Topaze NL (RTA) Tutorial #1

Transcription

1 Topaze NL (RTA) Tutorial #1 1. Introduction This tutorial provides a description of the options of RTA in KAPPA Workstation G5 through the analysis of a gas producer well example. We recommend that you follow this tutorial before anything else. 2. Creating a new document Create a document by clicking on the Blank icon in the New and recent RTA page. In the first window of the Main Doc Options dialog click on to keep the default values. In the following dialog, set the Pay zone thickness h to 100 ft and the Porosity to Click on, change the Reference phase to Gas. Gas will be the reference fluid for this analysis but it can be changed in the other analyses. The PVT must be fully defined. To do so, click on. Set the Reservoir pressure to 6650 psia and the Temperature to 300 F. Click on. Click on select a Centered Rectangle., set the default analysis tools to: No Storage, Finite radius well, Homogeneous reservoir and Click on. 3. Decline curve analysis It is possible to perform such an analysis as soon as a production history is available, regardless of the existence of a pressure gauge. Click on the Load Q icon in the main control panel to load the Rate History, click on the icon to select an ASCII file as source type, then browse for the data file RTAEX01.rat in the example directory. KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-1/16

2 Click on to go to the next dialog. Select Duration in the Time format left-hand panel. The first column contains the duration in decimal time and there is Gas rate in the second column. The default reading format can be used. Click on. Hold the Shift key and click on the icon Extract p to perform the Auto extract and generate the DCA plot. Maximize the DCA plot and right-click in the plot to access the split options of the dropdown menu. Split horizontally and vertically to end with three plots: Change the top right to q vs Q in the Drop list displayed by a right click: KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-2/16

3 Change the bottom one to log(q) vs log(t): Click on the Parameters icon and change the model to Duong. Move the slider to mid way between q and Q and run the regression on half q and half Q. KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-3/16

4 Change the abandonment rate to 500 Mscf/D, observe the abandonment time change (13.5 years) and the EUR (7.5 bscf). The below results may vary slightly depending on the position of the cursor between q and Q. Abandonment ratio 1e-3 Abandonment rate 500 Mscf/D 4. Loading Pressure and extracting the data interval Create a new analysis initializing from Analysis 1 and delete the DCA plot it will not be used anymore in this new analysis. In the RTA Settings accessible through plots as indicated below: located at the top right when under any tab, select the automatic KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-4/16

5 Click on the Load P icon to load the Pressure History, click on the as source type, then browse for the data file RTAEX01.pre in the example directory. icon to select an ASCII file Click on. Leave Points in the Time format left-hand panel. The first column contains the time points in decimal time (hr) format and there are Pressures (psia) in the second column. The default reading format can be used. Click on to finalize the data loading process. The bottomhole pressures are loaded here but if the gauge is not at reservoir depth the pressure data can be corrected for depth in the QAQC window after the well intake model was defined Data extraction We are automatically led to the Extract p dialog. Open the Time range dropdown menu and click on to select the extraction interval. The effect of the limit of the interval on the resulting loglog plot can be seen instantaneously on the extraction preview. Start time on the early plot part, end time on the late plot part: Reset the interval to the whole time range by clicking on to extract it., set the starting value to 1hr, then click on You may need to adjust the diagnostic tool lines. KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-5/16

6 Depending on the position of the limit markers distance values observed in the result window can be different. on the loglog plot, the North-South and East-West 4.2. Additional options Additional options are available in the top ribbon to edit the data and plots: In the Layout tool strip, to get a better presentation we can hide the minimized plots scale clicking on Scales. In the Miscellaneous tool strip, the extraction interval can be still selected by clicking on Selection and its impact on the plots is immediate. The loglog plot uses the equivalent time Te = Q/q, the resulting values can be filtered in order to avoid excessive values in case of small q values by clicking on Filter which gives access to the dialog: Certain subset of data points can be selected in a lasso by clicking Time interval selection, then click down in a plot and draw the lasso around the selected points, they are automatically highlighted in all other plots: KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-6/16

7 By selecting the Show values option of the right hand tool bar in any plot we can display the time and data values inside the plot, i.e. in the loglog plot: Click on the PVT icon to get access to the PVT dialog. In this dialog, we can select the m(p) to Normalized or Not normalized. Leave it to Normalized. KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-7/16

8 5. Diagnostic tool adjustment and analytical model Adjust the IARF line for the best fit with the derivative horizontal stabilization and set the boundaries distances by moving the markers on the loglog plot in order to get the two trends, half unit and unit slopes, to the derivative: Once more, depending on the position of the limit markers on the loglog plot, the North-South and East-West distance values can be slightly different. Hold the Shift key and click on the Analytical model icon to generate the automatic analytical model. The model dialog and its details are presented in the PTA tutorial. KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-8/16

9 By default the model calculation is set to single step which means that the displayed model corresponds to rate response to a constant pressure step. It is a way to remove the scattering effect of equivalent time Te = Q/q which is unstable when the pressure is not constant. In the top ribbon we can click on the Single step on icon to switch off the single step option and to visualize the true pressure response on the loglog. 6. Specialized analysis results to analytical through dashboard Maximize the Normalized rate-cumulative plot, click on the Show model icon to display the model. Draw a line through the P.S.S. data, using the line time selection option: Definition of the line calculation limits Calculated line Open the Dashboard by clicking on the Dashboard icon on the top ribbon. Select from the specialized analysis Normalized rate cumulative line and send the results to analytical model by clicking on the To analytical icon: KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-9/16

10 A model with the new parameters values is calculated. Click on the Improve icon. In the Targets tab of the Improve dialog, select Rates and Cumulative as targets and, in the Parameters tab, select the permeability k and the boundaries as regression parameters: Click on. KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-10/16

11 7. Forecast using numerical model Create a new analysis by copy of the previous one. Check on Use real PVT in the Main numerical options tab of the Analysis information dialog (access this option by clicking on the Info icon in the Analysis Ribbon). Click on the Numerical icon to open the Numerical Model dialog and click on, then on. Click now on the Forecast icon to get access to the Forecast calculation. KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-11/16

12 In order to perform a first Forecast input a pressure value of 1750 psia for a duration of 3 months in the dialog: Click on to start the calculation. The rate forecast is displayed on the history, normalized rate cumulative, loglog and Blasingame plots: A sensitivity can be run on the forecast results. Click on the Sensitivity icon to get in the Sensitivity setting dialog. We will choose to perform a sensitivity study on the production flowing pressure: KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-12/16

13 It can be displayed on the loglog or the history plot, select the history plot. The pressure values can be input one by one or automatically set between a maximum and a minimum value. Leave unchecked the option No values defined. Open the values table by clicking on the arrow. Set the automatic selection to 5 values between minimum 1400 and 1800 psia. Click on OK. The results are displayed in an additional history plot: KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-13/16

14 8. Alternative analysis Create a new analysis by copy. Check Desorption in the Main numerical options tab of the Analysis information dialog. Open the Numerical model dialog and click on to get access to the Desorption parameters dialog: Keep the defaults values and click on OK to exit. Generate the model. KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-14/16

15 Adding desorption to the model leads quite logically to an overall higher gas production. Click on the Improve icon. In the Targets tab of the improve dialog, select rate q and cumulative Q as targets and, in the Parameters tab, select the reservoir surface as regression parameter. Click Run. Run the Forecast option with this numerical model. KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-15/16

16 Again, run a 3 months forecast with a flowing pressure value of 1750 psia. 9. Comparison The two analyses can be compared on the various plots: history plot, loglog plot and normalized rate cumulative plot. Re-generate both analyses without forecast. Click on the Compare icon and select the analysis you want to display. The various models are displayed with a specific color in the various plots: KW v Doc v KAPPA RTA Tutorial #1 RTAEX01-16/16