Newsletter of The Mapping Guru

Transcription

1 Newsletter of The Mapping Guru Unearth A Masterpiece. EDITION Number 8 THE PETROSYS PLUG-IN FOR PETREL READ ABOUT HOW THIS NEW MODULE HELPS INTEGRATE PETREL SUBSURFACE MODELS WITH THE MANY OTHER DATA SOURCES IN THE PETROSYS ENVIRONMENT. RMS ERRORS GUIDE GRIDDING pg2 UNDERSTAND AND UTILIZE RMS ERRORS, WHICH ARE A HELPFUL GUIDE TO THE ACCURACY OF CELL SIZE WHEN COMPUTING GRIDS AND CONTOURS. pg2 Georeferencing of images With satellite imagery and remote sensing data sets playing a growing role in providing both geological insight and spatial referencing, raster image underlays have become a core component of EP mapping. Petrosys' ongoing investment in supporting the use of raster imagery has been extended with a georeferencing tool that allows interactive picking and editing of georeferencing locations, and the application of this georeferencing across a range of coordinate reference systems through the Petrosys CRS engine. Direct access to GoCad surfaces Improved access to irregular surfaces has allowed us to make direct use of surfaces stored in GoCad tri-surf files, which can now be colorfilled and contoured without import. HOW TO IMPORT LAT/LONG GRIDS TIPS THAT ARE ESPECIALLY USEFUL WHEN WORKING WITH DATA SETS LIKE GRAVITY, MAGNETICS AND BATHYMETRY. ALSO IMPORTANT FOR GRIDS AT BASIN SCALE. INTERACTIVE GRID WORKFLOWS Copyright 2008 Petrosys Pty. Ltd. pg3 WORKFLOW GRIDDING ALLOWS YOU TO BUILD, MODIFY AND SHARE MULTIPLE STEP MODELLING PROCESSES. READ ABOUT HOW TO MAKE THESE MORE INTERACTIVE. GRID ARITHMETIC FUNCTIONS CONSTRUCT NEW GRIDS FROM FUNCTIONS INVOLVING EXISTING SURFACES TO IMPOSE YOUR UN- DERSTANING OF GEOLOGICAL CONSTRAINTS. pg4 pg6 Display/Spatial of ZGF data ZGF files have been added to the growing list of supported files in the Display/Spatial option. This allows users to access the data without the need to convert or import the information. Enhanced data management Petrosys dbmap sites can now spatially index their PPDM well, seismic and lease data to provide seamless access to this information from dbmap, Oracle, ESRI and other GIS views. Large volumes of regional seismic navigation and well location data can now be displayed in a few seconds, without losing the ability to query the resulting display in the full context of the structured PPDM model. Spatial relationships can be incorporated into queries to select wells within leases or near collections of seismic lines, or to compute the length of seismic lines in leases. Spatially determined data selections can be extended to the selection of information from any linked data, thereby linking the value of corporate data stores and GIS information management. Read more in the Software Release Notes.

2 The Petrosys Plug-in For Petrel* The Petrosys Plug-in for Petrel allows geoscientists and engineers utilizing Petrel to present their insight, integrated with information from many other data sources, through the Petrosys map interface. This enables asset teams to make consistent use of Petrosys mapping and surface modelling as their focus moves from the regional overview, through the field, to the reservoir scale. Talk to your account manager to learn more or to test drive this functionality available now in Petrosys v16.4. Harness the power of the Petrosys plug-in for Petrel to: Start Petrosys mapping, surface modelling or 3D viz from icons in the Petrel application. Directly display Petrel surfaces and grids using Petrosys map colorfill and 3D viz displays, and directly contour these structures into Petrosys contour files. Use a range of other Petrosys display options to overlay geoscience and cultural data from OpenWorks, GeoFrame, ArcSDE, SMT, PPDM and many other data sources directly accessible through Petrosys. Map in many coordinate reference systems (CRS); the underlying CRS of maps can be switched as required to integrate surfaces across adjacent UTM zones or regional interpretation situations. To use other Petrosys surface modelling functions such as volumetrics, via a fast import facility, which regrids the irregular surface into a regular Petrosys grid. * Petrel is a mark of Schlumberger. Above: Gulfaks structure in Petrel model and Petrosys map. Both applications work side by side to support efficient workflows. Understanding RMS Errors when Gridding At the end of each gridding pass an RMS (Root Mean Square) error is reported. This is the approximate error at the grid node between the input data values and the calculated values, essentially characterizing the difference between the input data and the computed grid. The RMS error is reported in the units of the data, for example an RMS error of when gridding two-way-time values implies that the 'average' difference between the computed grid values and the input data is msecs in either sense. In terms of contouring, an RMS error of implies that we should not expect a match of better than +/- 8 msecs between the contours and the posted data values. In general the RMS error should decrease between gridding passes and reach a value less than 1. There is value in reviewing the RMS error. It can be used as a guide to the grid cell size in relation to the input data: In the final grid computation passes, if the RMS error reported is not decreasing, then your grid cell size is probably too fine. A larger RMS error may imply significant misties. If the RMS error oscillates, for example from 1 to 2 to 1 to 2..., your grid cell size is too small. Left: An example of the RMS error reported for creation of a TWT grid. As the convergent gridding takes place the RMS error is decreasing and the resultant RMS error is less than 1. Asia: Americas: 1888 PETROSYS Europe: Calgary:

3 Improved Importing Lat/Long Grids into Petrosys In Petrosys v16, geoscientists will be pleased to learn that it's possible to import large, regularly sampled data files straight into Petrosys grids, when the data values are in latitudes and longitudes. This is especially useful for data sets like magnetics, gravity, and also large bathymetry data sets. Further it s vital when structures cross natural CRS boundaries and geoscientists need to make maps in different co-ordinate reference systems. Step 1. Create Lat/Long CRS The first step is to create a LL CRS, easily done by: File/Maintain/CRS/Projected CRS Editor Click on any WGS84 CRS and then SaveAs Choose Site or Project CRS file, which ever is appropriate Give it a name like WGS84 LL (no projection) Click Projection box and select the No Projection(m) Step 2. Import and save the grid Go to Gridding and Contouring module to import the data by: File/Import/XYZ Grid File Select the output grid CRS choose Geographic CRS WGS84 and the Projected CRS of the one you just created - WGS84 LL (no projection) Click Scan Click OK to import Step 3. Display the grid The imported grid should now display in the correct location on any map sheet, regardless of the map projection system defined. This is a result of full reprojection capabilities of these grids inside of Petrosys. The map examples below, illustrate bathymetry data displayed in two different map projections from an imported grid. Notice how the edge of the grid is correctly reprojected along lines of latitude/longitude and follows the re-projection of coastline information. Right: Projected CRS creation dialog. Above: Grid import dialog. Mercator Map of Bathymetry Grid Van Der Grinten Map of Bathymetry Grid General: info@petrosys.com.au > Support: support@petrosys.com.au > Web:

4 Intelligent Gridding and Contouring with Workflow Functions Workflow gridding has been a part of Petrosys since version 15. It allows users to build, modify and share multiple step processes within the Gridding & Contouring module The workflow manager is commonly used for archiving and auditing modelling processes, efficiently and consistently, repeating defined processes and sharing complex operations. It is a valuable way to help with metadata capture in surface modelling. In addition to these traditional uses, the workflow manager contains several functions that facilitate the addition of intelligence and interactivity to your workflows, presenting the user with intuitive and professional looking interfaces. Workflows defined Let us outline the concept of workflows before we explore the interactivity and intelligence we can weave into these workflows (refer illustration above right). Petrosys workflows are sets of individual tasks (1) within the Gridding and Contouring interface. Workflows can be run in whole or in part with the run-task icons (2) or Workflow menu in conjunction with the task activity checkboxes (3). Workflows can be saved, opened, or merged via the File menu. A Petrosys workflow is interactively built by defining the individual Gridding and Contouring operations that comprise your workflow. For example, gridding formation tops from OpenWorks & SMT, flexing the depth grid to known well tops and computing volumetrics scenarios could comprise a common workflow (1). If necessary, you can copy, paste, re-order or describe tasks from the Workflow menu or by right-clicking on the task. To save, share and re-use the workflow, simply select Save As from the File menu, give the workflow a name and store it in a.tsk workflow file. 1 Workflows can have many steps. 7 shown 4 Stop the workflow processing 2 Controls to run part or full workflow 5 Cog icon provides shortcut to task parameters 3 Activity checkboxes turn on/off steps 6 Simple workflow reporting output Above. An overview of basic workflow concepts in Petrosys. Modifying workflow task parameters Now that we have looked at saving a workflow, let us look at how we can modify the workflow to make it a more powerful and reusable tool for ourselves or others. With the workflow open and displayed in the Gridding & Contouring module, highlight a task, and select Task Parameters from the Workflow menu. This view presents a list of parameters used in the gridding task. The parameters in question are easy to match up with those available during modification of a task. 6 Above. Task parameters dialog, shows a list of all of the parameters used in a given workflow task. Parameters are grouped and the user can also see the current value in the dialog. For example, the Output Grid from this workflow step will be called 2nd_wall_creek_depth.gri. Asia: Americas: 1888 PETROSYS Europe: Calgary:

5 Intelligent Gridding and Contouring with Workflow Functions Interactivity as a Simple Example of a Workflow Function The easiest way to add interactivity to a workflow is to set the task parameter to interactive. Select a single task parameter and click on the Interactive button. The letter I appears in the Status column of the task parameter. The next time this task is run, a value can be specified for the selected parameter through an appropriate data selection interface. This interactive task uses a workflow function that can be further refined. Click on the Edit button to see both the function and the interface we would use to implement other functions. In the example (below left), we have chosen to provide an output grid file name at runtime. The function being used is: {promptuser("outputgrid", file, "*.gri")} Other Types of Functions Re-using Values Get the value of another parameter in the current task by enclosing the parameter name in curly brackets (a list of all parameters in the current task is available to us via the + button next to the script in the Edit Parameter dialog). Alternatively, get user input once and use it repeatedly using the promptusershared() function. Sharing Information Between Workflow Steps Retrieve values from parameters in other tasks in the workflow. The taskprev(parametername) accesses the previous task or taskid (taskid,parametername) accesses any task by its ID number. Controlling Filenames and Other Text There are a number of functions that allow for the manipulation of text, whether it comes from Relevant Examples To prompt a user to enter a value for an oil water contact of a volumetrics reference plane, use the following simple script: {promptuser("oil-water contact", text)} To implement a grid file naming standard that writes a time stamp to the output grid and add a pre-fix of TWT to denote it's a two-way-time grid: TWT_{TimeStampNumeric()}.gri Use the grid name from the previous step to drive the output file name in this step. For example set the parameter OutputGridFile from the previous task, which had a TWT_ string in it, to create a corresponding file with DEPTH_ in place of TWT: {textreplace(taskprev (OutputGridFile),'TWT_','DEPTH_')} For more information, refer to Petrosys online help or discuss these capabilities with our support staff. Lucky Draw Winner from PGCE Kuala Lumpur Base guidelines from this first example that will help as we go forward: Functions are enclosed in curly brackets (everything outside of curly brackets is passed directly to the task parameter). Functions have parameters that determine what the function will return. These parameters are enclosed in parentheses. Click OK to save the changes to the task parameter. The next time this task is executed we will be presented with an interface denoting the prompt string OutputGrid, a button which launches a file selector, and the default file type *.gri (above right). user input, another parameter, or is given explicitly. This is often useful for naming intermediate files in a meaningful and understandable manner. Calculating Parameters - Evaluate a given expression and return a numeric value for use in the current or subsequent tasks. The expression can be made up of numbers, parameter names, function calls, and the operators +, -, *, / and ( ). Mike Brumby (Director / Sales and Services Manager Petrosys SE Asian Office based in KL) presents an ipod to Damla Abd Aziz of Petronas. Damla was one of 3 lucky ipod winners from the PGCE conference held in Kuala Lumpur earlier this year. General: info@petrosys.com.au > Support: support@petrosys.com.au > Web:

6 Understanding Petrosys Functions in Grid Arithmetic The grid arithmetic option allows you to create new grids from expressions involving existing grids. The expression can be constructed from a range of variables, operators & functions. For example, a simple depth conversion can be represented by the expression: NEW GRID = TWT * VAV / 2000 where TWT and VAV are variables representing existing grid files. A range of arithmetic operations are supported, such as: CLIP_MIN CLIP_MAX MIN MAX MERGE_MIN MERGE_MAX Clip a grid file against another grid, returning the lesser value. Clip a grid file against another grid, returning the maximum value. Returns the minimum of two grid entries. Returns the maximum of two grid entries. Merge and preserve the minimum of two grid entities. Merge and preserve the maximum of two grid entities. The examples below are displayed in the Petrosys 3Dviewer, which provides an invaluable mechanism for understanding the relationships between surfaces while gridding in Petrosys. Operators + (addition), - (subtraction), * (multiplication), / (division), etc MAX(A,B) MIN(A,B) Boolean Operators If, >, <, &&, etc Constants Integers or real numbers Functions Sin, cos, mod, etc There are also a number of pre-defined Petrosys functions available. This article illustrates what the Petrosys functions do. CLIP_MAX(A,B) A if A >= B, missing value if A < B CLIP_MIN(A,B) A if A <= B, missing value if A > B The Base Case: Input Data There are two input grids, FLAT & DIPPING in the base case. The flat grid is red, assigned variable A. The dipping grid is blue, assigned variable B. CLIP_MAX(B,A) B if B >= A, missing value if B < A CLIP_MIN(B,A) B if B <= A, missing value if B > A The output grid from the result of the functions is green in the examples (right). The two input grids have different geometries and the dipping grid has been clipped to a polygon. All grids are positive with depth increasing. MERGE_MAX(A,B) A if A >= B, B if B > A, missing value if A and B are both missing MERGE_MIN(A,B) A if A <= B, B if B < A, missing value if A and B are both missing General: info@petrosys.com.au > Support: support@petrosys.com.au > Web: