Topaze (RTA) Tutorial #1 1. Introduction This tutorial provides a description of the options and workflow in KAPPA-Workstation. This includes creation of new documents and analyses, loading of pressure and rate data, extraction of the loaded production data, Decline Curve Analysis, use of loglog analysis tools, example of analytical and numerical modeling, specialized plots, sensitivity and forecast, and the creation of interpretation file templates. The tutorial finishes by pointing to a few items that users may decide to explore on their own. Before starting this session, the user is expected to have installed KAPPA-Workstation and started the RTA (Topaze) module. The tutorial will use the three files (shown below) located in the Examples folder in the Installation directory. Topaze starts (below, left) and brings the user to the ‘File’ page. The active option is ‘New and recent’ and a ‘Blank’ icon can be seen towards the top left of the screen (below, right). KW v5.40 - Doc v5.40.01 © KAPPA 2003-2021 RTA Tutorial #1 • RTAEX01 - 1/28 2. Creating a new document Click on the ‘Blank’ icon. This starts a wizard that will take the user through six steps to initialize a new document and its first analysis. - Step 1: initialization of the main document options: reference time and location, general information, units and general comments. Keep everything as default and click . - Step 2: main options of the first analysis in this document. Input the main test parameters. Those highlighted with red fields have a significant impact on the results and should not stay at default value. If the default happens to be the answer one may enter the same value or right click in the field and select ‘Accept default’. If any field remains, a red warning message will be carried out throughout the interpretation. For this session, set the pay zone (h) to 100 ft and the porosity () to 0.08. Click . - Step 3: definition of the fluid and its physical diffusion in the formation. Define the fluid as single phase gas. Advanced PVT is required when the reference phase is gas, in order to compute pseudo properties. To access the advanced PVT definition, click on . In the PVT definition page, change the reference pressure to 6650 psia and reference temperature to 300 °F. Validate the PVT definition with and proceed to Step 4 using . KW v5.40 - Doc v5.40.01 © KAPPA 2003-2021 RTA Tutorial #1 • RTAEX01 - 2/28 - Step 4: definition of the constant parameters and/or pseudo-functions that will be used in analytical or linear numerical models (linearity is required for superposition). The computed pseudo-pressure and pseudo-time integral can be viewed in tabulated and graphical form using (below, right). The choice of pseudo pressures (none, not normalized or normalized) affects the plot axes only. The model is always generated in pseudo pressures. Click on . - Step 5: controls the level of complexity in the numerical model. The options in the left column are standard with Saphir and Topaze. The options in the right columns are Rubis functionalities. Although these models can be directly built from Saphir or Topaze, they do require a Rubis license to be available. The default numerical settings will be largely sufficient for now but will be visited later in this tutorial, so click on . KW v5.40 - Doc v5.40.01 © KAPPA 2003-2021 RTA Tutorial #1 • RTAEX01 - 3/28 - Step 6: the default model can be set at any stage of the analysis, even at initialization stage. If the user knows or suspects that a given model should apply there is no need to start with an irrelevant default. For this session, do not change the default at this stage. Click on . The document and its first analysis are initialized and the main Topaze window appears. The active tab is ‘Analysis’ with an empty workspace. The document is only in the active computer memory and it is named ‘Untitled1’. Save it and call it ‘RTA Tutorial 1’ using the Ctrl+S shortcut or select ‘Save’ in the File menu. KW v5.40 - Doc v5.40.01 © KAPPA 2003-2021 RTA Tutorial #1 • RTAEX01 - 4/28 3. Loading production data Click on the ‘Load Q’, , icon in the control panel on the left to load the Rate History. The rate information is stored in ‘RTAEX01 Rates.xlsx’. Click on and select the file to load. A file preview is shown (below, left). with the possibility to change the tab/worksheet. brings a dialog where the file information is interpreted line by line (below, right). The collapsible panels on the left offer detailed load options. The top right section has a set of editable information while the bottom left window gives the result of the format processing. As the input file is very simple, with time stored as durations, the default format will work. Click on to proceed. The main Topaze screen is displayed again with a history plot showing the loaded rates. KW v5.40 - Doc v5.40.01 © KAPPA 2003-2021 RTA Tutorial #1 • RTAEX01 - 5/28 4. Automatic extraction and Rate Decline curve analysis It is possible to perform a Decline curve analysis as soon as a production history is available, regardless of the existence of a pressure gauge. The ‘Extract’, , icon in the control panel accesses the manual extraction dialog. We will revisit the dialog later. The ‘Automatic Extraction’, , icon appears in lieu of the ‘Extract’ icon when the shift key is pressed. In this state, click on the icon and the entire loaded production history, using the default extraction settings will be extracted on a DCA plot, generated at the end of the extraction. Double clicking on the DCA plot title bar maximizes it, bringing additional options in the ribbon. Right-click in the plot to access the split options in the popup menu. Split horizontally and vertically to end with three plots. KW v5.40 - Doc v5.40.01 © KAPPA 2003-2021 RTA Tutorial #1 • RTAEX01 - 6/28 Change the top right plot to q vs Q by right clicking on it and selecting the plot type in ‘Decline curve options’ (below left). Similarly, change the bottom one to log(q) vs log(t) to end up with something as shown below, right: Click on ‘Parameters’, , in the ‘Plot options’ panel at the top and change the model to Duong. The slider bar at the bottom allows the user to set the relative weight of rates and cumulative production while regressing on the model parameters. Move the slider to mid-way between q and Q and run the regression on initial rate, M and A Exponents (each decline curve will have its own set of parameters): Change the abandonment rate to 500 Mscf/D, observe the abandonment time change (6.49 years) and the EUR (4.14 bscf). The results may vary slightly depending on the position of the slider between q and Q. KW v5.40 - Doc v5.40.01 © KAPPA 2003-2021 RTA Tutorial #1 • RTAEX01 - 7/28 Abandonment ratio 1e-3 Abandonment rate 500 Mscf/D Several DCA plots may be created with different decline models on each. Close the dialog and restore the DCA plot by double clicking on the plot title bar. KW v5.40 - Doc v5.40.01 © KAPPA 2003-2021 RTA Tutorial #1 • RTAEX01 - 8/28 5. Loading Pressure data Create a new analysis by clicking on ‘New’, , in the ribbon at the top (or using the Ctrl + M keyboard shortcut). When creating a new analysis, different levels of duplication are offered to the user. For this session, select the existing ‘Analysis 1’ to duplicate and keep all the selections. Click on . Delete the existing DCA plot in Analysis 2. Before proceeding with loading pressure data, access the ‘RTA Settings’ through located at the top right of the Topaze window and select the automatic plots as indicated below: Based on the above selection, when an extraction is made only the normalized rate – cumulative plot will be created (in addition to the loglog plot and Blasingame plot which are always created on extraction). This allows the user to save overcrowding the workspace with plots the user is not intending to use. The unchecked plots can always be created at any time during the analysis using the ‘New plot’, , option in the ribbon (subject to plot prerequisites being met). This will be visited later in the tutorial. KW v5.40 - Doc v5.40.01 © KAPPA 2003-2021 RTA Tutorial #1 • RTAEX01 - 9/28 Click on ‘Load P’, , in the main control panel to load the Pressure History. The pressure data are stored in the Ascii file ‘RTAEX01 Pressures.txt’. Click on the icon and select the file to bring a preview of the file content (below, left). Click on to proceed to the next dialog. The dialog is the same as when loading rates, where the file information is being interpreted line by line (below, right). Again, the format is simple, so keep the defaults and click on to proceed. Back in the Topaze main workspace, the history plot is displayed with both rate and pressure data. Since an extraction already existed, even though we deleted the DCA plot, loading pressure data will also launch the extraction dialog. This time, the extraction will be based on both pressures and rates, unlike before, when we had rates only. If no extraction had existed, the dialog can be manually called using ‘Extract’, , in the control panel. KW v5.40 - Doc v5.40.01 © KAPPA 2003-2021 RTA Tutorial #1 • RTAEX01 - 10/28 6. Extracting data interval and generating plots In the extraction dialog (below, left) the loglog plot resulting from the current extraction options is displayed on the right.