Micro-logging and cannon first arrival combined time-depth interpretation method

Abstract

The invention discloses a micro-logging and cannon first arrival combined time-depth interpretation method. The method comprises the following steps: selecting a cannon at a micro-logging position of an extremely thick earth surface for refraction interpretation; solving cannon time depth data corresponding to the micro-logging position according to a surface interpretation result; determining micro-logging time-depth data; time difference comparison statistics is carried out on the time-depth data of the cannon and the time-depth data of the micro-logging, and a time difference correction relation curve of the vertical travel time T0 of the cannon is fitted; correcting the vertical travel time T0 of the cannon by using the relation curve to obtain the corrected vertical travel time T0 of the cannon; combining the corrected vertical travel time T0 and depth data of the cannon with the vertical travel time t0 and depth data of the micro-logging to form a combined time-depth relationship; and forming a time-depth map based on the joint time-depth relationship for interpretation. Through effective fusion of the time-depth information of the micro-logging and the first arrival time-depth information recorded by the cannon at the same position, the combined interpretation of the time-depth relationship between the micro-logging and the cannon is realized, and the depth of the micro-logging survey is extended.

Description

Technical Field

[0001] The present invention relates to near-surface modeling technology, and more particularly to a micro-well logging and cannon first-arrival combined time-depth interpretation method. 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] In order to establish a high-precision surface model 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 undulations and complex underground structures, micro-logging surveys are generally used to obtain surface information and apply it to constrained inversion modeling. However, micro-logging is subject to comprehensive constraints such as surface characteristics, cost investment, drilling capabilities, and construction environment. The actual detection depth in "double-complex" areas is often insufficient, and only relatively shallow survey information can be obtained. The depth of a large number of micro-logging surveys does not meet the requirements for detecting the thickness of the low-velocity zone, resulting in insufficient depth of constraints when using micro-logging constraints, and limited accuracy of 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 solution adopted by the present invention is as follows:

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

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

[0009] Step S2: According to the surface interpretation results, the cannon time-depth data corresponding to the micro-logging position is obtained according to the predetermined rules. The cannon time-depth data includes the cannon vertical travel time T 0 Value and corresponding depth;

[0010] Step S3: Determine the micro-logging time-depth data, wherein the micro-logging time-depth data includes the micro-logging vertical travel time t 0 Value and corresponding depth;

[0011] Step S4: The vertical travel time T of the cannon determined in step S2 0 The value and the micro-logging vertical travel time t determined in step S3 0 The time difference is compared and statistically analyzed, and fitted into the vertical travel time T of the cannon. 0 Time difference correction relationship curve;

[0012] Step S5: Using the vertical travel time T of the cannon 0 Time difference correction relationship curve for cannon vertical travel time T below micro-logging depth 0 Correction is performed to obtain the corrected cannon vertical travel time T 0 ;

[0013] Step S6: The corrected cannon vertical travel time T obtained in step S5 is 0 and depth data and micro-log vertical travel time t 0 Combined with 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 a 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 an 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 refraction interpretation velocity model depth is within the micro-logging depth, the vertical travel time T based on the cannon first arrival interpretation velocity model is calculated according to the micro-logging sampling interval. 0 When the refraction interpretation velocity model depth exceeds the micro-logging depth, the cannon vertical travel time T is calculated based on the cannon first arrival interpretation velocity model according to the set depth interval. 0 .

[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 an embodiment of the present invention, the final depth range in step S2 should be greater than the thickness of the slow 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 include calculating the micro-logging vertical travel time t for different depths respectively. 0 The value is related to the vertical travel time T of the cannon at the corresponding depth 0 The time difference between the values.

[0024] According to one embodiment of the present invention, the fitting in step S4 to the vertical travel time T of the cannon 0 The time difference correction relationship curve includes a relationship curve fitted with the 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 cannon vertical travel time T below the microlog depth 0 The corresponding depth value is determined based on the depth value and the relationship curve to determine the corresponding correction time difference, which is greater than the vertical travel time T of the cannon calculated by the micro-logging depth. 0 The values ​​are added with the corresponding correction time difference to obtain the corrected cannon vertical travel time T 0 .

[0027] According to one embodiment of the present invention, the formation of the joint time-depth relationship in step S6 includes the time-depth relationship within the micro-logging depth range using the micro-logging vertical travel time t 0 The time-depth relationship beyond the micro-logging depth range uses the corrected cannon vertical travel time T 0 data.

[0028] Compared with the prior art, 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. Through the effective fusion of micro-logging time-depth information and the first arrival time-depth information 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 specific embodiments, 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 micro-logging and cannon first-arrival joint time-depth correction relationship curve 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 arrival according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is 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 used to limit the present invention.

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

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

[0035] Step S2: According to the surface interpretation results, the cannon time-depth data corresponding to the micro-logging position is obtained according to the predetermined rules. The cannon time-depth data includes the cannon vertical travel time T 0 Value and corresponding depth;

[0036] Step S3: Determine the micro-logging time-depth data, which includes the micro-logging vertical travel time t 0 Value and corresponding depth;

[0037] Step S4: The vertical travel time T of the cannon determined in step S2 0 The value and the micro-logging vertical travel time t determined in step S3 0 The time difference is compared and statistically analyzed, and fitted into the vertical travel time T of the cannon. 0 Time difference correction relationship curve;

[0038] Step S5: Using the cannon's vertical travel time T 0 Time difference correction relationship curve for cannon vertical travel time T below micro-logging depth 0 Correction is performed to obtain the corrected cannon vertical travel time T 0 ;

[0039] Step S6: The corrected cannon vertical travel time T obtained in step S5 is 0 and depth data and micro-log vertical travel time t 0 Combined with 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 micro-logging position on a very thick surface 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 cannon at 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 track the high-speed layer velocity.

[0043] In step S2, the cannon time-depth data (i.e., vertical travel time T) corresponding to the micro-logging position is obtained according to the surface interpretation results and the predetermined rules. 0 The predetermined rule is that when the refraction interpretation velocity model depth is within the micro-logging depth, the cannon vertical travel time T is calculated according to the cannon interpretation results and the different depth positions (i.e., sampling intervals) collected by the micro-logging. 0 When the refraction interpretation velocity model depth exceeds the micro-logging depth, the cannon vertical travel time T is calculated based on the cannon first arrival interpretation velocity model according to the set depth interval. 0 The depth interval should satisfy that one velocity layer has no less than 3 sampling points (cannon T 0 time).

[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, to calculate the vertical travel time T at a certain depth H 0 , assuming that this depth penetrates from shallow to deep, the refraction of the cannon first arrival explains two velocity layers (corresponding to velocity and thickness v 1 、h 1 ;v 2 、h 2 ), enter the third speed layer, the corresponding speed is v3. Then:

[0046] T 0 =h 1 / v 1 +h 2 / v 2 +(Hh 1 -h 2 ) / v 3 Formula (1)

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

[0048] When the depth range H is less than the micro-logging depth h (H<h), T is calculated according to the interpretation results of the first arrival of the cannon and the different sampling depths of the micro-logging. 0 (vertical travel time);

[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 T values ​​corresponding to the depths of “0.5m, 1m, 2m…5m, 6m…10m, 12m…20m, 23m…60m” are calculated respectively. 0 Micro-logging from shallow to deep t 0 The values ​​can be recorded as t 01 ,t 02 …t 0i ; Corresponding depth cannon calculation T 0 The 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 T according to the cannon first arrival refraction interpretation results at a certain sampling depth interval 0 The above interval depth should satisfy the requirement that one velocity layer should be calculated for no less than 3 T 0 . Cannon Calculation T 0 The 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 t 0 The micro-logging time-depth data can be determined by any method known in the art, for example, professional software can be used to interpret the micro-logging data and output the micro-logging t 0 value.

[0053] In step S4, the cannon T determined in step S2 is 0 The time value and the micro-logging t determined in step S3 0 The time values ​​are compared and statistically analyzed to fit the vertical travel time T of the cannon. 0 Time difference correction relationship curve. Among them, the time difference comparison statistics only compare the time difference within the micro-logging depth range.0 Time and Cannon T 0 The time difference (△t) of the values ​​was compared and statistically fitted into T 0 Time difference correction relationship curve. The above time difference refers to the time difference of micro-logging at different depths. 0 The value is the same as the T calculated by the first arrival of the cannon 0 The difference between the values ​​(△t). For example, micro-well logging from shallow to deep t 0 The values ​​are t 01 ,t 02 …t 0i ; Corresponding depth cannon calculation T 0 The 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 combined 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 △t, and x represents the logging depth value. When you want to calculate the time difference at a certain depth to measure the depth of the cannon T 0 When the time is corrected, the depth value is substituted into the x part of the equation to calculate the corresponding time difference y.

[0057] In step S5, the vertical travel time T of the cannon is used. 0 Time difference correction relationship curve for cannon T below micro-logging depth 0 Correct the time to obtain the corrected cannon T 0 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 1As shown in the figure, the maximum depth of the micro-logging well is 100m, and the correction relationship curve equation y is fitted through the time difference △t calculated within 100m. If you need to obtain the correction time difference of the depths of 120m, 140m, and 160m with a subsequent acquisition interval of 20m, you can substitute x=120, 140, and 160, and respectively obtain the corresponding time difference y values, 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 correction is performed. The cannon T that is greater than the micro-logging depth calculation 0 The time values ​​are added with the corresponding correction time difference, which are 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 T obtained in step S5 is 0 Time and depth data and micro-logging 0 The time and depth data are combined 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 T 0 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 arrival according to an 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 implemented using professional software.

[0061] This method has been explored and applied in three-dimensional seismic exploration in "double complex" areas such as Yingxiongling area in Qaidam Basin and Kulongshan area in Jiuquan Basin. Through the application of this method, the application effect of micro-logging survey velocity information is fully utilized, the cost of micro-logging survey in complex areas is reduced, the accuracy of "double complex" micro-logging constraint inversion modeling is improved, the equivalence of the surface velocity model is reduced, making it closer to the real velocity model, and improving 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, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope 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 suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0064] In addition, 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-well logging location on a very thick surface for refraction interpretation to obtain surface interpretation results based on the first arrival of the cannon; Step S2: according to the surface interpretation result, the cannon time-depth data corresponding to the micro-logging position is obtained according to a predetermined rule, and 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 a micro-logging vertical travel time t0 value and a 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 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 the 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; 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, characterized in that: 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 based on the first arrival of the cannon at the micro-logging position.

5. The method according to claim 4, characterized in that The maximum velocity of the refraction interpretation velocity model should track the high-speed layer velocity 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 in step S2 should be greater than the thickness of the slow 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 difference 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.

12. The method according to claim 11, characterized in that The correction in step S5 includes: 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.

13. The method according to claim 1, characterized in that The formation of the joint time-depth relationship in step S6 includes using the 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.

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