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Hampson-Russell Software Services Ltd .

Hampson-Russell Software Services Ltd. EMERGE WORKSHOP. Theory and Exercises. EMERGE Course Outline. EMERGE 简介 3 Exercise 1: Setting up an EMERGE Project 7 地震属性 32 交会图 54 Exercise 2: The Single-Attribute List 59 多属性 69 验证属性 76

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Hampson-Russell Software Services Ltd .

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  1. Hampson-Russell Software Services Ltd. EMERGE WORKSHOP Theory and Exercises

  2. EMERGE Course Outline • EMERGE 简介 3 • Exercise 1: Setting up an EMERGE Project 7 • 地震属性 32 • 交会图 54 • Exercise 2: The Single-Attribute List 59 • 多属性 69 • 验证属性 76 • Exercise 3: The Multi-Attribute List 82 • 使用褶积算子 89 • Exercise 4: The Convolutional Operator 94 • Exercise 5: Processing the 3D Volume 99 • EMERGE 里的神经网络 110 • Exercise 6: Predicting Porosity Logs 140 • 训练神经网络 162 • Exercise 7: Using Neural Networks 177 • Exercise 8: Predicting Logs from Logs 200 • EMERGE 课程总结 222

  3. EMERGE 简介 EMERGE 程序的目标: • EMERGE 是一个分析分析井曲线和地震数据的程序。 • 它寻找井点处的地震数据与测井曲线之间的关系。 • 它利用这个关系在地震数据体内“预测”或估算测井曲线属性。 EMERGE 使用的数据: • 一个地震数据体(通常是三维的)。 • 一些与地震数据标定好了的井。 • 每一口井包含一个将要预测的“目标”曲线,例如孔隙度。 • 每一口井也要包含时深转换信息,通常是时深校正过的声波曲线。 • (可选的):一种或多种3D地震属性。

  4. EMERGE简介 测井曲线必须加载到 GEOVIEW 数据库中: 这张图显示了单口井的数据:

  5. EMERGE简介 理论上来说,任何类型的测井曲线属性都可以作为 EMERGE 预测的目标。 实际上,下面的曲线类型都已经成功地预测过: • P波速度 • 孔隙度 • 密度 • 伽玛曲线 • 水饱和度 • 岩性曲线 唯一的要求是:每一口井必须有目标曲线作为样板。 因为 EMERGE 假设目标曲线是不含噪声的,在应用EMERGE 前编辑目标曲线是很重要的。 因为 EMERGE 把目标曲线与地震数据作相关,正确的时深转换是很关键的。因此,时深校正和手工相关是必要的。

  6. EMERGE 简介 EMERGE 可以被认为是常规迭后反演的扩展:

  7. Exercise 1: Setting up an EMERGE Project Estimating P-Wave Velocity from Seismic Attributes We are now ready to do the first EMERGE example. In this example, we will estimate p-wave or sonic log velocity from seismic attributes. The data set consists of the following: • A SEGY file, seismic.sgy, which is a 3D post-stack data set. • A SEGY file, inversion.sgy, which is the 3D result of performing inversion on the input seismic data. • 12 wells that tie the two SEGY files. Each of these wells contains a sonic log and a check-shot file. The objective of this analysis is to predict new sonic logs for the entire 3D survey, using the seismic data and the inversion result.

  8. Loading the Data If the GEOVIEW program has not been started, start it now by typing geoview in the command window. The GEOVIEW main window now appears: To load the complete well log database for this exercise, click on Database/Open. The menu will look like this:

  9. Loading the Data A database is identified by the extension wdb. Select the database guide.wdb as shown above and click on OK. Your GEOVIEW window will now look like this: As you can see, all 12 wells have now been loaded.

  10. Starting EMERGE Now that the logs have been loaded into GEOVIEW, we are ready to start the EMERGE program. To do this, click on the EMERGE button on the GEOVIEW main window. The following menu will appear: Click on OK to Start a New Project. The File Selection window now appears. Fill it in as shown below and click on OK (note that we are calling the new project velocity):

  11. Starting EMERGE The EMERGE main window now appears: Let us now review the EMERGE process. We wish to use the seismic data to “predict” new sonic logs at every location in the 3D seismic volume. To do this, we will collect some sample data around the well locations and find a relationship between the seismic at those locations and the measured logs. This step is called “training”. After the training is completed, we will assume that the derived relationship is valid for the entire 3D volume, and apply that relationship to the entire 3D data set.

  12. Starting EMERGE To start the training process, we need to read the sonic logs from GEOVIEW into the EMERGE main window. To do this, click on Wells / Read From Database. The following menu appears: Notice that this menu has a series of pages, which can be viewed by using the Next >> and << Back buttons. You will not be able to click on OK until the required pages have been filled in. The first page is the Wells page, which allows us to select which wells to include in the EMERGE analysis. As you can see above, the left column contains all the wells in the guide database. We wish to use all of them in the training, so click on Add all >>.

  13. Starting EMERGE The menu now looks like this: Now click on the Next >> button at the bottom of the menu. The new page will now appear:

  14. Starting EMERGE This page is used to tell EMERGE which of the logs in the database is the one that we are trying to predict, i.e., which one is the “Target”. For this guide example, we wish to predict the P-wave or sonic log, as shown above. Also, we are specifying that, although the log is measured in depth, the analysis (Processing Domain) will be done in time. This is because the seismic data is measured in time. We need to specify the sample rate correctly (Processing Sample Rate), so that EMERGE can do the depth-to-time conversion properly. Note that the check-shot corrected sonic log will be used for this conversion.Click on the Next >> button at the bottom of the menu. The new page will now appear:

  15. Starting EMERGE The Tops page allows you to specify the analysis window for training in terms of the tops that have already been entered into the GEOVIEW database. In this project, we have entered four tops: viking, mann, ch_top, and miss. As shown above, select the viking as the start of the analysis window and the miss as the end of the analysis window. Note that the analysis window can be changed later if desired. At this point, the OK button is enabled, indicating that EMERGE has enough data from the GEOVIEW database to proceed. Now that the entire menu has been filled in, click on OK. One more confirmation menu appears:

  16. Starting EMERGE This menu appears because for each of the selected wells, there are actually two P-wave logs. One is the original log and the second is the check shot corrected log. By default, the most recently created log will be used. This is the check shot corrected log, which is shown in the table. If you wished to use the other log, clicking on the words P-wave CheckShotCorrected for any of the wells will produce a pullDown menu allowing you to select the desired log. For our case, accept the defaults by clicking on Ok on this menu.The EMERGE main window now looks like this: The EMERGE window now shows the target log for each of the wells. The brown horizontal lines indicate the analysis window selected in the previous menu. We will examine how to change that later. By moving the horizontal scroll bar, you can see all the remaining wells.

  17. Starting EMERGE Now we wish to read in the seismic data near the well locations. As mentioned at the beginning of the guide, the seismic data actually consists of two SEGY files, seismic.sgy and inversion.sgy.Now we will read in the seismic training data. To do this click on Seismic / Add Seismic Input / From File. The following menu appears:

  18. Starting EMERGE On the file selection menu, select the file seismic.sgy and click Add >> to make it appear on the right column as shown: Click on Next >> on this menu. The next menus are used to specify the format and geometry of the SEGY file.

  19. Starting EMERGE The next menu that appears is this one: On this page, we must tell the program that we are loading a 3D volume that does not have either Inline/Xline numbers or X & Y coordinates in the trace headers. This means that the primary key for assigning traces will be set to “CDP(Rectangular)”, i.e., the seismic has a uniform series of inlines and crosslines.

  20. Starting EMERGE Click on Next >> to get this menu: In the box that defines the Type of Data, we must select the attribute type. When the menu first appears, it shows “<Unknown>”. Click in this box, and choose “Raw Seismic”, as shown. The attribute name will also be set to Raw Seismic automatically.

  21. Starting EMERGE Click on Next >> again to get this menu: This menu allows you to set attributes of the SEGY format. Since we have told the program that the seismic file does not contain inline/crossline numbers or X & Y coordinates, many of the parameters on this page are not active. Click on Next >> one last time. You will see a dialog that indicates that the data file needs to be scanned. Click on Yes on this dialog to proceed with the scanning.

  22. Starting EMERGE On this menu, we specify the geometry of the 3D volume. Note that the only change we have made is to set the Number of Cross-lines. Fill in the menu as shown above and click on Ok. Two new windows will now appear. One window shows a table, indicating how the wells are correlated with the seismic data:

  23. Starting EMERGE The second window shows the seismic data: For this data set, the correlation is correct because the X-Y locations were entered appropriately in the GEOVIEW database. For other data sets, you may need to modify the Inline and Xline columns of the table. Now click on Ok to get the next menu.

  24. Starting EMERGE This menu tells the EMERGE program how to extract the trace at each well location that is used in the training process. We will use a Neighbourhood radius of 1, as shown. This means that the composite trace will be the average of those traces within 1 Inline or Xline of the well location. This is an average of 9 traces. Alternatively, you could modify the Capture option to “Distance”, which will average all traces within a specified distance from each well. Make sure that the parameters on the menu are set as shown above, then click on Ok.

  25. Starting EMERGE The composite trace at each well location will be extracted from the SEGY volume and the EMERGE main window will be modified to show the added data:

  26. Starting EMERGE The final piece of data to add is an external attribute from the SEGY file inversion.sgy. To do this, click on Seismic / Add Seismic Input / From File. Fill out the next menu as follows: The next series of menus is identical to those used in adding the Raw Seismic.

  27. Starting EMERGE Specify the general format: We must tell EMERGE that this is an External Attribute with the name Inversion Result. Click on Next >> on this menu and the one that follows. When you see the dialog that says that the file must be scanned, click on Yes.

  28. Starting EMERGE Describe the geometry: When you click Ok on this menu, two things will happen. First, the seismic display window will be updated to show the inversion data in color:

  29. Starting EMERGE The second thing that will happen is that the Trace Extraction menu will appear again to allow you to specify parameters for extracting the External Attribute trace: Once again, click on Ok on this menu to extract a single trace, which is the average of those traces within one Inline or Xline of the well location. The EMERGE main window will be updated to include this new data.

  30. Starting EMERGE The EMERGE main window shows the analysis data for each well: the target log in red, the single seismic trace in black, and the external attribute in blue. The analysis window is also shown by brown horizontal bars on each log. Note that this window may be different for each well.

  31. Starting EMERGE To examine (and possibly change) the analysis window, click on Wells / Set Analysis Windows to get the following table: Since we are happy with the analysis windows as shown, click on Cancel to remove this menu. (End of Exercise 1)

  32. 地震属性 地震属性是地震道的变换,通常是非线性的。 两种类型的属性: 基于采样的:地震道上一个样点一个样点的计算出来的。 例如:振幅包络。 基于层位的:由两个层位之间的平均值计算出来 。 例如:两层之间的平均孔隙度 对EMERGE而言,所有的属性必须都是基于采样的。 地震属性的例子:

  33. 地震属性 EMERGE 能够计算下列的内部属性: 振幅包络 振幅加权的相位余弦 振幅加权的频率 振幅加权的相位 平均频率 视极性 瞬时相位余弦 差分 瞬时振幅的差分 主频 滤波切片 瞬时频率 瞬时相位 积分 绝对振幅积分 二阶差分 瞬时振幅的二阶差分

  34. 地震属性 EMERGE 也可以输入外部属性。 这些是不能通过内部计算得来的地震属性, 因为: 它们是特有的–比如: 相关性。 它们太复杂–比如地震反演, AVO属性, 等等。 内部属性可以归为以下几类: 瞬时属性 加窗的频率属性 滤波切片 差分属性 积分属性 时间(线性渐变) 以地震数据为例,现在来了解一下关于每一组属性的理论。

  35. h(t) A(t) Hilbert Transform f(t) Seismic s(t) Time 瞬时属性 Taner et al首先提出瞬时属性(Geophysics, June, 1979)的概念。瞬时属性从复地震道C(t)导出, C(t) 由地震道s(t)和它相应的Hilber变换 h(t)组成, h(t) 相当于将s(t)进行90 °相移。复数道以极坐标形式表示如下,我们得到了两个基本属性:振幅包络A(t)和瞬时相位f(t),(注意: 瞬时振幅与振幅包络表示同一个意思)。

  36. 瞬时属性 第三个基本属性是瞬时频率,它是瞬时相位对时间的导数。 方程如下: EMERGE中,其它的瞬时属性便是以上三种瞬时属性的组合, 如下所示: 视极性属性是振幅包络乘以地震道样点在波峰的极性符号而得,应用于波峰两边波谷之间的一段地震样点。

  37. 瞬时属性 现在,我们来看一下应用于所输入的3D数据体inline95线的每一个瞬时属性的例子。下面这条线用颜色表示振幅值上面覆盖了波形道,08-08井的声波测井曲线也覆盖在地震数据上了。

  38. 瞬时属性 inline 95线的瞬时相位 inline 95线的振幅包络

  39. 瞬时属性 inline95线的瞬时相位余弦 inline 95 振幅的加权相位余弦

  40. 瞬时属性 inline 95线的振幅加权相位 inline 95线的视极性

  41. 瞬时属性 inline 95线的瞬时频率 inline 95线的振幅的加权频率

  42. 加窗的频率属性 EMERGE中另一组属性是基于对地震道加窗的频率分析。在这个过程中,每一个地震道的付立叶变换时窗取为64个样点(缺省值)。在这个时窗里,或者选择平均频率振幅,或者选择主频振幅,这个值放在窗口中间。下一个窗口选择32个样点(缺省值),计算新的频率属性,如此进行下去。注意缺省值可以在Attribute/Attribute Parameters 菜单里改变,如下所示。

  43. 加窗的频率属性 inline 95线的主频 inline 95线的平均频率

  44. 滤波切片属性 EMERGE的第三组属性由地震道的窄带频率切片组成。 使用以下6个切片 5/10 – 15/20 Hz 15/20 – 25/30 Hz 25/30 – 35/40 Hz 35/40 – 45/50 Hz 45/50 – 55/60 Hz 55/60 – 65/70 Hz 下一张片子上的数字表示最低和最高的频率切片。

  45. 滤波切片属性 inline 95 线的5/10 – 15/20 Hz滤波切片 inline 95 线的55/60 – 65/70 Hz 滤波切片

  46. 导数属性 EMERGE中的第四组属性是基于地震道的一、二阶导数或振幅包络( 或瞬时振幅,瞬时振幅的同义词)。导数用以下的方式计算,这里, si =第 i 个地震或振幅包络样点,d1i =第 i 个一阶导数,d2i =第 i个二阶导数,and Dt =采样率: 下两张片子是inline 95线地震数据的导数的例子:

  47. 导数属性 inline 95线的导数 inline 95线的振幅包络的导数

  48. 导数属性 inline 95线的二阶导数 inline 95 线的振幅包络的二阶导数

  49. 积分属性 EMERGE的第五组属性是基于地震道或振幅包络的(或瞬时振幅,振幅包络的同义词)。积分值用以下方式计算,这里 si =第 i 个地震或振幅包络样点,Ii =积分值。注意这是一个连续求和。 在连续求和之后,对积分地震道应用了确省值为50个样点的圆滑滤波,并去除了结果中的低频趋势。通过除以总样点的最大最小值的差,对积分振幅包络进行归一化。注意确省值可以在 Attribute / Attribute Parameters 菜单里改变,前面已经介绍过了。 下张片子上的积分的例子来自于 inline 95线

  50. 积分属性 inline 95 线的道积分 inline 95 线的振幅包络积分

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