A combined time-depth interpretation method of micro-logging and first-arrival of large-scale artillery

Abstract

The present invention discloses a combined time-depth interpretation method for micro-logging and cannon first arrivals, comprising: selecting a cannon at a micro-logging location on a thick surface for refraction interpretation; obtaining cannon time-depth data corresponding to the micro-logging location based on the surface interpretation results; determining the micro-logging time-depth data; performing time difference comparison and statistics on the cannon time-depth data and the micro-logging time-depth data, fitting a time difference correction relationship curve for the cannon vertical travel time T0; using this relationship curve to correct the cannon vertical travel time T0 to obtain the corrected cannon vertical travel time T0; combining the corrected cannon vertical travel time T0 and depth data with the micro-logging vertical travel time t0 and depth data to form a combined time-depth relationship; and forming a time-depth diagram based on the combined time-depth relationship for interpretation. By effectively integrating the micro-logging time-depth information with the first arrival time-depth information of the cannon record at the same location, a combined interpretation of the micro-logging and cannon time-depth relationship is achieved, extending the depth of micro-logging investigations.

Description

Technical Field

[0001] The present invention relates to near-surface modeling technology, and more particularly to a time-depth interpretation method combining micro-well logging and first-arrival of large-scale artillery. Background Art

[0002] In recent years, the country has continued to carry out seismic research on oil and gas resource exploration in the "double complex" (complex surface and underground) areas in the west. However, due to the complex surface structure, it is difficult to accurately establish a near-surface model. The resulting static correction problems and low offset modeling accuracy have affected the acquisition of high-precision seismic results and have had an adverse impact on oil and gas exploration.

[0003] To establish high-precision surface models and improve the accuracy of static correction and offset modeling, strengthening field surface surveys has become a common practice. In "double-complex" areas with dramatic terrain and complex subsurface structures, micro-logging surveys are generally used to obtain surface information for constrained inversion modeling. However, micro-logging is constrained by surface characteristics, cost, drilling capabilities, and the construction environment. The actual exploration depth in these "double-complex" areas is often insufficient, resulting in only relatively shallow survey information. Many micro-logging surveys fall short of the required depth for detecting low-velocity zone thickness, resulting in insufficient constraint depth when using micro-logging constraints and limited accuracy in constrained inversion modeling.

[0004] Therefore, it is necessary to improve the existing interpretation methods to expand the investigation depth and improve the interpretation accuracy. Summary of the Invention

[0005] The object of the present invention is to provide a micro-logging and cannon first arrival combined time-depth interpretation method to solve at least one of the above-mentioned problems existing in the prior art.

[0006] In order to achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

[0007] According to one aspect of the present invention, a method for combining micro-logging and first-arrival time-depth interpretation is provided, comprising the following steps:

[0008] Step S1: Selecting a cannon at a micro-logging location on a thick surface to perform refraction interpretation to obtain surface interpretation results based on the cannon's first arrival;

[0009] Step S2: Obtaining the cannon time-depth data corresponding to the micro-logging position according to the surface interpretation result and a predetermined rule, wherein the cannon time-depth data includes the cannon vertical travel time T0 value and the corresponding depth;

[0010] Step S3: determining micro-logging time-depth data, wherein the micro-logging time-depth data includes the micro-logging vertical travel time t0 value and the corresponding depth;

[0011] Step S4: performing time difference comparison statistics on the cannon vertical travel time T0 value determined in step S2 and the micro-logging vertical travel time t0 value determined in step S3, and fitting them into a cannon vertical travel time T0 time difference correction relationship curve;

[0012] Step S5: using the cannon vertical travel time T0 time difference correction relationship curve to correct the cannon vertical travel time T0 below the micro-logging depth to obtain the corrected cannon vertical travel time T0;

[0013] Step S6: combining the corrected cannon vertical travel time T0 and depth data obtained in step S5 with the micro-log vertical travel time t0 and depth data to form a joint time-depth relationship;

[0014] Step S7: forming a time-depth graph based on the joint time-depth relationship and interpreting it.

[0015] According to one embodiment of the present invention, step S1 includes deploying the micro-logging position at the shot point position.

[0016] According to one embodiment of the present invention, step S1 includes deploying the micro-logging position within a range of less than 200 m from the shot point position when the surface structure does not change much.

[0017] According to one embodiment of the present invention, the surface interpretation result in step S1 represents a first arrival time-distance curve formed based on the first arrival time of the finely picked single shot seismic record, and refraction stratification is performed to obtain a refraction interpretation velocity model of the micro-logging position based on the first arrival of the cannon.

[0018] According to one embodiment of the present invention, the maximum velocity of the refraction interpretation velocity model should track the high-speed layer velocity in the low-velocity reduction zone.

[0019] According to one embodiment of the present invention, the predetermined rule in step S2 is that when the depth of the refraction interpretation velocity model is within the micro-logging depth, the vertical travel time T0 value based on the cannon first-arrival interpretation velocity model is calculated according to the micro-logging sampling interval; when the depth of the refraction interpretation velocity model exceeds the micro-logging depth, the cannon vertical travel time T0 is calculated based on the cannon first-arrival interpretation velocity model according to the set depth interval.

[0020] According to an embodiment of the present invention, the depth interval should satisfy the requirement that no less than three sampling points are calculated for one velocity layer.

[0021] According to one embodiment of the present invention, the final depth range obtained in step S2 should be greater than the thickness of the low speed reduction zone.

[0022] According to one embodiment of the present invention, the time difference comparison statistics in step S4 only compare the time differences within the micro-logging depth range.

[0023] According to one embodiment of the present invention, the time difference comparison statistics in step S4 includes calculating the time difference between the micro-logging vertical travel time t0 value and the cannon vertical travel time T0 value at the corresponding depth for different depths.

[0024] According to one embodiment of the present invention, fitting the time difference correction relationship curve of the cannon vertical travel time T0 in step S4 includes fitting a relationship curve with depth as the abscissa and the time difference as the ordinate.

[0025] According to one embodiment of the present invention, the correction in step S5 includes:

[0026] Determine the depth value corresponding to the cannon vertical travel time T0 below the micro-logging depth, determine the corresponding correction time difference based on the depth value and the relationship curve, and add the corresponding correction time difference to the cannon vertical travel time T0 value calculated greater than the micro-logging depth to obtain the corrected cannon vertical travel time T0.

[0027] According to one embodiment of the present invention, forming a joint time-depth relationship in step S6 includes using micro-logging vertical travel time t0 data for the time-depth relationship within the micro-logging depth range, and using the corrected cannon vertical travel time T0 data for the time-depth relationship beyond the micro-logging depth range.

[0028] Compared with the existing technology, the combined time-depth interpretation method of micro-logging and cannon first arrival provided by the present invention has at least one of the following beneficial effects: the advantages and disadvantages of the micro-logging and cannon first arrival methods are complemented, and the combined time-depth interpretation method of micro-logging and cannon first arrival is adopted. By effectively integrating the time-depth information of micro-logging with the time-depth information of the first arrival of cannon records at the same position, the combined interpretation of the time-depth relationship between micro-logging and cannon is realized, the depth of micro-logging investigation is extended, the demand of micro-logging information for constrained inversion modeling is met, and the modeling accuracy of "double complex" areas is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 A schematic diagram of a time-depth correction relationship curve between micro-logging and cannon first arrival according to an embodiment of the present invention is shown;

[0031] Figure 2 A schematic diagram showing the combined time-depth relationship of micro-logging and cannon first arrivals according to one embodiment of the present invention is shown. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0033] The present invention provides a method for combining micro-logging and first-arrival time-depth interpretation, which generally includes the following steps:

[0034] Step S1: Selecting a cannon at a micro-logging location on a thick surface to perform refraction interpretation to obtain surface interpretation results based on the cannon's first arrival;

[0035] Step S2: Obtain the cannon time-depth data corresponding to the micro-logging position according to the surface interpretation results and predetermined rules. The cannon time-depth data includes the cannon vertical travel time T0 value and the corresponding depth;

[0036] Step S3: determining micro-logging time-depth data, where the micro-logging time-depth data includes the micro-logging vertical travel time t0 value and the corresponding depth;

[0037] Step S4: performing time difference comparison statistics on the cannon vertical travel time T0 value determined in step S2 and the micro-logging vertical travel time t0 value determined in step S3, and fitting them into a cannon vertical travel time T0 time difference correction relationship curve;

[0038] Step S5: using the time difference correction relationship curve of the cannon vertical travel time T0 to correct the cannon vertical travel time T0 below the micro-logging depth to obtain the corrected cannon vertical travel time T0;

[0039] Step S6: combining the corrected cannon vertical travel time T0 and depth data obtained in step S5 with the micro-log vertical travel time t0 and depth data to form a joint time-depth relationship;

[0040] Step S7: forming a time-depth graph based on the joint time-depth relationship and interpreting it.

[0041] Each step in the method will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] In step S1, a cannon at a very thick surface micro-logging position is selected for refraction interpretation to obtain a surface interpretation velocity model based on the first arrival of the cannon. Specifically, the micro-logging position is deployed at the shot point position. When the surface structure does not change much (for example, the time difference caused by the velocity error within 200m is less than 4ms), the micro-logging position can also be deployed near the shot point position, for example, within 200m of the shot point. The micro-logging position (or nearby position) is selected for refraction interpretation. The above-mentioned refraction interpretation is to carefully pick up the first arrival time of the single-shot seismic record, form the first arrival time-distance curve through professional software, perform refraction stratification, and obtain the refraction interpretation velocity model of the micro-logging position based on the first arrival of the cannon. The maximum velocity of the refraction interpretation should be tracked to the high-speed layer velocity.

[0043] In step S2, the cannon time-depth data (i.e., vertical travel time T0 and corresponding depth) corresponding to the micro-logging location is obtained based on the surface interpretation results according to a predetermined rule. The predetermined rule is that when the depth of the refraction interpretation velocity model is within the micro-logging depth, the cannon vertical travel time T0 is calculated based on the cannon interpretation results at different depth locations (i.e., sampling intervals) acquired from the micro-logging. When the depth of the refraction interpretation velocity model exceeds the micro-logging depth, the cannon vertical travel time T0 is calculated based on the cannon first-arrival interpretation velocity model at a predetermined depth interval. The depth interval should ensure that each velocity layer has at least three sampling points (cannon T0 times).

[0044] The above time-depth data refers to different depths and the corresponding vertical travel time. The calculation method is as follows:

[0045] For example, if we calculate the vertical travel time T0 at a certain depth H, we assume that the refraction of the cannon's first arrival from shallow to deep penetrates two velocity layers (corresponding to the velocity and thickness v1, h1; v2, h2), and enters the third velocity layer, corresponding to the velocity v3. Then:

[0046] T0=h1 / v1+h2 / v2+(H-h1-h2) / v3 Formula (1)

[0047] The depth range obtained from the above time-depth data should meet the following requirements:

[0048] When the depth range H is less than the micro-logging depth h (H < h), T0 (vertical travel time) is calculated based on the interpretation results of the cannon first arrival refraction according to the different sampling depths of the micro-logging;

[0049] For example, if the sampling depths of micro-logging are 0.5m, 1m, 2m…5m, 6m…10m, 12m…20m, 23m…60m, then according to the interpretation results of the first arrival of the cannon and the principle of formula (1), the T0 values ​​of the corresponding depths of “0.5m, 1m, 2m…5m, 6m…10m, 12m…20m, 23m…60m” are calculated respectively. The t0 values ​​of micro-logging from shallow to deep can be recorded as t 01 , t 02 …t 0i ; The corresponding depth cannon calculation T0 values ​​are T 01 、T 02 …T 0i .

[0050] When the depth range H is greater than the micro-logging depth h (H>h): calculate T0 according to the cannon first arrival refraction interpretation results at a certain sampling depth interval. The above-mentioned interval depth should be such that at least three T0s are calculated for one velocity layer. The cannon calculated T0 values ​​can be recorded as T 0i+1 、T 0i+2 …T 0i+n .

[0051] The final depth range should be greater than the thickness of the low-velocity reduction zone to meet the surface modeling requirements.

[0052] In step S3, the micro-logging time-depth data, i.e., the micro-logging depth and its corresponding vertical travel time t0, is determined. The micro-logging time-depth data can be determined using any method known in the art, such as specialized software that interprets the micro-logging data and outputs the micro-logging t0 value.

[0053] In step S4, the time difference comparison statistics of the cannon T0 time value determined in step S2 and the micro-logging t0 time value determined in step S3 are performed, and fitted into a time difference correction relationship curve of the cannon vertical travel time T0. Among them, the time difference comparison statistics only compare the time difference within the micro-logging depth range. The micro-logging t0 time and the cannon T0 value are compared and statistically analyzed by time difference (△t), and fitted into a T0 time difference correction relationship curve. The above-mentioned time difference refers to the difference (△t) between the micro-logging t0 value at different depths and the T0 value calculated by the cannon initial arrival. For example, the t0 values ​​of the micro-logging from shallow to deep are t 01 , t 02 …t 0i ; The corresponding depth cannon calculation T0 values ​​are T 01 、T 02 …T 0i Then, △t i t 01 -T 01 , t 02 -T 02 …t 0i -T 0i .

[0054] The above-mentioned correction relationship curve refers to a relationship curve that is fitted with depth H as the horizontal coordinate and time difference △t as the vertical coordinate, and an equation is formed using professional software. Figure 1 A schematic diagram of a time-depth correction relationship curve of micro-logging and cannon first arrival according to an embodiment of the present invention is shown. The equation of the time-depth correction relationship curve obtained by fitting is:

[0055] y=-0.0009x 2 +0.3287x+7.1699,

[0056] Where y represents the time difference Δt, and x represents the logging depth. To calculate the time difference at a specific depth to correct for the cannon's T0 time, substitute the depth into the x portion of the equation to calculate the corresponding time difference y.

[0057] In step S5, the cannon vertical travel time T0 time difference correction relationship curve is used to correct the cannon T0 time below the micro-logging depth to obtain the corrected cannon T0 time. First, the correction time difference when the depth is greater than the micro-logging depth is obtained according to the correction relationship curve equation. Figure 1 As shown in the figure, the maximum depth of the micro-logging well is 100m. The correction relationship curve equation y is fitted by the time difference △t calculated within 100m. If the correction time difference of 120m, 140m, and 160m with a subsequent sampling interval of 20m is required, x=120, 140, and 160 can be substituted into the equations, and the corresponding time difference y values ​​can be obtained respectively, which are the corresponding correction time differences. Similarly, the correction time differences of all sampling depths greater than the micro-logging depth range can be obtained, which can be recorded as △t i+1 ,△t i+2 …△t i+n .

[0058] Then, the cannon time-depth data is corrected. The cannon T0 time value greater than the micro-logging depth is added with the corresponding correction time difference, namely T 0i+1 +△t i+1 、T 0i+2 +△t i+2 ,…T 0i+n +△t i+n ; can be expressed as T 0’i+1 、T 0’i+2 …T 0’i+n .

[0059] In step S6, the corrected cannon T0 time and depth data obtained in step S5 are combined with the micro-logging t0 time and depth data to form a joint time-depth relationship. When forming a joint time-depth relationship, the time-depth relationship within the micro-logging depth range uses the micro-logging time-depth data, and the time-depth relationship beyond the micro-logging depth range uses the corrected cannon T0 time and corresponding depth data, that is, the vertical travel time from shallow to deep is t 01 , t 02 …t 0i 、T 0’i+1 、T 0’i+2 …T 0’i+n . Figure 2 A schematic diagram showing the combined time-depth relationship of micro-logging and cannon first arrivals according to one embodiment of the present invention is shown.

[0060] In step S7, a time-depth map is formed based on the joint time-depth relationship and interpreted. The interpretation can be achieved using professional software.

[0061] This method has been explored and applied in 3D seismic exploration in "double-complex" areas, such as the Yingxiongling area in the Qaidam Basin and the Kulongshan area in the Jiuquan Basin. This method has fully leveraged the effectiveness of velocity information from micro-logging surveys, reduced micro-logging survey costs in complex areas, improved the accuracy of constrained inversion modeling for "double-complex" micro-logging, reduced the equivalence of the surface velocity model, bringing it closer to the true velocity model, and enhanced the accuracy of pre-stack depth migration imaging of seismic data in complex areas.

[0062] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0063] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0064] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for combining micro-logging and first-arrival time-depth interpretation, characterized in that: The following steps are involved: Step S1: Selecting a cannon at a micro-logging location on a thick surface to perform refraction interpretation to obtain surface interpretation results based on the cannon's first arrival; Step S2: Obtaining the cannon time-depth data corresponding to the micro-logging position according to the surface interpretation result and a predetermined rule, wherein the cannon time-depth data includes the cannon vertical travel time T0 value and the corresponding depth; Step S3: determining micro-logging time-depth data, wherein the micro-logging time-depth data includes the micro-logging vertical travel time t0 value and the corresponding depth; Step S4: performing time difference comparison statistics on the cannon vertical travel time T0 value determined in step S2 and the micro-logging vertical travel time t0 value determined in step S3, and fitting them into a cannon vertical travel time T0 time difference correction relationship curve; Step S5: using the cannon vertical travel time T0 time difference correction relationship curve to correct the cannon vertical travel time T0 below the micro-logging depth to obtain a corrected cannon vertical travel time T0, the correction comprising: determining a depth value corresponding to the cannon vertical travel time T0 below the micro-logging depth, determining a corresponding correction time difference based on the depth value and the relationship curve, and adding the corresponding correction time difference to each cannon vertical travel time T0 value calculated greater than the micro-logging depth to obtain a corrected cannon vertical travel time T0; Step S6: combining the corrected cannon vertical travel time T0 and depth data obtained in step S5 with the micro-logging vertical travel time t0 and depth data to form a joint time-depth relationship, wherein the time-depth relationship within the micro-logging depth range uses the micro-logging vertical travel time t0 data, and the time-depth relationship beyond the micro-logging depth range uses the corrected cannon vertical travel time T0 data; Step S7: forming a time-depth graph based on the joint time-depth relationship and interpreting it.

2. The method according to claim 1, characterized in that Step S1 includes deploying the micro-logging position at the shot point position.

3. The method according to claim 1, characterized in that Step S1 includes deploying the micro-logging position within a range of less than 200 m from the shot point position when the surface structure does not change much.

4. The method according to claim 1, wherein The surface interpretation result in step S1 represents the first arrival time-distance curve formed based on the first arrival time of the finely picked single shot seismic record, and the refraction layering is performed to obtain the refraction interpretation velocity model of the micro-logging position based on the first arrival of the shot.

5. The method according to claim 4, characterized in that The maximum velocity of the refraction interpretation velocity model should track the velocity of the high-speed layer in the low-velocity reduction zone.

6. The method according to claim 1, characterized in that The predetermined rule in step S2 is that when the depth of the refraction interpretation velocity model is within the micro-logging depth, the vertical travel time T0 value based on the cannon first-arrival interpretation velocity model is calculated according to the micro-logging sampling interval; when the depth of the refraction interpretation velocity model exceeds the micro-logging depth, the cannon vertical travel time T0 is calculated based on the cannon first-arrival interpretation velocity model according to the set depth interval.

7. The method according to claim 6, characterized in that The depth interval should satisfy the requirement that no less than 3 sampling points are calculated for one velocity layer.

8. The method according to claim 7, characterized in that The final depth range obtained in step S2 should be greater than the thickness of the low speed reduction zone.

9. The method according to claim 1, characterized in that The time difference comparison statistics in step S4 only compare the time differences within the micro-logging depth range.

10. The method according to claim 9, characterized in that The time difference comparison statistics in step S4 include calculating the time difference between the micro-logging vertical travel time t0 value and the cannon vertical travel time T0 value at the corresponding depth for different depths.

11. The method according to claim 10, characterized in that The step S4 of fitting the time difference correction relationship curve of the vertical travel time T0 of the cannon includes fitting a relationship curve with the depth as the abscissa and the time difference as the ordinate.

Images