This workflow procedure is a guide for the step-down analysis.
|Note:||Wellhead pressures must be converted to sandface pressures before conducting an analysis.|
1. Import rate and pressure data into WellTest.
2. Click the Production Editor tab and load the imported data into the Production Editor by selecting OK on the Data Selection dialog box.
3. Convert wellhead pressures to sandface pressures by clicking the Calc SFP icon on the Production Editor toolbar and specifying wellbore parameters.
4. Create a Step Down Analysis. In the main menu, select Step Down Test Analysis from the Analysis menu.
5. Select one data point per step rate. Click the white arrow to the left of each row in the grid. This puts the cursor in the point selection mode. Click a desired data point in the History or Zoom plot. This places an annotation arrow on the History plot and populates the appropriate row on the grid with data. You can use the Zoom plot to fine-tune the point selection.
6. On the bottom-right section, click the Step Down Plot tab to see a pressure vs. rate plot of the selected data points.
7. In the Model Parameters section (top-right), enter initial estimates of model parameters with which to history match the analysis data. A model is generated and displayed in the Step Down Plot when all input parameters have been entered.
8. Modify the model parameters, especially those with low confidence levels, to improve the match between the selected data points and the model's calculated values. Alternatively, select parameters for automatic estimation by checking the checkbox beside each parameter, and then click the Automatic Parameter Estimation () icon.
9. Evaluate results for consistency and reasonableness.
10. To generate a report, click the Reports tab and Preview Report sub-tab. A step down test report is generated.