layer, the slope of the fitting straight line is used as the layer speed of each fine speed layer, the depth coordinate of the intersection point of every two adjacent fine speed layer fitting straight lines is used as the thickness ending value of the previous fine speed layer and the thickness starting value of the next fine speed layer.
The embodiment of the present application further provides a device for interpreting a micro-logging, so as to get rid of the influence of human factors in the process of interpreting a micro-logging, avoid the problem of multi-resolution of the interpretation result of a micro-logging, and ensure the accuracy and uniqueness of the interpretation result of a micro-logging, the device including:
the acquisition module is used for acquiring first arrival time of propagation from an excitation point to a receiving point obtained through micro-logging investigation, converting the first arrival time into vertical time, and spreading the vertical time in a time-depth coordinate system;
the determining module is used for connecting the 1 st to the ith control points in a time-depth coordinate system and determining the first layer speed of the first fine speed layer to which the 1 st to the ith control points belong according to the depth difference and the vertical time difference of the 1 st to the ith control points;
the determining module is further used for determining a second layer speed of the medium between the ith control point and the (i + 1) th control point according to the depth difference and the vertical time difference of the ith control point to the (i + 1) th control point;
the judging module is used for judging whether the difference value between the second-layer speed and the first-layer speed determined by the determining module is greater than a speed difference threshold value or not;
the determining module is further configured to determine that the (i + 1) th control point belongs to the second fine speed hierarchy when the difference is greater than the speed difference threshold; when the difference value is less than or equal to the speed difference threshold value, determining that the (i + 1) th control point belongs to a first fine speed layer; connecting the 1 st to the (i + 1) th control points, and judging whether the (i + 2) th control point belongs to the first fine speed hierarchy according to a method for judging whether the (i + 1) th control point belongs to the first fine speed hierarchy or not until all control points in the first fine speed hierarchy are determined;
the determining module is further configured to determine a first control point after the last control point belonging to the first fine speed hierarchy as a 1 st control point of the second fine speed hierarchy, and determine all control points in the second fine speed hierarchy according to a method for determining all control points in the first fine speed hierarchy until the control points of all fine speed hierarchies are determined;
the determining module is further configured to perform fitting by using all control points in each fine speed hierarchy to obtain a fitting straight line of each fine speed hierarchy, use a slope of the fitting straight line as a layer speed of each fine speed hierarchy, and use a depth coordinate of an intersection point of every two adjacent fine speed hierarchy fitting straight lines as a thickness ending value of a previous fine speed hierarchy and a thickness starting value of a next fine speed hierarchy.
In the embodiment of the application, by utilizing the principle that the layer speeds of two adjacent fine speed layers are different and the difference value is greater than the speed difference threshold value, the control point in each fine speed layer is determined by calculating the layer speed of a medium between the control point and the control point, and the layer speed and the thickness of each fine speed layer are determined by the fitting straight line of all the control points in each fine speed layer. Because the control points are determined, the straight line fitted by the control points is determined, and the layer speed and the thickness of each fine speed layer are further determined to be unique, so that the problem of the multi-solution of the interpretation result of the micro-logging is effectively solved. After the interpretation of the same micro-log, the interpretation results of different interpreters and the same interpreters in different times are the same. Through practical data verification, the method for explaining the micro-logging in the embodiment of the application can meet the requirement of exploration precision, and provides powerful data support for ensuring the precision of a subsequent well depth model and a static correction model; a foundation is laid for improving the quality of the original single cannon; and a more accurate initial constraint condition is provided for the first-arrival wave inversion, so that the static correction precision is improved, and the imaging effect of the seismic section is effectively improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts. In the drawings:
FIG. 1 is a flow chart illustrating a method of micro-logging in an embodiment of the present application;
FIG. 2 is a schematic diagram of a microlog velocity hierarchy in an embodiment of the present application;
FIG. 3 is a schematic diagram of an interpretation result of micro-logging in an embodiment of the present application;
FIG. 4 is a schematic diagram of the vertical and depth profile of a microlog excitation in an embodiment of the present application;
FIG. 5 is a time-depth plot obtained when interpreting micro-logs using the method of interpreting micro-logs provided in the examples of the present application;
FIG. 6 is a time-depth plot from a prior art manual interpretation of micro-logs;
FIG. 7 is another time-depth plot from a prior art manual interpretation of micro-logs;
FIG. 8 is a schematic diagram illustrating an apparatus for micrologging in an embodiment of the present application.
Detailed Description
To make the objects, technical solutions and advantages of the embodiments of the present application more apparent, the embodiments of the present application are further described in detail below with reference to the accompanying drawings. The exemplary embodiments and descriptions of the present application are provided herein to explain the present application and not to limit the present application.
In an embodiment of the present application, a method for interpreting a micro-log is provided, as shown in fig. 1, the method includes steps 101 to 108:
step 101, obtaining the first arrival time of the propagation from the excitation point to the receiving point obtained through the micro-logging survey, converting the first arrival time into vertical time, and spreading the vertical time in a time-depth coordinate system.
Vertical time, i.e., one-way vertical travel time, is in milliseconds (ms), as is first arrival time.
Specifically, the vertical time t corresponding to the first arrival time t is determined according to the following formula0：
If an excitation point is set in the micro-logging, H represents the depth of the excitation point in the micro-logging, and D represents the distance between a ground receiving point and a wellhead; if the micro-logging is provided with a receiving point, H represents the depth of the receiving point in the micro-logging, and D represents the distance between the ground excitation point and the wellhead. H and D are both in meters (m).
And 102, connecting the 1 st to ith control points in a time-depth coordinate system, and determining the first layer speed of the first fine speed layer to which the 1 st to ith control points belong according to the depth difference and the vertical time difference of the 1 st to ith control points.
Generally, the number of control points of each fine speed hierarchy is greater than a specified number, and the distance between the 1 st to the first specified number of control points is not less than a specified distance. Therefore, the value of i is taken within a specified number (including a specified number), and thus, it can be determined that the 1 st to ith control points belong to the first fine speed hierarchy.
Generally, the set range of the specified number is 3-7, the set range of the specified distance is greater than 1-5 m, and the specified number and the specified distance are determined according to the actual geological condition of the area where the micro-logging is located.
It should be noted that if the specified number is less than 3, such as 2, the layer speed determined by 2 control points has no statistical effect, which may result in inaccurate layering. The designated distance is set to ensure that each fine speed layer has a certain thickness, and the designated distance is set by referring to the point distance between the control point and the control point. On the premise that the designated number is greater than or equal to 3, the designated number is influenced by the designated distance. Assuming that the distance of each fine speed layer cannot be less than 3m according to the actual geological condition, if the distance between 2 points is 0.5m, the number of points cannot be less than 7; if the distance between 2 points is 1.0m, the number of points cannot be less than 4.
In particular, the layer velocity v of the medium between two control points is determined according to the following formula:
where Δ H represents the depth difference of the two control points; Δ t0The vertical time difference of the two control points is indicated.
The layer velocity of the medium between any two control points can be determined by using the formula, such as calculating the layer velocity of the medium between the 1 st to ith control points or the layer velocity between the ith to (i + 1) th control points.
And 103, determining a second layer speed of the medium between the ith control point and the (i + 1) th control point according to the depth difference and the vertical time difference of the ith control point and the (i + 1) th control point.
And 104, judging whether the difference value between the second-layer speed and the first-layer speed is greater than a speed difference threshold value.
The speed difference threshold value is the minimum value of the speed difference between adjacent fine speed hierarchies, and the value is the basis for automatically distinguishing each fine speed hierarchy of the near-surface structure. According to actual seismic data statistics, the set range of the velocity difference threshold is 100-300 m/s, the velocity difference threshold is determined according to the requirement of surface layer investigation interpretation precision, when the velocity difference value of adjacent fine velocity layers in the near-surface structure is larger than the velocity difference threshold, the layers are automatically judged to be layered, and otherwise, the layers are treated as one layer. In seismic exploration, a layer is generally considered to have a velocity difference of less than 200m/s between adjacent 2 layers.
And 105, if the difference value is larger than the speed difference threshold value, determining that the (i + 1) th control point belongs to the second fine speed hierarchy.
That is, if the difference between the second-level velocity and the first-level velocity is greater than the velocity threshold, it is determined that the control points of the first fine velocity hierarchy in the near-surface structure are from the 1 st control point up to the ith control point, and the control points of the second fine velocity hierarchy start from the (i + 1) th control point.
Illustratively, fig. 2 shows a schematic diagram of a microlog velocity profile when the difference between the second-zone velocity and the first-zone velocity is greater than the velocity difference threshold, and as can be seen from fig. 2, the 1 st to ith control points are used to explain the first fine velocity profile.
Step 106, if the difference value is less than or equal to the speed difference threshold value, determining that the (i + 1) th control point belongs to a first fine speed layer; and connecting the 1 st to the (i + 1) th control points, and judging whether the (i + 2) th control point belongs to the first fine speed hierarchy according to a method for judging whether the (i + 1) th control point belongs to the first fine speed hierarchy until all control points in the first fine speed hierarchy are determined.
If the difference between the second layer speed and the first layer speed is less than or equal to the speed difference threshold, it indicates that the control points of the first fine speed hierarchy are insufficient, n control points still need to be further added until the layer speed of the medium between the (i + n) th to (i + n + 1) th control points and the layer speed of the medium between the (1) th to (i + n) th control points are greater than the speed difference threshold, and the (1) th to (i + n) th control points are all the control points in the first fine speed hierarchy.
Step 107, determining the first control point after the last control point belonging to the first fine speed hierarchy as the 1 st control point of the second fine speed hierarchy, and determining all the control points in the second fine speed hierarchy according to the method for determining all the control points in the first fine speed hierarchy until the control points of all the fine speed hierarchies are determined.
That is, if the first control point after the last control point of the first fine velocity layer, that is, the first control point in the second fine velocity layer is m, the third layer velocity of the second fine velocity layer between the m to m + i control points is calculated first, and then the fourth layer velocity of the medium between the m + i to m + i +1 control points is calculated, and if the difference between the fourth layer velocity and the third layer velocity is greater than the velocity difference threshold, all the control points of the second fine velocity layer are m to m + i; and if the difference is less than or equal to the speed threshold, continuously judging whether the (m + i + 2) th control point belongs to the second fine speed hierarchy or not until all control points in the second fine speed hierarchy are determined. In the same way, all control points in each fine speed hierarchy can be determined.
However, it should be noted that after all the control points in each fine speed hierarchy are determined, it is determined whether the control points in the last fine speed hierarchy meet preset conditions, where the preset conditions include that the number of the control points is greater than a specified number, and whether the distance between the 1 st control point and the last control point is greater than or equal to a specified distance; and if the control point in the last fine speed layer does not meet the preset condition, discarding the last fine speed layer and not taking the last fine speed layer as an independent layer.
And 108, fitting by using all control points in each fine speed layer to obtain a fitting straight line of each fine speed layer, taking the slope of the fitting straight line as the layer speed of each fine speed layer, and taking the depth coordinate of the intersection point of every two adjacent fine speed layer fitting straight lines as the thickness ending value of the previous fine speed layer and the thickness starting value of the next fine speed layer.
The control points in each fine velocity layer can be fitted using a least squares method to obtain a fitted straight line.
For example, fig. 3 shows a schematic diagram of an interpretation of a micro-log. As can be seen from FIG. 3, the first fine velocity layer has a layer velocity v0The initial thickness is 0m to h0Rice, h0The vertical coordinate of the intersection point of the control point fitting straight line in the first fine speed hierarchy and the control point fitting straight line of the second fine speed hierarchy, namely the depth coordinate; the layer velocity of the second fine velocity layer is v1Thickness of h0m to h0+h1Rice, the third fine velocity layer velocity is v2Thickness of h0m to h0+h1+h2And (4) rice.
Determining the layer velocity and thickness of each fine velocity layer also completes the whole link of micro-logging interpretation.
In the embodiment of the application, by utilizing the principle that the layer speeds of two adjacent fine speed layers are different and the difference value is greater than the speed difference threshold value, the control point in each fine speed layer is determined by calculating the layer speed of a medium between the control point and the control point, and the layer speed and the thickness of each fine speed layer are determined by the fitting straight line of all the control points in each fine speed layer. Because the control points are determined, the straight line fitted by the control points is determined, and the layer speed and the thickness of each fine speed layer are further determined to be unique, so that the problem of the multi-solution of the interpretation result of the micro-logging is effectively solved. After the interpretation of the same micro-log, the interpretation results of different interpreters and the same interpreters in different times are the same. Through practical data verification, the method for explaining the micro-logging in the embodiment of the application can meet the requirement of exploration precision, and provides powerful data support for ensuring the precision of a subsequent well depth model and a static correction model; a foundation is laid for improving the quality of the original single cannon; and a more accurate initial constraint condition is provided for the first-arrival wave inversion, so that the static correction precision is improved, and the imaging effect of the seismic section is effectively improved.
In order to verify the method for explaining the micro-logging provided by the embodiment of the application, the explanation work of the micro-logging is carried out for one micro-logging by relying on a three-dimensional seismic exploration acquisition project of a complex near-surface area of a Tarim basin, and the specific implementation conditions are as follows:
1) the experiment adopts well excitation and ground receiving, the distance (namely offset) from a ground receiving point to a well mouth is 1m, and when the acquired first arrival time is converted into vertical time, the following table I shows that:
watch 1
And spreading the vertical time in the first table in a time-depth coordinate system to obtain a schematic diagram of vertical time and depth spreading shown in fig. 4.
2) Determining control points for interpreting a first velocity hierarchy in a near-surface structure
Set i to 4 and the speed difference threshold to 200 m/s.
First, the 1 st to 4 th control points are connected in a time-depth coordinate system (the distance between the 1 st and 4 th control points is not less than 1.5 m).
Calculating the speed V according to the following formula from the depth difference and the vertical time difference of the 1 st to the 4 th control points0；
V0＝1000×(2-0.5)÷(4.97525125-1.788854382)≈471(m/s)
Then connecting the last control point (4 th point) of the fine speed layer and the control point (5 th point) behind the last control point, and calculating the layer speed V of the medium between the 4 th control point and the 5 th control point0s：
V0s＝1000×(2.0-1.5)÷(5.773964421-4.97525125)＝626m/s
Due to the difference in velocity Δ V ═ V0s-V0626-.
Then connecting the 1 st control point and the 5 th control point to calculate the layer velocity value V1：
V1＝1000×(2.5-0.5)÷(5.773964421-1.788854382)≈502(m/s)
And the layer velocity V of the medium between the 5 th control point and the 6 th control point1s：
V1s＝1000×(3.0-2.5)÷(6.231663414-5.773964421)≈1092(m/s)
Due to the difference in velocity Δ V ═ V1s-V11092-.
3) Determining control points for interpreting the velocity layer in each remaining fine velocity hierarchy in the near-surface structure
According to the method in the step 2), the other control points for explaining each fine speed hierarchy except the first fine speed hierarchy are determined. Through calculation, the first fine speed layer is controlled by 1 st to 5 th points; the second fine speed layer is controlled by 6 th to 15 th points; the third fine speed layering is controlled by 16 th to 22 th points; the fourth fine speed layer is controlled by 23-28 points.
4) Obtaining the thickness and speed value of each fine speed layer in the near-surface structure
According to the control points used for explaining each fine speed layer in the near-surface structure determined in the step 2) and the step 3), a least square method is adopted to fit straight lines layer by layer, and the slope of each layer of straight lines is the speed of the fine layer and is 521m/s, 1319m/s, 1693m/s and 2041m/s respectively; by reading the depth value of the intersection point between different straight lines, the thickness of each fine layer can be obtained, which is 2.6m, 12.2m and 21.7m respectively.
Referring to fig. 5, a time-depth curve diagram of the micro-logging in step 4) is explained, referring to fig. 6 and fig. 7, two manually explained time-depth curve diagrams of the micro-logging are illustrated, it can be seen that the layer speeds and thicknesses of each fine speed layer obtained by the micro-logging in the explanation of fig. 6 and fig. 7 are different, while fig. 5 is not interfered by human factors, and a plurality of micro-logging explanation results cannot appear.
The whole link of the automatic interpretation work of the micro-logging results is completed through the steps 1) to 4).
The embodiment of the present application further provides an apparatus for interpreting micro-logs, as shown in fig. 8, the apparatus 800 includes an obtaining module 801, a determining module 802, and a determining module 803.
The obtaining module 801 is configured to obtain first arrival time of propagation from an excitation point to a receiving point obtained through micro-logging investigation, convert the first arrival time into vertical time, and spread the vertical time in a time-depth coordinate system.
The determining module 802 is configured to connect the 1 st to ith control points in a time-depth coordinate system, and determine the first layer speed of the first fine speed hierarchy to which the 1 st to ith control points belong according to the depth difference and the vertical time difference of the 1 st to ith control points.
The determining module 802 is further configured to determine a second layer velocity of the medium between the ith to (i + 1) th control points according to the depth difference and the vertical time difference between the ith to (i + 1) th control points.
A determining module 803, configured to determine whether the difference between the second layer speed and the first layer speed determined by the determining module 802 is greater than a speed difference threshold.
The determining module 802 is further configured to determine that the (i + 1) th control point belongs to the second fine speed hierarchy when the difference is greater than the speed difference threshold; when the difference value is less than or equal to the speed difference threshold value, determining that the (i + 1) th control point belongs to a first fine speed layer; and connecting the 1 st to the (i + 1) th control points, and judging whether the (i + 2) th control point belongs to the first fine speed hierarchy according to a method for judging whether the (i + 1) th control point belongs to the first fine speed hierarchy until all control points in the first fine speed hierarchy are determined.
The determining module 802 is further configured to determine a first control point after the last control point belonging to the first fine speed hierarchy as a 1 st control point of the second fine speed hierarchy, and determine all control points in the second fine speed hierarchy according to a method of determining all control points in the first fine speed hierarchy until the control points of all fine speed hierarchies are determined.
The determining module 802 is further configured to perform fitting by using all control points in each fine speed hierarchy to obtain a fitting straight line of each fine speed hierarchy, use a slope of the fitting straight line as a layer speed of each fine speed hierarchy, and use a depth coordinate of an intersection point of every two adjacent fine speed hierarchy fitting straight lines as a thickness ending value of a previous fine speed hierarchy and a thickness starting value of a subsequent fine speed hierarchy.
In an implementation manner of the embodiment of the present application, the determining module 803 is further configured to determine whether the control points in the last fine speed hierarchy meet preset conditions, where the preset conditions include that the number of the control points is greater than a specified number, and whether a distance between the 1 st control point and the last control point is greater than or equal to a specified distance.
The determining module 802 is further configured to discard the last fine speed hierarchy when the determining module 803 determines that the control point in the last fine speed hierarchy does not satisfy the preset condition.
In an implementation manner of the embodiment of the present application, the obtaining module 801 is configured to:
according toDetermining a vertical time t corresponding to the first arrival time t0；
If an excitation point is set in the micro-logging, H represents the depth of the excitation point in the micro-logging, and D represents the distance between a ground receiving point and a wellhead; if the micro-logging is provided with a receiving point, H represents the depth of the receiving point in the micro-logging, and D represents the distance between the ground excitation point and the wellhead.
In one implementation of the embodiment of the present application, the determining module 802 is configured to determine a layer velocity of a medium between two control points according to the following method:
according toDetermining the layer velocity v of the medium between two control points;
where Δ H represents the depth difference of the two control points; Δ t0The vertical time difference of the two control points is indicated.
In the embodiment of the application, by utilizing the principle that the layer speeds of two adjacent fine speed layers are different and the difference value is greater than the speed difference threshold value, the control point in each fine speed layer is determined by calculating the layer speed of a medium between the control point and the control point, and the layer speed and the thickness of each fine speed layer are determined by the fitting straight line of all the control points in each fine speed layer. Because the control points are determined, the straight line fitted by the control points is determined, and the layer speed and the thickness of each fine speed layer are further determined to be unique, so that the problem of the multi-solution of the interpretation result of the micro-logging is effectively solved. After the interpretation of the same micro-log, the interpretation results of different interpreters and the same interpreters in different times are the same. Through practical data verification, the method for explaining the micro-logging in the embodiment of the application can meet the requirement of exploration precision, and provides powerful data support for ensuring the precision of a subsequent well depth model and a static correction model; a foundation is laid for improving the quality of the original single cannon; and a more accurate initial constraint condition is provided for the first-arrival wave inversion, so that the static correction precision is improved, and the imaging effect of the seismic section is effectively improved.
The embodiment of the present application further provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the processor implements any one of the methods described in steps 101 to 108 and various implementations thereof.
The embodiment of the present application further provides a computer-readable storage medium, where a computer program for executing any one of the methods described in steps 101 to 108 and various implementation manners thereof is stored in the computer-readable storage medium.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The above-mentioned embodiments are further described in detail for the purpose of illustrating the invention, and it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.