Well seismic calibration method in horizontal well while-drilling process

Abstract

The invention relates to a well seismic calibration method in a horizontal well while-drilling process, and belongs to the technical field of seismic data interpretation. The method comprises the following specific steps: main data preparation work; time-depth conversion is carried out, and a construction absolute error value of each marker layer is determined; solving an error grid of the horizon velocity field of each marker interval; correcting the horizon velocity field of each marker bed, then carrying out three-dimensional space interpolation to obtain a new velocity field as a stacking velocity, carrying out projection contrastive analysis, and determining the structure absolute error value of each stable marker bed at the upper part; the inter-layer speed is continuously corrected by comparing and solving the layer speed error of each mark layer, the corrected speed field is utilized to extract a speed curve for well-seismic calibration, the correlation coefficient after well-seismic calibration is gradually improved, reaches a target value and meets a structural relative error standard value, and the spatial position in a target layer can be finally obtained. According to the well seismic calibration method, the target-entering prediction precision and the working efficiency are remarkably improved.

Description

Technical Field

[0001] The invention relates to a well seismic calibration method in a horizontal well while drilling process, and belongs to the technical field of seismic data interpretation. Background Art

[0002] When drilling to the target layer, a well with a well section inclination angle greater than 80° and a horizontal displacement distance exceeding 10 times the thickness of the target layer is called a horizontal well. It can effectively increase the drilling length of the oil and gas layer and the oil and gas supply volume after the later fracturing transformation, improve the oil and gas recovery rate, and is one of the effective means to increase production. Geosteering technology refers to the technology of monitoring and controlling the wellbore trajectory based on the use of three-dimensional seismic data to establish a geological model, based on the logging while drilling technology, combined with engineering technologies such as logging and drilling. It integrates three-dimensional seismic data, reservoir geology, logging, engineering technology and computers to ensure that the actual wellbore passes through the reservoir and is located in the best position in the oil and gas layer, thereby maximizing the drilling rate of the oil and gas layer in the horizontal section and ensuring the later development benefits. Geological steering technology originally belonged to the category of drilling. It mainly used the measurement of engineering parameters such as well inclination, azimuth, torque, etc. while drilling to ensure the construction process of horizontal wellbore trajectory. With the continuous development and combination of three-dimensional seismic prediction technology, drilling and logging technology, especially since the 1990s, the gradual updating and iteration of while drilling instruments such as MWD, LWD and rotary steering, the lithology, oil content, trajectory and other parameters of the drilled formation can be recorded in time during the while drilling process. How to combine these parameters with three-dimensional seismic data to deepen the application, guide the trajectory optimization adjustment during the horizontal well drilling process, and maximize the guarantee of the horizontal well reservoir drilling rate is the research background of the present invention. Summary of the invention

[0003] In order to solve the above-mentioned problems existing in the prior art, the present invention discloses a method for well seismic calibration during the drilling of a horizontal well. The method can realize the in-depth application of geological data, establish a well-seismic correspondence relationship in combination with three-dimensional seismic data, and solve the spatial projection of the trajectory on the three-dimensional seismic data, so as to predict the bottom hole drilling adjustment plan in advance and ensure that the trajectory of the horizontal well passes through the effective reservoir to the maximum extent. This seismic geological guidance mode and method significantly improves the prediction accuracy and work efficiency of horizontal well targeting, and can effectively guide the trajectory optimization and adjustment work during the drilling of the horizontal well. This work is directly related to whether the horizontal well can achieve the design purpose and the problem of the later horizontal well production capacity.

[0004] In order to achieve the purpose of using three-dimensional seismic data to guide horizontal well optimization during drilling, the technical solution adopted by the present invention is: a well seismic calibration method during drilling of a horizontal well, the specific steps are as follows:

[0005] Step 1: Prepare the main data before entering the horizontal well;

[0006] Step 2: Before entering the target, the time domain data volume is converted by stacking the velocity field to obtain the three-dimensional seismic data volume in the depth domain, and the structural absolute error value of each marker layer of the horizontal well being drilled and the adjacent wells is clarified;

[0007] Step 3: Calculate the error grid of the velocity field along the layer of each marker layer segment by using the time horizon of each marker layer in the 3D seismic time domain data volume and the absolute error value of each layer structure obtained in step 2;

[0008] Step 4: using the error grid of the along-layer velocity field of each marker layer segment obtained in step 3, correct the along-layer velocity field of each marker layer obtained by the stacking velocity field corresponding to the three-dimensional seismic data volume to obtain the corrected along-layer velocity field of each marker layer;

[0009] Step 5: Use the velocity fields of each marker layer corrected in step 4 to perform three-dimensional spatial interpolation to obtain a new velocity field as the stacking velocity, perform time-depth conversion on the three-dimensional seismic time domain data volume, and convert it into a three-dimensional seismic data volume in the depth domain;

[0010] Step 6: Perform projection comparison analysis on the three-dimensional seismic data volume in the depth domain obtained in step 5 of the drilling well, analyze the degree of consistency between the drilling horizontal well and the adjacent wells and the structural and seismic profile reflection characteristics, and clarify the structural absolute error values ​​of the upper marker layers;

[0011] Step 7: Repeat steps 3 to 5, and continuously correct the interlayer velocity between different layers of the horizontal well being drilled and the adjacent wells by comparing and obtaining the velocity errors of each marker layer of the horizontal well being drilled and the adjacent wells. Use the corrected velocity field to extract the velocity curve as the velocity of the horizontal well being drilled to perform well-seismic calibration on the time domain data volume, so that the correlation coefficient after well-seismic calibration is gradually improved and reaches the target value, gradually conforming to the geological and seismic understanding and meeting the standard value of the structural relative error, and finally the spatial position of the horizontal well being drilled in the target layer can be obtained.

[0012] Furthermore, in the step 1, the main data preparation before the horizontal well enters the target includes understanding the logging instruments and zero length of the drilling equipment; collecting the altitude, logging, logging, 3D seismic time domain data volume, stacking velocity field corresponding to the 3D seismic data volume and other data of the adjacent wells in the drilling area of ​​all the horizontal wells being drilled, so as to lay a data foundation for the subsequent analysis.

[0013] In the step 2, the horizontal well being drilled and the adjacent wells are projected and compared on the three-dimensional seismic data volume in the depth domain. The purpose of comparing and analyzing the degree of coincidence between the trajectory of the actual drilled horizontal well and the structural and seismic profile reflection characteristics is to obtain the structural absolute error value of each marker layer;

[0014] Furthermore, in step 7, the target value of the correlation coefficient must be at least greater than 0.8.

[0015] Furthermore, in step 7, the relative error standard value is less than 1‰.

[0016] In step 7, the spatial position of the horizontal well in the target layer is finally obtained, and the well inclination is adjusted in time in combination with the spatial position prediction to provide a basis for trajectory optimization and optimize the well trajectory drilling plan; through continuous correction, the consistency of the designed trajectory and the actual drilling results is ensured, so that the effective reservoir is always drilled and the reservoir drilling rate is guaranteed.

[0017] The invention discloses a well seismic calibration method in a horizontal well while drilling process. The method has the beneficial effect of introducing the vertical and horizontal resolutions of three-dimensional seismic data into the horizontal well while drilling guidance technology for the first time by fully combining the actual drilling curve and the results of three-dimensional seismic data processing and interpretation. In combination with key parameters such as seismic interpretation and drilling data, a well seismic calibration method in a horizontal well while drilling process is established. The method can realize the in-depth application of geological and seismic data, establish a well-seismic relationship in combination with three-dimensional seismic data, solve the spatial projection position of the trajectory of the drilling horizontal well in the target layer of the three-dimensional seismic data, and timely adjust the well inclination angle in combination with spatial position prediction to provide a basis for trajectory optimization, optimize the well trajectory drilling plan, and ensure that the trajectory of the horizontal well passes through the effective reservoir to the maximum extent. The method significantly improves the prediction accuracy and work efficiency of the horizontal well entering the target, and can effectively guide the trajectory optimization and adjustment work in the horizontal well drilling process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 Shown is a comparison analysis of vertical depth with the adjacent well Y56-1;

[0020] Figure 2 The following is a grid diagram of the velocity error along the layer in wells such as Y22-8-3;

[0021] Figure 3 Shown is the synthetic seismic record profile and correlation coefficient diagram of Y22-8-3 well;

[0022] Figure 4 The seismic profile of the Y22-8-3 well after synthetic record calibration and superposition of the well trajectory is shown;

[0023] Figure 5 Shown is a comparison chart of the actual measurement of Y22-8-3 well (black) and the calculation and calibration of this method (blue).

[0024] Specific implementation methods

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Because the logging while drilling curves of the horizontal well drilling process only have natural gamma, resistivity and well trajectory data, but no acoustic time difference curve, how to relatively accurately combine the three-dimensional seismic data to establish the well-seismic relationship and solve the problem of the accuracy of the spatial projection position of the trajectory on the three-dimensional seismic data, so as to predict and form the bottom hole drilling adjustment plan in advance and ensure that the trajectory of the horizontal well passes through the effective reservoir to the maximum extent is the key to ensuring the oil layer encounter rate of the horizontal well. The present invention is a method for relatively accurately obtaining the spatial projection position of the horizontal well trajectory on the three-dimensional seismic data.

[0027] In order to further understand the content of the present invention, the present invention is further described below in conjunction with specific implementation methods.

[0028] Unless otherwise specified, the methods used in the following embodiments are all conventional methods. The specific embodiments of the present invention are further described in detail below in conjunction with the flow chart.

[0029] Example 1: Taking the Y22-8-3 horizontal well implemented in a certain work area as an example, the application effect of the well seismic calibration method in the horizontal well while drilling process is described in detail.

[0030] like Figures 1 to 5 As shown, this embodiment provides a method for well seismic calibration during drilling of a horizontal well, and the specific steps are as follows:

[0031] Step 1: Main data preparation before horizontal well targeting: Understand the logging instruments and zero length of the drilling equipment; collect the altitude, logging, mud logging, 3D seismic time domain data volume, and stacking velocity field corresponding to the 3D seismic data volume of all adjacent wells in the drilling area of ​​the horizontal well being drilled;

[0032] Step 2: If Figure 1, and compared with the adjacent well Y56-1, the actual formation position of the adjacent well was clarified. Through comparative analysis, it is believed that when the vertical depth of Y22-8-3 well is 2682m (inclined depth is 2853m), it is equivalent to drilling into the adjacent well Y56-1 at a vertical depth of 2674m; after comparison, it is believed that the absolute structural error value of the first marker layer closest to the vertical depth of 2682m in the upper part of Y22-8-3 well is 1.65m;

[0033] Step 3: If Figure 2 As shown in the figure, combined with the actual drilling results of Well Y22-8-3, the interval velocity error of the first marker layer in the upper part of Well Y22-8-3 closest to the vertical depth of 2682m is obtained, and the velocity error grid of the adjacent wells such as Well Y56-1 and Well Y22-8-3 is re-established using the obtained interval velocity error;

[0034] Step 4: Using the error grid of the along-layer velocity field of each marker layer obtained in step 3, the along-layer velocity field of each marker layer obtained by the stacking velocity field corresponding to the three-dimensional seismic data volume is corrected to obtain the corrected along-layer velocity field of each marker layer. The corrected velocity field can further improve the accuracy of the along-layer velocity due to the addition of actual drilling results;

[0035] Step 5: Use the velocity fields of each marker layer corrected in step 4 to perform three-dimensional spatial interpolation to obtain a new velocity field as the stacking velocity, perform time-depth conversion on the three-dimensional seismic time domain data volume, and convert it into a three-dimensional seismic data volume in the depth domain;

[0036] Step 6: Perform projection comparison analysis on the three-dimensional seismic data volume in the depth domain obtained in step 5 of the drilling well, analyze the degree of consistency between the drilling horizontal well and the adjacent wells and the structural and seismic profile reflection characteristics, and clarify the structural absolute error values ​​of the upper marker layers;

[0037] Step 7: Figure 4 As shown in the figure, repeat steps 3 to 5, and continuously correct the interlayer velocity between different layers of the horizontal well being drilled and the adjacent wells by comparing and obtaining the velocity errors of each marker layer of the horizontal well being drilled and the adjacent wells. Use the velocity curve extracted from the corrected velocity field as the velocity of the horizontal well being drilled to perform well-seismic calibration on the time domain data volume, so that the correlation coefficient after well-seismic calibration is greater than 0.8, as shown in the figure. Figure 3 As shown in the figure, it gradually conforms to the geological and seismic knowledge and the standard value of the structural relative error is less than 1‰. At this time, it is considered that the interlayer velocity is reasonable, the structural error of the depth domain data body is the smallest, and it is closest to the actual underground form. The spatial position of the horizontal well being drilled in the target layer can be finally obtained. Combined with the spatial position prediction, the well inclination angle is adjusted in time, the well trajectory drilling plan is optimized, and the basis for trajectory optimization is provided; through continuous correction, the consistency of the designed trajectory and the actual drilling results is guaranteed, such as Figure 5 As shown, it is possible to always drill into effective reservoirs and ensure the reservoir drilling rate.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calibrating well seismic data while drilling a horizontal well, characterized in that: The following steps are involved: Step 1: Prepare the main data before entering the horizontal well; Step 2: Before entering the target, the time domain data volume is converted by stacking the velocity field to obtain the three-dimensional seismic data volume in the depth domain, and the structural absolute error value of each marker layer of the horizontal well being drilled and the adjacent wells is clarified; Step 3: Calculate the error grid of the velocity field along the layer of each marker layer segment by using the time horizon of each marker layer in the 3D seismic time domain data volume and the absolute error value of each marker layer structure obtained in step 2; Step 4: using the error grid of the along-layer velocity field of each marker layer segment obtained in step 3, correct the along-layer velocity field of each marker layer obtained by the stacking velocity field corresponding to the three-dimensional seismic data volume to obtain the corrected along-layer velocity field of each marker layer; Step 5: Use the velocity fields of each marker layer corrected in step 4 to perform three-dimensional spatial interpolation to obtain a new velocity field as the stacking velocity, perform time-depth conversion on the three-dimensional seismic time domain data volume, and convert it into a three-dimensional seismic data volume in the depth domain; Step 6: Perform projection comparison analysis on the depth domain 3D seismic data volume obtained in step 5 of the well being drilled, so as to clarify the absolute structural error values ​​of each upper marker layer; Step 7: Repeat steps 3 to 5, and continuously correct the interlayer velocity between different layers of the horizontal well being drilled and the adjacent wells by comparing and obtaining the velocity errors of each marker layer of the horizontal well being drilled and the adjacent wells. Use the corrected velocity field to extract the velocity curve as the velocity of the horizontal well being drilled to perform well-seismic calibration on the time domain data volume, so that the correlation coefficient after well-seismic calibration is gradually improved and reaches the target value, gradually conforming to the geological and seismic understanding and meeting the standard value of structural relative error, and finally obtaining the spatial position of the horizontal well being drilled in the target layer.

2. The method for well seismic calibration during drilling of a horizontal well according to claim 1, characterized in that: In step 1, the main data preparation before the horizontal well enters the target includes understanding the logging instruments and zero length of the drilling equipment; collecting the altitude, logging, logging, 3D seismic time domain data volume, and stacking velocity field corresponding data of the 3D seismic data volume of all adjacent wells in the drilling area of ​​the horizontal well being drilled.

3. The method for well seismic calibration during drilling of a horizontal well according to claim 1, characterized in that: In step 2, the method for obtaining the structural absolute error value of each marker layer of the horizontal well being drilled and the adjacent wells is to perform projection comparative analysis on the three-dimensional seismic data volume of the horizontal well being drilled and the adjacent wells in the depth domain, and analyze the degree of consistency between the horizontal well being drilled and the adjacent wells and the structural and seismic profile reflection characteristics, thereby obtaining the structural absolute error value of each marker layer.

4. The method for well seismic calibration during drilling of a horizontal well according to claim 1, characterized in that: In step 6, the projection comparison analysis is performed on the degree of agreement between the drilling horizontal well and the adjacent wells and the structural and seismic profile reflection characteristics, thereby obtaining the structural absolute error values ​​of the upper marker layers.

5. The method for well seismic calibration during drilling of a horizontal well according to claim 1, characterized in that: In step 7, the target value of the correlation coefficient must be at least greater than 0.

8.

6. The method for well seismic calibration during drilling of a horizontal well according to claim 1, characterized in that: In step 7, the relative error standard value is less than 1‰.

7. The method for well seismic calibration during drilling of a horizontal well according to claim 1, characterized in that: In step 7, the spatial position of the horizontal well in the target layer is finally obtained. Combined with the spatial position prediction and timely adjustment of the well inclination, a basis is provided for trajectory optimization and the well trajectory drilling plan is optimized. Through continuous correction, the consistency between the designed trajectory and the actual drilling results is ensured.

8. The method for well seismic calibration during drilling of a horizontal well according to claim 5, characterized in that: The correlation coefficient is 0.9.

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